#294 ‒ Peak athletic performance: How to measure it and how to train for it from the coach of the most elite athletes on earth | Olav Aleksander Bu
02:33:43 Share

Hey everyone, welcome to The Drive Podcast. I'm your host, Peter Attia. This podcast, my website, and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, and we've established a great team of analysts to make this happen.

It is extremely important to me to provide all of this content without relying on paid ads. To do this, our work is made entirely possible by our members. And in return, we offer exclusive member-only content and benefits above and beyond what is available for free.

If you want to take your knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of a subscription. If you want to learn more about the benefits of our premium membership, head over to peteratiamd.com forward slash subscribe.

My guest this week is Olav Alexander Bu. Olav is an endurance coach, exercise scientist, engineer, and physiologist. He is the head of performance for Norway Triathlon and is best known for coaching two of the world's greatest triathletes, Christian Blumenfeldt and Gustav Iden.

and he coaches the Norwegian Olympic sailing team and consults for multiple world tour cycling and elite track and field teams. In this episode, we were only able to cover a fraction of what I was hoping to cover as we ended up going so deep on VO2max and performance. Safe to say this will be the first of several interviews that I do with Olaf. In this interview,

We look at the relationship between VO2max and ATP production efficiency, energy, and power. We speak about the quality of low-intensity training as it relates to VO2max, how weight impacts VO2max, absolute versus relative VO2max values,

and why we maybe ought to pay a little more attention to the absolute numbers than just the relative, as I have typically done, the different ways to test for VO2 max, and the different ways to train to improve your VO2 max, and of course, Olav's work with his athletes.

We also have a pretty deep discussion around the role of lactate testing and its role in performance. So a couple of things I want to say just to put this into context. Of course, if you're listening to this podcast, you have heard me go on and on about the importance of VO2max. And so to really have the masterclass in VO2max here alone is worth the price of admission. But there are so many other nuances we get into here around

different terms that people have heard and sometimes confused. So what's the difference between lactate threshold one, lactate threshold two, LT1, LT2, and zone two? How are these actually measured? And even if you think, well, gosh, I really have no interest in doing the kind of deep testing that Olav does or even the stuff that Peter does on himself, you're still going to learn a lot about the physiology of this stuff here. One final thing I'll say, during the course of this discussion,

I learned about something called the VO2 Master, which is a portable VO2 max unit that Olav uses extensively with his athletes. Now, I've certainly heard of these types of devices in the past, though not specifically the VO2 Master. So it's always with a bit of skepticism that I assume that these things can't be that accurate. But during the course of the podcast and then after the podcast, Olav and I got talking about it and my curiosity was piqued so much that I actually got one of these devices.

Needless to say, I have been blown away by this device. I consider it the single best investment I've made in tracking and the accuracy is staggering. It's really remarkable that I can put this thing on and go outside and do a workout on my bike or do a workout on my StairMaster. Basically, I can test my VO2 Max on my own. And again, this is just one of the many nuggets that came out of this

I'm not suggesting you have to go out and buy a VO2 master, though if you're like me, I would highly recommend it. So anyway, without further delay, please enjoy my conversation with Olav Alexander-Boo. Olav, thank you so much for making time to sit down with me today. I'm really excited about this episode and I'm going to try to contain my own enthusiasm such that the people listening to this will understand what we're talking about because this

the topic we're going to go into today is really one that fascinates me to no end. But more than that, you are someone who brings a level of expertise that is so high that it really allows me to engage at a level of curiosity that I rarely get to engage in. And

I don't think I've taken more notes coming into a podcast than I have for this one. I fully expect we will not get through half of what I've written down in terms of topics that I want to explore, but nevertheless, I'm going to apologize in advance to you and to everybody else for just how enthusiastically I want to address the subject matter of human performance.

Perhaps before we get into that though, maybe you could just tell folks, let's assume people don't know anything about you and who you are, Olav, just tell them who you are, what you do, and the types of athletes that you work with. To try to make a liner story, I actually grew up on a farm on the west coast of Norway. I had to participate in a lot of work at the farm when I was a kid.

against my will because I saw my neighbors and others were playing and I would very much like to do that as well. But I think for sure in my now today and already a long time ago, I already started to really appreciate all the hardship more or less.

Fast forward, I already developed a very keen interest for technology already as a kid, and I was extremely curious. I liked to really pick things apart and understand how things were put together. Fascinated about everything from the universe and rockets and so on. And of course, living at the farm, you also get the possibility to pick apart a lot of machineries and other things and see how this is working and so on.

Being with animals, I have a very strong connection with animals. I also started to develop as I started to grow a little older. I started to get very interested in more things that were more extreme. I had an attraction towards things that were extreme. So extreme sports, typical, were a thing that resonates a lot with me. There are probably no extreme sports I haven't participated in. Call it on an okay level. Yeah, and then I took my degree in electrotechnics.

Went on to engineering, found out that I was not cut for the eight to four working style. For me, it was more about entrepreneurship. I like to build things, innovate new things, solve things that nobody has solved before. Those, again, a little bit extreme things that basically are abstract really, really fascinates me. So in 2011, there was an event happening in my life. This was after I actually started my second company. We were into the mountains.

We had to use helicopter to get into the mountains.

There was a big, or basically had, yeah, half my family died on this trip into the mountains. Again, it made a shift in my life. And I decided to, for various reasons, I got even more into sports. So I was then asked to start to combine the field of exercise physiology and technology, or my strength in technology, and see whether we could start to take more of

There's more research. A lot of research that typically happens in laboratory settings or even in microbiology where you're taking out components and looking at how does it react. But we very rarely are able to transform that back into humans in a way that makes us the same difference. So how could we now study people, use technology to study people, especially elites, for example, in the setting where they normally exercise and even use that to continue to drive performance? And then...

Of course, today, two of my personal, at least three of my personal athletes, Christian Blumenfeld, Gustav Yden, Ken Janina, they hold all the records that are in triathlon, short course, long course, Olympic medal, world championship medal, short course, the Ironman world championship, 70.3 and full distance from Kona and St. George last year. And yeah,

Yeah, it's been an incredible journey because one thing is, of course, what I have contributed to with them, but I really like a collaborative way of working. So I learn always from them as well because I'm very curious about how they feel, what they see, how they perceive different things, because there is a lot of things we can measure with data and there's a lot of things we can't measure with data still. So you need also to that context as well.

And mainly today, we are actually building a company where we're scaling these companies using AI, so numerical models, large language models, into a company called Enthalpy. I like physics, of course, so Enthalpy and thermodynamics are some fundamental laws humans can't escape, no matter how you look at it.

we think we are and then on the other side i work also as a coach for coaches mainly so i'm more coaching coaches at olympic level world tour level racing at the highest levels so yeah that's a long introduction uh on me

Well, let's start with some fundamentals because we're going to spend a lot of time today talking about extreme performance and peak performance around the types of sports in which you're coaching athletes. So the triathlete is kind of a remarkable athlete in several levels. The first being that he or she must be very good in three disciplines that are related but quite distinct.

Different body types. If you look at the world's best swimmers, the world's best cyclists and the world's best runners, they actually have quite different physiology depending on the distances they race and certainly different methods of training. And the triathlete therefore has to be really respected because they have to be almost world class in each of those things to be world class in their sport.

And their physiology as a result of that is remarkable. And there are so many things that we're going to talk about today, including temperature management, energy expenditure, energy consumption, all these things. That said, I want to make sure that the listener is able to follow where we go. And we're going to get into some really serious weeds, right? We're going to talk about MCT transporters for shuttling lactate out of cells and all of those things, because that's where I want to go. But

I want to make sure people understand the fundamentals, the very basics. So humor me as we go through kind of the 101 of ATP production and utilization. So you and I are sitting here right now having a discussion.

And of course, our body is converting all the while chemical energy into electrical energy, back into chemical energy. And it requires the substrates of oxygen and hydrocarbons to do that. Can you explain, you know, in a little bit of detail exactly what that process looks like for us right now as we're sitting here under obviously a very low physiologic demand?

On a very deep level, or do you want more like a high level? Let's start high level. Okay. I think one of the things, Roche, there's a really beautiful map, call it a map, made by Roche. I think it's called Roche. They are a medical supplier. You mean the Swiss pharmaceutical company? Yes, exactly. ROCHE, yeah. Yeah, exactly. They made a really beautiful map.

map which is still not exhausted we are continuously learning new things that we can add to this map and this map is called there are two maps they basically distinguish between and is one that they call the metabolic pathways another one they call the signaling pathways

And on the metabolic pathways, we have, of course, many ways that we can convert energy from mainly, of course, its proteins, its fats, its carbohydrates that we are converting basically from a substrate or from the food that we ingest and we store in our body to food.

to then basically ATP, which is the main fuel source that the muscles, different muscles in the body are using or different functions your body is using in order to survive. And of course, to convert those substrates also into ATP, also there's oxygen required, but there are many, many different pathways. And the problem a little bit with this as well is that even though this is a field which we have studied quite a lot before,

We are still learning more and we don't fully understand it still either. And that's why very often actually to bring it up maybe to where I think is more useful very often to work on this is that if you dig too much into some of these different things that you lose track, you start to lose track exactly of how do you increase performance of somebody as well.

To use another example, today we have, for example, smartwatches and other things as well that are trying to say something about our sleep. It's derived or inferred basically from movement from your wrist, for example, and it's based on HRV. But the problem is also when we're looking at, okay, what is performance? So if you say the calamity, so again, back to thermodynamics or fundamental laws, on the one side, humans need to move. That's what we do. So we're sitting here now in these chairs, we're moving around, gesticulating with my hands and these kind of things, we are nodding with our heads, right?

And all this requires energy in order to do that. And that's movement. You can track this movement. You can even quantify it in centimeters or meters or whatever over a day for each of the components or globally when we are running, for example, the distance we cover. But in order to do so, we

We need an energy source. We need energy from somewhere. And of course, the currency for the muscles or for anything in your body is basically ATP. But in order to create ATPs, then basically we need different substrate to be broken down. And in order for combustion to take place, we need oxygen. Most people probably remember the fire triangle where basically you need oxygen, you need temperature, and then we need something to combust.

And of course, oxygen is probably the most practical way today, of course, to measure exactly how much energy are we using at any given time.

And then, of course, we can always start to break this down and try to understand how much ATP is this release or what is the energy yield from that amount of oxygen. But this is also highly different also in humans. Some humans will be more efficient. So typically elites are very efficient at this, while normal population would probably be less efficient at this to create energy. So typically then to round that up, I would say that

The way that I very often work today is to not lose track. On one side, of course, I have a large team around me with people that are extremely good at this. One of the researchers that I work with, he was just actually now recognized as the number one researcher in the cycling world.

this year. And they are digging a lot into everything from enzymatic activities to how energy is being released and so on, how can we do this better. But one thing that I found very much more useful is actually that we need sometimes just to blackbox this, and we have to remember what is important there. We know movement is the most important part to humanity, so being able to move. If we can sit at work, we can sit at the podcast, but then basically afterwards this

we still have an energy surplus that allows us to come home and move around with our kids and play and be kind to our wives and help them out at home and so on. That's a situation we all feel good with. That's what we all want. So then the question is, how do we do that? So how can we track different parameters to understand how we can get there? And this is where I think very often that looking at more of, let's say, humans as an engine,

As a machine, there's a fuel and an energy input. So you look at oxygen consumption, for example, because this you can do with the cars. And then you look at, okay, you have power. So most people will probably have a power meter, but if they are cycling and a little bit more, if you don't have, it really is not that important because anyway, the output from this process will be distance per time. And one thing that we see also between, let's say, less...

trained people or to put another way people are putting in less volume into their training is also that very often in order to do a certain amount of work or let's say moving a certain distance has a higher oxygen cost or basically higher calorie cost for them to

move that distance as well. So I think on the one side, I'm very fascinated about breaking down things into the smaller details. But the problem is that we have a limit to how much time we have available and how do we then make sure that we get the best or how can we then make sure that the things that we do, the interventions we plan, the changes we make to our lives, how can we then quantify that?

what it has an effect. One, of course, is the ultimate measurement of this is ultimately distance per time. But in order to understand what mechanisms are actually happening here now, we can measure, of course, if you have a power meter or power meter technology, we can start, is it biomechanically driven? So are you improving your biomechanics? Or we can look between power, so work basically, and calimetry. Is it the biochemical part that is improving? And we can even then decide just to say, okay, we blackbox it,

We don't necessarily need to understand it because we can see whether things are improving or not improving. If it does improve, continue to do more of it. If it doesn't improve, then we basically say, okay, fine. We can dig more deeper into it. And that's where, of course, we have specialists and others around us that basically are trying to understand exactly what is happening on a deeper level. Let's use some real examples on that. And I want to just synthesize what you said a little bit because it's very interesting. One of the first things you said is, look,

The metric that matters is velocity. You described it as distance per unit time, but of course that's velocity. So if you're a runner, if you're a cyclist, if you're a swimmer, if you're a triathlete, the winner and loser is determined by velocity, not power output, not any other metric. Obviously there's a very strong correlation between power normalized to weight and velocity, but it is not one-to-one. I'll use an example.

especially in a triathlon or a time trial where aerodynamics matters significantly. You can have people that put out more power, but they create more drag. Obviously, that's very true in swimming as well. In running, obviously, there's running efficiency that can speak to energy expenditure versus velocity. Velocity is king. I like the way you broke it down into two drivers. You can have

How efficient are you at using the energy source to make the ATP? What is your loss ratio there? So presumably majority of that energy is lost in the form of heat. We typically, I remember, used to use like a one to five ratio. So you could sort of take the number of kilojoules, divide by five. That was approximately going to be your energy expenditure. But let's come back to that because that's obviously very crude.

But then you said, no, no, no, look, you also have to be equally focused on your mechanical efficiency. That gets to what I just talked about. First of all, is that a reasonable synthesis of what you just said?

Yeah, and you can split that also into because here it helps to when you look at mechanical part is also when you look between power and velocity, then you can, of course, say that one component is, of course, the biomechanical part. But another part of it is also the work economy or where you basically look at equipment, for example, so aerodynamics and other things as well. So there are two components, but purely if you look at the human locomotion, then basically it's exactly like you break it down here.

I'm going to share with you one really funny example before we come back to this. So 10 years ago, back when I used to ride a bike and the only thing I would do was time trial. That was my favorite event to do. I had two partners that I trained with who were both much better than me, collegiate cyclists. And we used to do this workout every Saturday, which was an 80 kilometer ride on a time trial circuit closed off. It's flat. Each loop was maybe seven or eight kilometers.

But here was the thing we used to do. We used to not allow ourselves to go over 200 watts. So we had a power meter and

The SRM will tell you exactly what your wattage and your average wattage is. So you had to keep that average watt at 200, not 201, not 199. And each week we would see if we could get faster and faster while keeping the wattage at 200. And as you know, 200 watts is not a lot of watts, of course. So it was not hard to hold that for the 80 kilometers.

But over the span of a year, I think if I remember correctly, we were able to increase our velocity from maybe I want to say like 20 and a half miles per hour to maybe 22 miles per hour.

which is a very significant improvement in efficiency. And I'm curious, how much of that do you think we did by getting better in our CDA, our coefficient of drag times frontal surface area, didn't require new equipment? And then how much of that do you think we did metabolically? In other words, that we metabolically got better at turning energy into power?

So first of all, of course, when you have a power meter, you don't know how much the metabolic efficiency... We missed the VO2 data. We have no idea what oxygen consumption did in that year. That's right. Exactly. So that part is not a part of the equation. But if you look at a work economy, then I think there are a couple of things there. Mainly, of course, since a power meter on a bike like the SRM only measures, let's say, the net mechanical power. So it basically only measures the components of...

of power that actually goes in the direction that you are actually moving the crank arm. And of course, already there are two components. We don't have to focus on that here, but that's where the difference between net mechanical power and gross mechanical power comes in, of course.

I don't know, maybe we touch even further on this because there are also several ways to produce 200 watts as well, because you can also have a very large intracyclic power. Sorry, I should make this point. The goal was to keep average power and normalized power the same. So no bursts of power. Yeah. But even there, actually what most people don't realize is that when basically your power meter shows 200 watts and you keep it super steady around 200 watts as well,

you'll actually have inside one second or one revolution, for example, you already there have a variation of power. Let's say it's 200 watts. You will have a peak power production, I would say probably for you because of your focus and how determined you were there. Probably you were sitting on the nicer side of it, but I wouldn't be surprised for some people riding 200 watts to be pushing 1,000, 1,200 watts, for example, peak throughout every single revolution. Wow.

Yeah. Wow. This is something we already quantify by the power meters. But since we don't have to focus on that part here because you're measuring the locomotive part of the power component, then I would say there's a couple of things that is very interesting. One is, of course, that you say that you are already riding at the power output, which is very comfortable. And I think that is important in many senses when you really want to work on your work economy for here. Because here we have already excluded the biomechanical part of it.

because since you are not looking at the difference between gross mechanical power and net mechanical power, then we are already said that we don't care even about the biomechanical part. We are only looking now basically on, let's say, what is transferred into forward propulsion or velocity. But when you're riding to it, what I think is really important and undervalued is that the harder we go, more of our oxygen and blood will basically be prioritized towards energy.

One, driving the muscles forward. Secondly, also even more for cooling. You hit it pretty spot on when you say there's a 20% efficiency, 80% heat, 20%. That's what we see pretty much for elites, not for people. As you said, we'll come back to that probably.

So then basically when you are focused on this, I think that there are no better setting when you ride at a little bit lower power. It allows you to be very mindful and cognitive present to your movement and how you are in the bike there and everything there.

And this is some things that I see very often is a difference between also the specialists and the triathletes as well. Because the triathletes are much more inclined to solve tasks brute force than the specialists are. The specialists are because they simply have more time on lower intensity, medium intensity and high intensities, or let's say especially lower intensities.

they tend very often exactly to build a better feeling for how they are moving through the landscape more efficiently by doing exactly like you say. You look at the 200 watts and it becomes so measurable because you can start to evaluate what is happening with your velocity as a function of that. You just see, okay, I'm creeping down with my head a little bit and you start to feel these nuances because to maybe end it a little bit here is that

when you go to a wind tunnel, one of the problems with going to a wind tunnel is that you go in there and you do something that is like a spot. It's a spot picture exactly of the position that you're holding for the moment. I don't know how many hours are spent in the wind tunnel, but for various purposes, but obviously part of that has been looking at aerodynamics of an athlete. The

The problem is that the moment you take that athlete off the bike and you put him on the chair and you ask him to go back into the position, if he doesn't have an outline in front of him that tells him exactly the position to be in, that can already start to offset any other margins that you're looking to gain from, for example, clothing and other things. So in order now to reevaluate clothing on an athlete and not on a dummy or a doll, but basically on a live athlete, the problem with that is exactly that.

If you go off the bike, come back on again, you won't have the same position unless you have an outline that you see that you're fitting yourself into. And the problem with that is exactly that you haven't gotten the time to rehearse your position and actually start to feel and get aware about your whole body position in

exactly that position there, which is completely the contrary to when you're riding 200 watts. You're riding at a power output that allows you exactly to have that cognitive access to evaluate yourself, feel yourself, be aware of the surroundings and everything there. And you are basically programming that into your backbone for that this is the position. So when you go out

Say in a race, you have trained that position so deep into your body that you can almost do it blind. I think you're spot on here, Olof, now that we discussed it. I actually think that that, whatever it is, 5% improvement came almost entirely through frontal surface area. And as you said, it's so relaxed. I mean, we're talking as we're doing this ride.

It's not a hard ride, which meant all of your cognitive reserve goes into wiggling your way into how narrow can I get my shoulders? What's the best position of my knees on the top tube, all of that kind of stuff. So that's very interesting. And it's also interesting that you point out that it's a luxury that the one sport athlete has, because at the time that was the only thing, I mean, I swam, but most of my energy was on the bike and yes,

I think a triathlete would have a harder time maybe justifying that. Do you think a triathlete would benefit, however, from doing some of that kind of training that seems sort of like junk mileage because it's so low in intensity?

So this is where I would differ because it becomes junk mileage when you're not mindful about that. So of course, this is also where, for example, I know that a lot of people talk about when you do a quality or a high quality or a quality workout, it's a high intensity workout. But basically how I basically see it instead is that low intensity, medium intensity and high intensity should all be high quality. All of them should be mindful workouts because you can use them for different purposes and

Exactly. When you're doing the lower intensity, it allows you exactly to have that cognitive reserve to basically use your senses to give you better biofeedback and learn better what you can improve, which you don't will have the cognitive reserve to do when you do the higher intensity workouts, because then you are exactly focusing more on surviving instead. So

Yes, absolutely. This, I think, becomes most evident in swimming. In cycling, we actually do see that the triathletes, because the movement pattern and other things, there are very, very few degrees of freedom when you're sitting on a bike. So in cycling, we see that, for example, the best triathletes in the world are on par, close to or on par with actually the best cyclists in the world.

In running, this, of course, starts to become a little bit bigger difference between them, simply because now you start to allow for a little bit more degrees of freedom. And swimming is, of course, the worst. This is where you have so many degrees of freedom and so poor feedback values. You need to have a very good spatial awareness of your body and what you're doing there in order to allow you to have or to utilize your oxygen for maximum propulsion. To give you an example, we were in the flume.

at Tenerife T3. This is not like a counter current pool where there's a jet sitting in front of you and pumping some water to it. This is a full fledged wind tunnel. Basically, water is circulated full crush sectional area around in a huge circle. And there is basically three times three meters wide

one and a half meter deep, five meter, five, six meter long cross-sectional area of water just passing over or past you like you were in an endless ocean, swimming in an ocean. Water quality is perfect. There's no turbulence, no nothing, just pure water running past. But sorry, the athlete is able to swim in place. So it's not like,

You know, an endless pool where you're being blasted with a five mile per hour current two feet from your face. You're out far enough in the pool that it just feels like you're in the ocean and you're not moving, but you're using a natural stroke.

It looks very similar to a wind tunnel. It has the honeycomb structure on both on the front and the back here. And then basically there are some huge fans, pumps sitting in another part of there. So it's not sitting where you are swimming, but basically sitting on a return section instead there.

So basically what happens here is that you're laying in this tank and the water is just passing. So you can just set the speed here in the same way as you do with an endless pool or countercurrent pool. So you set the speed to, for example, 1.5 meters per second, and you just jump in and you're just swimming there. And you want, whether you go left or whether you go right or forward or back, the current is exactly the same here. There is no turbulence anymore.

So the interesting thing now is that we built, we took a gold standard metabolic cart and then basically we made hoses and everything and an apparatus that allows them to use this while they are swimming. So meaning you are able to measure the ventilatory rate of oxygen consumption, carbon dioxide production. Everything. So the input, basically you're measuring the fuel consumption of the car and you're looking at what other certain... And the exhaust, yeah. Yes, exactly. Yeah. Not the only exhaust, but well, the exhaust is measured, but also the back wheels basically of your car.

So then basically when they are in the flume there, we know that Christian and Gustav, for example, have an equally high or higher VO2 max than the elite swimmers in the world. And now I'm not talking about where you're comparing running with swimming. We are taking them and measure this in swimming. And the same thing I've done also on elite swimmers. And basically where we say Christian and Gustav has a higher VO2 max, so a bigger engine than the best swimmers in the world.

The people are winning gold in the Olympics. Yep. So in other words, when you push the speed high enough to the point where they reach the maximum amount of oxygen that they're going to be able to consume, which is equivalent to or linearly equivalent to the maximum energy expenditure.

And we always know that the bigger that number, the bigger the engine. They do more. They are able to consume more oxygen and put more calories to work than the world's best swimmers. But of course, you're about to tell us they're not as fast. Exactly. And the difference is so big, you don't even want to know it. So for example, we had the bronze medalist from the Olympics swimming in the flume there. He's 195, 195 tall. He weighs more than, I think, let's

let's say around 90 kilograms or more. Massive guy, a lot of muscles. He goes into the flume, swims at the same velocity as Christian is doing, and is using almost a liter less of oxygen. At that point, that was close to 25% less oxygen. And what we also do know, the more muscles you have in the body,

the more oxygen you can also consume. Because they have almost no muscles, obviously there won't be a lot of oxygen consumption because it's the muscles mainly that are using oxygen during basically exercising. So now when you have an athlete that is this massive, obviously you would assume that okay he is using also a lot of oxygen because there's a lot of muscles involved. But because he's so efficient, he actually swims at the same velocity with almost 25% less oxygen consumption

then the best triathletes in the world is doing. And that is a little bit mind-boggling, but it just tells how important also efficiency or movement efficiency is into this whole equation as well. I would argue that is only mind-boggling to someone who has not swum.

But as a former swimmer myself, this doesn't surprise me one bit, not one iota, because I came to swimming late in life. I'm an adult onset swimmer, so I didn't swim until I was 31 years old. That's almost 20 years ago. And it never ceased to amaze me. Even when I was at my absolute fittest on the bike, when my VO2 max was more than five liters, I

how people with seemingly such a lack of fitness could destroy me in a swimming pool. These people were technically so superior that I could consume five liters of oxygen, they would consume three, no comparison. And that's where exactly being mindful, using that cognitive reserve, not to do junk miles, but doing really mindful miles in the pool, on the bike, exactly like you did,

It's so important, but very undervalued and it could have been used so much better. Super interesting. Well, let's start talking about some of these things. We've already alluded to VO2 and VO2 max, and you've already made a very bold claim, which in the pool is easier to accept, but let's extend it now and let's talk about what it means to

on the bike and on the run because people who listen to this podcast have heard me say over and over again that VO2 max is the greatest predictor of lifespan. This is kind of a remarkable statement and I'll repeat it because it is so profound.

Whether you smoke or don't smoke, whether you have diabetes or don't have diabetes, whether you have end-stage kidney disease or don't, heart disease or not, hypertension or not, all of those things play an important role in predicting the length of your life, but not as much as having a very high VO2 max.

This rises above every other biomarker we have to predict the length of life. And the reason I argue that that's probably the case is

is that VO2 max is an exceptional integrator of work that is done. So for the few times I have patients that will tolerate the mathematical equation, I would say, loosely speaking, VO2 max equals the integral from T1 to T2 of work as a function of time dt.

And we know that that work is very valuable for your health, right? We can quantify why it is that exercise helps you live longer. Why is it good for the brain? Why is it good for the heart? Why is it good for the immune system? And therefore VO2 max becomes a very reproducible way to document that work.

And it can't be changed quickly. So it's not a cheap biomarker like vitamin D, where you can just take a bunch of vitamin D supplements and immediately change your vitamin D level. So with all of that said, when we get into the minutiae of exceptional human performance, VO2 max is not the best predictor.

So let's put swimming aside because it's so obvious there, but why would it not be the best predictor of performance in something like cycling, for example, or running where the aerodynamic contribution in the case of cycling is easier to mitigate, still nowhere near as bad as swimming?

and where the efficiency maybe isn't as important. So where do we see VO2 max not become the most important driver of endurance performance? So first of all, I could not agree more with you on that VO2 max is probably, or still today, the holy grail for endurance.

understanding basically longevity or or let's say the best marker or metric we have in order to quantify it because to just elaborate a little bit further on that you can also say that well vo2max is a measure of something so we are measuring something in the end there

And to be a little bit crude, you could say that, okay, fine. Some people could say, well, having a good heart is a good predictor of longevity, for example. But I'm pretty sure we can find people that are in the bed and they are really sick that still have a really good heart. You understand that, well, there has to be more nuances to this than just the heart itself. You can have people that has a great heart. Everything looks good. Lungs perfect, everything like this.

but they have neurological diseases for example. All of these will limit you from reaching a high VO2 max which is again so integral. It basically just encompasses all this kind of thing because you can't reach a high VO2 max if any of these functions here are not good. I couldn't agree more with you. VO2 max is the absolute best predictor of mostly everything just because that it encompasses all these kind of things.

Then on to why doesn't VO2max become a very good predictor of performance in cycling? I would argue it does, but then we are also starting to reach some more limitations as well. You want to have as a high VO2max as possible, even as a cyclist. The only problem is that we are now facing some other problems as well when you are an elite athlete. And that is something we call maximum sustainable energy expenditure.

So obviously, to turn around more calories per time, that obviously means also that over time you will use more calories as well. And this in order now to support growth, you obviously have to input more calories also because you're burning more, you need to bring more in. Otherwise, you are starting to run into deficit and you worst case end up with problems. So feeding that less a calorie consumption becomes crucial.

Further, the problem is that VO2max is closely related. So if we wanted to have a surrogate metric for VO2max, we typically do make an athlete run all out for, let's say, a couple of minutes, one to five minutes, let's say three minutes to make it simple. Or we can have cyclists do a three minute or four, five minute, but something short, not too short, but absolutely not too long.

Yeah, like four minutes is a pretty good spot. Exactly. Yes, exactly. This is, again, a very good proxy to understand or as a surrogate to understand, of course, what is your view to Max as well. But then what we have to understand as well that...

This is not necessarily what you need in Tour de France. You don't need to be the best four-minute athlete. This is more important for a track cyclist. A track cyclist that has the working time for four hours, for four minutes, then V2 Max becomes maybe the best predictor of performance again. So it's a little bit depending on context.

But because we already said now there's another limitation here as well, and that is the maximum sustainable energy expenditure. How much energy can you expend on different, let's say, intensities in order to increase, let's say, the speciality of what you're going to be good at? So if you are going to be best in the world riding 160 kilometers and then sprinting towards the finish line over a couple of hundred meters, you can even not argue that it's a sprint even, but let's say you are really going fast the last kilometers, then

The problem with this is that if you spend most of that energy that you have available now to increase your view to max, you're spending obviously less time on specializing what you're really going to be good at. And you won't find a track cyclist that you can put into Tour de France and think that he will win Tour de France. And you won't find a Tour de France rider that you can put on a track and become the one kilometer winner there. Obviously, because they are specializing on two different durations.

So simply because we have a limitation for how much energy that we can turn around per day, per week, and so on, sustainably, because that's the key here, sustainably. It basically means also that we have to focus more on that exact specificity that we're looking to excel in. And then, yes, VU2max will still be the best predictor, but not necessarily having the highest number. That is the nuance to it.

Yeah. And let's stay with cycling and even keep it simple and just talk about not include the track, which is far closer to an anaerobic effort. It's sort of on the anaerobic side of a peak aerobic effort. But even if you think about, let's go back to the distance of the 112 mile time trial that a triathlete is doing in an Ironman.

So for the most part, I mean, there's no sprinting in there. He's not sprinting at the very end. In fact, he's probably trying to keep that relatively constant in effort to prepare himself or herself to do the marathon run that's following. Even in that system, let's go back and talk about two athletes. If there are two athletes that have the same VO2 max,

Does power at VO2 max give you another layer of insight? Let's just say Christian and Gustav each have a VO2 max of 80 milliliters per minute per kilogram, but one of them is doing that at 80.

450 watts and one of them is doing it at 425 watts. Does that give you a new piece of information or is it still limited because that's really only speaking to a four minute, five minute effort? Yes and no.

That is, of course, where you can black box, of course, a little bit. Now, we just talked purely about VO2max, we may focus on that. But of course, there will be a fairly good correlation also between oxygen consumption, let's say, at VO2max, because you could argue that there's really no power at VO2max, as long as you are above what we call VO2 steady state. So you have a couple of different steady state scenarios. You have typically one that a lot of people know about, which is the maximum lactate steady state. But

But then, of course, above there, again, you have something called VO2 steady state. And at the moment you start to exceed over VO2 steady state, then basically it's just a matter of duration before you will basically elicit VO2 max. But obviously, the closer you stay to your VO2 steady state, the lower the power you will basically output in. If you put out a too high power, obviously you won't be able to reach VO2 max because you will not be able to contract your muscles efficiently anymore. And you won't be able to bring your ventilation or oxygen consumption up to a max.

But there's a sweet spot there, more or less, where basically any power that sits between, let's say, VO2 steady state and a higher power number will elicit VO2max. It's just the amount of duration that is needed in order to get there. So, of course, this adds uncertainty because you need to know this. You need to know this. I think it's important just so the listener understands that you can't necessarily just go out and people start talking about power at VO2max and their VO2max.

Because then suddenly people will get confused because you have to know also then what was the duration of it as well.

How did you get there? And yeah, yeah, exactly. Yep. Yep. Yeah. Maybe let's take a quick aside because you and I are speaking about this with such a degree of familiarity. I want to make sure the listener understands how you're measuring VO2 max in the lab. This is a test that I believe every human being, athlete and non-athlete should have done because everybody needs to know their number and everybody needs to know where they stack up against people their age and their sex.

because again, it is one of the most important, if not the most important modifiable metric we have to speak to both the length and quality of life. So if I came into your lab tomorrow to have my VO2 max measured, tell me what we would do. So the good thing now, of course, is that also VO2 max is being, or let's say metabolic measurements are being democratized as well.

For example, we work very closely with a Canadian company called View2Master that allows you basically to put now a mask. So it's like the old age, basically, when you have these big computer towers and everything. Today, we have iPhones and Androids that basically have computational power that exceeds millions of times even what the Apollo 11 expedition had running on them.

Yeah. So the same thing is, of course, happening also to metabolic analyzers as well, from basically being these huge towers that were basically exclusive to labs to basically where it's now being democratized. And you basically have like this super portable analyzer just sitting on your face, meshing your oxygen uptake.

But to bring it to the lab setting, what happens is that you come into the laboratory setting. I don't work so much with relative values, but a lot of people will do. So obviously, we're going to measure your weight. So we get your weight there. You mentioned Christian, or let's say an elite athlete, you said 80 milliliters per minute per kilogram. So we have normalized this to kilogram. That's why we need to measure your weight.

So what we do is that depending on what kind of modality that's important to you, so let's say that it's running, for example, what you'll do is that you get on a treadmill. And basically there are a couple of different ways to do this. Whereas the method is pretty much the same, but it can be a little bit of a different gear. Some people will use something that we call mixing chamber system and some people will use what we call the breath systems.

But it would basically involve basically you having either a mouthpiece in your mouth where there sits a turbine with a sample line from it. Basically, when you're exhaling in this mask there or through this mouthpiece, we are measuring the flow or how much air you are breathing in and out per time.

If it's a turbine, then basically we correlate it to how many RPMs this turbine is spinning at. So now we know whether you are breathing, for example, 50 liters or 100 liters, 150 liters per minute. But then, of course, now we only measure your ventilation. We don't know anything about your oxygen consumption yet. We only know something about your ventilation. So then what we also have to do is we need a sample line that sticks in there as well, that basically collects now the concentration of oxygen and carbon dioxide as well.

So what we then do is that because we know that the ambient oxygen condition and ambient CO2 conditions is basically, let's say, 20.9% oxygen and then 0.05% CO2, more or less, roughly speaking. While you are now running and you're breathing, you're obviously breathing in a certain amount of oxygen into your lungs, and then you're consuming some of the air into your lungs, which contains basically 20.9% oxygen.

When that comes into your lungs, parts of that oxygen, far from all of it, actually only closer to 25% of that oxygen, you are actually taking up in your lungs and it's being now transported through your body and you're exhaling actually 75%, roughly speaking 75% oxygen, you actually exhale out again now.

Since we are measuring now the oxygen concentration with this device, we can measure, we know now the delta concentration that sits between what is the oxygen concentration when it goes in, how much is oxygen concentration that goes out. And since we also measure the volume of air, we know we can now extrapolate that and say, okay, this is the amount of oxygen you're actually extracting from there. And this is how we know your oxygen consumption. So why is oxygen consumption important? Well, this comes back to basically calimetry techniques.

Calametry actually is very often, people think then immediately of nutrition and foods and these kind of things, but it's actually just a unit. It's actually just a unit, a scientific unit actually for knowing how much energy is needed to heat water from 14 to 15 degrees, for example, a certain amount of that, and then how much calories is needed. So we could even use gasoline for this, but it basically comes back to the fire triangle. You need something to combust, you need oxygen and you need temperature.

And basically, when we know, when you combust, there's a field, now I'm getting really nerdy here, but there's a field, so there's a field in biochemistry, which is called, or actually not only biochemistry, yeah, well, biochemistry, chemistry in general, which is called stoichiometry. So in stoichiometry, there we can basically look at...

So when we have, like you mentioned initially in the call as well, you talk about hydrocarbons, for example, but let's say carbohydrates, carbon, hydrogen, and oxygen. And then we know how many atoms there are of each of these in that molecule there. And then basically, when we want to convert this into ATPs, for example, then we are breaking this down. So for example, if you look at the glycolysis, we are taking, for example, glucose, which is C6H12O6, and we are breaking that down into two pyruvates, or basically C3H5H2O6.

But we've got two of them now. But in this process of releasing ATP there, at the same time, what happens is also we are releasing hydrogen ions. And this is actually when you feel a burning sensation in your muscles. This is actually, it's not the lactate. It's actually this that you are feeling in your muscles. Lactate is actually a super fuel. If the muscles...

get access to both lactate and glucose, it will actually use lactate as a preferred source before even glucose. But then basically because C3H5O3 basically lacks one hydrogen molecule now, as long as you have an excess of this, then basically you are able to bind back that hydrogen molecule in there and you get C3H6O3 which is a lactate molecule. We've got two of them, so you split one glucose molecule effectively now down to two lactate molecules.

When you're looking now at the energy yield here, basically we know that when you burn, when you convert from glucose to lactate, for example, there is a certain amount of energy or joules that is released in this process. We can even say, okay, let's forget about even ATP and make it even a little bit simpler. What is the potential joules that sits in a glucose molecule? And then when we split this glucose molecule, how many joules are we releasing in this process? And basically, because it's a C3 molecule,

or basically C6H12O6, we know there are six oxygen molecules there. And now we can actually calculate, or we can know actually from your oxygen consumption, because that's O2 molecules going in, and then there comes out CO2 molecules, or both O2 molecules, but also CO2 molecules.

But what we can know now is that we can know exactly because we can use stoichiometry and we can basically calculate how much joules has been now released in this process. And that ties back to V2max. The more oxygen you are capable of turning around per time, the more calories, or let's say the more fats

proteins, carbohydrates, you are able to break down and release energy that you can use forward propulsion in the process. And that's why VO2 measurements is a holy grail metric. We can always talk about direct calamity, but that's so, let's say, call it

intrusive into a process and so little practical to do so indirect calamity measured with vo2 max or vo2 and vo2 max is a superior method to understand how much energy are you able to release in this process and also then just to come back a little bit to your field as well

medicine, if you have a low VO2max, it basically means also at the moment you start to have stress in your lives, you have infections in your lives, anything like this, you are utilizing a much higher percentage of that ability because to get healthy as well, you need energy to get healthy as well. Do whatever, transporting blood around in your body or whatever. So an athlete that has a huge VO2max that becomes sick

There's a fractional change, basically, or relatively small change of their capacity or reserve that is utilized now in this process. So at the moment they release, basically, their training or they reduce the training volume, they get a...

huge excess of energy or ability to recover now and if you're quick enough to do it you won't almost increase in infection at all because the body gets so much energy excess to help aid in the recovery process now compared to a person which has a solo view to max that even walking up the stairs

I think that's such a great point. And I don't think people fully appreciate what a physiologic stress significant illness is. So I won't bore people with all of the details, but if you go and do the chemistry on what it takes to raise the body's temperature from 98 Fahrenheit to 103 Fahrenheit, that is an enormous energy cost.

When we look at cardiac patients, when we look at any patients in the ICU, and you look at the change in cardiac output that might be required to support a systemic inflammatory response syndrome, it is profound. So I think this is absolutely spot on, and it really comes down to just having more reserve. I want to ask you several questions. Let me try to take them in order. First,

You mentioned that you prefer to look at VO2 max in absolute terms. So how much does Christian and Gustav weigh? Those guys probably weigh 75 kilos?

So the funny thing is that leading into the Olympics, one of the things we actually looked even at is basically what happens because we have tried to reduce the weight very conservatively by global standards, even in sports to reduce the weight because we had already ingrained in our heads from basically a past and other people saying that, well, you need to bring up your relative view to match. And that is done very simply by reducing the weight. The interesting thing was we found after we had done this a couple of times and a little bit by accident because we do so much measurements,

is that we saw actually that, well, the relative U2 max didn't come up and the absolute U2 max came down even more than the weight came down. So let's just make sure people understand exactly what you said. It's very important. And we should use some numbers so people understand. So I'm making this up, but if they weigh 80 kilograms, their maximal oxygen consumption is six liters. You take six liters or 6,000 milliliters divided by 80, and you're going to get a big number. And you're saying, well, gosh,

I mean, the tried and true method here is we have to lower that body weight. Why don't we take that body weight from 80 kilos to 75 kilos? And now 6,000 divided by 75 is a much bigger number. All things equal, we're much better. The problem is it's not all things equal because that 6,000 milliliters of oxygen might have come down to 5,500 milliliters per oxygen. And now that ratio has actually gone down.

Exactly. So both absolute have gone down and also relative have actually gone down. It's a little bit, I think, shocking because most people, we of course have a lot of theories of why, one, why this is happening, but also why do people still cling to the idea of reducing? So you come up to a certain level.

Let's say that you had hundreds of athletes through your program. Suddenly comes this really good, like this guy that just responds, a girl that just responds to your training. He goes to junior level, starts to win, senior level, starts to win, starts to go to the championships and whatever. But now you're starting to really have to fight for the sports. Okay, what do you do?

Okay, my training program is perfect. That's something that's very easy to sometimes think, or you're afraid of making changes to the program because you don't necessarily understand exactly why you got there. But we have got ingrained with that. Okay, fine. Let's reduce the weight now because that will be the next step now because we are not able to make you more powerful. So let's start now to reduce your weight. There are two things happening now. One thing is, of course, the things we have observed, the view to max starts to come down. Absolute and relative value starts to come down.

Does that happen because you're unable to control where you're taking the weight off? So, for example, are you losing disproportionately lower body muscle mass, which is, I think, disproportionately contributing to VO2 max relative to upper body?

No, unfortunately, it is more complicated than that because it is without even losing muscle mass. So it is related then to basal energy expenditure. If your total body mass is coming down, your basal energy expenditure is coming down. That is probably altering fundamental metabolic pathways at rest that must be translating to what's happening under stress. Most probably, yes.

This is, of course, something I haven't had enough time to dive into because on the one side, I'm looking more to drive performance. There are some findings that we really want to understand better, but we have to say, okay, that's going to happen in the next life or next period or whatever. I mean, an interesting experiment to do here, sorry to interrupt, would be to...

to actually use doubly labeled water under the weight reduced setting compared to the previous setting, obviously you could do indirect calorimetry during rest. You wouldn't be able to get total energy expenditure, which is what you want, and see if that drop proportionately corresponds to the drop you saw in VO2 max absolute.

Yeah, so this is also something because you can think of it and maybe this is just a temporary phase. So maybe this is a temporary phase before you stabilize the weight. And then at some point it will start to come up again as well, but it doesn't either. So that's a little bit of thing here. Also, we can venture a little bit into double-labeled water because we spent our fortune on doing several double-labeled water blocks. And this, it's a nice method, but it also has...

several pitfalls so actually what we have started to do much more of lately is exactly doing resting metabolic rates so again having the portable metabolic analyzer like the view to master it allows us basically we do measurements before dinner we do it after dinner just to look at the foods for example we do after training to see basically what happens there and we even see that it even sometimes dips below normal normal resting levels for example even

We can only theorize on why that is happening. But the thing is that there's a couple of mechanisms that we just need to control and we need to become even better at it. But back to a little bit to view to Max and Issa. So why do I work on absolute values versus relative values?

One of the things that we do see is that, first of all, Christian and Gustav now, they weigh 73, 74 for Gustav and 80 kilograms for Christian. And he's 175 tall. You would almost say that, hey, he's stocky, right? 175 centimeters at 80 kilos. He looks like a muscular guy. He's not a beanpole guy.

Exactly. But you'll also see that he actually a little bit of extra fat on his body compared to what you would expect to have from an indented. But we can't look at it that way because I'm not looking to build aesthetic machines. No, no, no. It's performance. Philosophy matters. Exactly. Exactly. When you make things relative, because if you look at a power number, so

So you can have two guys, for example, that has, let's say, five watts per kilogram. They are producing five watts per kilogram over a certain distance. But one of the guys is just moving much faster, everything equal. So aerodynamics would be equal to everything like this. But the problem is only that the raw power from a bigger guy that has five watts per kilogram is much higher power produced.

which basically then with aerodynamics are the same, he will move much faster for this. And this goes the same also with view to max as well. If you look at relative values, okay, it is nice to have an idea of what kind of level people are at. But if you just want to look now purely at propulsion, then basically you have to look at it in absolute terms instead. Because most of the racing that is being done today is not very hilly. There are very few

that are very hilly. And of course, if it starts to become very hilly, then of course, then you can start to say, okay, fine. Now relative values will maybe give you a better predictor of the performance necessarily than absolute values would give. Yeah. So that's the main reason. That's very interesting. So again, a couple of things. One is, yeah, in cycling, especially in the Tour de France, I've heard it stated that

And the data for this are a bit confounded because they were based on the two decades of cycling when EPO was widely used. Every single top cyclist was using EPO. But that said, I think that still normalizes it and makes it clear. And basically, you...

You could look at predictions of who would win the tour absent a strategic blunder or an accident, and it was all predicated by functional threshold power in watts per kilo. So if you could know how

how many watts a cyclist could hold for 60 minutes divided by their weight, and you line those up in descending order, all things equal, that was going to be your championship finish. And of course, it's never exactly equal because as I said, you can make a strategic blunder, there can be an accident, lots of things can happen. But I suppose that

That doesn't surprise you given the vertical nature of the Tour de France. It is mostly one in vertical distance, not horizontal distance.

Exactly. Just to add to that also, I think one problem there is a little bit when you talk about 60 minute power. So you take 60 minute power and you divide it by kilograms to make it relative. I think that then you are starting to get a fairly robust metric for it. The problem very often is that people use much shorter durations. Right. They use eight minute power, 10 minute power, and it's a very different bet. Yep. Yeah. And then the problem, if you now extrapolate that, then you still call that functional traditional power, for example, and you divide it by your weight.

What you don't know when you're looking at it this way is how much of energy comes from oxidative phosphorylation and how much comes from the glycolysis, for example. And the shorter the duration is and you're extrapolating that up to a larger value. The more dangerous it is metabolically. Yeah, let's actually make sure people understand why. If you're doing this analysis based on five minutes, to your point, what if during that five minutes, 80% of the energy was glycolytic, which is producing a lot of lactate.

And we've just described, and we're going to come back to lactate. Lactate's great. It's the hydrogen that comes with it that's going to paralyze you. And so your 80% of that energy source, you will not be able to do that for 90 minutes or 60 minutes. But if you push the test out to 60 minutes, you can't fake it, basically. You will not be able to do an 80% glycolytic effort for 60 minutes.

Exactly. There it becomes a really good predictor. But that's what I also like when people talk about, okay, my 60-minute power, this is my 60-minute power. That's extremely precise way of describing your capabilities because then you at least you have a single point or you have two points. You have a power and you have a duration that you're capable of holding in. And that gives you already a fairly good idea of the level of the athlete.

Of course, if you start to have two data points now, so of course now maybe they are, you ask them also, what's your five minute power? What's your 30 minute or yeah, yeah, yeah. Yeah, yeah, or five minute power, for example, because then you're already starting to get a slope as well. So you can start to even understand a little bit what kind of characteristics that is behind this athlete. So typically a sprinter will have a higher ratio between the five minute power

than 60 minute power. While our TT specialists would typically have a lower ratio between the five minute power and 60 minute power. Obviously, back a little bit to the maximum sustainable energy expenditure and VO2max, why it's not necessarily a good predictor always of performance when you look at these long or these endurance events, simply because...

specificity becomes so important there as well. But this is again, yes, I agree. When you talk about 60 minute power and you divide it by kilogram and you're using that to compare it across at least in Tour de France, then it starts to become at least a pretty good metric to understand, or at least if I'm going to bet my money on

It's a safer bet where you would go with the money looking at a higher number. Yeah. Yeah. When you go back to, again, because the data are most available when you actually go now and talk to cyclists like Lance Armstrong and Jan Ulrich and these guys, and they'll tell you, I mean, again, I think today cyclists are very guarded of those data, but back in the heyday of oxygenated performance enhancing drugs, these guys were able to put out six and a half Watts per kilo for 60 minutes. Yeah.

I think today people believe that they're only able to do five and a half watts per kilo for 60 minutes. So that's giving you a relative sense of the difference on and off these agents. I want to come back to another thing you said. Twice now you've alluded to less technical, more portable indirect calorimetry devices than what I'm

I'm used to in the lab if I'm doing a VO2 max test. Now, I was under the impression, and I'd love to be corrected here, that these portable devices are probably decent for measuring VO2, i.e. the consumption of oxygen, but their accuracy is sorely lacking for measuring VCO2, the production of carbon dioxide. And therefore, it might be a good tool for estimating VO2 max in

But it's not a great tool for estimating total energy expenditure, which is calculated by using VO2 and VCO2, and nor is it a great tool for measuring fat oxidation, because there you must be able to look at a very accurate ratio of VCO2 and VO2. So

Are there devices out there that we could be buying, that we could be testing ourselves on every month at home that would meet the criteria of being accurate enough in those domains?

Yes. So I think the accuracy of the devices are starting to become fairly good. We do very often back-to-back testing between the devices. Of course, in a laboratory setting, we are using mixing chamber system, which is, of course, is validated against many different methods. Which system do you use in your lab? So I am actually sticking still to an old system. Parvo? No, actually, no, not the Parvo. I'm actually using a Jaeger Oxygen Pro

with a mixing chamber system. But I also really like the AEI Moxus as well, simply because it has some superior technologies in it.

compared to most of the other devices on the market. Most of the devices on the market, we're not going to go into this. Most of them are using galvanic fuel cells to measure oxygen and then use infrared sensors to measure the CO2. But one of the things that, for example, the AEI MOXUS is doing is that it actually measures it using a zirconia cell instead. And zirconia cell is actually one of the most sensitive cells that we have. For example, if you want to look at the photosynthesis, for example, you can't use a galvanic fuel cell because it's not oxidized.

sensitive enough while a zirconia cell is sensitive enough but nevertheless the same technology now sits in the portable devices so it's still using those are the portable devices now are using galvanic fuel cells we of course i mentioned the view to master one of the benefits we have had is that we enter into a partnership with them to advance the technology several years back i did a screening on the market of all kinds of different metabolic or portable metabolic devices

What I am in need of is that I need to find a compromise. It doesn't help me necessarily to find a device that is a little bit more accurate than the VO2 Master, for example, if it at least doesn't want to use it because it has a rucksack and it has a lot of procedures. It is a horrible user interface and all this kind of thing. Then basically I bought a super nice device. I'm able to get at least to measure it one or twice time, but that's not where the strength is.

of data comp. The strength of data comes exactly from what you say. You need to measure regularly all the time there, and it has to be done in a way that the athlete doesn't feel it as intrusive or invasive into their lives.

Tell me a little bit about the VO2 Master because I'm aware of some of the other portable devices, but not this one. So obviously the hallmark of this is you're going to be plugging the nose. You've got a mask that creates a perfect seal and therefore very clearly at a minimum can measure the air flow rate in and out, correct?

Yeah, so the thing is actually you don't need to plug your nose. It actually uses a Hans Rudolf mask. So most labs you'll very often see at least are using these blue masks more or less. So the cool thing is that what they did is they actually designed a device that sits, actually mounts on this Hans Rudolf mask that is around in the labs. And then basically what it does is the same as you do with a metabolic cart that sits in the laboratories. It has galvanic fuel cells because this is made by maybe there are five manufacturers of galvanic fuel cells in the world.

And basically everybody purchases from more or less these five different manufacturers. So it's the same galvanic fuel cells that sits in the V2 master. And then basically the main differences between this device is that they have removed the turbine and they're using the same way of measuring flow that you do in Formula One and aerospace. So they use differential pressure instead to quantify the flow of what you're doing. So basically this is a device that just sits here.

It's a headgear. There's no wires. They know nothing. It basically connects to your phone, watch, whatever that you have. And then basically, this is how you now collect your oxygen consumption.

So I could go out for a bike ride. If I'm going to go and do VO two max intervals and hill repeats, my favorite workout is the four to five minute hill repeat. I could be wearing this thing and that's it. And I come home and it's going to say, if I did 10 sets, it's going to tell me peak oxygen consumption per each set. Yeah.

You can even connect it to your Garmin computer and you go into your Garmin account and you can see it there, all the views. So you can see your breathing frequency, tidal volume. You can see your fraction of expired O2, your VO2, all the values basically combined there in the same together with your power, with your velocity, with your position, everything there, like in one place. You don't need to look at one separate report for your VO2 numbers. And then basically looking at your Garmin numbers, they are overlaid. So

So it's going to show me heart rate versus power versus VO2 at every moment in time. Exactly. And how accurately is it measuring VO2 relative to what you can do in the lab? And how about VCO2? So VCO2 is, of course, that's a place where we have been very fortunate because we are a little bit ahead of the curve there. So we have had their device that has CO2 now for this must be soon two years, I think. The VO2 master also does VCO2?

Yeah, in the prototype, this is probably going to be released to the market sometimes during next year. Then basically the whole market will have access to it. So we also have the CO2 capabilities as well. But yes, basically you can go out how it compares with basically a metabolic cart. I think here there are two things to keep in mind. One is, of course, that measure of VO2 is a measure of VO2. So obviously they should on one side be the same.

But one thing also we know that between different devices, so the Oxycon Pro, for example, we have the option to basically use it as a breath-to-breath device, or we can use it as a mixing chamber device. If you use it as a breath-to-breath device, then basically you're breathing straight through the turbine. That's it. So there's minimal resistance.

Then, of course, on the other side, we can use the mixing chamber system. And then you have a 2.7 meter long host. If you want to know, I can come back to why it's 2.7 meters later on. But anyway, it's connected to a mixing chamber. And then basically what happens here is the breathing resistance now goes up a little bit. And as we know, also, breathing is not free either. Your lungs, in order to breathe, they also need energy. They need ATPs to contract or basically breathe. Simple as that.

And basically, the more resistance there is to the breathing, the higher the oxygen consumption obviously will be. So you will actually see now for the exact same device, the exact same sensor, but just depending on the method they're using, that there will be differences between the two machines there. Simple as that. Further, when you go out and you actually do biking, one thing that is important to keep in mind is that you are creating a very high headwind.

most likely when you are going fast. Of course, you can go in a hill or these kind of things and you bring down the velocity to very low velocities, but you put out big power there. But what we have to remember is that any system that is based on measuring flow and you now have an interference from basically flow reaching or hitting the turbine, hitting the VO2 master or any metabolic device there will most likely also start to influence a little bit the numbers there.

Because we have to remember also that we are not really measuring the flow and we are not really measuring total oxygen consumption. We are inferring it based on methods that are basically saying that when we see that the turbine is rotating at this many RPMs per minute, for example, then basically we know that that correlates to a certain flow.

So there will always be a little bit of uncertainties. And that's why, for example, when you're in a lab setting where basically you have no headwind, you have very controlled conditions and all these kind of things, the ability to get a higher accuracy will always be higher than it is out in the field. But then we know that what you do in the laboratory is still quite far from what you do out in the field because you're already starting to limit the way that you're moving. The cooling, yes, maybe you have a fan on this, but cooling will be different. There are a lot of things that already are different there. So the question is always...

Do you want accuracy of what really you are looking at? Or do you are just looking at oxygen consumption and then you create an artificial setting, which is not necessarily representable for what you're doing? So it is a little bit of a give and take where basically, yes, you give a little bit in one place, you lose maybe a little bit of, let's say, absolute accuracy from the device because you're introducing some more unknown variables there. But at the same time, you're looking at it now in real life.

conditions where you want to see, okay, what is it looking like here? And you get that accuracy in there, but on a compromise of absolute, let's say, measurement. And how much of a difference are you seeing in one of your athletes between what you're doing gold standard on an ergometer in a lab and

versus if you put the mask on them and you make them go and do four-minute hill repeats where the velocity is not that high, but they're probably still going 18 to 20 miles an hour up a hill, pushing a massive gear to hit that VO2 max. How much of a difference are you seeing in the VO2 and the VCO2?

Between the two devices. So between the lab and the portable, the VO2 master. Typically, when we do back-to-back testing there between the two devices, we would see normally for Christian and Gustav, let's say difference of maybe 50 milliliters between the two devices. That's it? Yeah. That's nothing. Yeah, exactly. I thought you were going to say 500 milliliters. No, then we could just throw the device out the window. Then it has no value anymore. Yeah.

No, no, that wouldn't be acceptable. Okay, okay, okay. But 50 milliliters of oxygen, you guys are putting out probably, you guys have an absolute of probably six liters. Seven. Seven liters. Oh my God. So understandably, it makes a difference at their level. But for someone at my level and for most of the people listening here, a 50 milliliter difference is nothing. It's less than nothing. This is so exciting to me because...

I was under the impression that these devices were still so far away that they were not even worth entertaining the use of.

No. One thing that, of course, you also start, which is a little bit interesting there, obviously, because we use mixing chamber system. That's where we come from. You'll ask the question if you think it's interesting to your listeners, whether they want to understand why there are mixing chamber systems and so on. But to spare them for that for now, basically, what we do know is that when you have a mixing chamber system, just because you have a little bit the higher resistance in a system like that,

Typically, we see also a more stable breathing pattern just because they're actually being reminded more about exactly how they're breathing because they feel a little bit more the resistance. What you do see is as a system gets less resistance, you naturally also start to see a little bit of more variation going up and down and these kind of things. Because even though if you look at a power meter, people that are not used to ride with a power meter, they only used to use heart rate and you give them suddenly a power meter.

The first time they get a power meter, they don't understand anything because power goes all over the place there because they are not used to focus on a power and it becomes almost like they're chasing a number that they don't have. They don't have the coordination or the skills to basically keep it or relax around that very stable power and how to basically read it. Breathing is even worse.

Breathing is even worse than power because now you're even one order further away from performance. So velocity obviously is first principle, first order. That's where exactly the performance happens. Power, you're one step further away. And this is, of course, a system that is very responsive as well to what you do. You won't necessarily see...

If you suddenly get a spike, let's say you're riding 200 watts. If you went to 210 watts for a second and back down to 190 to 200 watts, your speed wouldn't change at all. Your velocity would be the same, more or less. But still, you have the volatility there. So if you're now using velocity as the gauge for whether a system is correct or not, you always say, hey, this cannot be correct. I went to 210 watts. It should be...

immediately giving me this but again the sensitivity to velocity how the velocity is measured is not good enough necessarily to capture the small changes that are happening intra-cyclic in the power production there in between it's being smoothed out because of inertia measurement weaknesses and so on

This gets even worse when you get to velocity, because what we know is the body exactly because of... When we get to ventilation. Yeah, ventilation, yeah. Good clarification, because exactly we are meshing on the exhaust even here. And between basically where we are doing work and basically when we are breathing in and we are exhaling out again, there are so many compensating regulatory mechanisms in the body that are compensating for the lack in one place and here...

back and forth all the time, more or less, to make sure that we deliver energy as efficiently as possible to sustain that propulsion that we're doing. And now when you are measuring VO2 here, you can have quite a bit of fluctuation in this, and there are, let's say, kinetics involved here. To give an example,

If you are running at, let's say you're running 15 kilometers power and you have a certain oxygen consumption now at 15. So I'm just making up a number. Let's say that you are, or to use power, you're riding at a constant power to make a simple constant power of 300 watts. And you're consuming now four and a half liter of oxygen. You can still output those 300 watts there. But if you hold your breath now, what happens? VO2 comes down, ventilation comes down, or tidal volume and breathing frequency comes down.

But you start to feel that something builds up in your body. You're still able to output those 300 watts there. At the moment you start, at some point, you either are forced now to stop or you have to start breathing again. You're forced to start breathing again. And at the moment you start breathing again now, you have a huge depth in your body. And what will happen?

is that basically you get a huge spike in ventilation, huge spike in VO2. But what you also see is that when you break this down, is that obviously the big spike comes from both that you're driving a much larger tidal volume, reading frequency goes up a lot, but also your fraction of expired O2. So the delta between how much of the oxygen you are consuming now, you are going much deeper than the 25% we said initially. But then basically because there are, things are not reacting extremely quickly on the exhaust part here,

You'll see basically that here is almost like a regulator, like a PAD regulator that are trying to bring this back to that stable centix there. And it happens, okay, yes, your breathing comes down again, but still maybe you have a high VO2 and then suddenly VO2 undershoots a little bit because fraction of a spiral O2 comes up a little bit higher, but then says, oh, this is not enough. This is too little oxygen, so I need to increase the extraction a little bit again before

it comes back again. And this just tells to Basic that, yes, 300 watts there, but you can still have a lot of variations there. Just by the fact that you're sitting on the bike and you're sipping that bottle there, you're holding your breath when you're sipping that bottle there, that will already influence your breathing and your VO2 for the next

half a minute on there. If you are swallowing, just the fact that if you start to have a lot of spit, for example, in your mouth and you're swallowing there, you are building a miniature debt there now that you have to pay for again afterwards there. What one has to be careful about there is

I don't like standardizing and saying, "You can't drink, you can't swallow, you can't do it. You have to be a machine," because that's not who we are. We have to learn to look past the noise of the data by collecting a lot of data and knowing exactly that we are not machines. Well, you could maybe say that we are machines as well, but

But there are so many things happening in between there that you can't necessarily, exactly like you also say, you can't one-to-one ratio. Well, we're much more complicated machines. Yes. You've alluded to F1 twice now. That happens to be my favorite sport. And as much as we can look at those cars and say they are the most remarkably engineered machines.

things with wheels that have ever been produced. Everything from the engines that they build, these hybrid internal combustion engines, through the chassis and the aerodynamics. Again, most people are shocked to learn that the aerodynamics of that car are such that it can drive upside down at 100 kph. All of those things are remarkable. I still think we're far more complex. I mean, hands down.

Because every element of that car can be modeled. There is an equation that explains every piece of it, whereas there is no equation to explain what you just described. And by the way, there's an element of chaos in that system. One thing that I'll suggest listeners try if they have power meters, it's just a great example of what you said. So if you have a heart rate monitor and a power meter, next time you're on your bike,

make a deliberate effort to change your ventilatory rate. Vent a lot and vent a little and watch what the heart rate does even as you hold the power constant. And of course, this is because that CO2 is very soluble and CO2 is tracked by the brain very closely as a proxy for pH. And the body is very particular about keeping the pH at 7.4.

As you slow down your ventilation rate and hold your breath and your carbon dioxide levels rise and your pH falls, you will see that heart rate start to spike with no additional input in power output. And of course, the reverse is true. It's just a great example of what you said.

but it's one where you can sort of be the guinea pig and watch it. I still to this day get a kick out of playing that game to see how much I can move my heart rate just by interfering with my ventilatory rate. But I can say that I think that that's also why some people become better also and others not, because I think that one thing that we very often tend to lose as we get older or we go through, for example, different training is that we lose that ability to play.

And exactly going out and playing is one of the best ways to learn actually what influences and increase our awareness of that.

Because one of the things is that I've learned also with elites is that elites are not necessarily perfectly calibrated either. They need to actually be calibrated because you have some athletes that typically, if you ask them to go out and do, call it a threshold workout, or let's say a workout that has, let's say, intervals, a combined duration of intervals that are between 60 to 80 minutes, and that should be fairly close to all out, or let's say to bring it to exhaustion on the last interval. Right.

you'll see that some athletes, elite athletes, they are ending up going out too hard and they end up dropping the power towards the end. Some athletes, they go out a little bit too light and they have to go really hard towards the end to bring it up there. But both scenarios, if you were able to keep it up

at a very calibrated or accurate level there, you would see that the total amount of kilojoules you were able to accumulate on those 80 minutes or 60 or 80 minutes or whatever the length there would be, would be higher than if you ended up going progressive or worst case you end up ending up going regressive because you go too hard

in the beginning and not supposed to come down towards the end there. What standard do you use, by the way? So let's use that as a quick example. So again, I said I'll use myself because I'm trying to get as much free coaching as I can here. So if I love doing my VO2 max sets on a bike, on a hill, I have a fixed distance that I ride. So it really depends on the wind. So if I have a headwind, it'll take about five minutes. And if I have a tailwind, it could take

345. That's how much the wind can play a role on this hill. But basically, it's not an all out effort because you want to be able to do it multiple times, but it's a very hard effort, followed by about a one to one ratio of recovery. And that's the workout after a warm up. It's over and over and over and over again. It's like an hour of doing that.

Now, I typically, and I think this is because I've become softer in my old age, I typically ascend in power. So I will typically start out at a very conservative power where at the very end, I am not dead. But by the end, by the last one, I might be doing...

10% more power than on the first set. And I'm absolutely at my limit. How would you recommend I change that? You want that to be within 5% the whole way through, or how would you recommend that? If again, the goal is maximizing that workout to maximize VO2 max and to increase the engine size.

Maybe we should add one more dimension to this now, because I think that very often we confuse, for example, also when we talk about FTP, just FTP, and we black box a metric as FTP instead of saying 60 minute power or 20 minute power, whatever. What's really accurate with the 20, when you say 20 minute power, 60 minute power, you basically know that, okay, you can hold that power for that duration. That's the maximum, for example, before you basically end up dropping too much and you just call it the day of it.

Very often when we talk about VO2max, it's very often confused with aerobic capacity, while in reality it's not. It's aerobic power. You're measuring how much oxygen for undefined time. Yes, we have normalized it as milliliters per minute, but you can have a big range between athletes that has the same VO2max. Some can do that for several minutes. Some can only do that for, let's say, one minute, for example.

And this is where the importance is because we're looking for to provide signal, signaling or stimulus to the body. If you go out and you do one five-minute interval, more or less, then basically, okay, fine. That's the stimulus that you're providing yourself there. So this is about how, okay, you've got a certain amount of time available to go out and do that VO2max session today, for example. Let's say there's 90 minutes. Then basically, of course, now this is one-dimensional because we're not talking only about a single workout as well.

I think the most undervalued thing, which is not very sexy to talk about, and also the most undervalued thing is that basically it's consistency. Consistency in the training over time. And that means that you need to leave a little bit in reserve there. And we haven't even touched on the topic of psychology yet either, because we are very much now talking about the things in physiology that we are good at measuring and these kind of things.

But there are also plenty of things that we are not able to measure. And even the things that we like to say that we are so good in stoichiometry or are so good in understanding metabolic pathways or signaling pathways, there are still things added to this where we basically understand that, no, we don't. And then we haven't even dived into the topic of microbiome. It's a world, undiscovered world, that we are basically taking on now.

So one of the things that is that when you're doing this exercise, but a good thing with VO2 is that, of course, that we're measuring a quantity, we're measuring a volume of something. It's much in the same way when we talk about power versus work. So you talk about work, for example, to make this a little bit more practical.

So when you say, okay, I want to basically do my VO2 max workouts, I go a little bit progressive. I would normally say that's a good thing to do because also what happens is there's a priming effect also happening in the body as well. So if you go out like where you think that you maybe would be able to sustain throughout the workout, you might figure out that you still are able to go a little bit higher. At some point, it's the opposite. One thing that we have done multiple times over the last half decade

is that very often people think that, okay, when I've done a view to max effort, then basically I'm done. I won't be able to repeat that. I need two days of rest or maybe a week of rest or whatever before I can do that. That's not true either. We know that, for example, if you do a view to max effort and then basically you give an adequate time of rest in between, you are able to go even harder on the next one now, even though that was completely too exhaustion on the first one.

Say more about that. So put some time and numbers to it so I can understand what you're saying. So you could take one of your athletes and what duration of an interval would you have them push to?

So for example, here, let's say that we are using an old fashioned way of quantifying VO2 max, you say that you do a graded exercise test. So you increase the power by 5%, for example, every minute that goes there until you basically come to exhaustion. Let's say that now that the epit finishes around 500 watts and

around seven liters of oxygen. For the listener, those are world-class numbers that are obscene. You're not running into people on the street that can do that, but carry on. Yeah, and here already, I haven't told what's happening before there as well, because if I only took them fresh doing this, then the power number would be different. So again, this comes back a little bit to talking about power at VO2 max, where this is already manipulated depending on what you've done before this as well.

So now basically they do this. So let's say that they last for six minutes and then finish the last one on, let's say, 500 watts. Last minute on 500 watts. Maybe they go a couple of seconds longer into the next one. And this is also important. So when you do a greater exercise test, if you come to the next step now and you feel that, oh, this is too hard.

Push as long as you can because every second counter, because it's more work. It's more work, it's more oxygen consumed. They're stronger stimulus, more or less. I wouldn't advise doing this very often, but we can come back to that a little bit later because I'm not a big fan of doing very often two exhaustion workouts that you should put them in very sparingly into your program. And that ties back to consistency. But anyways, now given in between, let's say if we give 10 minutes of rest in between and a little bit more rest in between there,

Then basically, if you do now a new view to max, the same athlete we bring now to more than seven liters or 7.1 or maybe even a little bit higher. And power output is also now, for example, comes up now maybe one more minute at one higher power output. So now we are already at maybe 525 watts for one minute as well. You're saying that that's happening because they've been primed by the first set to be able to do that with only 10 minutes of rest?

If it goes too long resting between there, then basically you start to lose the effect. So if the duration of the rest in between there, then you are not able to draw the effect of that anymore. That can be, I think you could probably extend it up to 15 or maybe 20 minutes. But when you get past 20 minutes,

I'm not so sure whether that would hold true anymore. So it needs to be shown. And this can also come back to because we know also that oxygen, when we think about hemoglobin as well, the affinity for oxygen and CO2 to the hemoglobin is also affected by the temperature of the blood or the body and the hemoglobin as well.

So this is also improving, actually, with a higher temperature than it is at a cola. So when you get 20 minutes, obviously, temperature of your body will also come further down, come longer down than it is at 10 minutes. 10 minutes, it will also come down, but maybe not as much. But the most interesting thing that happens also now is the RER value is heavily skewed towards oxygen consumption and less oxygen.

carbon dioxide production. Even when you do this, you would even say that this doesn't qualify for a VO2 maxes. So the VO2 numbers now are equally high or higher, but the carbon dioxide production is actually now just maybe a little bit higher than one in our air value. And normally we would say that

If you just went by the papers or the old school books, you would say that, okay, in order for it to qualify a VO2max, you should, for example, one of the criteria is often they say that you need to exceed an RIR value of 1.1, for example, for it to be valid. Of course, what are you going to say? The VO2max value was higher. Are we not going to disqualify it? It was a higher oxygen consumption than it was in the previous one. It's also equally more now.

Let's explain this to people. You and I already alluded to this very briefly, but we didn't make a big point of it. So the RER is calculated instantaneously at any moment in time as the ratio of VCO2 to VO2. So let's go back to, you're going to put one of your athletes on the bike and he's

he starts riding really slowly. In that moment, he's at 100 watts, so he's not even breaking a sweat. What is his RER at that moment? The thing is that this is actually a little bit funny because here it's very easy when we look at the values. When you look at RER, we typically look at a ratio of concentration and we already exclude a little bit of volume of oxygen and volume of CO2 that is there. And of course, there is a requirement for a certain amount of energy to be turned around per time. That's why, for example, if you look at lactate as a surrogate,

Again, if you go back all the way to stoichiometry, and we already said C6H12O6 glucose broken down to lactate and these kind of things, we already know here how much CO2 that is being produced in this process there of certain ratios. But since we also know the ratio between glucose and lactate as well, we can use that also as a surrogate to have more or less the same confirmations as well, or the same indications as

as well. The difference is only that VCO2 is a volumetric measurement, while lactate is a concentration metric. And concentration metrics are influenced by many other factors as well. So that's why lactate can be a little bit more unpredictable and it's not as a good indicator as VCO2 is.

But coming back to that, basically at 100, typically there, you won't see necessarily a very good ratio between VO2 and VCO2. So our value that can actually be quite high because two things that are playing into account there. Your resting metabolic rate already plays a much bigger factor or a relatively larger percent

of the total oxygen consumption and carbon dioxide production now, as opposed to when you start to go to a higher number. So the higher the number are, the smaller the percentage of the resting, because when we measure VO2 and VCO2, we measure actually the gross percentage

oxygen and gross CO2. We're not measuring only oxygen as a function of exercise, but actually of both exercise. Yes. And basal resting. Okay. So now this of course is going to be heavily influenced by their diet and the carbohydrate content of their diet, but I'm assuming your athletes are on a pretty high carbohydrate diet. Oh yeah. Yeah. So that means that they're resting RER is probably 0.85 to 0.9. Or higher. Okay. Okay.

So that means that they get a nadir in their RER when energy expenditure gets high enough that it starts to dwarf basal energy expenditure. And you're really achieving maximal fat oxidation, which is probably occurring at...

I don't know, about at a wattage that probably corresponds to 75 or 80% of their best one hour power. I'm guessing that in and about that wattage, they are at maximum fat oxidation and they probably are at minimum RER.

Actually, it's even higher for endurance athletes or especially triathletes or long course triathletes, because this comes back also a little bit to now we are getting a little bit deeper into it. But this also comes back to why it's not necessarily viewed to max a good predictor of performance, especially the longer the events becomes. So, for example, to let people in on a little bit of our let's call it secret sauce, secret sauce, but secrets.

And that is that actually for Christian and Gustav to win the world championships, so last year, basically we had a consequence of the specialization we did. VO2 max came down significantly. From then, basically racing in the Olympics, clocking in, so using relative values, which is maybe a little bit more easier to relate to, both Christian and Gustav would typically test in around, let's say, close to 90 milliliters per minute per kilogram. But at...

Ironman, in order to set new records in Ironman, we had to bring it down to actually below 80 milliliters per minute per kilogram. And you did this purely because of energy demand and energy consumption?

purely because you can't sustain. Because think of it more like a curve. You had to detune the engine, basically. You had to bring the fuel flow rate and oxygen flow rate in the engine down to do Le Mans versus do a Formula One race.

Exactly. Because you can't now prioritize keeping doing those five-minute power surges or micro intervals anymore, because it's too far away from basically what you need in an Ironman. And you need to build more, let's say, towards the higher energy demands or let's say higher power outputs in an Ironman, the lower ones or the sustainable ones and so on, and maybe even building a little bit longer as well. You basically don't have the time anymore. Or basically, that's not right. You have the time, but you actually are not able...

to consume enough energy over weeks and months to sustain a program that allows you to both increase your V2 max at the same time as you're building up that long duration power output. Let's say that four hour power as well at the same time. I think what would be interesting for folks to understand is, so there's something called the WIC equation, which technically

tells us the relationship between energy consumed and oxygen consumed and CO2 produced. I used to know it off by heart, but I think it's basically energy expenditure is 3.75 times VO2 in liters per minute.

plus 1.25 times VCO2 in liters per minute. Does that sound right? Actually, I would make it even simpler because basically we know that from one milliliter of oxygen, basically there's a 20 joules, there are 20 joules of energy being, and then we know already, as you said,

You already said that, well, the efficiency of the body is approximately 20% propulsive and 80% are thermal. So you can actually do this far simpler in that sense that you can just look at, okay, how many milliliters of oxygen you're consuming and multiply it actually just by 20 roughly speaking. Yeah.

At six liters per minute of VO2, and I guess the reason you can make that simplification is by the time you're at six liters of VO2, you can assume what VCO2 is. You don't have to measure it. The approximate, let me just do the math, so that's about five, that's 30 calories per minute of energy consumption. 1,800 calories per hour of

of energy consumption at six liters per minute. And at that point, you now exceed the capacity of the human digestive system. There is no means by which a human in any form can ingest 1800 calories in an hour and actually get those calories out of the gastrointestinal system into the circulatory system, into the muscles.

So really at this level, it becomes an energetic problem as much as a problem of stroke volume, heart rate.

and capillary efficiencies. You can even say that you don't even care about heart rate or stroke volume or cardiac output anyway, because that's what you even started with, which also resonates so well with me. VO2 encompasses exactly that stroke volume because cardiac output is just a function of VO2 in the end anyway, because what you really need, the cardiac output is just to supply you with oxygen and

Really, it's the oxygen, which is the key metric here. So again, yes, the energetic demand becomes so crazy that you just have to start to prioritize. And you just say, okay, how important is it for you to be able to do like super high five minute watch surges in Ironman? Not important at all. Yeah.

Never, exactly. So you can't spend time on training it. If you could feed more energy, so if you somehow would be able to even feed more energy, yes, then you can definitely uphold more of that. And that's, of course, what we did there. We looked exactly at how can we stay in this perfect balance there, living at the edge, where we can keep the view to max as high as possible, or let's say the whole curve as high as possible, because that in the end will give us a better ability to race than necessarily our competitors setting records.

Now, given these huge energetic differences, let's just make sure people understand the distances we're talking about. At the Olympics in Paris next July or August, it's an Olympic distance triathlon, so we won't need to go into the distances, but let's just tell people a world-class athlete is doing that in what, an hour and 40 minutes or maybe even less at this point? Where are they?

140, 145 is basically where you need to be. And that's basically 51.5 kilometers, 1500 meters swimming, 40 kilometers biking, and then basically 10 kilometers running. Conversely, if you look at Ironman distance at the other end of the spectrum, we're 2.4 miles in the water, 112 on the bike, full marathon run. The world class guys are doing that in what, seven and a half hours, 740 ish.

Yeah, seven and a half. Christian went 721 on the fastest. Again, it's simply unfathomable to anybody who's done any of those things that they're going that fast. But the energy demand, if you're trying to do something all out for an hour and 40, that is a much easier fueling strategy than if you have to go at a submaximal effort for seven and a half hours. So is it surprising to you

that you can have one athlete who can be exceptional and world-class at both? Because I have to be honest with you, it's a little counterintuitive to me, based on this discussion, that you could be the best in the world at both of those. Is there another sport where we would see such disparity? We wouldn't expect that the best 400-meter runner is also going to be the best 10K runner. And we wouldn't expect that the best 5K runner would be the best marathoner.

This is where I think that we have hugely benefited from using science because it allowed us to break down the arm and distance and understand where basically we could gain much more time than what had been done before. Because what we have to think is that the training, let's say the method for training, we can come back to it because you mentioned the five minute intervals and how you were executing this to basically do your view to max session. We can come back to that because if you're thinking of it, we are organic creatures. So we respond to stress.

by normally getting stronger.

given that we are providing the conditions to allow it to grow stronger. So now basically when you are out and you are doing your five-minute efforts, you have a finite amount of time that you can do this exercise. So let's say you had 90 minutes. You can twist this around instead and say that in the same way that you go out and you play a little bit with your breathing to see what you can do with your heart rate at a certain power. Now you can just say that, okay, fine. I'm actually now looking to provide the maximum amount of stimulus possible

To increase my view to max, we already said that, for example, five minute power or three minute power is a good proxy or surrogate to understand how high your view to max is. Now think of it this way instead, that when you go out, you're looking actually to accumulate the maximum amount of work that you can do at a certain output. That is actually a better way of looking at how can I actually provide the best possible stimulus for me now to grow my engine, to grow my view to max.

Sorry, just to be clear, you're saying you might go out and say for an hour, what's the most number of kilojoules that I can expend as opposed to what's the highest VO2 max I could sustain for that period of time? Are you basically saying we should just use kilojoules or we could just use kilojoules as the metric?

Yeah, because you can think of it this way, that the further away we are from, because in the end, you can say that, okay, velocity is the ultimate measurement of form. And the further away we move from this, the more gray it becomes because there are more mechanisms compensating and that has an influence on what is happening there. So we could think of it this way, that, okay, the reason why we want to grow an engine is because we want to become faster on the one side. But then when you go out, you are not measuring VO2 max. You're not measuring milliliters per minute or how much oxygen you're consuming.

when you're doing your exercise now. But we know that the higher intensity you go, the more oxygen you will consume per time. So then we are saying that now we are providing a stimulus to the body to say that we need more oxygen. You need to respond to this and basically facilitate this

Moving forward, because this guy, he might be crazy enough to go out and do this session again next week or something like this. So again, the theory of super compensation, that's why normally we would say, okay, the reason why we get stronger is because we exercise or we provide a controlled stress to the body that the body is able to respond to and grow from.

So now when you're out and exercising and you're doing these hill repeats there, now you can instead think of it this way. Okay, so when I did my five minutes, my five minute efforts, let's say you accumulated, how many repeats would you do during an hour? Or let's say, how many repeats would you do during a session?

Six to 10. Six to 10. So then basically when you do six to 10, that means basically then you are accumulating between 30 to 50 minutes of, let's say, that high intensity. Of work, yes, that's right. Of work there. So of course you do more work, but you do that specific work there with the idea of that this will give you a bigger engine. But ultimately, actually what you're really looking for is to become faster. That's what you're really looking for.

And that can be done, like we also mentioned initially as well. And once that you can say, you don't really care either. If your view to a max comes down, but you just come faster. Okay, well, efficiency have increased, but okay, that's most likely not going to be the race. The outcome of it, it would probably be a mix between a lot of things there. But now you can think of it this way. And that is that when you go out and you do, so let's say that you ride now at 400 watts and you accumulate 30 minutes at 400 watts. So let's say something like that.

Those days are over, by the way. Okay.

That used to be the case. I wish I could still do 400 watts for five minutes, but anyway. Let's say 300 watts. It doesn't matter. It doesn't matter. 300 watts, and this is close to exhaustion. Close to exhaustion. You have a little bit of reserve, so you can repeat this. Like you say, you have enough even in reserve that you even are able to progress throughout the session a little bit on this. So let's say that now you're accumulating an average at 310 watts, you accumulate 30 minutes of work around there.

Because if you go to 50 minutes, a normal consequence of this would normally be that either now you have gotten fitter or you just had a lot more in reserve when you do the 30 minutes and you really didn't bring yourself close to exhaustion at all. So then the stimulus and then the stress on the body is also much less.

Worst case, if you were capable of doing now 50 minutes, accumulating 50 minutes at 300 watts or 310 watts, for example, two weeks ago, if you now do it only for 30 minutes, that's already detraining of the ability to stay at 300 watts if you do too many of these sessions now moving forward, unless you only use this one as a way to just provide some adaptation or make yourself ready for something bigger to come forward.

But now you can look at it another way. So let's say again, 300 watts, 30 minutes, that's approximately where you're sitting or 310 watts, 30 minutes, that's approximately where you're sitting, then you're close to exhaustion.

The time you have got available for this training that you had there now, maybe that was 60 minutes or less. How long are these sessions lasting typically from basically when you start and to you stop the session in total? Not that much longer because the warmup and the cool down is 20 minutes in total. So most of the set, I could be door to door from my house in 75 to 90 minutes easily.

Okay, but brilliant. So basically here we're talking about 75 to 90 minutes in total of training time available. It's very different. So just to be clear, when I used to train, I exercise now, I don't train. When I used to train, my coach on the really big days would sometimes want me to not begin the VO2 max set until I had done 2000 kilojoules. So I would go out and do a relatively...

like a 200 watt, 2000 kilojoule ride, and then finish with a very big main set of hill repeats, short hill repeats. So six minute hill repeats. And so that was an enormous total amount of energy expenditure, but most of it was actually at

at zone one to zone two, pure aerobic efficiency, and then finishing with the VO2 max. Again, I don't remember what the rationale was for where the, get those 2000 kilojoules of work in before you go there, but those were much longer days, obviously. Again, today, because I'm not training, for me personally, velocity doesn't matter anymore, nor does power. Frankly, I'm only training for the conditioning of it.

I'm basically asking the question, how long can I keep my VO2 max high? One of the things I think about is at what age will my VO2 max in relative terms, mils per kilogram per minute, be smaller than my age in numbers?

That's an interesting question. Where do we make that crossover? I think this is also something that we will probably have a completely new picture of also over the next five to 10 years as well, just because a lot of measurement equipment that we have available becomes more democratized.

One thing I can also say is that from all the data, I collect so much data on my athletes as well. And also many of the coaches I work with, they collect so much data on the athletes. But the problem is that we even see that we can use the data to even make the athletes faster. So we even haven't gone as fast as it is possible to do yet. But the time that is available to basically analyze all these metrics and bring it back into our sound program is so time consuming to do that you sometimes just have to skip this and you have to focus on the more important part of it.

So one of the things that we are doing is we have a company called Entalpy and where we basically are building AI, but of course, LLMs or natural language processing systems and numerical models where we basically allow us to start to utilize even more of this data.

in order to provide even more deeper individualization for athletes. But even when you go out and basically exercising and you're looking at it, because we can break this even further down, because again, your ability to put out 300 watts, for example, is also a function of force and circumferential velocity, or let's say torque and cadence. Because it's very easy sometimes when you go out and you're thinking that, okay, now I'm going to go max. What you feel is the torque. You don't feel the power in the same way. You feel really the torque.

But if you aim for something that really feels like super heavy, that's a big torque, but it doesn't necessarily yield a very high power output at all. And power is basically what drives the energy demand for the body. It's not the torque. Okay.

Of course, it's not entirely, it's a mix of a little bit of the two, but- Do you subscribe to the idea, again, using this example where if you shift more towards higher torque, lower velocity, you're putting more of the stress on the musculature of the legs. If you switch more towards a higher velocity by velocity, I mean, crank velocity, lower torque, you're switching more of the demand in the direction of the cardiovascular system. I mean,

Remember, people used to talk about this all the time between Lance and Jan, right? One was pushing 95 to 100 RPM. The other was pushing 65 to 70 RPM. They're putting out the same power, but two different strategies. Do you think about that distinction for the cyclist?

Well, yes, I do. And this is also something that's very easy to measure. So for example, if you're out and you put on a VO2 master and you go for a certain power output and you drop, for example, that cadence, so you bring up the torque. Yeah, you can basically make VO2 the metric that helps you decide. And that should correspond most to fatigue.

Well, actually, the interesting thing is that what you're seeing now is that you might actually bring down the VO2 as a function of that you're increasing the torque. So you get a little bit better ratio there. But what can happen actually as a function of it is that you also see that CO2 comes up a little bit more. So you actually are shifting a little bit to substrate CO2.

That's right. Yes, exactly. And of course, the mechanism behind this is probably also like it's fairly easy to rationalize. And simply because when you are starting to use a higher torque, you are activating a larger cross-sectional area of your muscles. So you're also recruiting more type two fibers versus only type one fibers as well. So you're becoming much more glycogen dependent as you make that recruitment. Yeah.

It's not entirely black-white like that, but in general, yes. But also here you can say that because then we're thinking, okay, but we have heard about the expression slow twitch and fast twitch fibers and should more of that be activated when you start to pedal faster? Well, yes, but you're not even approaching the limit of basically a slow twitch fiber or type 1 fiber contractile velocity when

When you're at 90 or 100 or 110, it's more a pure limitation of coordination or being able to coordinate.

your pedaling motion in order to have a better balance between your gross power and your net power. And this is basically where people sometimes they forget this, that what happens, you start to go at a higher cadence. If you now actually measure your gross power and your net power, you start to see that, yes, the net power is the same, but the gross power actually starts to go up when you're starting to bring up your cadence as well, which tells why the VO2 now also starts to go up. The

The VO2 or the oxygen consumption doesn't care about your propulsive power. It cares about how much power is required now. It's counting both the usable and wasted energy. Exactly. So this is one thing that you see if you go with a little bit lower cadence. Typically, what happens is that you have a bed that is easier to coordinate.

your pedaling motion versus for example when you start to go with a higher cadence let's say you do a graded exercise test if you aim for a low torque the problem is there as the ergometer basically now starts to force you to go to higher power higher power higher power higher power and you go with a low cadence this will basically start increase the motor unit

motor unit activations, you're recruiting more and more of muscle fibers, and you won't be able to get up to an equally high power output simply because the limitation that comes in now is that you have no more motor units, you have no more muscles to recruit anymore, and you are forced to stop. The only way now to compensate for this is that you have to bring up your cadence instead as a function, because if there's no more muscles to recruit there, well, then the only thing you can do is start to work faster instead or bring up the cadence faster.

So to bring it back again to your question a little bit about, okay, so you're looking to conditioning or creating the ability to put out a big power there. Again, we know that there's a very good correlation between power and VO2. Obviously, more work, more oxygen consumption, simple as that. You can almost say it's a liner relationship. So if you increase your power by 10%, you will normally increase your oxygen consumption by 10% as well.

For those people that are really into the pudding here, of course, they understand that this is not entirely the case. This is a curvilinear relationship. But for the simplicity, we keep it this way for now. And just to complete that, you will not increase velocity by 10% in that situation because of the relationship, the square relationship between velocity and drag. So just so folks understand, while those two things are moving up in a curvilinear relationship, the velocity relationship is actually a squared or a power relationship.

And therefore it gets harder and harder when you're talking about athletes at the level that you're coaching to eke out an additional kilometer per hour when they're already going 48 kilometers per hour. It becomes seismic to try to add 5% to that.

Yeah, exactly. So then back to your question. Here you can think of it this way. Since we know that there is a fairly good correlation between, or not a fairly good, it's an extreme good correlation between power and oxygen consumption. Now you can think of it this way. Okay, so how can I then increase my oxygen consumption? Because now we're not talking about milliliters per minute. Now we are talking about milliliters accumulated. So in the same way we talk about power and the relationship between power and work, we could talk about

Also, the difference between milliliters per minute and milliliters per, let's say, session, for example. So then we can think of it this way. Okay, so how do I provide a stronger stimulus, let's say, to the cardiovascular system, respiratory system, to everything? So basically, I get a higher view to max. Well, I would then say that you have already a power meter. So you already have something that we know have an extremely close relationship with oxygen. So how can we now increase the oxygen, total oxygen consumption during that session there?

Then basically, I would probably argue that saying doing five minutes on, five minutes off, for example, will not necessarily yield the maximum work that you can do at that. Because we're not looking at total work during the session, because obviously that would be better if you brought down the intensity in total. But now you're looking for the specific, you want to increase the maximum oxygen output. So we're not looking at something that sits in this range there, that is high intensity.

So I would rather look at it more like go out and play a little bit and look a little bit, okay, what kind of intervals do I have to do here to pack as much as possible kilojoules of work here at that power output during that session that you got available? And I'm pretty sure if you do this over a month and you go back into the lab and you test your V2Max, you'll already see now that you have a higher V2Max than what you did have before.

And just to give a sense of what some of those games could look like, again, I used to experiment with every type of interval from 30 seconds on to 30 seconds off up to eight minutes on, eight minutes off. The only thing that was constant was the one-to-one work-to-rest ratio. But as I just alluded to, right, the work-to-rest could be as little as 30 seconds, one minute, two minutes. Even less. Yeah. Even less, yeah. Yeah.

And so what is your intuition? Because again, the classic thinking, classic cycling physiology is maximizing VO2 max and maximizing PVO2 max, powered VO2 max, critical power, for example, is going to be attained at three to eight minute intervals. Now, it doesn't mean you don't

improve the engine size when you're doing intervals less than three minutes or more than eight minutes, but you're most efficient in your training time at those intervals. Are you arguing? That's not necessarily true. There could be gains outside of that if you're using maximum kilojoules per unit time as your metric.

Yeah, accumulated inside a session. Think of it this way. We are looking for a stimulus. So to again make it or to be a little bit blunt, rude, you can think of it if you do one minute. No, if you do five minute interval, that's the only thing you do. The stimulus that you are providing now at let's say P VO2 max or power at VO2 max, for example, or let's say you had an oxygen mask and you could measure now your oxygen up, you will see that the total accumulated oxygen that you have been using now during that session is very, very little.

So the reason for why you do intervals and you don't try to do, for example, if you try to do it even as intervals, you even try to just combine those 30 minutes into one power output at all, you won't be able to put out the same amount of power if you just did it in one go, 30 minutes there. Probably then you would be forced to do maybe to bring it down to 280, 270, if it was 300, for example, what's when you did it as five-minute intervals, maybe even more down.

Now we can think of it this way, in the same way. We can just bring it down. So why five minutes? Why did you land on five minutes? Could it also be four, for example? Could it be three? Could it be two? Because what we're really looking at here is the maximum. But we want to make sure we don't make the interval too small, that we're quote unquote cheating and using pure glycolytic power.

which obviously has its benefits, but won't necessarily increase, presumably at some level, mitochondrial function and mitochondrial throughput. I mean, because we're so focused on VO2 max here, we want to make sure we're increasing an energy system that is flexible enough to oxidize both glucose and fatty acid through the mitochondria and therefore with oxygen. So at some level, don't those interval durations get so short that we

That we can be misled by what we're seeing, assuming we don't have the oxygen mask. So if we have the oxygen mask, of course, we'll notice that. But if we're only relying on power, that correlation between power and VO2, that linear curve starts to separate in lower durations, doesn't it?

One thing to bring in here, so disclaimer, which is very important to think. I think that there's no single workout that is the golden workout. We need different kinds of stimulus. When you do different kinds of intervals at VO2 max, they will elicit different stimuli.

Functions in your body or different benefits in your body. For example, if you do micro intervals, one of the things that might be there is that you won't necessarily bring your core temperature as high up as you would do if you do a long workout, for example. And we know that also, for example, one thing that's very beneficial to our body is to have more plasma. More plasma is good for us.

And we also know that that also has an influence on VO2 max as well, for example. So bringing up the core temperature, let's say also like working on fatigue or being able to focus on relaxing when you get more fatigue in your body as you're doing longer intervals, there are many benefits of doing longer intervals as well. But now we are purely looking at one thing here. So we just said, okay, fine. Let's see how can we bring the VO2 max to the highest. We disregard everything else. We don't talk about necessarily about endurance,

fatigue resistance, all these kind of things that we just neglected for now.

So now you can think of it this way: What is it that causes us to bring up the oxygen? Why does it come up? Here I think it is useful to think of also what is the measurement method that we're using as well, very often to quantify this. We have to remember that this oxygen apparatus, when we are measuring oxygen consumption, we are not measuring what's happening inside the muscle. We are measuring what comes out in the exhaust here, and then we are quantifying VO2max as a function of that.

If we go into, so for example, if you do mitochondrial respiration, so if you take the mitochondria, so you do a biopsy, you take out now the mitochondria and you put it into chambers, specific chambers to measure now the mitochondrial respiration.

We are not talking about 90 milliliters per minute per kilogram anymore. Even for not well-trained athletes, you're already at 200 milliliters per minute per kilogram. We know that for elites, you're more than 300 to 500 milliliters per minute per kilogram if you go into what the mitochondria is capable of using of oxygen there. Just to make sure we understand that, Olav, what you're saying is we are never limited at the level of the mitochondria.

I would say statistically speaking, so if you're not talking about... I mean, not talking about people with mitochondrial disease, but if you're talking about you and me and your athletes and most of the people listening to this, when we ask the question, where is the rate limiting step in oxygen consumption or more to the point oxygen utilization, it is not at the mitochondria. It's not that we are unable to put more oxygen through the system at the final stage.

Point where it is needed for combustion. By the way, I've always thought it's at the level of stroke volume that it's actually at getting the plasma to the muscle. Is that what you believe?

Getting the oxygen, getting the hemoglobin transported to the cells is the most important thing, more or less. So it's more of a central limitation than a peripheral limitation we're talking about there. Because the periphery, if you look at it, for example, from a mitochondrial perspective, the ratio between what it can use is so extreme compared to what we are able to pump around.

Or take up in our lungs and pump around to the body compared to what we can use without touching into that. That actually goes also from when we look at it, for example, you mentioned that or my athletes are using a lot of carbohydrates for fueling and so on. We also know that basically the 60 to 90 grams per hour, that's not a limitation either. It's much, much, much higher than that.

How do we quantify this? We use isotope tracers. So we add isotope tracers to the carbohydrate. And then basically we similar concept as double label water, but here we add it actually to the carbon instead to look at the carbohydrate uptake. So we know that there's also as much higher. This is a lot of research that we have done with Morton, specifically on Christian and Gustav.

And we know that, again, if you do muscle biopsies, then we see basically that the carbohydrate is so much higher than what we are able to supply to our system. So again, it's... Sorry, meaning you're limited in what the gastrointestinal tract can tolerate, not at the substrate utilization in the mitochondria.

Exactly. Now I'm going to be very crude here. Put it this way. What brings us to VO2 max? It's not because we're thinking that we want to have a high VO2 max. Oh, now I want to. You can start to breathe. Increase your ventilation now as high as you want. Yes, you will increase your oxygen. Right, but you'll never get to your maximum level without sufficient work. You need work. Exactly. Not even close to it. You will bring it up because you're breathing more and you're working more when you're doing that. But then coming back to micro intervals and whether this is glycolytic or not, I

I think that if you go into the muscles and you measure in the muscles, you'll see that basically what happens there is that basically muscles are trying to use all, absolutely all, basically energy systems immediately, instantly. But because we have a lot of buffer mechanisms in our body, if the burst is short enough, then basically it won't show up.

as something here because you are basically just feeding it to our body. And then basically you have a long taper or let's say you will never get the spike in VO2, but you can see that you have an elevated VO2 consumption over a little bit longer time. If you measure longer, if you just measure during the interval, it won't show up on the exhaust because you take off the mask before it basically shows up there. But if you keep the mask on now and you keep it on there for, let's say, a couple of minutes after, you will see that now that basically you have an elevated oxygen consumption compared to before you did that interval there.

So basically, we can say that when you do a burst, it will use most likely all energy systems instantaneously, all of them as much as possible. If you say that, okay, now it's first we use stored ATPs, and then we shift to PCR, and then it becomes glycolytic, and then basically we go off to beta oxidation. I think the more correct way to view this, basically, the reason why you can have a high power output, short and high power output, is because you are able to supply from all the energy systems instantaneously.

But then you're depleting the different energies. Yeah, then all of a sudden the phosphorylated creatine comes down immediately and then the glycolytic and then yeah, yeah, yeah. Exactly. That makes sense.

Yeah. So now basically coming back then to micro intervals versus longer intervals, as long as you start to accumulate enough work during that session, because we also talk about VO2 and VCO2. VCO2 is really useful for getting an instantaneous picture of, of course, what kind of substrates are you using? And whether you are at an RIR value of, let's say, 0.8 or even, let's say, below 0.8, for example, but let's say that you are 0.8

or your 0.9 or your 1 in RR value, basically it doesn't make that much of a difference in your energy yield. So one milliliter of oxygen, if you use 20 joules of energy, 20 joules as a number to basically understand your energy demand there, you won't go very wrong whether you had been using. So if you put this into the formula and you start to look, okay, how much big of a difference it is there, it's not a massive difference. Yes, there is a difference, but it's not massive. So if you want to be accurate, obviously you want to do this.

But if you want to understand more of a fueling strategy perspective, then of course you need CO2 to better understand, okay, where are you, how are you using fuels at different times. But here also we have to remember now that when we go into a lab and we test there as well, this is a completely different picture than what it would be if you brought someone into the lab at the moment they went over the finish line in a race. Because now you would basically see that the velocity that they hold there at the end or the power they hold at the end there, even though maybe it's much lower, it's still...

very close to their VO2 max because basically they are not able. So the VO2 max, anything can come down. Yeah. So there's a missing time component into this very often when we look at research papers, when we talk about this, because we talk about it very often as a spot picture or something that happened in a fresh state, rested state or whatever. Yeah. Ideal states.

And then coming back to the question and to round that up, I think exactly that when you do micro intervals and so on, we talk about glycolyting and so on. Basically, you can use here also your heart rate as a gauge. If you start to see that when you do micro intervals and you're packing in, let's say that you did 310 watts and you were able to accumulate 30 minutes of that during that session there.

If you now do micro intervals, so let's say you're able now to bring it to 330 watts, for example, and you do 30 minutes of that. Maybe you're able to do 330 watts average and you even accumulated now, for example, 35 minutes of that. What you'll see there, because now it starts to become quite a lot of them there, is that most likely you'll see that you also have a very high heart rate and maybe equally high heart rate as you did when you did the five minute interval.

intervals unless you look at accumulated heart rate there. Because you can here also use heart rate as an indicator of how much time you have accumulated close to VO2 max. Because we know that one of the conditions that has to be met also for you to reach VO2 max is that you also are thinking then you need to pump a maximum amount of oxygen around in your body in order to do that. And we do know that that is a combination of a very, very high heart rate, close to maximum heart rate, and stroke volume as well.

So it's just occurred to me that I've got eight pages of notes here of things I want to talk about with you, and we are halfway through the first page. So clearly this is part one of many podcasts we're going to have to do together. Hopefully the next one will be in person. There are, however, a few things I want to discuss before we part today. We have yet to do kind of a more thorough discussion around lactate, and if I can only...

discuss one more thing with you for maybe another 15 to 30 minutes before we go. I'd like to do a little bit of a deep dive into lactate. Now for some background,

Since I kind of abandoned any athletic goals and the only thing I train for now is my health, right? It's for my longevity. It's for something I call the centenarian decathlon. So being as fit and strong as I can be in my 80s and 90s without necessarily worrying about what I'm doing today in terms of trying to maximize my performance today, I'm trying to maximize my performance tomorrow.

A very important part of my training, because my training volume is now so much lower than it used to be when I lived on a bike or lived in the water, I'm trying to be maximally efficient, which is always risky because sometimes you just have to put the miles in.

But what I do spend is about three hours a week in zone two. And again, there's so many different ways to describe zones. So I'm not doing this in terms of heart rate. I'm really defining this in terms of mitochondria. So zone two is my highest power output where my lactate stays below two millimole.

So this is very sustainable from an RPE perspective. It's RPE six to seven. I can talk, but I'm not comfortable talking, but I can talk. It's definitely below my one hour functional threshold power, but it's more challenging than that 200 Watts riding around in circles, having fun, trying to just purely focus on position.

And I do use my lactate. I do check my lactate constantly to make sure that I'm really hitting that spot. Now, what's the rationale for that? Well, the rationale for that is that 2 millimole is about the tipping point about which you can be in a steady state of producing lactate, clearing lactate. And once lactate starts to get into the 3 and 4 millimole range,

You wouldn't have indefinite access to that energy system. You're going to start accumulating so much hydrogen that at some point your physics of performance are going to be compromised. So let's now talk about this in terms of world-class athletes. So if you had a continuous lactate sensor on an Ironman in his seven hours and 30 minutes, give me a sense of what his lactate tracing looks like.

So this is where I differentiate between volumetric measurements and concentration metrics. Lactate is a concentration metric, so we don't measure the volume of lactate. And the plasma volume is decreasing as the athlete is running, so you would expect the lactate concentration to go up slightly, even if the production of lactate is constant.

Yeah. Also further here is that we have made some discoveries over the last years as well, which is when we start to do Ironman training, for example, which also are...

very different from a lot of the understanding that currently is there. There are some things there that are changing and we will definitely touch on this in, let's say, an upcoming podcast. But to give you the trace now, first of all, I think that two middle levels, when you have little time to train during a week, for me personally,

if for example you came to me and say hey olav i need some training advice for me longevity that's the most important for you or wellness but we can always say that well in the end it's about whether you have a high view to max really doesn't matter if you're not capable of moving very efficiently around just because you're wasting energy so we can say that for like universally maybe more universally it's about being able to move more per time like we said

the beginning even moving your head is movement it's just better we break it down to a global movement of the body or we break it down to basically say local movements of parts of our body but

But movement is actually the most important thing in the end here for all of us. If you came to me, I would very much look at, okay, most important thing would be to bring joy of exercising and sense of achievement into your training moving forward, because that's what's going to get you out in the day. That's what's going to get you out of the bed. If you look forward to exercising because you find it enjoyable, you'll do more of it.

That's the easier way to get you out and even where you would start to prioritize it over other things you are doing instead of pushing it always in front of you. And then finally, you get out and exercise because you know you should do exercising exactly to meet your expectations. So that would be the most important thing. But if we look away from that, the differences between riding also at one millimoles versus two millimoles...

As long as one millimole is more sustainable for you, let's say over months and years, because it brings more joy to you, it allows you to maybe be more present or let's say almost use it as a mindfulness session. If that becomes more sustainable, you can think about what you accumulate. Because we very often, again, this is a problem very often with research and many things, is that we give a spot picture of something. We look at something in one session or over a couple of sessions instead of actually looking at it over a lifespan or over a long period.

And then this is where I think exactly that we very often we undervalue the joy of exercising because we go out with an expectation that, okay, I have to go hard. I have to go all out and this kind of thing, which is very demanding and taxing on the body, especially if you're not prepared for this. I'll interject there that I can completely relate to that. And I've accepted that as a part of the transition in my life.

So there was a day, there were many days, there were many years where I had a belief system that said every single day, without exception, you must burn the pack of matches fully at least once. So it didn't matter what the workout was.

there was still an all out effort of about three to five minutes somewhere in the day that would probably when I measured it, I wouldn't always measure it, but it would take lactate into the 16 to 18 millimole range, like incredible pain. And truthfully, I can't do that anymore because I don't have the mental fortitude for that much suffering anymore. And,

I love to exercise. There's never a day that I don't want to, but I also don't have to look forward to that degree of suffering anymore. And I think that that's okay. That's the difference between being 50 and being 30. And I also don't think I need to suffer that much, certainly on a daily basis, maybe once in a while. But that said, I still really enjoy quantifying my training.

And I know that there are many people who don't. For example, most of my patients are absolutely not measuring their lactate levels during their cardio training. If 2% or 5% are, that would probably be accurate.

And for most people, it's what you say. It's what do I need to do to make you enjoy this and use your rate of perceived exertion as the guide tool. But look, I still have a little bit of a data person in me and I like using this metric to maximize the efficiency. And it's a great way for me to track my progress. Am I able to get watts higher and higher and higher while keeping heart rate and lactate

more or less the same. And so I'm just guessing that at your level, this must be a relatively important metric, right? I mean, in terms of, first of all, maybe just define for folks what a lactate threshold is. We haven't even talked about it. It's not something I particularly care about anymore, but talk about what a lactate threshold is, how it's measured. Do you guys even still do lactate performance curves?

Yeah, more as a function of other metrics that I collect. Lactate for me, again, is a concentration metric, is a marker of something. And for me, it's a marker more of substrate utilization, not an extremely accurate one, but it's a good one. So I would say that lactate for me is a way that allows me to collect. This is a redundant metric to other metrics as well, to basically be more precise in the way that I would prescribe or change even the training on a session.

So I would say that there are plenty of good surrogates or proxies that you can use instead to do the exact same thing without lactate. But if you're looking more, let's say, for example, you want to know better now, for example, your subsidization or have an idea of that, I would say even argue that you can't necessarily only do one measurement. You have to do a little bit of couple of, let's say, a little bit change in intensities, not much, but a small range there with a couple of measurements to get an idea because you're, let's say, call it your lactate

or your maximum lactate steady state concentration, for example, in a session can also vary based on, for example, dehydration. So for example, if you go out, you have one lactate concentration today, this might already change in two days time, for example. That's one. I mean, I'll tell you how we used to do it.

it and it was probably much cruder than what you would do, but we would do repeated intervals at descending pace. So ascending effort, descending pace. So if it was in the pool, we would swim, uh,

100s or 200s that change the pace. So you'd go out pretty easy for the first one, check the lactate, fully recover, repeat it, fully recover, repeat it, and you're getting faster and faster and faster. So then you make a graph. The X axis is the speed. We would note heart rate as well, but we would really focus on speed. And then the Y axis was the lactate concentration, and it becomes a power curve.

And again, this is very crude. So I can imagine that now the methods are much better, but you can eyeball them as sort of two separate linear curves and their intersection becomes the inflection point at which you go from kind of sustainable to unsustainable lactate production or nonlinear parabolic lactate production. And we would sort of say, look,

Let's just assume that that intersection occurred at 3.5 millimole concentration of lactate. And we would note what the pace was there. We would say to that athlete, you have to be mindful of exceeding that pace. Now, this speaks to everything you just said. I mean, that pace is going to change depending on your hydration, depending on your energy reserves.

depending on your fatigue. So of course it's crude, but directionally that's what we thought about as you have to be very careful every time you exceed that pace in a race because you're now tapping into a very finite reserve.

Is that kind of how you still do it, albeit probably with much more accuracy? What I really like with what you say is, one, you talk about the infliction point, because this is very misunderstood. Some people still today go by fixed blood lactate accumulation values or concentration values.

So they stick, for example, to four millimoles or something like this. And okay, if you're going to publish a paper and you want it to be able to compare with other papers that are out there, that's fine. But already here, the problem with that is that four millimoles can be accumulated in a whole range of different ways.

you can go just above your second infliction point or just above maximum like this state and then you creep up towards four millimoles meaning that now you have to have a smaller power output in order to get there or you can go with a very high power output and it will take a short time for you to reach that four millimoles there so how do you know go backwards and say that okay well four millimoles should call it to this power

It's highly dependent on the protocol that you're doing there already. The way that you described that you basically said it is something I would say that this is fine because the two most important thing, if you want to use it as a way to control your intensity, so you want to, let's say, a different way of controlling intensity as opposed to, for example, heart rate or other things. And we know, of course, again, heart rate, again, also influenced by hydrations and other stressors and other things as well.

So when you are using lactate now, one, I like the way that you describe it. You talk about the infliction points perfectly and make it as simple as you said as well. Depending on how long your protocol is now, you can draw three lines. You're looking at basically drawing one line that goes through the flat section of your profile more or less of the lactate. Then you get one that goes more on, let's say, on the liner increase. For every step you increase in pace, then basically you also see there's an increase in lactate. But at some point you see there's a complete decrease.

departure between increase in pace and lactate and it goes very hard up yeah almost vertical yeah yeah so this is where you could say that also then talking back to for example metabolism you could say that the first infliction point is not too far off where normally where you would see your fat maxis and the second one is typically where you would see your maximum lactate steady state is more or less and some people i think in the nomenclature call that lt1 lt2

Yes, we use that very much. I like to be specific in this sense, because when you talk about LT and LT2, then you already have distinguished it away from, for example, MLSS. A fixed one. Yeah, yeah. Yeah, because if you talk about MLSS, this actually normally requires you to do a very specific profile. So you would do, for example, longer intervals. So you could, for example, do 30 minute or 20 minute intervals.

rolling effort, for example, and you're looking at lactate as a function of, let's say, every five minutes to see whether the lactate value is stable or whether it starts to increase. So maximum lactate steady state is basically what it says in the names is the highest lactate value that you're able to sustain steady state. If you go now

a little bit higher in effort or in intensity, or let's say you are accumulating a little bit more fatigue, then basically you already start to see that now lactate is not stable anymore. For the same power output, it will actually start to see that lactate starts to accumulate up, going upwards. So it's not steady state anymore.

And what capacity or duration is built into that assumption of LT2? Because again, LT2 cannot be sustained indefinitely. So there's some point at which it ceases to be a true steady state. What does that look like in an athlete?

So this, again, depends a little bit because at maximum active steady state, depending on how powerful the athlete is, and here is also a misconception. A lot of people think that maximum active steady state is the equivalent of RR value of one. This is not correct. Not at all. Yep. So one thing you very often see is that for actually this is something that we discovered.

with our athletes through different when we went Ironman and when we went Olympic racing so short long and other athletes as well and that is what you see is that the maximum relative steady state typically occurs at a lower RAR value depending on the distance you're doing so the longer the distance you do you'll actually find that that sits at the lower RAR value it is logical if you look at it

From a physics perspective, or let's say you're talking about stationary action principle, for example, or thermodynamics, then basically how do you supply the bodies with the most sustainable energy, the simplest possible way? Yeah, it comes back to that.

At an Olympic distance, are they able to hold LT2 for the whole race? Whereas at the Ironman, are they well below LT2 and closer to LT1? The problem with very powerful athletes is that already, because now this is the problem where lactate comes in, because lactate only looks at concentration. It doesn't look at volume. So the problem is that the LT1 will already occur. So very high utilization of VO2 max for an Ironman athlete.

How high? Just give us a sense. Well, I have to sit down now because now it's more than a year ago since we did the argument. Roughly speaking, I would say that it sits in at around close to 80% of VO2 max. That's right. So if the VO2 max is six liters per minute, at 80% of that, at 4.8 liters per minute, they're at about LT1.

Yeah. And that you already do know that that's not sustainable because you're already now turning around so much carbs per hour that this doesn't work anymore. So you have to go eat. Hang on, hang on. It depends a little bit on the RER, right? Because you're now at maximum fat oxidation. Yes. And so what are your athletes? Now your athletes have one thing working for them and one thing working against them.

The thing that they have working for them is they have the healthiest mitochondria on the planet. But the thing they have working against them is they're on a very high carbohydrate diet. And I'm saying for and against them in terms of fuel utilization. So they actually have the capacity for insane fat oxidation, but their system is tuned towards a faster fuel, not a more energy dense fuel. So let me guess, would they hit 0.8?

Eight grams per minute of fat ox. Are they getting that high? Put it this way. We have had blocks where we just have been looking at how high we can get them in fat ox and this extreme high, but I have to go back. You're probably getting close to one gram per minute then. No, even higher. Okay. And that's on a high carb diet. Yeah. It's absurd to me that we are out of time here. And if it weren't for the fact that I had a hundred patient calls today that I can't just cancel, we would just continue to do this.

So we have officially covered two thirds of one page out of eight pages. We have not yet talked about what I want to discuss around muscle biopsies. We have not talked about getting into anaerobic threshold, a term that I don't pay any attention to, but I think we should talk about. We haven't talked about the use of temperature probes and understanding the effect of cooling during both competition and training. We haven't talked about heart rate, heart rate variability, training, desire, performance and recovery.

We have not talked about some questions I have about the use of PEDs and why they don't seem as prevalent in triathlon as they do in other endurance sports. I could go on and on. That's just finishing what's on the first page. I wanted to really get into MCT density. I wanted to talk about too many things for me to even rattle off now. So you said you're going to be in the US at some point. I hope we could do round two of this in person.

Would be fantastic. All right. Yeah, this has been really cool for me as well. I want to say also one final thing here. We, of course, we talk very much about terminology and how we see things and so on. One thing that is important for me to be very clear on is that

Terminology is one thing, but we have to remember also that people might use these terminologies also differently as well. And as long as a coach and an athlete, for example, have an understanding of something and that works for them, don't get discouraged or don't start quarreling over definitions and these kind of things. Because the most important thing is exactly that you have a language and it does work for you. And that's most important. People like us come and hammer them with a lot of terminologies and a lot of definitions.

They obviously have gotten something right and it's important to have respect for that. And it's also a lot of things that we don't know. There's a reason why we are continuing to do all this research as well, because we are so curious. We want to understand more and we understand that there's so much still to discover as well about everything we even covered now during this call. Well, thank you, Olaf. That was really wonderful. I very much look forward to round two. The same. Thank you so much.

Thank you for listening to this week's episode of The Drive. It's extremely important to me to provide all of this content without relying on paid ads. To do this, our work is made entirely possible by our members. And in return, we offer exclusive member-only content and benefits above and beyond what is available for free. So if you want to take your knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of the subscription.

Premium membership includes several benefits. First, comprehensive podcast show notes that detail every topic, paper, person, and thing that we discuss in each episode. And the word on the street is nobody's show notes rival ours.

Second, monthly Ask Me Anything or AMA episodes. These episodes are comprised of detailed responses to subscriber questions, typically focused on a single topic and are designed to offer a great deal of clarity and detail on topics of special interest to our members. You'll also get access to the show notes for these episodes, of course.

Third, delivery of our premium newsletter, which is put together by our dedicated team of research analysts. This newsletter covers a wide range of topics related to longevity and provides much more detail than our free weekly newsletter. Fourth, access to our private podcast feed that provides you with access to every episode, including AMA's sans the spiel you're listening to now and in your regular podcast feed.

Fifth, the Qualies, an additional member-only podcast we put together that serves as a highlight reel featuring the best excerpts from previous episodes of The Drive. This is a great way to catch up on previous episodes without having to go back and listen to each one of them. And finally, other benefits that are added along the way. If you want to learn more and access these member-only benefits, you can head over to peteratiamd.com forward slash subscribe.

You can also find me on YouTube, Instagram, and Twitter, all with the handle PeterAttiaMD. You can also leave us a review on Apple Podcasts or whatever podcast player you use. This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional healthcare services, including the giving of medical advice. No doctor-patient relationship is formed.

The use of this information and the materials linked to this podcast is at the user's own risk. The content on this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice from any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions.

Finally, I take all conflicts of interest very seriously. For all of my disclosures and the companies I invest in or advise, please visit peteratiamd.com forward slash about where I keep an up-to-date and active list of all disclosures.