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cover of episode Recap: Is the new obesity medication too good to be true? | Dr. Louis J Aronne

Recap: Is the new obesity medication too good to be true? | Dr. Louis J Aronne

2025/7/1
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ZOE Science & Nutrition

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Dr. Brad Schoenfeld: 随着年龄的增长,肌肉萎缩会导致功能独立性丧失,增加跌倒和骨折的风险,甚至可能导致死亡。肌肉萎缩不仅影响身体功能,还会对心理产生负面影响,降低生活质量。此外,肌肉萎缩还会影响血糖调节和骨骼健康,增加患糖尿病和骨质疏松的风险。因此,保持肌肉健康对于维持晚年生活质量至关重要。与年龄相关的肌肉流失并非不可避免,而力量训练是关键。通过持续进行有挑战性的力量训练,人们不仅可以延缓肌肉萎缩的发生,还可以保持甚至增加肌肉量,即使在60、70甚至80多岁时,肌肉量也可能超过20岁时。力量训练是指肌肉对抗一定阻力的活动,可以通过举重、体重锻炼、弹力带等方式进行。力量训练通过将机械力转化为化学信号,促进蛋白质合成,从而增加肌肉。即使时间有限,也应专注于推、拉和髋部铰链运动。只要尽力,用轻重量进行多次重复也能达到与用重重量进行少次重复相似的肌肉生长效果。对于有关节活动问题或其他损伤的人,轻负荷训练是一个可行的替代方案。

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This chapter explores the importance of resistance training in maintaining muscle mass and functional independence as we age, dispelling the myth that age-related muscle loss is inevitable. It introduces sarcopenia as a diagnosed medical condition and highlights the benefits of resistance training, even for those in their 70s and 80s.
  • Muscle loss leads to functional dependence and increased risk of falls and mortality.
  • Resistance training, including bodyweight exercises, can prevent sarcopenia and maintain muscle mass.
  • Studies show significant strength and muscle growth increases in individuals 75+ after 8-12 weeks of resistance training.

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Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're talking about resistance training. When we think of exercising in our 70s and 80s, we often focus on gentle activities like walking, swimming some lengths in a pool. However, are we overlooking a crucial part of the fitness puzzle? Something that could truly transform our later years? Strength training.

Because as we age, muscle loss isn't just about losing tone. It's about losing independence. Dr. Brad Schoenfeld joins me to share how resistance training can preserve strength, improve ability, and support a long and active life. Whether you've got five minutes or 50, he'll show you how to get started. No gym membership required.

When muscles begin to shrink and they get weaker, you do not have sufficient strength to carry out basic tasks. And then you lose your functional independence, which is the primary reason that most people go into nursing homes to care facilities as they age. It also can lead to falls, hip fractures, which often are fatal over time. That mortality in those elderly individuals who undergo falls is significant.

close to 50% over a period of a couple of years. The functional disabilities, of course, are far-reaching as far as people's ability to carry out activities on their own, which not only is really bad as far as their ability to engage in life, but it's also demoralizing mentally. There's aspects far beyond that that also are important. Muscles store glucose.

So glucose, of course, is stored in muscles as a glycogen. If your muscles start to shrink, you have less ability to store glucose. That tends to lead to diabetes. Also, the functionality of the muscle themselves in terms of their

insulin receptors, their ability to get glucose into the muscles was not just the size and their ability to store a certain amount of glucose, but it's their ability to take in the glucose. And by the way, you mentioned earlier, also by pulling on the bones, they help to strengthen bones or when they weaken, they facilitate the decrease in bone density. So there's just really all organ systems kind of

can be affected by muscle. I mean, I guess I really want to follow up on that first part, because I guess for many people listening to this, this idea about having freedom for as long as possible and having good health for as long as possible is really central. And I grew up just basically sort of saying like, as you get old, you know, you get wrinkly and you get weak and you stop being able to do things. And that's just how it is. And this is going to happen to you anyway. To what extent is that

true as far as your muscles are concerned? And is there anything that you can do now when you might be in your 40s or your 50s or your 60s or whatever that is going to affect that loss of muscles that is having this effect on losing freedom as you get older?

Yeah. So the age-related loss of muscle is called sarcopenia. It's actually now a diagnosed medical condition. And it is not inevitable that resistance training is really the key. Now, certainly other activities can help in that regard, depending upon what they are. But ultimately, resistance training, which

can be defined as the activities that promote muscle working against a given force. And that can be accomplished through lifting weights, as often thought of as the most common exercise.

But I mean, it can be body weight exercise, can push ups, body weight squats can be forms of resistance training. You can use bands, resistance bands. You can use cable machines and other types of units. So and it can be integrated. I mean, there's yoga that involves resistance where they do various exercises.

So anything where your body, your muscles are working against a given force. And to answer your question then, if you engage in resistance training that substantially challenges the muscles over time, you can not only stave off sarcopenia, but you can maintain more muscle. There's certainly people in their 60s, 70s, and even 80s that have more muscle than they had when they were 20, when they started resistance training later in life.

and that have more muscle than 20-year-olds do at a given age. So I would say that the key, in my humble opinion, to staving off sarcopenia is resistance training. Well, I love that. It's really positive, right? Because I think often in this area, everything's very depressing about the idea there's nothing you're going to do. You're going to get older. You're going to lose everything. And I think...

what you're saying is actually there's a lot you could do and it's not too late, right? If you didn't do any exercise in your 20s, you're saying it's not, oh, that's too bad. I love this idea of being in my 60s or 70s and having more muscles than I had in my 20s. There's...

I just want to interrupt and say there is research. We actually carried out a meta-analysis on the oldest of old, which were people 75 years and older who were sedentary and given resistance training. And a meta-analysis is a pooling of all the studies on the topic. There was marked increases in strength, and we see hypertrophy increases in muscle growth differences.

And these are short periods of time, by the way. We're talking 8 to 12 weeks. Again, 75 plus. So these are minimum 75 years old. Could you explain a little bit, because I think we sort of jumped over a little bit, this link between...

doing this resistance training and preventing your muscles shrinking? Why does that happen? How does these two things fit together? - When you resistance train, so you're applying force to the muscles,

the forces that you're applying to the muscles are converted into chemical signals. These chemical signals carry out protein synthesis. They create more protein to the body to produce more muscle proteins, which give you larger muscles. When you are resistance training,

at an intense level, you are challenging the muscles to a greater extent than when you are walking. So will walking be better than lying down all day? Of course. So if you're just lying down all day, if you're bedridden and then you get up and walk around, that will help to build some muscle.

but it's going to be very minimal. The body only builds muscle to the extent that it's challenged. To achieve greater muscle, you have to provide a greater stimulus to it. All the body cares about is survival. So

So maintaining muscle is energetically expensive, and we are still living in the bodies of our paleolithic ancestors. So the body doesn't realize that we can just go out for food whenever we want, et cetera, and it tries to be resourceful. So to maintain muscle will be energetically expensive, which would have a negative survival impact when you are scavenging food in the historic days. Yeah.

So to bring this back home, when you're lying down all day, let's say you're just not doing anything, you're very inactive, the body realizes it doesn't need this or thinks it doesn't need this extra muscle and it's energetically taxing to keep it. So why bother? Why would we need to maintain it if we're not going to be using it? That is the use it or lose it principle. When you're lifting weights that challenge the body because you're

you might want to talk about, you don't necessarily need to lift heavy weights. But when you're lifting weights that ultimately become challenging, the body realizes that or thinks that it needs to be able to maintain muscle to carry out these activities for survival.

And again, everything revolves around what the body is perceiving as its survival needs. So imagine that someone says to you, I have literally 15 minutes in my individual session to exercise, Brad. I've done some exercise before, so it's not the first time I've ever done it, but I've only got 15 minutes that I'm going to do. What would you...

what we should tell, and I understand that it's different between people, but what would be the basis of what you'd be telling them to do? Let's say they're at home. If time is a barrier, focus on pressing and rowing type movements or pulling movements, which can generally be a row. Those are the common movement patterns. And then what is called a hip hinge for the lower body. So there are three basic movement patterns.

So a press, and generally you'd want to do a press for the chest area and a press for the shoulders. So there's two pressing movements. Generally want to do two pulling movements, which can be rowing type movements. So if you have access to like a lat pulldown in the gym, that's another pulling movement. And then your hip hinge type movements like squats. You could do a leg press as a hip hinge movement, which is a machine-based movement.

Squats and lunges can require a lot of balance and coordination. And for people just starting out, certainly older people can have issues with that. 15 minutes isn't a lot of time, but you could do, let's say, focus one day on your

squat and a chest press. The next time you come in, you do a lunge and another movement. A bit like the same thing you said about actually how little time you need to do to really make a difference. Again, you're not describing an incredibly complex

set of 25 different exercises you have to do in order to get any benefit. You're saying that these core exercises is working out quite a lot of different muscles. And so this, again, there's a sort of an achievable first step for people that doesn't involve the same complexity maybe of being able to participate in a sport. Correct.

I'd love to talk about the weight that's involved because this is something that I hear so many different people say different things, including that unless you're using a very heavy weight and pushing yourself at the extreme, then none of this really matters. And I think for a lot of people, that's a bit scary or they're worried about injuries

I know, again, this is something that you've studied. What is the way to think about the weights that you're using in terms of getting these benefits? Yeah, so this is something that's been very eye-opening to me and it goes against what, when I was an up-and-coming exercise science student, that we'd been taught. But you can use relatively very light weights that you can lift, let's say, 30 or 40 times

and achieve similar muscle growth as you would lifting five to eight times, so a heavy weight that you're lifting five to eight times, provided that you are lifting with a high degree of effort, that you are, the last few repetitions are challenging to complete.

Now, that said, from a strength standpoint, you do get somewhat better strength gains with the heavier load. But even that, the difference between the strength is not anywhere near what people generally would think. So I would say that, yes, if your goal is to maximize strength, some heavier loading is needed.

But for most people, I think they will get the functional transfer of strength from the light loads that would be sufficient to carry out their activities of daily living.

that it's not going to substantially compromise their, number one, their ability to do their functional tasks and really to have any meaningful effect on their lives. So just to make sure I've got that, I think you're saying it doesn't really matter how heavy the weight is, provided that you're doing the exercise often enough that it starts to get

like hard. If you're above, let's say, 40 repetitions, then, which is a lot. I mean, if you're lifting 40 repetitions, that's almost a two-minute set. The set's going to be just, it's going to start to become a cardiovascular endeavor. So again, when you're

Most people would get very bored doing weight slide in that. But we're talking very light loads that you just keep lifting. Yeah, the last few repetitions, as long as you are challenging the muscles to the point where it becomes very difficult to lift on the last few repetitions,

the gains are relatively similar, certainly for hypertrophy. They're going to be almost identical. That's really interesting. I've said a personal level, I think I always find it easier when it's quite heavy, since I don't really like doing anything that's hard. So if it's heavy, that it's hard for a short period of time, whereas it's a bit less heavy, it's still quite hard for longer. And I don't know whether this is just me, but I personally feel like actually it's

It's easier to do something that's really heavy a few times than something that's quite heavy a lot of times. I don't know if that even makes any sense as I describe it to you, Brad.

Yeah, I wouldn't use the term easier, but it is less onerous. It is less onerous because like you said, both of them are going to produce discomfort, but you're just having a discomfort for a shorter period of time. And what I would say is the discomfort with lighter loads comes from what's called acidosis.

So that's a buildup of acids within the muscles. And then you get a real intense burn where you don't, to the same extent with the heavier loads. But that said, a lot of people, particularly as people age, do not have the ability to tolerate heavy loads, their joints. So they develop osteoarthritis and other joint related conditions, which can impair their ability to use heavier loads.

And in that case, Rider-Roads is an option. We had a lot of questions from our community about people saying, "I've got joint mobility issues or some other sort of injuries, disabilities. And does that mean that therefore I can't do any of this strength? Because I don't think I could lift some really big heavy weight." Using Rider-Roads becomes a viable alternative.

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