Deep Dive
Shownotes Transcript
From the brains behind Brains On, this is the Moment of Um. Moment of Um comes to you from APM Studios. I'm Molly Bloom. Um.
Growing up, I remember being around the same height as all the other kids. I could easily give them high fives, look them right in the eye, look out into the world and see the same objects they did. But then something weird happened. They kept getting taller and taller, but I sort of slowed down while they seemed to speed up. As a full grown up, I stand at five foot one inches tall. Some may call that short, but I call it just right.
It does have me wondering, though, how do our bodies decide when they're done growing? Why don't we just grow taller and taller? If anything, we seem to shrink a bit over time. Listener Amelia was thinking about all of this, and now I'm thinking about all of this. Hi, my name's Amelia, and I'm from Bothell, Washington. And my question is, why do we stop growing taller at some point in our lives?
Shrinking is probably a little easier to explain because you actually lose bone mineral mass over time. So as you start out life, the amount of calcium in your bones gradually increases until you're about 25. And then when you're about 35, you start losing about 1% of the calcium every year. And those bones get weaker. And so gravity exerts their force on them and they collapse a little bit. Not a big time collapse, but just a little bit.
This is Frank Rehm. I'm an infectious diseases physician at Lina Health. So the question about why you stop growing is actually a much more difficult question. It really goes back to evolution. Each creature, each species has to exploit a particular environment to get energy and to avoid predators. And
For each niche that different species live in, there turns out to be an optimal size. And evolution pushes you toward that size. So if you're in the business of being an elephant in Africa, you survive by being so big that the lions and the tigers and the cheetahs can't get you. And so the evolutionary pressure on animals
animals that eat vegetables, vegetarians as they were, the evolutionary pressure is either toward fast or toward big. So if you're a Cape buffalo, if you're a giraffe, if you're a rhino, if you're an elephant, the pressure is on you to get big. If you're an eland or an antelope, the pressure on you is to be fast. And so those creatures are very slight but very fast. So there's an optimal size for
for whatever niche you live in that evolution pushes you toward. So if you're a worm, you're eating decaying vegetation in the soil. Not very wise to be an elephant because it's a little hard to crawl through the soil when you're an elephant.
So now how it is that your body, as you grow up, produces that optimal size is something beyond my understanding. So our genes are very clever at getting us to be where they want us to be. Exactly how that happens, I've got to say, I don't know.
So even though we're not sure why we are the heights that we are, I can rest assured that evolution has put me at my optimal size. Hey, you want to hear a fun fact? The tallest person in the world was Robert Wadlow. He was 8 feet 11.1 inches tall. He had an enlarged pituitary gland, which is the part of the body responsible for dictating how much growth hormone a human has.
He died in 1940, but you can visit a life-size statue of him in his hometown of Elton, Illinois. If you like this episode, take a second to subscribe wherever you listen to podcasts. And if you want to get a bigger brain emoji but don't have time to read book emojis and just love putting on headphone emojis because it makes you smiley face emoji, check out the Forever Ago podcast where we have a whole episode all about, you guessed it, emojis.
If you have a moment of um question, we would love to help you answer it. Drop us a line by going to brainson.org slash contact. See you next time and the next day and every weekday. Until then, um. Hey, friends. Molly, Sandin, and Mark here with some very big news. Drumroll, please. Drumroll.
We're hitting the road in search of adventure, fresh air, and you. That's right. We're going to be live at the Boulder Theater in Boulder, Colorado on Sunday, April 27th. Our science-themed live stage show takes the audience on an adventure through the brain, complete with magic tricks, dance moves, out-of-body experiences, mystery sounds, and a game show. Molly, you almost left out the most important part.
Yeah, Molly, don't forget the big party. Oh, right. After the shows, we're throwing a brain-tastic bash. Join us afterward for a VIP party where we'll play games, guess mystery sounds, pose for photos, and give as many high fives as humanly possible. Snag a spot by purchasing a VIP pass when you buy your show ticket. Oh, that reminds me. I've got to start training. These hands aren't going to high five by themselves. Five and five. Good idea.
And remember, spots are limited, so grab your tickets today at brainson.org slash events.