That Neuroscience Guy - The Neuroscience of ... Wearing Less Clothes?

Episode Date: June 16, 2023

As humans have evolved, we have relied more and more on clothing. From long sleeve shirts to thick-soled shoes, the modern human is very dependent on clothes. But what if that isn't good for us? In today's episode of That Neuroscience Guy, we discuss the neuroscience behind clothing coverage, and how more sensory exposure can help our brains. 

Hi, my name is Olof Kregolsen and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. I was having a really interesting conversation with a colleague of mine the other day. His name is Dr. Paul Zare. In fact, you might have even heard of Paul. He wrote a book called Becoming Batman. It's an excellent book. It's all about what you would have to do to actually become Batman. Now, not the part where you're a millionaire and have all the gadgets, but more just physically what you have to do. And if you're interested in superheroes, check him out because he's written books about Iron Man and about Captain America. And it's all about the science behind these

superheroes. But that's not actually what we're talking about. What we're talking about is a really interesting concept. From an evolutionary perspective, a long time ago, we ran around essentially naked. And one of the advantages to this is the sensory receptors in our body were exposed to the environment. Now, what do I mean by that? If you just look at your hand right now, what's underneath the skin of your hand? Well, you know there's bone and there's muscle, but there's also tons of sensory receptors. There are touch receptors. So if you touch your hand, you feel that stimulus. You know, you can feel that you've touched it. And if you touch somewhere else on your hand, you can detect that. And we actually call it the size of the receptive field.

If you get really interested in this stuff, you can take a pin and you can gently explore the receptive field. And what you should find is that if you gently touch yourself with a pin, you can probably detect something that's about half a millimeter apart, maybe a bit less. But if you went to your shoulder, for instance, and tried this, you'd find that the size of the receptive field is bigger. And that's just because we don't have as many sensory receptors on our shoulder as we do in our hand. But we also have pain receptors and we have cold receptors and heat receptors. And all of this sensory information is brought into the brain. It goes up through the spinal cord and ends up in the primary sensory cortex, which we've talked about before. But why is this important and what were we thinking? Well, like I said, from an evolutionary perspective, for the vast majority of

the human span of time on this planet, we have been exposed to the world. All of these sensory receptors were giving us information. But what have we done in the more recent past? And I mean in the last couple thousand years. Well, what we've done is we've covered it up. All right. We wear clothes that cover up our arms and our legs, and we wear shoes that protect our feet from the world. Now let's just think about the clothing issue. If you are wearing a long sleeve shirt, all of that sensory information that your body would be receiving is covered up. You don't get it. Your brain's getting less information about the world. Now this is very subtle information. All right. This is literally, imagine if you're going for a walk or a run, you're getting just,

you know, literally the wind that goes by as you move your arms. But you're getting information about heat as well and cold and other things. And your brain can use this information to optimize performance. All right. So your brain literally adjusts how your body performs when it's got more information. Now, why does this matter? Well, I guess if you're talking Olympic records, maybe it matters a lot, but your body needs that information. It's using it to move better and we're taking it away. And I've actually been playing around with this since we chatted. You know, I've been varying out what I wear on my morning walk, you know, from wearing a pair of short running shorts and a very minimal tank top to wearing a long sleeve shirt and track pants. And you can notice a difference. I dare you to try it yourself.

In fact, you know, you could imagine clothes that are designed to let that sensory information in, as opposed to blocking it out. Now there's some environments where we need to cover up. You know, if you're going to go hiking in Northern Canada in the winter, you obviously don't want to wear a pair of running shorts and a singlet because you'll freeze to death. But there are a lot of situations where we need that sensory information. Now, what does that sensory information actually do? Well, it adjusts for at a low level, the reflex system in your body. So the way our bodies work is we have a reflex system and that reflex system basically helps us control movement.

All right. So you can imagine neurons firing that are literally adjusting how the muscles are functioning. And those muscle, those neurons that fire, those reflexes that control the muscle tension and the joint tension and how well things move, well, they rely heavily on sensory information to do this. And if you cover it all up, guess what? You don't have the information to make those fine adjustments. Now, of course, you can still move. We're talking about the difference between optimal performance and acceptable performance.

It's not like you put on a pair of sweatpants and all of a sudden you can't walk. All right, I'm not saying that, but these things do help you move. Now, you can go a step further than this, and I mentioned feet. Well, the feet are particularly interesting because you have almost as many sensory receptors on the bottom of your feet as you do on your hands. And obviously with your hands, all right, you have tons of dexterity. You can sense different things. You know, if you run your fingers across sandpaper as opposed to across, you know, something very soft, you can feel that difference. Well, the same is true for your feet. All right. Your feet are incredibly sensitive.

Try walking around barefoot for a bit, even outside. It's going to feel a bit weird because our feet are being desensitized because we cover them up. But you actually get more sensory information in bare feet than you do with your shoes covered up. And guess what? It helps you walk better. I actually have a particularly bad right ankle. I'm actually waiting for surgery, years of playing basketball and not listening to physiotherapists. But when I wear shoes that have a lot of cushion in them, I actually have more problems with my ankle because I don't get sensory information about the position of my foot as well as when I'm barefoot.

So I actually walk better when I'm barefoot. And why is that? It's because all of that sensory information is coming up through my feet. All right. And I can use that to adjust the muscles and those reflexes I talked about. So you adjust the reflexes that allows you more fine control of your muscles and you walk more efficiently. Now, am I promoting a world where we walk around bare feet? Well, yes and no. The problem with walking bare feet, of course, is there might be glass on the ground or it's incredibly uncomfortable. You know, there's lots of environments where it doesn't work, but there are solutions. You know, there are minimal, minimalist shoes they're called. You know, there's various companies like Nike or Vibram that make shoes that are designed to

give you a bit more sensory information. I wear a pair of five finger Vibrams, those kind of funny shoes that have got the toes in them. And what's interesting when you wear them is they are incredibly uncomfortable in the sense that you feel everything. Like, you know, if you step on a small rock, you feel it, but you get used to it pretty quickly. And what you realize is you're actually, you're walking more efficiently. And if you're interested in this, there's a book called Born to Run. It's actually a sort of based on a running perspective but it talks about this idea but the whole idea is increasing the sensory information now just to be clear i'm not promoting running barefoot

or running in five finger vibrams in fact when the five finger vibrams came out a bunch of people tried running in them and very quickly developed knee problems and hip problems and ankle problems and ankle problems. And that's because people just weren't used to it. If you're used to all the cushioning in a modern running shoe and you try running with these five-finger shoes, well, it's a problem. Okay, you do do jam into your joints. But you can walk in them, all right? You have to get used to them.

So when I first got mine, I walked a little bit and then I walked more and then I walked more. And if you don't want to switch to five-finger Vibrams, I own no shares in the company, so I'm not promoting them that way. But I just encourage you to try that. Try walking around your house, even just barefoot, and then wear a pair of shoes with a very thick sole

and just notice the difference in the sensation and notice the difference in gait. And in fact, you know, I do a lot of hiking as well, living in Canada, it just seems to be part of the package, but when, and I've got a really great pair of Solomon hiking boots, but when you're in those boots, yes, they protect your ankles, but you also have less sensation to the ground, which is kind of counterintuitive, right? Because if you put your foot down on a rock and your ankle starts to roll, well, great that you've got that boot to protect your ankle.

But because you're not getting the sensory information, you're more likely for that to happen. However, if you did that barefoot, it would be an ouch. But you probably wouldn't roll your ankle because you're getting sensory information and those reflexes can react more efficiently. So hopefully you found that interesting. You know, is this the take home message is, is that just think about what we've done. We live in a world where

we've taken away most of the sensory information our body gets, you know, our faces exposed, our hands are exposed, and that's really about it. You know, in the summer, in the Northern hemisphere, moving to summer, we wear running shorts and t-shirts and swimsuits and flip-flops. So we're getting more sensory information, but a lot of our lives, we're removing all that sensory information. And the net message from that is that your body is moving less efficiently and you're less able to detect the world around you. Anyway, that's a little, a random thought that came from a conversation on Paul Zaheer's fishing boat. And I hope you found that interesting. Anyway, don't forget, the website's up, of course, thatneuroscienceguy.com. There's links to

Patreon where you can support the podcast. All the money that's donated goes to graduate students in the Kregolson Lab. Of course, there is also links to our Etsy store where you can buy some merch. I keep promising new t-shirt designs. I promise we're thinking about it and getting there. But of course, if you have ideas for merch or something that would be funny or cool in terms of neuroscience, you can follow me on Twitter at that Neurosci guy and DM me. And of course, DM me ideas about show ideas. Most of the season that we're currently

in is all ideas from you. We want to know what you want to know about the neuroscience of daily life. And last of all, thank you for listening to the podcast and subscribing. It means so much to us. My name is Olaf Kregolsen and I'm that neuroscience guy. I'll see you soon for another neuroscience bite.