Why does my skin wrinkle in water?

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After a hard day at work, a bath feels pretty great. Taking a long soak in the tub with some peace and quiet can do wonders to help you relax. It’s so easy to lose track of time while you’re in there, though, and once you jump out, you might be surprised by what you see. We’re talking specifically about your fingers and toes here – do they ever look wrinkled? A nice half hour unwinding in the bathtub suddenly ages your body several decades, and you might not be sure why. If you’re feeling pretty mystified, listen to this.

Autonomic nervous system at work

The reason your fingers and toes start to look like prunes is due to the narrowing of blood vessels, a process that is caused by your autonomic nervous system. Don’t know what that is? It’s a pretty influential system in your body that, among other things, regulates breathing and keeps your heart beating without you having to do anything. Essentially, it keeps you alive.

It also helps you grip things, too. That’s why parts of your body start to shrivel up when exposed to water for so long. When they’re wrinkled like this, it’s easier for water to drain away because it just flows through the grooves created in your skin. It’s the same reason why things like tires have treads and aren’t just a smooth surface – grip is important.

The significance of grip

It might not make much sense for your fingers to need better grip when you’re just chilling in the tub, but that’s because your bathroom isn’t the right environment. We have the luxury of buying food from the store these days, but our ancient ancestors weren’t so fortunate. Once upon a time, they had to catch and kill their food, and there’s a good chance that some of the animals they hunted were fish.

Have you ever tried to catch a fish? It’s not easy, but our bodies have at least evolved to give us a bit of a leg up in that area. The wrinkling of our fingers makes it easier to grab hold of them, and better navigate through wet environments. They also make it easier to climb trees that are wet, because our fingers have more grip on the slippery bark. The same goes for toes too – our ancient ancestors didn’t have shoes, after all. While these qualities may seem useless to us now, they could have meant the difference between survival and starvation all those years ago.

How do we know?

It’s all well and good making these assertions, but how do we know for sure? Well, the honest answer is that we don’t, because none of us existed back them (obviously). Scientists can only make assumptions, albeit strong ones, on what they understand about the human body and evolution. While they might not be 100% certain, though, they did test their theory to see if it made any sense. They asked participants to pick up wet and dry marbles, with one group attempting to do so with shriveled fingers. It was this collection of people that were able to complete the task quickest, because they had a better grip on the wet marbles.

There’s still so much we don’t understand about ourselves, no matter how hard scientists work to learn what they can about the world. We reckon that this theory is pretty sound, but maybe there’s another reason our bodies wrinkle in water. Perhaps it’s just a warning that too much time in the tub will age us prematurely.

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