You're listening to Shortwave from NPR.

It's July and here in Washington, DC that means hot, sweaty, sticky days.

Sarah Evers, here's complaints about sweaty summers a lot.

She's the author of the new book The Joy of Sweat.

I've always kind of worried that I might sweat a little bit too much or sweat more than

average and you know I think that that's something that a lot of people feel.

And me too. Right. And as a science journalist I just kind of thought, well hey I can learn more about

this thing that we all do and you know perhaps find a little serenity in it.

As Sarah dug into the fascinating science of sweat she learned that it's an evolutionary marvel.

A highly efficient way to prevent our bodies from overheating.

We effectively dispatch water to our skin and as it evaporates it whisks heat away from our bodies.

And in order to do that it kind of is most efficient on a naked surface and low and behold

we are the naked ape. Compare that to how furry mammals cool down like dogs or chimps.

They pant and so they stick out their tongue and evaporate saliva off their most naked part

which is their tongue. But instead of you know relying on like a very small amount of real estate

we have our whole body off of which we can evaporate liquid.

Sweating allowed our species to survive and thrive. It allowed us to adapt to very hot places

to run long distances without overheating.

Which enabled our ancestors to chase and catch prey because the prey would tire out faster.

And so it's actually this incredible kind of superpower that we have.

And anyone who's embarrassed or grossed out by sweat Sarah says think again it could have been

so much worse. So like vultures will poop on their legs. It's very liquidy to evaporate that liquid off.

...