The science of sweating

Everybody does it, but we usually try to hide the evidence. Sweating is a normal part of living, an essential function that helps keep us alive. It’s satisfying during hot yoga sessions or a long workout, but for the most part, we spend our adult lives trying to hide the evidence with anti-perspirants, dress shields, moisture-wicking fabrics and, for the particularly sweaty among us, Botox injections in the armpits to paralyze sweat glands.

Sweat is more than just something that stains our favorite shirts, according to Sarah Everts in her book The Joy of Sweat, published earlier this year. It’s a built-in cooling system, a complex network of glands that release fluid, which evaporates from heated skin and produces a cooling effect that lets us go outside on a hot day or enjoy a workout without risking death. And far from being gross and unsightly, sweat is an evolutionary marvel, an adaptation that allowed early humans to disperse into diverse climates and forage for food during daylight hours while many predators retreated to the shade for survival.

And that unpleasant odor that we associate with sweat? Our bodies don’t actually create that. Larger sweat glands, such as those in the armpits and groin, secrete sweat with a slightly different molecular profile, with fatty particles that bacteria love to feast on. In turn, the bacteria produces waste that, to human noses, smells like rancid butter and wet dog, among other things, according to Everts.

But even if your armpits are a little ripe, don’t kick yourself over it because, as Everts reminds readers, it could be much worse. Some animals spend their days rolling in mud, while others urinate or vomit on themselves to produce a similar, though much less efficient, cooling effect.

Image by janeb13