An Ode to Sweat

The Boston Globe (went to school there) has a daily feature called Starting Point. Today it's "An Ode to Sweat" and I celebrate.

TODAY’S STARTING POINT

As the dog days of summer arrive with their smothering embrace, I’d like to take a moment to thank our human ancestors who did us a major solid about 2 million years ago, when they ditched their thick fur.

 

Those “hairless” apes must have looked a little funny on the African savannah, but that shedding allowed for the development of one of the two human superpowers – sweat.

 

I’m currently preoccupied with sweat, and not simply because my wife opened our electric bill and then opened the windows. No, I’m in the midst of a years-long midlife crisis that consists of trying to get my head around the body of the animal I was born into, the one that somehow evolved to walk upright, and talk, and make fire and Doritos.

In my research (meaning: I read the introduction to a book about evolution, then daydream), I’ve developed a deep appreciation for the role of sweat in our story. So I’ll try to use the other human superpower, storytelling, to have this make sense (though, admittedly, I’m better at sweating).

The ability to thermoregulate through sweat is extremely rare in the animal kingdom, and the only animals that are truly great at it are humans and horses. Cattle are decent, and a few others use sweat in a limited sense. But the rest cool themselves with other strategies, such as the very-popular panting (dogs are a great example, though scientists haven’t figured out why they insist on doing it with a tennis ball in their mouth); using extra-large ears as radiators (elephants, jackrabbits); or wallowing in mud (pigs, hippos).

In human evolution, there is something known as the persistence hunting theory. I am fascinated by this idea, and would very much like to be buddies with the Harvard paleoanthropologist Daniel Lieberman, who is among its biggest proponents and seems like a cool dude who would totally enjoy starting a podcast with me where I ask dumb questions and he gives smart answers.

I’ve nearly finished all of his book introductions, and he argues that our prolific sweat glands, plus arched feet and some specialized muscle fibers, allowed for endurance-based predation. In other words, our hunter-gatherer ancestors simply ran down and exhausted their prey, who had to stop and pant. That’s when we got ‘em, and that huge supply of protein, not to mention the energy savings of not having to grow and maintain thick fur, paved the way for the development of the large brain that I am currently using to read too much into this.

There are other theories as to why we ditched our thick fur: when we started the whole walking upright thingy, less of our body surface was exposed to direct overhead sunlight, so we only kept the fur on our heads; the mastery of fire and clothing made it unnecessary to keep warm at night; or the simple fact that less fur meant less hiding places for parasites.

Kinda doesn’t matter; what does is that we got sweat. Glorious, salty, slickery sweat. And this time of year in New England, we have so much of it that we invented Gold Bond. But I say bring it on, and again thank those anonymous workers in the ancestor factory who selected for this trait that we all get to enjoy.

 

Anthem of the Overheated

To the guys in the gym with dark gray crescent under arms,
To the dudes on the turf ignoring thermal alarms,
To the youth running hard till their t-shirts turn sheer,
To the sheer dedication of dropping a gear.

You glisten, you drip, you puddle the floor,
A gallon of moisture leaking out more.
No towel can save you, antiperspirant blight,
Just pure honest sweat from morning till night.