Weekend Special: Guess What? Sweat Is Not Smelly! (So Why Do I Smell?)

It’s hot today. Really, really, hot; over a 100 degrees Fahrenheit hot, and so I’m sweating.

Sweating is what we people do to cool off, which is good. But sweating is also what makes me … what’s the word? Odoriferous. (Latinate for stinky, which is not so good.)

Here’s my question: If I swipe a little sweat trickling down my leg and hold it to my nose, it smells fine. But if I take a swipe from my arm pit (or several other places I choose not to mention) it’s very un-fine. Why the difference?

Why does sweat sometimes smell and sometimes not?

The answer comes from my Radiolab pal Josh Kurz (here working for Distillations, a chemistry podcast sponsored by Chemical Heritage magazine). In this very sweaty video, featuring a warmly clad Louis Pasteur, Josh discovers that sweat, when it’s just plain sweat, doesn’t smell. But sometimes sweat bonds with a particular group of proteins, and it’s those proteins that smell, not the sweat. You’ll see. Just hold your nose.


If you haven’t sweated enough, last year cartoonist Lev Yilmaz and I teamed up on a cartoon video that asked, How Much Heat Can A Person Stand? We describe an experiment conducted by several British gentlemen 200 years ago and their very surprising discovery which, once again, was all about sweat. (And also involved a dog, an egg and a steak.) Josh Kurz’s videos are part of a Distillation series called Blood, Sweat and Tears. He’s doing a video about each.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.