
There’s nothing smelly concerning the salty sweat dripping out of your face after a run. It’s simply your physique throwing off in any other case harmful warmth.
Werayuth Tessrimuang/EyeEm/Getty Images
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Werayuth Tessrimuang/EyeEm/Getty Images

There’s nothing smelly concerning the salty sweat dripping out of your face after a run. It’s simply your physique throwing off in any other case harmful warmth.
Werayuth Tessrimuang/EyeEm/Getty Images
Phew, this summer time was scorching — and a few locations are nonetheless roasting! With individuals all over the world experiencing dangerously excessive, record-breaking temperatures, we have all been sweating it.
You may discover perspiration a nuisance more often than not, however that salty liquid oozing out of your pores and skin is vital to conserving you cool. And there’s a lot extra to the briny stuff than meets the attention.
Several NPR science staffers braved the warmth this summer time to get the grime on sweat. These classes are primarily based on their reporting:
1. Sweat retains you cool by turning right into a fuel
Let’s begin with the fundamentals. Sweat is generally simply water and salt secreted by hundreds of thousands of glands in your pores and skin. Those glands are principally coiled loops that assist transfer among the liquid sloshing round within the areas between your cells, bones and organs up and out via the physique’s floor.
When the sweat in your pores and skin evaporates, reworking from a liquid right into a fuel, it takes some warmth from the blood proper beneath your pores and skin with it. The now-cooler blood then travels round your physique and again to your core, serving to hold all of your interior elements on the proper temperature to operate.
2. Most sweat would not stink
Perspiration is generally odorless — at the least that is true of the sweat dripping out of your brow and arms after a run. But one thing is completely different concerning the sweat out of your armpits and groin that makes it stink. The sweat glands in these locations are known as apocrine glands, they usually launch a protein-rich type of perspiration that will get eaten by micro organism. It’s the byproducts of those micro organism, feeding in your sweat, that produce physique odor.
3. The micro organism behind BO are literally your allies
Even in the event you’re anxious about your smelly sweat, do not go scrubbing your self with antibacterial cleaning soap in pursuit of recent pits simply but. The microbes that give rise to physique odor assist defend your pores and skin from harmful pathogens and even assist forestall eczema.
A lightweight sudsing with common light cleaning soap ought to be sufficient to knock down the stink, at the least quickly, with out wiping out bacterial buddies.
4. Most animals do not sweat
Now let’s be clear. You are the sweatiest of all of them. OK, nicely not simply you, however all people.
Scientists suppose our ancestors developed sweat glands between 1.5 million and a couple of.5 million years in the past as we moved from beneath the cool cover of the forests into the grasslands and prairies, lengthy earlier than we developed our massive brains.
But most different animals do not sweat, and they should discover different methods to maintain from overheating — via panting, for instance — if they can not discover shade, a river or a pool. As NPR’s Rebecca Hersher recounts in her rhyming exploration of the methods numerous creatures keep cool, lions in a Maryland zoo this steamy summer time received an additional deal with — frozen bloodsicles — to assist decrease everybody’s temperature.
5. A heat tub is best than a chilly bathe to stop overheated nights
It could appear counterintuitive, however while you get out of a heat or lukewarm night tub, researchers say, the water evaporates out of your pores and skin, pulling warmth out of your physique and cooling you down earlier than you fall asleep. This life hack works greatest about an hour earlier than bedtime, scientists advised NPR reporter Joe Palca — and you will sleep higher and extra deeply while you’re cooler.
6. Some bugs search the salt in human sweat
Unfortunately for us, mosquitoes, together with many different bugs, are drawn to human sweat. Insects want the sodium in salt, identical to the remainder of us, and our salty perspiration has what they want.
Scientists suspect that hundreds of thousands of years in the past, some sweat-drinking ancestors of mosquitoes found there was an much more nutritious substance beneath human pores and skin — our blood. Those bloodsucking biters gained an evolutionary edge over the nonbiters and thrived.
7. Astronauts want further assist to do away with physique warmth
Perspiration is usually a massive downside for individuals in a low-gravity setting reminiscent of area as a result of, even after nice exertion, sweat would not precisely drip off the pores and skin with out gravity. Instead, it simply sort of sits there and swimming pools up, which might disrupt digital gear and make spacewalks extra-uncomfortable.
So astronauts put on particular underwear on their spacewalks; it is stuffed with cooling tubes that whisk the warmth away. One bonus within the managed setting of an area station: Any further moisture from sweat that does get into the air is sucked up by the air flow system and recycled into recent water for the astronauts to drink.
Reporting for this story was drawn from our summer time sequence on sweat by NPR’s Geoff Brumfiel, Ari Daniel, Michaeleen Doucleff, Nell Greenfieldboyce, Pien Huang, Rebecca Hersher, Joe Palca and Lauren Sommer. Still thirsty for extra candy sweat science? Brumfiel, Greenfieldboyce and Hersher sat down lately with the hosts of NPR’s science podcast Short Wave to take extra questions and spill what they’ve discovered.