And Why It's Actually Brilliant
I don't know about you, but sweating has never felt like something to celebrate.
We buy antiperspirants, carry deodorant, avoid grey T-shirts and apologise if we've walked a little too quickly on a warm day.
Yet sweating is one of the cleverest things your body does.
Every single drop of sweat begins as part of your bloodstream. Deep under your skin are around 2–5 million tiny sweat glands. They take water from your blood, mix in a little salt, and send it to the surface of your skin.
Then something amazing happens.
The sweat doesn't cool you. Its evaporation does.
As it disappears into the air, it takes heat with it, acting like your own built-in air conditioning. Without sweating, even a warm summer's day—or a brisk walk—could become dangerous.
Humans are actually among the best sweaters in the animal kingdom. It might not sound like much of a superpower, but it's one of the reasons we can walk, run, garden, dance, play football and generally keep going in hot weather while many animals have to stop and pant.
Here's another surprise: sweat doesn't usually smell.
Fresh sweat is almost odourless. The smell we associate with body odour comes from the bacteria that naturally live on our skin. They feast on sweat and skin oils, producing the familiar aromas we'd often rather avoid!
That's why deodorants and antiperspirants do different jobs. Deodorants tackle the smell, while antiperspirants reduce the amount of sweat reaching the skin. They don't switch your sweat glands off—they simply slow them down a little.
Some people, though, sweat far more than they need to. A condition called hyperhidrosis means the nerves controlling the sweat glands are a little too enthusiastic. Imagine your body's thermostat constantly saying, "Just in case... let's make some more sweat!" It can be incredibly disruptive, but there are effective treatments available.
We also talked about a condition called hidradenitis suppurativa, or HS. For years, doctors thought it was a problem with sweat glands. We now know it usually starts around hair follicles and involves the immune system. It's a reminder that medicine is always learning and that sometimes our understanding changes completely.
Perhaps the most surprising thing I discovered is this: evolution spent millions of years making us brilliant at sweating... and modern life has spent the last hundred years trying to stop us doing it.
Maybe we've been looking at sweat all wrong.
Rather than being something embarrassing, it's evidence that an extraordinary biological system is quietly working away every second of every day, protecting your brain, your heart and every other organ from overheating.
Maybe that's the real lesson. So many of the things our bodies do that we find embarrassing, frustrating or inconvenient are actually extraordinary. Sweating isn't a design flaw—it's one of the reasons we're here at all.
So the next time you feel a bead of sweat on your forehead, don't just think, "I'm hot." Think, "My body has just switched on one of the most remarkable cooling systems in the natural world."
I think that's something worth celebrating.
https://www.mixcloud.com/harbourradio/dr-sarah-on-call-experiment-17-sweat/