
Could you run out of sweat?
It might help with nervous moments...
Asked by: Derrick Rhodes, Ramsgate
Sweat doesn’t sit in a separate reservoir or fuel tank that can be temporarily drained dry. The eccrine glands in your skin take fluid directly from the plasma in your blood; in effect sweat glands are a kind of modified, leaky capillary. At maximum levels of production, the human body can sweat as much as three litres per hour. That’s equivalent to your entire blood volume in just an hour and forty minutes. But if you didn’t drink you would die from hypovolemic shock or heart failure due to electrolyte imbalance before then.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Authors
Sponsored Deals

Subscription offers you will love!
- Spread the cost and pay just £3.50 per issue when you subscribe to BBC Science Focus Magazine.
- Alternatively, lock in for longer and pay just £37.99 per year, saving 51%!
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.