Question: Why do we sweat

Sive Finlay answered on 17 Nov 2013:

Hey,
Sweat is the body’s way of regulating temperature. Our skin is covered in sweat glands which constantly secrete a small amount of liquid made up of water and salts. When we’re cold or at normal temperature we don’t notice the sweat because there are only small amounts and a lot of the liquid is re-absorbed back into the blood.
When we heat up – from exercise or increased metabolic activity because we’re nervous or excited – this stimulates the sweat glands to secrete more sweat which makes its way to the surface of the skin. Our body’s relatively hot temperature causes the sweat to evaporate into the air which effectively lifts some of the heat away with it and helps us to cool down. If the surrounding air is very humid though then the sweat doesn’t evaporate as readily which is why you can get so over-heated in tropical, humid areas.
Sweat doesn’t have any odour itself. The smell comes from the bacteria living on our skin and hair which breakdown the sweat and produce smelly compounds.
So we sweat because we’re endotherms – animals that produce their own body heat and can regulate their temperature. Animals such as reptiles are exotherms – they can’t regulate their own temperatures internally so they rely on basking in the sun to heat up and staying in the shade to cool down so they don’t sweat.
Sive