Question: why do people sweat?

Mark Burnley answered on 15 Jun 2011:

Sweating is one of four ways of removing heat from the human body. These ways are conduction, convection, radiation and evaporation. Conduction is where you touch something of a different temperature and heat transfers from the warmer body to the cooler body. For example, if it is 18 degrees celcius in a room, then your body will conduct heat to the air. This is why a room will warm up with lots of people in it. If the room was 40C, you would GAIN heat by conduction, because your core temperature is about 37C. Convection involves the movement of molecules from one place to another, for example the blood carries warm blood from your core to the skin, where the temperature is usually lower. Radiation is a tricky one to understand, but basically as you are reading this you are giving off infrared radiation (which is thermal energy). Lastly, evaporation (water transferring from liquid to gas) also cools you down, as to do this requires energy (gas is more “energetic” than liquid). Lick the back of you hand and blow on it. That’s evaporation, and it by far the most effective way of losing heat. Humans therefore have millions of sweat glands all over the body, and during exercise it is a major means of losing heat, preventing heat exhaustion.