There are four different mechanisms by which heat can be lost from the skin.
Radiation Describes the movement of heat directly through the air and this can be a mechanism for heat loss if the skin is warmer than the surrounding air. However, on a sunny day the skin can be directly warmed by the sun’s rays through radiation.
Convection If there is movement in the air or of the body, hot air will rise and be replaced by cooler air. This mechanism is hampered by the presence of clothes (which will therefore keep a body warm) and facilitated by a fan.
Conduction This simply describes the movement of heat through an object that the body comes into contact with.
Evaporation When eccrine sweat is excreted onto the skin, the heat from the skin is used to evaporate it away into the atmosphere. The net effect is to cool the surface of the skin (see section on
sweat glands for more details).
