How does the body dissipate heat?
There are three mechanisms by which objects either gain or loose heat: • Radiation is heat transfer by infrared rays. If the body is hotter than the environment it will loose heat to the environment by radiation. In direct sunlight, the body absorbs radiant heat from the sun. • Conduction is the process of heat transfer by direct contact with another surface. If the skin touches a frozen piece of metal, heat is lost from the skin by conduction. • Convection occurs when air or fluid passes over a heated service. When standing in front of a fan which is blowing air at the same temperature as the environment, you loose heat by convection. If you are a swimmer, you don t typically notice that you are hot until you stop. A great deal of heat is lost to the water by fluid movement across the body surface when swimming.
