What is the primary purpose of sweating during heat exposure?

• A. To increase metabolic rate.
• B. To regulate body temperature through non-evaporative means.
• C. To dissipate heat through evaporative cooling.
• D. To absorb heat from the environment.

Answer: (C)

Sweating during heat exposure mainly serves to dissipate heat through evaporative cooling. When sweat evaporates off the skin, it absorbs a large amount of heat from the body, lowering skin temperature and, with time, core temperature as well. This is the most effective way the body loses heat in hot conditions. How well this works depends on how easily sweat can evaporate, which depends on air flow and humidity: dry, moving air promotes evaporation and cooling, while high humidity slows it down. Increasing metabolic rate would generate more internal heat, not help cooling, and absorbing heat from the environment would raise body heat instead. So the primary purpose of sweating is to shed heat via evaporation.