The main process in which heat is dissipated from the human body is?

• A. Conduction
• B. Convection
• C. Evaporation
• D. Radiation

Answer: (C)

Sweating and the evaporation of that sweat from the skin is the main way the body loses heat. When sweat evaporates, it requires a lot of energy to change from liquid to vapor, so a large amount of heat is carried away from the body. This latent-heat loss makes evaporation especially effective during heat stress or exercise, where sweating is extensive.

Conduction and convection also help cool, but they depend on the surroundings touching or moving air, and their cooling effect is usually smaller than the big, heat-sponging effect of evaporation. Radiation is always at play, but it generally removes less heat than evaporation does during typical sweating and exercise conditions. Humidity can slow evaporative cooling, but evaporation remains the dominant mechanism for dissipating heat.