A man develops fever after completing a 10-km run. The fever returns to normal primarily due to which mechanism?

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

Answer: (B)

During fever, the body raises its temperature set point in response to pyrogens, so heat is produced and retained. Once the fever breaks, the main way the body returns to normal temperature is by getting rid of that excess heat. Evaporation of sweat provides the largest cooling effect because turning liquid water on the skin into vapor requires a lot of latent heat. As sweat evaporates, a substantial amount of heat is carried away from the body, rapidly lowering core temperature. Other heat-loss routes like radiation, convection, or conduction contribute, but evaporation is the dominant mechanism driving the return to normal temperature after fever, especially during and after exercise when sweating is plentiful.