What environmental condition reduces the body's ability to remove heat by sweating in hot weather?

What environmental condition reduces the body's ability to remove heat by sweating in hot weather?

• A. Humidity
• B. High wind speeds
• C. Cold air
• D. Direct sunlight

Answer: (A)

Evaporative cooling from sweating is how the body shed heat, so sweating only helps if the sweat can evaporate off the skin. Humidity makes the air already moist, which slows evaporation. When sweat doesn’t evaporate efficiently, the body loses less heat, so cooling is reduced in hot, humid conditions. In contrast, high wind speeds actually boost cooling by moving moisture away, direct sunlight adds heat rather than reducing sweating effectiveness, and cold air doesn’t limit evaporative cooling in the same way humidity does.

Evaporative cooling from sweating is how the body shed heat, so sweating only helps if the sweat can evaporate off the skin. Humidity makes the air already moist, which slows evaporation. When sweat doesn’t evaporate efficiently, the body loses less heat, so cooling is reduced in hot, humid conditions. In contrast, high wind speeds actually boost cooling by moving moisture away, direct sunlight adds heat rather than reducing sweating effectiveness, and cold air doesn’t limit evaporative cooling in the same way humidity does.