Which description most accurately defines hyperthermia?

• A. The body is exposed to more heat than it can lose.
• B. Heat evaporates a significant amount of body water.
• C. The core body temperature exceeds 99.5°F (37°C).
• D. The body eliminates more heat than it can generate.

Answer: (A)

Hyperthermia occurs when heat gain exceeds the body's ability to dissipate it. The body normally cools itself through sweating (evaporation), plus heat loss by radiation, convection, and conduction. When environmental heat, clothing, or activity push heat production and heat load beyond what these cooling mechanisms can handle, the core temperature rises. That makes the description of being exposed to more heat than the body can lose the best fit.

The other statements describe consequences or conditions that aren’t the defining heat-balance idea: heat loss causing dehydration is a result of cooling, not the definition; a normal body temperature isn’t hyperthermia; and losing more heat than produced leads to hypothermia, not hyperthermia.