Which of the following is a sign of heat exhaustion?

Pale, usually sweaty skin is a classic sign of heat exhaustion. During this condition, the body is unable to cool itself effectively due to prolonged exposure to high temperatures or strenuous activity in hot environments. As the body struggles to manage its temperature, blood vessels dilate, and sweating increases to try and cool down. The skin may appear pale and moist as blood is redirected from the skin to vital organs, in an effort to maintain core temperature and protect essential body functions.

Excessive thirst may also occur in cases of heat exhaustion, indicating dehydration, but it is not as definitive as the skin characteristics. High blood pressure is generally not associated with heat exhaustion; in fact, blood pressure may drop as the condition worsens due to dehydration and reduced blood volume. Severe headache can be a symptom related to heat-related illnesses, but it is not specifically a sign of heat exhaustion, as it could also be related to other factors such as dehydration or other medical conditions. Therefore, pale, usually sweaty skin is a clear and recognizable symptom of heat exhaustion.