Which of the following is a sign of heat exhaustion?

Heat exhaustion is characterized by the body's response to overheating, often due to prolonged exposure to high temperatures, particularly when combined with dehydration. Profuse sweating is a key sign of heat exhaustion, as the body attempts to cool itself through the evaporation of sweat. When the body is overheating, it produces more sweat in an effort to regulate its temperature.

The presence of profuse sweating indicates that the body is still capable of sweating but is struggling to cool itself effectively. In cases of heat exhaustion, individuals may also experience symptoms like weakness, dizziness, fatigue, and nausea, but the excessive sweating is a primary indicator.

Other options such as hot dry skin or no perspiration are more closely associated with heat stroke, a more serious condition where the body's temperature regulation systems fail, leading to an inability to sweat. Cool, clammy skin can also suggest some degree of heat-related illness but is not as definitive for heat exhaustion as profuse sweating. Understanding these signs is crucial for distinguishing between different heat-related illnesses and providing the appropriate first aid.