What indicates a swimmer may be experiencing heat exhaustion?

Heat exhaustion is a condition that can occur when a person becomes overheated, often due to prolonged exposure to high temperatures or vigorous physical activity in hot weather. The symptoms of heat exhaustion typically include heavy sweating, which is the body's mechanism for cooling itself, accompanied by feelings of weakness and nausea.

Heavy sweating indicates that the body is attempting to regulate its temperature but can lead to dehydration if fluid and electrolyte loss is not addressed. Weakness is often experienced because the body's systems are under stress, and when coupled with nausea, it suggests that the individual is struggling to maintain homeostasis. These signs are crucial for identifying someone who may need immediate cooling measures and hydration to prevent progression to more severe heat-related illnesses, such as heat stroke.