What is the primary cause of heat exhaustion?

The primary cause of heat exhaustion is overheating, which occurs when the body becomes unable to regulate its temperature effectively due to prolonged exposure to high temperatures, particularly in combination with physical exertion. When the body’s thermostat struggles to maintain a normal temperature, it can lead to various symptoms, including heavy sweating, weakness, dizziness, nausea, and even fainting.

Overheating is particularly concerning because it can escalate into more severe heat-related illnesses, such as heat stroke if not addressed. The body's natural cooling mechanisms, primarily sweating, can become overwhelmed if the environmental conditions—including temperature and humidity—are extreme, leading to an inability to dissipate heat effectively.

While high humidity plays a role in how uncomfortable and potentially dangerous hot conditions can be, it is the inability of the body to cool itself, usually through sweating, that primarily leads to overheating. Dehydration can exacerbate heat-related conditions but is not the direct cause of heat exhaustion in terms of temperature regulation. Cold exposure, on the other hand, is unrelated and typically leads to hypothermia or other cold-related issues rather than heat exhaustion.