Heat Stroke (Hyperthermia)

What Is It?

The human body usually can regulate its temperature. When the body gets too hot, it uses several strategies to cool down, including sweating. But if a person spends too much time in the heat without taking in enough fluids, the body's cooling processes can't work properly. When the body becomes dehydrated, it can no longer cool itself by sweating. When this happens, body temperature can rise high enough to make the person sick. 

The first symptoms of heat illness occur as the body temperature climbs above normal, and can include headache, nausea, vomiting, muscle cramps and fatigue. These early symptoms sometimes are called heat exhaustion. If steps are not taken to reduce body temperature, heat exhaustion can worsen and become heat stroke.