Victims of heatstroke usually don't sweat much. Their pulses are very rapid and their skin is hot and dry. They also have extremely high body temperatures. Heatstroke victims should be cooled off as quickly as possible by wrapping or immersing them in ice or cold water. After taking these emergency measures, take victims to the hospital immediately.
Heat exhaustion is a less serious but much more common condition.
Warning signs include excessive urination, gradual weakness, nausea, anxiety or agitation, and excessive sweating. Unlike heatstroke, heat exhaustion causes pale, clammy skin, and a weak, slow pulse. Victims of heat exhaustion often feel faint or disoriented. The best thing to do for victims of heat exhaustion is to have them take it easy for a while. Find them a shady spot or an air-conditioned building to sit or lie down in.