Drink clear juice or a sports beverage. Don't do anything strenuous for a few hours after the cramps subside. See a doctor if heat cramps persist more than an hour. This is your body's response to an excessive loss of both water and salt. Warning signs of heat exhaustion may include heavy sweating, pallor, muscle cramps, tiredness, weakness, dizziness, headache, nausea or vomiting, fainting, fast and shallow breathing, and a fast and weak pulse.
Heat exhaustion can progress to heat stroke, which can be deadly.
Seek medical attention immediately if your symptoms are severe or last longer than an hour, or if you have heart problems or high blood pressure. In the meantime, be sure to rest, drink cool fluids, and, if possible, take a cold shower or recover in an air-conditioned site. Heat stroke Heat stroke occurs when all your body's means of coping with heat shut down, allowing your body temperature to quickly soar. Heat stroke can kill or cause permanent disability if not dealt with immediately. These signs warrant immediate emergency medical attention.