Heat exhaustion and heatstroke are potentially serious conditions in which there is a loss of body fluids and a rise in body temperature due to excessive heat. In a hot environment, the body loses heat by diverting blood to the skin and sweating. Excessive loss of fluids due to profuse sweating may lead to heat exhaustion, with symptoms such as tiredness, weakness, lightheadedness, dizziness, headache, muscle cramps, nausea, and intense thirst.
If exposure to heat continues, the body temperature rises and heatstroke may develop, causing symptoms including rapid breathing, confusion, seizures, and unconsciousness.
Untreated, heatstroke may cause life-threatening complications, such as heart failure or severe brain damage. Heat exhaustion can usually be treated by cooling the person down and giving them plenty of fluids.
Heatstroke requires urgent medical treatment.