Heatstroke is a condition caused by your body overheating, usually as a result of prolonged exposure to or physical exertion in high temperatures. This most serious form of heat injury, heatstroke can occur if your body temperature rises to 104 F (40 C) or higher. Heatstroke requires emergency treatment. Untreated heatstroke can quickly damage your brain, heart, kidneys and muscles. The damage worsens the longer treatment is delayed, increasing your risk of serious complications or death.
Heatstroke symptoms include:
- High body temperature. A body temperature of 104 F (40 C) or higher is the main sign of heatstroke.
- Altered mental state or behavior. Confusion, agitation, slurred speech, irritability, delirium, seizures and coma can all result from heatstroke.
- Alteration in sweating. In heatstroke brought on by hot weather, your skin will feel hot and dry to the touch. However, in heatstroke brought on by strenuous exercise, your skin may feel moist.
- Nausea and vomiting. You may feel sick to your stomach or vomit.
- Flushed skin. Your skin may turn red as your body temperature increases.
- Rapid breathing. Your breathing may become rapid and shallow.
- Racing heart rate. Your pulse may significantly increase because heat stress places a tremendous burden on your heart to help cool your body.
- Headache. Your head may throb.
Heatstroke can occur as a result of:
- Exposure to a hot environment. In a type of heatstroke, called nonexertional or classic heatstroke, being in a hot environment leads to a rise in body temperature. This type of heatstroke typically occurs after exposure to hot, humid weather, especially for prolonged periods, such as two or three days. It occurs most often in older adults and in people with chronic illness.
- Strenuous activity. Exertional heatstroke is caused by an increase in body temperature brought on by intense physical activity in hot weather. Anyone exercising or working in hot weather can get exertional heatstroke, but it’s most likely to occur if you’re not used to high temperatures.
- Wearing excess clothing that prevents sweat from evaporating easily and cooling your body
- Drinking alcohol, which can affect your body’s ability to regulate your temperature
- Becoming dehydrated by not drinking enough water to replenish fluids lost through sweating