Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get Started
About our e-newsletters
- Free e-newsletters
- Mayo Clinic expertise
- We do not share your e-mail address
Housecall, our weekly general-interest e-newsletter, keeps you up to date on a wide variety of health topics with timely, reliable, practical information, recipes, blogs, questions and answers with Mayo Clinic experts and more. Our biweekly topic-specific e-newsletters also include blogs, questions and answers with Mayo Clinic experts, and other useful information that will help you manage your health.
Housecall Archives
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Causes
By Mayo Clinic staffHeatstroke is the escalation of two less serious heat-related conditions. If you don't take steps to treat these lesser conditions quickly, your condition may worsen and become heatstroke:
- Heat cramps. Heat cramps are caused by initial exposure to extreme temperatures or physical exertion. Signs and symptoms of heat cramps usually include profuse sweating, fatigue, thirst and muscle cramps, usually in the stomach, arms or legs. This condition is common in warmer weather or with moderate to heavy physical activity. You can usually treat heat cramps by drinking fluids containing electrolytes (Gatorade or other sports drinks), resting and getting to a cool spot, like a shaded or air-conditioned area.
- Heat exhaustion. Heat exhaustion occurs when you don't act on the signs and symptoms of heat cramps and your condition worsens. Signs and symptoms of heat exhaustion include a headache, dizziness or lightheadedness, nausea, skin that feels cool and moist, and muscle cramps. Often with heat exhaustion, you can treat the condition yourself by following the same measures used to treat heat cramps, such as drinking cool nonalcoholic beverages, getting into an air-conditioned area or taking a cool shower. If your symptoms persist, seek medical attention immediately.
The cause of your heatstroke depends on the activities you do that bring on your condition. Heatstroke can occur in these ways:
- Environmental conditions. In a type of heatstroke called nonexertional heatstroke, your condition is caused by extreme environment temperatures that cause your body temperature to increase. You may be doing some light or moderate activity, but activity is not the primary cause of your heatstroke. This type of heatstroke is typical in warmer, more humid weather.
- Strenuous activity. In a type of heatstroke called exertional heatstroke, your condition is caused by strenuous activity that increases your body temperature. You can have exertional heatstroke even if you're accustomed to working or exercising in very hot temperatures, though heatstroke is more likely to occur if you're not accustomed to high temperatures.
In either exertional or nonexertional heatstroke, your condition can be brought on by:
- Wearing excess clothing that doesn't allow your sweat to evaporate easily
- Drinking alcohol, which can affect your body's ability to regulate your temperature
- Dehydration
- Extreme heat: A prevention guide to promote your personal health and safety. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp. Accessed July 7, 2009.
- Heatstroke. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/print/sec21/ch318/ch318d.html. Accessed July 7, 2009.
- Zimmerman JL, et al. Hyperthermia. In: Hall JB, et al. Principles of Critical Care. 3rd ed. New York, N.Y.: McGraw-Hill Professional; 2005. http://www.accessmedicine.com/content.aspx?aID=2282701. Accessed July 7, 2009.
- Bouchama A, et al. Heat stroke. New England Journal of Medicine. 2002; 346:1978.
- Hyperthermia: Too hot for your health. National Institute on Aging. http://www.nia.nih.gov/HealthInformation/Publications/hyperthermia.htm. Accessed July 7, 2009.
