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Medically reviewed by Last updated on Oct 31, 2022.

What is heatstroke?

Heatstroke is when your body severely overheats. Heatstroke happens when you do physical activity in hot conditions without drinking enough liquids. Normally, the body has a cooling system that is controlled by the brain. The cooling system adjusts to hot conditions and lowers your body temperature by producing sweat. With heatstroke, the body's cooling system is not working well and results in an increased body temperature.

What increases my risk of heatstroke?

  • Older age or young children
  • Obesity
  • Certain medicines, such as those used to treat allergies, pain, or heart problems
  • Illegal drugs or alcohol

What are the signs and symptoms of heatstroke?

  • Your temperature is 104°F (40°C) or higher.
  • Your skin may be red and dry or clammy.
  • You have a headache, nausea, or vomiting.
  • You have muscle cramps.
  • You breathe fast or feel like your heart is beating faster than normal.
  • You feel faint, dizzy, weak, or tired.
  • You may have a prickling feeling in your arms or legs.
  • You may have a seizure or faint.

How is heatstroke diagnosed?

Your healthcare provider will take your temperature. You may also need any of the following tests:

  • Blood and urine tests may show the levels of electrolytes (salt and minerals) in your blood. You blood gasses may also be tested for the amount of oxygen and carbon dioxide.
  • An EKG may be needed to check for heart problems related to heatstroke.

What first aid can I do for heatstroke?

  • Move to an air-conditioned location or a cool, shady area and lie down. Raise your legs above the level of your heart.
  • Drink cold liquid, such as water or a sports drink.
  • Mist yourself with cold water or pour cool water on your head, neck, and clothes.
  • Apply ice packs on your neck, armpits, and groin.
  • Loosen or remove as many clothes as possible.
  • Have someone call 911 immediately for medical assistance.

How is heatstroke treated?

  • Cooling materials such as ice soaked blankets may be used to quickly decrease your body temperature.
  • IV fluids may be given to treat dehydration.
  • Medicines may be given to prevent a seizure, or raise your blood pressure.
  • Extra oxygen may be needed if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

How can I prevent heatstroke?

  • Wear lightweight, loose, and light-colored clothing.
  • Protect your head and neck with a hat or umbrella when you are outdoors.
  • Drink lots of water or sports drinks. Avoid alcohol.
  • Eat salty foods, such as salted crackers and salted pretzels.
  • Limit your activities during the hottest time of the day. This is usually late morning through early afternoon.
  • Use air conditioners or fans and have enough proper ventilation. If there is no air conditioning available, keep your windows open so air can circulate.
  • Never leave children alone inside cars, especially during hot weather.

Call your local emergency number (911 in the US) if:

  • You cannot stop vomiting.
  • You are confused or cannot think clearly.
  • You cannot move your arms and legs.

When should I seek immediate care?

  • Your temperature is 104°F (40°C) or higher.
  • You feel faint, dizzy, weak, or tired.
  • You breathe fast or feel like your heart is beating faster than normal.

When should I call my doctor?

  • Your skin is red and dry.
  • You have muscle cramps or twitching.
  • You have nausea and vomiting.
  • You have numbness or prickling feeling in your arms or legs.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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