What are the symptoms of heat exhaustion?

Dr. Leigh Vinocur, MD
Emergency Medicine Specialist

If you're sweating heavily, you could be developing heat exhaustion, but there are other less obvious signs. Learn what they are—and when to get immediate medical help—by watching the video.

Heat exhaustion is the middle category of heat-related illness and can quickly turn into heat stroke, if not treated. Following are symptoms of heat exhaustion:

  • Headache. As a heat-related illness progresses, a headache may become more severe.
  • Dizziness or lightheadedness. Shakiness and a feeling of instability or weakness often accompanies heat exhaustion.
  • Nausea or vomiting. The body prepares for systemic shut down by purging contents in the stomach, including liquids, which can lead to a faster deterioration of health through further dehydration.
  • Reduced urination. As the body tries to regulate temperature, it begins to shut down organs, like the kidneys. This can lead to acute kidney injury.
  • Fainting. This is the body’s way of taking over to protect vital organs against loss of fluids.

People with heat exhaustion will generally be sweating profusely. They commonly have cool, clammy, pale skin and a rapid but weak heart rate. Body temperature is usually only slightly elevated, no higher than 104 degrees. Other signs and symptoms might include confusion or dizziness, decreased urination, nausea and vomiting, headache, fatigue/weakness and malaise.

This answer provided for NATA by the Marist College Athletic Training Education Program.

Signs of heat exhaustion include cool, moist, pale, ashen or flushed skin, as well as:

  • headache
  • nausea
  • dizziness
  • weakness
  • exhaustion.
Dr. Kathleen Handal, MD
Emergency Medicine Specialist

The following are signs and symptoms of heat exhaustion:

  • Sweating, moist clammy skin
  • Muscle cramps, weakness and fatigue
  • Nausea, vomiting
  • Slightly elevated body temperature
  • Headache
  • Dizziness
Doc's First Aid Guide: Read It Before You Need It

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Doc's First Aid Guide: Read It Before You Need It

In a medical emergency, time is of the essence. "Doc's First Aid Guide" is an illustrated, first-aid pocket handbook designed to be used as a quick reference and includes the latest CPR guidelines....
Brett Snodgrass
Oncology Nursing Specialist

Symptoms of heat exhaustion include nausea vomiting, lethargy, increased heart rate, increase temperature. It is important to continually hydrate yourself with water or Gatorade-type beverage. Avoid caffeine or alcoholic beverages. It is important to listen to your body, don't continue to push yourself in extreme heat.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.