Signs and Symptoms of Heatstroke and Heat Exhaustion

Contemporary ClinicAugust 2016
Volume 2
Issue 4

Heatstroke occurs when your body can no longer cool itself and your body temperature becomes dangerously high.


Heatstroke occurs when your body can no longer cool itself and your body temperature becomes dangerously high. Heatstroke can occur if your body temperature is 104°F (40°C) or higher and is usually a result of prolonged exposure to, or physical exertion in, high temperatures.1

Heatstroke can result in a number of complications, depending on how long the body temperature remains high. Severe complications include organ damage to the brain, heart, kidneys, and muscles. The damage worsens the longer treatment is delayed, increasing serious complications, including death.1Heatstroke is a medical emergency.


Heat exhaustion is when your body becomes very hot and starts to lose water or salt.2Heat exhaustion is often a precursor to heatstroke. If you develop signs and symptoms of heat exhaustion, take action quickly to prevent heatstroke.


The signs and symptoms of heat exhaustion include the following:

  • Tiredness and weakness
  • Feeling faint, dizzy, or sick
  • Muscle cramps
  • Intense thirst
  • Decrease in blood pressure
  • Urinating less often and having much darker urine than usual

If symptoms of heat exhaustion continue to worsen, you may develop heatstroke.


The following are signs and symptoms of heatstroke:

  • High body temperature
  • Hot, flushed skin
  • Alteration in sweating (skin may be dry when heatstroke is brought on by extreme temperatures or moist when brought on by physical exertion)1
  • Confusion and disorientation
  • Seizures
  • Loss of consciousness
  • Nausea and vomiting Headache
  • Rapid, weak pulse
  • Rapid, shallow breathing


Although anyone can develop heatstroke, the following individuals are at higher risk:

  • Babies and young children
  • Pregnant women
  • Homeless people
  • Elderly individuals
  • Individuals with long-term health conditions, such as diabetes or problems with their heart or lungs
  • Individuals who are already ill and dehydrated Individuals doing strenuous exercise for long periods, such as military personnel, athletes, hikers, and manual-labor workers
  • Individuals on certain medications, including diuretics, antihistamines, beta-blockers, antipsychotics, and recreational drugs, such as amphetamines and ecstasy2
  • Individuals with a previous history of heatstroke


Because of the potential of severe complications from heatstroke, you should take each of the following measures to prevent it:

  • Be aware of heat warnings and advisories in your area or areas where you will be traveling.
  • Stay out of the heat when possible; if not possible, try to limit your exposure between 11:00 AM and 3:00 PM, when temperatures are at their highest.2Also take regular breaks when engaged in physical activities on warm days.
  • If you must be out in the heat, try to stay in the shade, apply sunscreen, and wear a hat. Protect against sunburn, which affects your body’s ability to cool itself. Wear a wide-brimmed hat and sunglasses, and use a broad-spectrum sunscreen with an SPF of at least 15.1Apply generously- and reapply every 2 hours (more often if you’re swimming).
  • Wear light-weight, loose, and light-colored clothing. Avoid clothing that is tight and restrictive or that doesn’t allow the body to cool properly.2
  • Cool yourself down. Use cool, wet towels on the back of your neck and top of your head.
  • It’s easy to become dehydrated by not drinking enough water to replenish fluids lost through sweating. Therefore, drink plenty of fluids. Staying hydrated will help your body sweat and maintain a normal body temperature. Plan to drink 1 to 2 liters of fluid for every hour outside.3Limit intake of alcohol, caffeine, and hot beverages. Drinking alcohol can affect your body’s ability to regulate your temperature.
  • Keep your environment cool. Have curtains or shades pulled during the day to help keep indoor temperatures down. Use air conditioners and/or fans when possible. Turn off unnecessary lights and electrical equipment, as they can generate heat.2
  • Never leave anyone in a parked car, even for a short period. When parked in the sun, the temperature in your car can rise 20°F in 10 minutes.1
  • Watch out for those individuals who are at higher risk for developing heatstroke. In particular, keep a close eye on sick or elderly individuals and very young children. Frequently check on elderly or sick neighbors, especially those who may not have adequate cooling systems in place.


Heatstroke is a medical emergency. Therefore, if you believe anyone is experiencing heatstroke, including yourself, seek immediate medical attention because home treatment is not sufficient for the treatment of heatstroke.1However, there are measures that can be taken while waiting for medical assistance to arrive. Take the following immediate actions to cool the overheated individual:

  • Get the individual into a shaded area or inside and out of the heat.
  • Remove excess clothing.
  • Cool the individual with whatever means available, including running a cool shower, immersing in cold water, spraying gently with a garden hose, or sponging with cool water. A bath of cold or ice water also can quickly lower body temperature.
  • Use evaporation cooling techniques: mist cool water on the skin while fanning warm air over the body, which causes the water to evaporate and cools the skin. You can also wrap wet sheets around the body and place the person in front of a fan or air conditioner.3
  • Pack the body with ice. Apply ice packs to the groin, neck, back, and armpits to lower body temperature. If no ice is available, place cool wet towels on the person’s head and neck.

Between 2004 and 2014, an average of 124 individuals died in the United States due to heat-related illnesses.4Don’t become a statistic. Use appropriate measures to prevent heatstroke, and if you observe someone with heatstroke, seek immediate medical attention.


  1. Mayo Clinic Staff. Diseases and conditions: heatstroke. Mayo Clinic website. Accessed June 3, 2016.
  2. Heat exhaustion and heatstroke. National Health Service website.
  3. Accessed June 3, 2016.
  4. Heat safety — heat-related illness. Arizona Department of Health Services website. Accessed June 5, 2016.
  5. Health Hazard Report: 2014 heat related fatalities. National Weather Service website. Published May 13, 2016. Accessed June 5, 2016.
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