Heat Exhaustion and Heat Stroke

The body carefully maintains its internal temperature at around 98.6 degrees. In hot weather, perspiration cools it off. But sometimes, even the best cooling system can be overwhelmed.

Always be alert to the symptoms of heat stroke or exhaustion, especially when you or your friends exercise in hot weather, or work in hot, humid areas that don’t have some form of ventilation.

Heat exhaustion is a milder heat-related illness, but if untreated, it can lead to heat stroke, a potentially life-threatening condition. Heat stroke occurs when the body’s internal temperature rises to dangerous levels because the body’s normal cooling mechanism breaks down.

If you’re exercising or working in very hot weather and not drinking enough water or other fluids, your body may not be able to produce enough sweat to cool itself. If the body temperature remains elevated above 103 degrees for very long, heat stroke can occur and lead to even higher temperatures. A temperature that remains above 106 degrees can cause organ shutdown, brain damage, and possibly death.

As we age, our bodies become less efficient at cooling, and so people who are elderly as well as those who have circulation problems should be especially concerned about being in prolonged heat. More than 600 people die every year due to excessive heat exposure — a number that has been on the rise, according the Centers for Disease Control.

What to look for

Symptoms of heat exhaustion include the following:

  • Excessive sweating
  • Cool, clammy skin
  • Pale or ashen appearance
  • Rapid heartbeat
  • Headache
  • Dizziness
  • Nausea or vomiting
  • Abdominal or muscle cramps
  • Fatigue
  • Fainting
  • Weakness
  • Slight fever

What to do if you suspect heat exhaustion

  • Move the victim to a cool, shaded site and loosen tight or sweat-soaked clothing.
  • If the person is alert and able to swallow and breathe without difficulty, let him or her drink cool water (without ice), and follow that with a weak salt solution (1 teaspoon of salt in 1 quart of water) or a sports drink containing electrolytes, such as Gatorade. You can also give a pediatric oral rehydration formula such as Pedialyte. Do not give the victim salt tablets.
  • Have the person lie down and elevate the legs and feet.
  • Give the victim a sponge bath or pour cool water over him or her.
  • If you have one available, use an electric fan or a hair dryer set on cool to fan the victim. If not, use a magazine or your hand. This helps lower the skin temperature.
  • Using a thermometer, take the victim’s temperature every few minutes. Continue cooling the person until body temperature has dropped to 101 or 102 degrees Fahrenheit. But be careful that the person doesn’t become chilled. If the victim’s temperature begins to climb again, repeat the cooling process.
  • If the person’s condition does not improve quickly, call 911 or go to an emergency facility immediately. In some cases, the victim may need to get intravenous fluids or to be resuscitated.

Heat Stroke: What to look for

Heat stroke is much more serious than heat exhaustion, and it can come on suddenly. Symptoms of heat stroke include the following:

  • High body temperature, 103 degrees Fahrenheit or more
  • Red, hot, or dry skin
  • Racing pulse
  • Rapid and shallow breathing
  • Confusion
  • Seizures
  • Hallucinations
  • Unusual behavior, such as irritability or aggressiveness
  • Dark urine
  • Nausea
  • Throbbing headache
  • Unconsciousness

What to do if you suspect heat stroke

  • If the person shows serious signs of disorientation, falls unconscious, or begins twitching, he or she needs immediate medical attention.
  • Call 911 or go to an emergency facility right away.
  • While waiting for help, move the victim to a shady area and into an air-conditioned location if possible.
  • Quickly remove the outer layers of clothing.
  • Cool the victim rapidly using the best means available: Spray the person with a garden hose or spray bottle, sponge with cool water, place in a tub of cool water, or wrap in cool, wet sheets and fan vigorously.
  • Put cold compresses or ice packs under the victim’s armpits and on the neck and groin.
  • Monitor body temperature using a thermometer. Continue treatment until temperature has dropped to 101 or 102 degrees Fahrenheit, and keep checking every few minutes to ensure that it doesn’t climb again.
  • Remember, do NOT give the victim an alcoholic drink, even if it’s cool. This can raise body temperature. Avoid tea and other stimulants as well.
  • Do not give the victim antihistamines or pain relievers such as aspirin.
  • If the ambulance is delayed, call the emergency room for instructions.


Handbook of First Aid and Emergency Care, American Medical Association, pp. 207-208.

American College of Emergency Physicians, First Aid Manual, pp. 173-174.

The American Red Cross First Aid & Safety Handbook.

Heat Exhaustion. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp

Heat Stroke. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp

Recognizing and treating heat-related illness. The Cleveland Clinic. www.clevelandclinic.org.

Extreme Heat and the Elderly. Rhode Island Department of Health. http://www.health.ri.gov/elderheat.php

Mayo Clinic. Heat Exhaustion. http://www.mayoclinic.com/health/heat-exhaustion/DS01046/DSECTION=complications

Centers for Disease Control. Frequently Asked Questions (FAQ) About Extreme Heat.http://www.bt.cdc.gov/disasters/extremeheat/faq.asp

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