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Hot Weather Health Emergencies

Even short periods of high temperatures can cause serious health problems. Doing too much on a hot day, spending too much time in the sun, or staying too long in an overheated place can cause heat-related illnesses. Know the symptoms of heat disorders and overexposure to the sun, and be ready to give first aid treatment.

Heat Stroke

Heat stroke occurs when the body is unable to regulate its temperature. The body's temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. Body temperature may rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not provided.

Warning signs of heat stroke vary but may include the following:

  • An extremely high body temperature (above 103°F, orally)
  • Red, hot, and dry skin (no sweating)
  • Rapid, strong pulse
  • Throbbing headache
  • Dizziness
  • Nausea
  • Confusion
  • Unconsciousness

What to Do

If you see any of these signs, you may be dealing with a life-threatening emergency. Have someone call for immediate medical assistance while you begin cooling the victim.

  • Get the victim to a shady area.
  • Cool the victim rapidly using whatever methods you can. For example, immerse the victim in a tub of cool water; place the person in a cool shower; spray the victim with cool water from a garden hose; sponge the person with cool water; or if the humidity is low, wrap the victim in a cool, wet sheet and fan him or her vigorously.
  • Monitor body temperature, and continue cooling efforts until the body temperature drops to 101 to 102°F.
  • If emergency medical personnel are delayed, call the hospital emergency room for further instructions.
  • Do not give the victim fluids to drink.
  • Get medical assistance as soon as possible.

Sometimes a victim's muscles will begin to twitch uncontrollably as a result of heat stroke. If this happens, keep the victim from injuring himself, but do not place any object in the mouth and do not give fluids. If there is vomiting, make sure the airway remains open by turning the victim on his or her side.

Heat Exhaustion

Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids. It is the body's response to an excessive loss of the water and salt contained in sweat. Those most prone to heat exhaustion are elderly people, people with high blood pressure, and people working or exercising in a hot environment.

Warning signs of heat exhaustion include the following:

  • Heavy sweating
  • Paleness
  • Muscle cramps
  • Tiredness
  • Weakness
  • Dizziness
  • Headache
  • Nausea or vomiting
  • Fainting

The skin may be cool and moist. The victim's pulse rate will be fast and weak, and breathing will be fast and shallow. If heat exhaustion is untreated, it may progress to heat stroke. Seek medical attention immediately if any of the following occurs:

  • Symptoms are severe
  • The victim has heart problems or high blood pressure

Otherwise, help the victim to cool off, and seek medical attention if symptoms worsen or last longer than one hour.

What to Do

Cooling measures that may be effective include the following:

  • Cool, nonalcoholic beverages
  • Rest
  • Cool shower, bath, or sponge bath
  • An air-conditioned environment
  • Lightweight clothing

Heat Cramps

Heat cramps usually affect people who sweat a lot during strenuous activity. This sweating depletes the body's salt and moisture. The low salt level in the muscles may be the cause of heat cramps. Heat cramps may also be a symptom of heat exhaustion.

Heat cramps are muscle pains or spasms — usually in the abdomen, arms, or legs — that may occur in association with strenuous activity. If you have heart problems or are on a low-sodium diet, get medical attention for heat cramps.

What to Do

If medical attention is not necessary, take these steps:

  • Stop all activity, and sit quietly in a cool place.
  • Drink clear juice or a sports beverage.
  • Do not return to strenuous activity for a few hours after the cramps subside, because further exertion may lead to heat exhaustion or heat stroke.
  • Seek medical attention for heat cramps if they do not subside in one hour.

Above content provided by the Centers for Disease Control and Prevention in partnership with Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor

Posted June 2013

Contact Information

Beth Israel Deaconess Medical Center
330 Brookline Avenue, Boston, MA 02215
Main Switchboard: 617-667-7000
Find a Doctor: 800-667-5356
Directions by Phone: 617-667-3000
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