Health Topics for Prepare for Emergencies

Department of Emergency Medicine

Emergency Medical Services Learning Resources Center

Heat stress

Heat stress is a group of illnesses that occur following excessive heat exposure. These include heat cramps, heat exhaustion, and heat stroke. Heat stroke is a life-threatening condition. People who are at high risk for heat stress are older adults, obese individuals, those with heart disease or other chronic illnesses, and people who work in a hot environment.

It is important to be aware of factors leading to heat related illnesses. High temperatures especially with high humidity, should make everyone more cautious. The use of alcohol and other drugs, including the use of some prescription drugs, can increase the risk of heat-related illnesses. But anyone who exerts himself or who spends an extended time in a hot environment must be careful.

Heat cramps are muscle pains or spasms that happen during heavy exercise in a hot environment. The muscles of the abdomen, arms and legs are most commonly affected. Heat cramps are an early warning that the body is having trouble staying cool and may be a sign of heat exhaustion.

Heat exhaustion is a form of heat stress that happens when the body gets too hot. It is caused by excessive sweating without replacing the body's fluids, such as during prolonged exposure to high temperatures or heavy exercise. Signs of heat exhaustion include dizziness, faintness, nausea, or headache. What to do if you suspect heat cramps or heat exhaustion:

• if the person has heart problems or is on a low sodium diet, get medical attention
• have the person stop exercising and lie down
• have the person rest in a shady or cool place
• loosen the person's clothing
• give the person plenty of cool non-alcoholic fluids, such as water, clear juice or a sports drink (Do not give iced drinks.)
• cool the person's skin by fanning or spray, sponge or bathe the person with cool water and
• seek medical attention if the symptoms get worse or last longer than 1 hour

Watch the person carefully for signs of heat stroke. Heat stroke happens when the body's temperature control system stops working. This is a serious emergency.

The signs of heat stroke include:

• body temperature of 104 degrees Fahrenheit (40 degrees Centigrade) or higher
• rapid heartbeat
• rapid and shallow breathing
• confusion, loss of judgment, fainting, or loss of consciousness and
• red hot, dry skin (no sweating)

What to do if you suspect heat stroke:

• call for help by dialing 911 or your local emergency number
• move the person to a cool place
• have the person lie down
• cool the person's skin any way you can (for example, wrap the person in a wet sheet or towel; put the person in a cool shower or tub of cool water; fan the person vigorously; or spray with cool water from a hose) and
• if the person can drink safely, give non-alcoholic beverages

To prevent heat stress:

• Drink plenty of fluids. Avoid beverages that contain alcohol, caffeine, or large amounts of sugar. Drink more than you would like and drink before you are thirsty.
• Stay indoors, and if possible, in an air-conditioned place. Taking a cool bath or shower can help your body cool off.
• Avoid strenuous exercise during the hottest part of the day. Temperatures are usually cooler before noon and in the evening.
• If you must be outside, protect yourself by wearing lightweight, light-colored, loose fitting clothing and a wide-brimmed hat, sunglasses, and sunscreen. Take rest breaks in a shady place.
• Do not take salt tablets.
• Never leave anyone in a closed, parked vehicle.

Last Reviewed 2005

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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