Heat-Related Illness Fact Sheet (PDF)
What is heat-related illness?
Heat-related illnesses occur when the body's temperature gets too high. The body normally cools itself by sweating, but under some conditions, sweating is not enough and a person's body temperature rises rapidly. Very high body temperatures may damage the brain or other vital organs.
What factors increase the risk for heat-related illness?
- Age (children under 4 years and adults over 65 years are at highest risk)
- Certain health conditions, such as obesity, heart disease, and poor circulation
- Certain medications
- High levels of humidity (sweat does not evaporate as quickly, preventing the body from releasing heat quickly)
- Exertion in hot weather
- Lack of air conditioning
- Alcohol use
- Sunburn
- Fever
- Dehydration
What are symptoms of heat-related illnesses?
Heat cramps happen when sweating reduces the body's salt and moisture levels. Low salt levels in muscles cause painful cramps. Symptoms of heat cramps include:
- Heavy sweating
- Muscle cramps
- Pain or spasms in the stomach, arms, or legs.
Heat exhaustion is the body's response to a large loss of the water and salt, usually through a large amount of sweating. Symptoms of heat exhaustion may include:
- Headache
- Irritability
- Fainting
- Nausea
- Muscle cramps
- Cold and clammy skin
- Dizziness
- Thirst
- Fast, weak pulse
- Weakness
- Heavy sweating
- Elevated body temperature
Heat stroke is the most serious heat-related illness, occurring when the body becomes unable to control its temperature; the body's temperature rises rapidly and sweating fails to cool down the body. Heat stroke can cause death or permanent disability if emergency treatment is not given. Symptoms of heat stroke can include:
- Slurred speech
- Rapid breathing
- Fast, strong pulse
- Headache
- Profuse sweating
- Seizures
- Confusion/altered mental state
- Skin that is hot and dry, damp, or flushed
- Very high body temperature
- Loss of consciousness (coma)
What should I do if I notice these symptoms?
Heat Cramps
- Stop physical activity and move to a cool place.
- Drink water or a sports drink.
- Wait for cramps to go away before resuming physical activity.
- Get medical help if you have heart problems, are on a low sodium diet, or if cramps do not subside within 1 hour.
Heat Exhaustion and Heat Stroke
- For suspected heat stroke, call 911 right away. Heat stroke is a medical emergency.
- For suspected heat exhaustion, get medical help right away if you are throwing up, your symptoms get worse, or your symptoms last longer than 1 hour.
- Move to a cooler place.
- Loosen clothing.
- Put cool, wet cloths on your body or take a cool bath.
- Sip water.
How do I prevent heat-related illness?
Stay Cool
- Wear appropriate clothing.
- Stay in air-conditioning as much as possible.
- Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Cool showers or baths, or moving to an air-conditioned place, is a better way to cool off. Use your stove and oven less to maintain a cooler temperature in your home.
- Schedule outdoor activities carefully, and pace yourself.
- Wear sunscreen.
- Do not leave children or pets in cars.
Stay Hydrated
- Drink plenty of fluids, but stay away from sugary or alcoholic drinks as they can lead to dehydration.
- Replace salts and minerals with sports drinks or fruit juice if you are sweating heavily.
- Keep pets hydrated as well by providing plenty of fresh water in cool, shady areas for them.
Stay Informed
- Check your local news for heat alerts and safety tips.
- Know the signs of heat-related illness and monitor those at high risk.
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