Heat Related Illnesses

With summer is the potential for heat related illnesses. While most forms of heat-related illness are mild, the problem can cause significant mortality. Nearly 5,000 heat-related deaths have occurred in the U.S. over the last 23 years. In most cases, these deaths are preventable.

Persons at higher risk include those who perform strenuous activity outdoors, those with lung and heart diseases, those with chronic mental disorders, and those taking medications that interfere with salt and water balance. Early recognition of symptoms and rapid cooling are crucial, because progression to heat stroke is a medical emergency. The types of heat-related illnesses and how to treat them include:

Mild illness – includes cramps, edema, passing out and exhaustion.

Heat cramps can occur in any setting but are more common when exercising in hot and humid environments. Dehydration, depletion of electrolytes, and sodium losses from sweat all accelerate in this type of environment, especially in those who sweat profusely.

Treatment includes rest, prolonged stretching of affected muscle groups and oral salts with water or sports drinks.

Heat exhaustion includes the common symptoms of headache, weakness, dizziness, goose flesh, nausea, vomiting, diarrhea, irritability, and loss of coordination. The skin may appear pale. Importantly, normal mental clarity such as thinking and decision making is maintained and a body temperature of less than 104 degrees continues.

Treatment includes moving to a cool environment, lying down with legs elevated, oral hydration fluid replacement, and removal of excess clothing. Those affected should be transported to an emergency facility if symptoms do not improve after 20-30 minutes.

Severe illness – includes heat stroke

Heat stroke is a true emergency that requires immediate recognition and treatment. It is defined by an elevation of core temperature of 104 degrees F or greater associated with confusion, dizziness, hallucinations, headache, nausea/vomiting, and passing out. Perspiration may stop or it may continue.

Treatment includes calling an ambulance immediately. Rapid reduction of the body temperature is very important. Do not wait for the ambulance to arrive before giving treatment. Cold water immersion is the most effective, such as in a large tank or tub. Application of ice packs or cold, wet towels to the head, neck, armpits, and groin is another option. Rapid air movement with a fan, in combination with spraying a moderate-temperature mist of water is also effective. The individual should also be moved to a cool, shaded environment and have excess clothing removed.


When the heat index is higher than 95 degrees F, mortality increases. A heat index chart can be accessed at www.nws.noaa.gov/os/heat. When the heat index approaches this mark, cooling mechanisms should be in place. Employees should be encouraged to wear lightweight, light colored clothing. Shaded rest areas should be provided. Proper hydration (water or sports drinks instead of coffee, tea, or soda pop) should be encouraged. Frequent rest breaks should also be provided.

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