Preventing Heat Illness

Trying to keep cool

When a person spends an extended period of time in hot temperatures, they may experience heat stroke. Heat stroke also occurs when a person is active during warm weather and does not rest to cool down or take in enough fluids. The body temperature climbs to 104 degrees Fahrenheit. Generally, the condition occurs after other milder forms of heat illness, including heat cramps, heat exhaustion, and heat syncope or fainting. Children and older adults are more susceptible to the condition.

Types of Heat Illness

Heat illness typically occurs in a progression. Before a person has full-blown heat stroke, they may experience heat cramps, heat edema or swelling, heat exhaustion or heat rash. Heat cramps usually occur in the muscles of the legs. Exercising in very hot weather typically brings them on, as the body loses salt through sweat, which makes the muscles contract. Resting and massaging the muscles when the cramps occur helps relieve them.

Heat edema occurs when a person's hands or feet swell in warm weather. Hot temperatures cause the blood vessels to dilate, so that blood flows more easily into the appendages. Swelling is more common in older people or in people who are not used to hot weather. Some people also experience a condition known as heat syncope in hot weather. Syncope means the person feels dizzy or faints during hot weather. The person may faint after standing for a long period of time or may feel dizzy after standing up quickly.

Another heat illness is prickly heat, sometimes called heat rash. It usually affects babies, but can occur in children and adults as well. The sweat ducts on the skin become blocked, so that sweat is trapped under the skin. The trapped sweat causes inflammation and redness. People can get heat rash from being outside in hot weather. They may also get it if they are confined to a bed and have a fever.

Heat stress, or heat tetany, occurs when a person works in a stressful situation in hot weather. For example, a person working in construction or another job that requires physical exertion may experience heat stress. Signs of the condition include hyperventilating or spasms in the muscles. A person may also have general breathing problems due to heat stress.

Heat exhaustion tends to occur before heat stroke. It usually occurs in hot weather when a person has not had enough to drink. Treatment is needed right away so that the condition does not progress to heat stroke. Moving to a cooler area, drinking water and taking a cool bath can help relieve heat exhaustion.

Heat headache

Signs and Symptoms

Symptoms of heat illness vary based on the severity of the condition. When a person has heat cramps, they may sweat a lot, feel tired, and experience pain in the legs and arms. As the illness progresses to heat exhaustion, the person may have a headache, have clammy, cool skin, and feel weak. The person may also be irritable. As the body temperature increases to full-blown heat stroke, the person may act confused. Fainting or falling into a coma can also occur. Other symptoms of heat stroke include a rapid heartbeat, nausea, and red skin.


People can experience heat illness simply by being in a hot environment. In some cases, the heat illness occurs after physical exertion.Certain factors make heat illness more likely to occur. These factors include wearing a lot of clothing, drinking alcoholic beverages, or failing to drink enough fluid. Alcohol makes it difficult for the body to control its temperature. Other causes of heat illness include taking medications such as diuretics or having a problem with the sweat glands.


Heat illness can be prevented. On very hot days, people should avoid engaging in very strenuous activity outside. If activity cannot be avoided, a person should make sure to rest often in a cooler area. They should also wear loose-fitting clothes and clothes that are light in color, as dark-colored clothing absorbs heat. Drinking enough fluids such as water is also important for preventing heat illness.


Treatment and Prognosis

Treatment of heat illness depends on how advanced it is. Heat exhaustion and other early stages of heat illness can be treated by having a person rest in a cool, air-conditioned area. They should drink cool, but not cold, water or a sports drink. The person may also take a cool bath or shower or sit by a fan. If the person has heat stroke, they usually need treatment from a doctor. A doctor may use evaporative cooling, or spraying the person with water, to help lower their body temperature. In some cases, a doctor may have a person sit in a bath of cool water.

Treatment is absolutely essential. With treatment, most people recover. Without it, a person can experience shock or organ failure. In some cases, untreated heat stroke can be fatal.