Symptoms, duration & what to do?

Quick overview: Frequently asked questions and answers

How does heat exhaustion manifest itself? Signs include heavy sweating, dizziness, nausea, headache, pale, cool skin and an increased heart rate.

What is the difference between heat exhaustion and heat stroke? In heat exhaustion, the body temperature usually remains normal or only slightly elevated, whereas in heat stroke it rises above 40 degrees Celsius and the skin is dry and hot.

How do you treat heat exhaustion? Immediate measures include moving to a cool area, drinking electrolyte-containing drinks, cooling the body with wet towels and elevating the legs. If the person is unconscious, call emergency services.

How long does it take to recover from heat exhaustion? With proper treatment, symptoms usually subside within a few hours. If symptoms worsen or do not improve, medical attention should be sought.

Article contents at a glance:

What is heat exhaustion?

Heat exhaustion is a form of heat injury that occurs when the body is exposed to high temperatures for a long period of time and does not absorb enough fluids and electrolytes.

At high temperatures, the body’s own heat regulation is particularly challenged in order to keep the body temperature at the target value of around 37 degrees Celsius. In older people, people with chronic illnesses or small children, however, the mechanisms for heat regulation are limited or not yet as effective. They are at increased risk of heat exhaustion on hot days.

How does heat exhaustion occur on hot days?

Physical exertion in high ambient temperatures, especially when there is high humidity, promotes the development of heat exhaustion. Another risk factor is a lack of air circulation in hot weather. This happens especially in large crowds in public places or stadiums. Physical exertion in hot weather also promotes the development of heat exhaustion.

The most important mechanism for regulating heat is sweating, because sweat cools the skin when it evaporates. When you sweat a lot, your body loses a lot of water and minerals. If you don’t compensate for the loss by drinking enough, you risk dehydration and your blood volume will decrease. This also causes your blood pressure to drop.

Another mechanism of heat regulation puts additional strain on the circulatory system: the blood vessels under the skin expand and absorb more blood in order to better dissipate heat through the skin.

Symptoms of heat exhaustion

As a result, the typical symptoms of heat exhaustion can occur:

Important difference to heat stroke: No high fever

The body temperature is not or hardly changed in heat exhaustion. This is an important difference to heat stroke, the most dangerous form of heat injury. The symptoms of heat stroke include a greatly increased body temperature of over 40 degrees Celsius and hot, dry skin.

Drinking and shade: Treating heat exhaustion

If you notice symptoms of heat exhaustion in yourself or someone else, you should act immediately: First, those affected should get out of the sun and lie down with their legs slightly raised to relieve the pressure on their circulation. Any exertion should be avoided.

In addition, the body should be actively cooled, for example with cool compresses or cool packs, especially on the groin, neck, feet and hands. Drinks containing electrolytes such as mineral water or broth help to compensate for the lack of fluids and minerals.

If unconsciousness occurs, the emergency doctor must be called and the affected person must be placed in a recovery position.

Heat exhaustion: duration of recovery varies

The measures mentioned above are usually sufficient for those affected to recover after a while. Anyone who has suffered from heat exhaustion should avoid extreme heat for at least three days.

However, the time it takes to recover from heat exhaustion can vary, depending on the severity of symptoms and how quickly treatment measures were taken:

• In milder cases, if action is taken early, the symptoms usually subside within a few hours.

• In more severe cases, it may take several days for the body to fully recover.

If those affected do not feel better or if the symptoms worsen in the days following heat exhaustion, they should consult a doctor.

Prevent heat exhaustion

Like other heat injuries, heat exhaustion can be prevented by the following measures:

• Wear light, breathable clothing

• Drink a lot, at least two to three liters per day

• Eat watery fruits and vegetables to provide the body with additional fluids

• Avoid alcohol as it puts additional strain on the circulatory system

• Avoid physical exertion in hot weather, rather do it in the cooler morning or evening hours

• Avoid direct sunlight, especially between 11 a.m. and 3 p.m.

• Do not go out into the sun without a hat

Providing cooling for people in need of care

For elderly or sick people, it is important to ensure that there is sufficient cooling in the living area, for example with fans, in addition to the measures mentioned above to prevent heat exhaustion. A drinking plan can also be useful to ensure that the person in need of care drinks enough.

Certain medications such as

• sedatives,
• Antidepressants,
• Diuretics and
• various antihypertensive agents

can worsen the body’s adaptation to heat. In this case, it is advisable to consult a doctor to see whether a change in medication is advisable during a heat wave.

Children are particularly sensitive to heat

Infants and children are also particularly susceptible to heat damage. When temperatures are high, they should stay in the shade wherever possible and reduce physical exertion. In addition, parents should give them twice to three times as much to drink as usual when temperatures reach 30 degrees Celsius or more.

Important: Do not leave a child in the car when the sun is shining or in summer in general, even with the window slightly down. Because of the lack of air circulation in the small space, temperatures in the vehicle quickly rise to critical levels that can cause heat exhaustion or even dangerous heat stroke.