Heat stroke is heat damage that occurs primarily at high temperatures. Other heat injuries are sunstroke or heat convulsions, which, however, differ in their extent and origin from heat stroke. Heat stroke describes the physical temperature increase to over 40 degrees Celsius, caused by increased ambient temperatures.


The most important cause is a strong one Overheating of the body. In contrast to sunstroke, direct sunlight is not absolutely necessary for this, but greatly increased ambient temperatures can be sufficient. Usually the body has several ways to cool down the body temperature. The most important of these high temperature methods is that sweat. By releasing droplets onto the body surface, which evaporate there, the skin cools down considerably. In the case of extremely strong heat, these regulatory mechanisms can no longer compensate for this.

Important factors for overheating are direct sunlight, a heat-retaining environment and high humidity. Typical situations in which heat stroke can occur are going to the sauna or leaving children alone in a closed car at high temperatures. In the latter situation, high temperatures of around 70 degrees can develop in the car.

The main causes of heat stroke are the processes that take place in the body as a result of the heat. The worst consequences of heat stroke are a collapse of the cardiovascular system and water retention from the blood vessels into the brain matter, so-called "Brain edema". The latter lead to the commonly perceived symptoms such as drowsiness, visual disturbances or loss of consciousness.


It is extremely important to recognize the first signs of an impending heat stroke. Since this is a potentially life-threatening situation, action must be taken at the first sign. First of all, those affected should become aware that their body temperature rises and the feeling of glow and the "unbearable" heat becomes stronger. With children where this is not possible, parents often find that Face flushes is, the temperature rises and the Skin dry becomes. The entire skin may turn bluish-red in color. This is a typical sign that the body is no longer in control of temperature regulation.

As a result, one can increasingly feel in oneself, but also in other people Disorientation, sleepiness and Drowsiness determine. These signs are to be taken very seriously, as they may already have had effects on the brain.

Concomitant symptoms

Aside from the obvious overheating, dehydration and reddening of the skin, accompanying symptoms can increasingly be identified as the heat stroke progresses. The Cardiovascular system also shows reactions to the high temperature and the dehydration. The blood thickens and the Heart rate increases. Due to the anemia it can in an emergency in addition to one Drop in blood pressure come that in the unconsciousness ends. This condition is called "hypovolemic shock" designated. If the heart rate exceeds the upper blood pressure value, this can be an indication of an acute circulatory collapse.

The brain is also affected by heat stroke. It can lead to water retention in the brain, so-called "brain edema". This can initially lead to drowsiness, drowsiness, dizziness and loss of consciousness. Headaches, seizures, nausea, visual disturbances, ringing in the ears, restlessness and fatigue can also occur.

Diarrhea from heat stroke

Diarrhea is a rarer symptom acute heat stroke. The exact connection has not been clearly established. One possible cause is the imbalance in the electrolyte balance caused by the increased temperature. Just as the fluid flows from the vessels into the brain, the stomach cannot absorb the fluid, which leads to diarrhea.

With diarrhea you are in one Vicious circle, as diarrhea increases the effects of heat. Severe diarrhea and lack of fluids combined with high temperatures can trigger heat stroke again.

In addition, especially with prolonged, high temperatures in the summer months, the number of diseases and Gastrointestinal infections increases. In the event of heat stroke that occurs in connection with previous diarrhea, an accompanying intestinal infection must always be considered.


The diagnosis needs to be made quickly as it is sometimes life threatening acute medical situations. The anamnesis after high temperatures and strong sunlight together with a rectally measured temperature of over 40 degrees is sufficient for the diagnosis of heat stroke.

First aid measures

The most important measure is to avoid the heat and immediately Body temperature cooling. An ambulance should also be called immediately so that there are already potential cases Cerebral edema therapy can be initiated.

An important measure to cool down the body temperature despite high outside temperatures is to store in the shade and remove all heat-storing clothing. Then the body should with cool water getting washed. In addition come cold compresses and ice packs in the neck, on the forehead and the rest of the skin. Cold air created by fans can also cool the body considerably. The legs should be where possible not elevated as this can promote potential brain edema. Then you have to do a lot to balance the fluid and electrolyte balance Drank water If available, drinks containing electrolytes are also available.

Therapy of heat stroke

The most important steps in the treatment of heat stroke consist of first aid measures to prevent the symptoms from progressing and to keep the cardiovascular system stable before it collapses. As soon as the medical attention arrives, further measures are available. About fast chilled infusions the water and electrolyte balance can be adjusted. Once the temperature has normalized, a medical therapy to treat the Brain edema respectively.

Duration of heat stroke

The duration depends on the severity of the heat stroke. Often, the drowsiness and other neurological symptoms can be detected early before damage occurs. The normalization of body temperature and the equilibration of the fluid balance can be achieved within less hours occur. In cases without long-term consequences, fatigue and drowsiness can persist for several days.

What are the consequences of heat stroke

It is often underestimated that acute heat stroke is a life-threatening acute situation. Especially that Heart and brain can be damaged by heat stroke. Even after the treatment, the brain may have suffered long-term damage from the edema. This can lead to very different mild to severe neurological disorders, disabilities and deficits. Through the resulting in an emergency hypovolemic shock other organs can also be affected. For example the kidneys are heavily dependent on continuous blood flow and can be damaged if blood pressure drops.

What is the difference to sunstroke?

A sunstroke is one disorder limited to the headcaused by direct sunlight. Long-wave sun rays are to blame in the brain too Cerebral edema and Meningeal irritation being able to lead. The symptoms are similar, but unlike heat stroke, sunstroke cannot occur through overheating alone. From sunstroke are particular Toddlers and bald people affected.