Heat disorders

"Heat stroke treatment is a vital emergency, since its mortality is lower if the patient is cooled down as soon as possible".


What is heat stroke?

Heat stroke is an uncontrolled rise in temperature due to a failure of thermoregulatory mechanisms, and can lead, if not treated early and properly, to serious multi-organ failure and death.

In this case the patients have a fever, almost always higher than 39-40ºC, alteration of the level of consciousness, which can reach a deep coma, and the skin is hot and dry, unlike what happened in heat collapse.

A heat stroke can occur due to an excessive increase in the external temperature. This is the so-called passive or classic heat stroke, which is typical of summer, especially in countries where very high and sustained temperatures are reached.

But there is also active or endogenous heat stroke, such as that produced by exercise.

Doing intense or prolonged physical exercise in hot conditions, and more so if humidity is high, is associated with a very high risk of heat stroke.

What are the most common symptoms of heat stroke?

The diseases produced by the heat in an acute way are frequent, although generally of little gravity in our environment.

A first mild manifestation is heat cramps, which occur in people who do physical activity in hot or humid conditions.

A more important picture is the so-called heat exhaustion or heat collapse, which is characterized by a good response of the hypothalamic thermoregulatory center, but there is nevertheless a failure in the cardio-circulatory mechanisms of adaptation to heat.

The most common symptoms are weakness, headache, dizziness, nausea and vomiting, but it can progress to situations of muscular incoordination and altered level of consciousness, making it difficult to differentiate these more serious forms of heat stroke.

A characteristic fact in heat stroke is that the patients are pale and sweaty, but their temperature is normal or only slightly elevated.

The most common symptoms are:

  • High body temperature.
  • Cramps.
  • Weakness.
  • Headache.
  • Dizziness.

Do you have any of these symptoms?

You may have a heat disorder

What are the causes of heat stroke?

Environmental Causes

  • Ambient temperature higher than body temperature.
  • High atmospheric humidity.
  • Heat overload due to radiation (metal buildings, cars).

Endogenous causes:

  • Fever.
  • Muscular effort for work or sport.
  • Malignant hyperthermia.

There are many other factors that favor the development of heat stroke. It is more frequent in people whose regulatory mechanisms are more deficient, such as children and the elderly. Also in debilitated, dehydrated or obese people.

Finally, the coexistence of other diseases (such as diabetes, hyperthyroidism, neurological, cardiovascular, pulmonary or renal diseases, etc.), alcoholism and taking different types of medication also increase the risk of suffering from heat stroke.

What is the prognosis?

Despite adequate treatment, mortality from heat stroke remains high, and survivors may have various neurological and other sequelae.

The disease has a worse prognosis in older people if there is severe neurological involvement, signs of multiorgan damage, or if cooling is delayed for more than an hour.

Therefore, the best strategy in this disease is prevention. Some of the basic tips that help prevent heat damage in all its forms are:

  • Avoid exposure to the sun and physical exercise during the central hours of the day.
  • Protect yourself from the sun properly, since sunburn makes heat dissipation difficult.
  • Maintain good hydration throughout the day. Do not wait until you are thirsty.
  • Drink especially before, during and after physical exercise. You can use water and, even better, isotonic solutions.
  • Reduce physical activity as much as possible if the temperature and humidity are high.
  • Avoid drinking alcoholic beverages.
  • Use lightweight, light-colored, loose-fitting clothing that is appropriate for the temperature in summer.
  • Do not keep children excessively warm during the hot season.
  • Ventilate the houses adequately.

How is heat stroke treated?

The treatment of heat stroke is a vital urgency, since its mortality is lower if the patient is cooled down as soon as possible. For this reason it is very important to diagnose the syndrome early and to suspect it in any patient with high fever and neurological alteration.

As soon as it is possible, the patient will be transferred to a hospital, but until then the objective to achieve is the reduction of the body temperature of the patient until it is between 38 and 39ºC. To do this, he should be placed in the coolest place possible, his clothes removed and he should be cooled with cold water compresses.

The patient can also be immersed directly in cold or warm water, but bearing in mind that too rapid and excessive contrast with the cold can contract the blood vessels of the skin and stimulate the appearance of chills, which can delay the cooling.

Once moved, cooling will continue and the necessary support measures will also be taken.

Therefore, the best strategy in this disease is prevention.

Where do we treat it?


The Department of Internal Medicine
of the Clínica Universidad de Navarra

Its integrative vision and polyvalence allow us to provide the best medical assistance to multipathological and multisymptomatic patients, who present a difficult diagnosis or who suffer from prevalent diseases of a hospital nature.

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clínica?

  • State-of-the-art diagnostic technology.
  • Quick diagnosis to start the most appropriate treatment early.
  • Teamwork with the rest of the professionals in the Clinic.

Our team of professionals