Heat intolerance: causes and symptoms

Ambient temperature can affect people differently. In this sense, many greatly dislike hot weather. However, the problem relapses when, beyond a dislike, is unable to withstand elevated temperatures, which may be known as heat intolerance.

In order to understand this phenomenon, it is important to know that the body automatically regulates its temperature. This is achieved through the hypothalamus, which activates various peripheral mechanisms to keep it within normal values.

Heat intolerance is a syndrome in which people are extremely uncomfortable in high temperatures. This can lead to excessive sweating and a feeling of overheating.

What can be the causes of heat intolerance?

The specific reason why this syndrome occurs is still unknown. However, studies show that an error in the transcription of certain genes can be a predisposing factor. On the other hand, some specialists prefer to treat it as a psychological problem.

Generally speaking, all situations that affect central or peripheral temperature regulation can trigger heat intolerance. In addition, pathologies or substances that accelerate the metabolism of individuals are also causal agents.

Menopausal hot flashes are a common cause of heat intolerance among women over 40 years of age.

Drug consumption

This is likely the most common cause of heat sensitivity. Drugs such as decongestants used to treat allergies and antihypertensives are responsible for cases of heat intolerance.

All of these medications prevent the production of sweat, so the body cannot dissipate heat on its own. Added to this, decongestants increase muscle activity, so the body will produce even more heat.


Caffeine is a stimulant substance that has the ability to increase the heart rate and speed up the metabolism. In this way, the body will be producing more heat than under normal conditions, which can trigger the problem.


This is a pathology characterized by an overproduction of thyroid hormones, especially thyroxine. This hormone intervenes in the growth and development of the individual by increasing energy production. In excess it tends to accelerate metabolism, which increases body temperature.

You can also read: Thyrotoxicosis: what is it and what is its treatment?


Upon reaching a certain age, women begin to suffer a hormonal imbalance that ends their reproductive stage; this is known as menopause. The hormonal changes suffered will generate a series of symptoms, including sensitivity to heat, which can manifest as a feeling of flushing.

Multiple sclerosis

Multiple sclerosis is a serious disease that affects the central and peripheral nervous systems. The same is characterized by an autoimmune reaction in which the myelin sheath covering the nerves is destroyed. This means that nerve impulses cannot be transmitted properly.

Heat intolerance is a common complication of this disease, as the hypothalamus is unable to efficiently send the command to lower the temperature. However, the increase in body temperature in these patients is also related to physical, cognitive and psychosocial fatigue.

When to visit a doctor?

This health problem may take time to appear, however, once manifested, it can last between 1 and 2 days. In most cases, people who suffer from it know the trigger. However, you should always see a doctor when there is no apparent cause or when symptoms last more than two days.

On the other hand, those who suffer from multiple sclerosis should be very attentive to the symptoms. It is important to visit the doctor if vision becomes blurred, since it could be in the presence of Uhthoff phenomenon, a series of neurological changes, especially visual, originated in thermal failure.

Diagnosis of heat intolerance

The diagnosis of this condition is quite complex and often represents a challenge for the specialist. First of all, the clinic should be specified. Symptoms that may appear include the following:

  • Exaggerated feeling of heat with hyperhidrosis or excessive sweating.
  • Headache and dizziness.
  • Muscle weakness with cramps.
  • Elevated body temperature

All these symptoms usually appear in warm environments that are well supported by other people. In addition, to try to find the possible cause, the doctor must analyze the patient's medical history and perform various tests.

The danger of heat intolerance is its derivation in hyperthermia that affect normal cell metabolisms.

Discover: 6 effects of heat on the body

Treatment and prevention

To prevent all the symptoms of this syndrome it is important to stay in cool areas. The ideal is to have an air conditioning, however, fans can also be useful.

Furthermore, it has also been shown that drink a glass of cold water during physical exercise decreases the likelihood of a heat intolerance attack.

On the other hand, if symptoms are already being suffered, it is important to suspend activities and remove the person from the warm environment. The main objective will be to lower the body temperature, so the patient must drink plenty of water and stay in a cool place.

Prevent heat intolerance to reduce damage

It is important to take all the necessary precautions to avoid suffering from this condition, especially if you have already had previous episodes or if you have a predisposing factor. In this sense, loose and light clothing should be worn, in addition to avoiding physical activity at high temperatures.

On the other hand, it is important to control heat intolerance once it occurs, since it can lead to a very dangerous state called hyperthermia or heatstroke. Therefore, it is a syndrome that should not be underestimated at any time and should not be taken lightly.