Why is sauna so exhausting?

A sauna session is usually very relaxing. But why do we feel limp and sleepy after a sauna session? There is a lot going on in your body that is causing your sleepiness. In this short article, you will learn why a sauna session can be both beneficial and exhausting for your body.
Why you feel tired and exhausted after the sauna session?

Why you feel tired and exhausted after the sauna session?

The heat that you find so pleasant and soothing is the cause of your sleepiness and exhaustion. The high temperature in the sauna increases your heart rate, and your blood vessels dilate. This, in turn, leads to a decrease in blood pressure. This is a natural and typical reaction to the heat in the sauna and can be positive for your health in many ways. However, it is a sign that your body is working harder and differently than it is used to. As a result, you may feel exhausted and tired.

Thermoregulation requires effort

Another body function is affected by sauna use and leads to fatigue. Thermoregulation is the mechanism that keeps the body temperature balanced and within the usual range. Two features of sauna affect thermoregulation and fatigue. When the central nervous system detects a rise in temperature, it instructs a brain region, the hypothalamus, to respond and deal with it. The hypothalamus, in turn, activates the rest of your body. The nervous system, muscles, organs and glands all go into action at the same time. Blood vessels also respond by dilating, a process called vasodilation, to cope with the increased blood flow and sweating.

Thermoregulation also affects the circadian rhythm

The circadian rhythm refers to a series of internal activities that contribute to your natural sleep-wake rhythm. Normally, your body temperature rises during the day and begins to drop at nightfall to allow you to sleep. The high heat of the sauna, followed by a gradual drop in body temperature, is consistent with this natural pattern.

When your body temperature drops, your body interprets this as a signal to sleep. It’s not surprising that you feel exhausted after a sauna session! After all, your body performs numerous tasks for you. In addition, other factors related to sauna use can also contribute to feelings of exhaustion and fatigue.

What happens after leaving the sauna?

When you leave the sauna, your body has to readjust. Cooling down is not a natural process. Your body has to work hard to achieve this cooling down. Vasoconstriction restores the natural diameter of blood vessels, and a process called thermogenesis allows your muscles and organs to generate heat. In other words: Your glands release hormones to boost metabolism and generate heat. Thermoregulation is very strenuous and stressful on the body. This is one of the main reasons why saunas require so much energy.

Other reasons that can contribute to exhaustion

In addition to our body’s natural reactions to the heat in the sauna, there are other factors that can contribute to fatigue and exhaustion.

  • Dehydration is a common result of intense sweating in the sauna. Excessive fluid loss leads to acute dehydration, which leaves us tired and exhausted. Therefore, make sure you drink enough water before taking a sauna and afterward to compensate for fluid loss.
  • People with certain medical conditions, such as diabetes or heart disease, should consult their doctor before using the sauna. Sauna sessions can aggravate these conditions and cause additional fatigue.
  • The high temperatures in the sauna speed up your heart rate and circulation. This can interfere with the distribution of some medications in your body and/or metabolism, leaving you fatigued and putting your health and safety at risk. It has been reported that corticosteroids and nicotine patches, as well as other medications, may be affected by sauna use. Consult your doctor or pharmacist if you are taking medications to make sure sauna use is safe for you.
  • If you disregard sauna safety rules and maintain an excessively high room temperature or stay in the sauna too long, you may endanger yourself and become fatigued. Also, never stay in a regular sauna for more than 15 minutes or in an infrared sauna for more than 20 minutes.


Remember why you are exhausted after your sauna session. Your organism has worked hard, it is actively involved in the recovery process, and thermoregulation signals you that it is time to sleep. You should use the sauna later in the day and take at least an hour to an hour and a half to cool down (otherwise, the higher temperature will keep you awake).


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