Medically reviewed by Katrina Carter, DPT
Saunas are often used for relaxation or health benefits, but some people may wonder of saunas burn calories. A sauna is a heated room that may increase the amount of calories burned during the 10 or 20 minutes a person is using it. There is a scant data demonstrating this temporary effect. But overall, the health benefits of saunas are still being investigated.
This article will cover how a sauna may be used, what the effects could be on the body, and who may be at higher risk for health problems when using a sauna.
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How a Sauna Is Used
A sauna could be a room or it could be a separate building itself. Saunas are temperature-controlled to heat the air to somewhere between 150 degrees F (65 degrees C) and 195 degrees F (90 degrees C). There are both dry heat and wet heat saunas.
Saunas are often located in gyms or spas, although some people may have them in their homes. A sauna might be used after a workout to relax muscles.
Saunas are places of relaxation, so people will usually sit on a bench. The temperature may be adjustable, depending on the sauna and if it’s public or private. In public spas, it may be recommended or required to wear a bathing suit or a towel. However, some saunas may allow full nudity.
A sauna may be used regularly or infrequently. People may spend anywhere between 10 and 20 minutes in a sauna, depending on their heat tolerance.
Some users may spend longer than 20 minutes in a sauna, but there are safety considerations to keep in mind with spending long periods of time in the heat. Feeling dizzy or weak is a reason to exit the sauna to a cooler area.
Calories Burned in a Sauna
Research into calories burned while using a sauna is lacking. Studies are not large or robust enough to understand how different sexes and body types respond to time in a sauna.
How many calories are burned depends on many factors, but one study looked at the duration of time in the sauna and a person’s body mass index (BMI), a calculation based on height and weight.
One study using a dry spa was done on sedentary young men. Four 10-minute sessions were used, with 5 minutes in between. The men burned about 73 calories in the first 10-minute session. In the fourth 10-minute session, the average calories burned increased to 134. Men with a higher BMI burned about 20 calories more than that average during the last session.
A Note on Gender and Sex Terminology
Verywell Health acknowledges that sex and gender are related concepts, but they are not the same. To reflect our sources accurately, this article uses terms like “female,” “male,” “woman,” and “man” as the sources use them.
Type of Weight Lost in a Sauna
The weight loss during a sauna session occurs through the loss of body fluids through sweat. There may be a small effect on weight loss from burning energy stores.
A study done in Poland looked at the weight lost after using a dry sauna. The young men and women included in the research were age 19 or 20. They were placed in a sauna for two sessions of 10 minutes each, with a five-minute cooldown in between.
The people in the study lost body mass because of fluid loss. People with a higher BMI lost more water and were more likely to become dehydrated. The authors stress that hydrating during a sauna session is important to prevent dehydration.
Another study on young men showed they lost body mass after using a sauna. However, this was largely due to losing body fluids through sweat. Again, study participants with higher body mass and more body surface area lost more fluids. The study’s authors reinforced that people with a higher BMI should drink more fluids to replace those lost during a sauna session.
Health Benefits of Sauna
There could be some health benefits from regular use of a sauna. Acute heat beyond what humans find comfortable is stressful. However, people can become used to the heat over time and are better able to tolerate it.
One review paper examined the research on how Finnish saunas affected health. Some of the benefits that the authors of this study found included:
- Decrease in risk of death from heart disease or other causes
- Improved relaxation
- Lower blood pressure
- Reduced incidence of Alzheimer’s disease and dementia
- Reduced incidence of lung disease
Another paper based on health effects of regular users of Finnish saunas stressed that sauna bathing is relatively safe for people who have stable cardiovascular health. Using a sauna might have the same effect on the body as a high-intensity walk.
It’s thought that the overall health benefits may come from some changes to the body that include lowering blood pressure, reducing inflammation, nervous system regulation, and lowering cholesterol levels.
Precautions and Drawbacks of Sauna
For healthy people, sauna use is thought to be safe, as long as it’s enjoyed in moderation. Using a sauna too often or for too long each time could lead to health risks. Some of these can include:
Dehydration is a risk of sauna use. Losing too much of the body’s fluids through heat stress can lead to serious health issues. Losing between 8% and 10% of the body’s fluids could be fatal.
People with high blood pressure (hypertension) should talk to their healthcare provider about the use of a sauna. The use of a sauna may be safe when blood pressure is well controlled. Taking care to move slowly from an area of extreme heat to one that’s cooler is important.
Anyone using a sauna should be aware of the risks of dehydration. Replacing the lost fluids is important. Healthy people can replenish by drinking more fluids, most importantly water. Increasing fluid intake can be done both during the use of the sauna and after. Electrolyte formulas are usually not needed.
Other guidelines for safe sauna use include:
- Avoiding alcohol
- Avoiding medications that reduce the body’s ability to sweat
- Avoiding using a sauna when feeling ill
- Cooling down gradually
- Only using a sauna for 15 to 20 minutes at a time
Research is limited on whether you burn extra calories by sitting in a sauna, but you may burn some additional calories. Sauna use is not a substitute for a healthy diet, regular exercise, or a sustainable weight loss method.
Losing fluid through sweat is a risk of sauna bathing. People who are at risk for dehydration for any reason should talk to a healthcare provider before using a sauna.
Using a sauna regularly for a typical 10- to 20-minute session is thought to be safe for healthy people. There may be health benefits for some people with regular sauna use.
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