No, a Sauna Is Not a Substitute for Exercise.
Spending time in a sauna can be enjoyable, but it can also be accompanied by some suffering; after all, if the weather outside were the same temperature as the sauna, you’d probably want to hide in the air-conditioned room all day. Something about the unpleasant physical sensations makes us think they’re somehow beneficial, and so the sauna has acquired a reputation for being beneficial, a reputation it doesn’t quite deserve. Here’s a quick overview of what a sauna can and can’t do for you.
Saunas do not burn fat.
Technically, it’s true that you can lose weight while sitting in a sauna, but it doesn’t happen because your body burns fat, but because you sweat, and sweat is made up of water, and water weighs. Once you rehydrate—which is essential—the scale will return to its original value. After all, as I mentioned in the context of exercise, sweating doesn’t mean you worked out well or burned calories. It just means you were hot.
Saunas and sauna service providers like to tout their calorie-burning benefits, but there’s no evidence that you burn significantly more calories sitting in a hot room than sitting on a couch at home. Some more skeptical websites cite a modest figure of 1.5-2 times more calories than you would burn sitting at room temperature, but without citing a source. If true, that’s about the same difference as sitting versus standing—so you might want to skip the sauna and just spend half an hour standing.
So why does your fitness tracker show you burned a ton of calories in the sauna? First of all, don’t take your phone into the sauna —it’s bad for your battery. But since you did, I’ll explain. Your watch’s calorie-counting algorithms estimate calories burned based on your heart rate , assuming you’re exercising . If your heart rate increases but you’re not exercising, the calculations are off. Calorie burning during exercise occurs because muscles throughout the body are constantly contracting. This doesn’t happen in a sauna.
Saunas do not “cleanse” the body of toxins.
It’s 2026, and as a society, it’s time to put an end to the concept of “detoxification,” which has been repeatedly debunked. Common discomforts like fatigue are sometimes not caused by hidden toxins constantly poisoning you, and even if you have health problems due to toxins, you should seek medical attention rather than expect a smoothie or sauna to cure you.
Saunas are not a substitute for exercise.
Both saunas and exercise heat the body and cause sweating, but beyond that, they have little in common. Remember that exercise makes us stronger and improves cardiovascular endurance (for example, by increasing VO2 max ). Sweating in a hot room doesn’t do the same.
Even this review by a sports science researcher , whose title draws parallels between running and sitting in a sauna, contains the following warning: “Before you think about canceling your gym membership and investing the savings in a hot tub, know that regular saunas or hot tubs cannot replace all the health benefits of exercise, such as fat burning and muscle gain. Hot tubs or saunas should not be considered a substitute for exercise.”
Sauna can be beneficial for blood vessels.
After a caveat, the researcher notes that there are several lesser-known benefits of exercise that appear to be related to increases in body temperature and heart rate, rather than the more obvious strain on the lungs or muscles.
When body temperature rises, blood vessels near the skin’s surface dilate, a process that can promote cell growth and repair. In other words, simply raising your body temperature can be beneficial for your blood vessels. We don’t usually think about it, but healthy blood vessels are part of a healthy cardiovascular system.
Relaxation is a reality.
If visiting a sauna relaxes you—and many of us do—it may have health benefits in itself. Of course, these benefits aren’t as specific as they sometimes seem. You won’t cure depression or heart disease simply by relaxing in a sauna every now and then. But if you enjoy sauna sessions, they can certainly help reduce stress and improve mental health. Pro tip: if you don’t have access to a sauna, a hot bath can also have many of these benefits.
The heat has its pros and cons.
For other ailments and sports, the advantages and disadvantages of a sauna boil down to the advantages and disadvantages of heat itself. If you have muscle pain, heat often provides relief, which is why athletes often enjoy sauna use.
Some skin conditions respond well to the dry air of a sauna, while others may be aggravated by dry air but may benefit from the humid air of a steam room. Use common sense and consult a doctor if you plan to use a sauna to treat any condition.
Saunas also carry risks.
If we’re talking about health benefits, it’s only fair to discuss the risks. Saunas are relatively safe, but people with medical conditions are often advised to avoid them or consult a doctor before visiting. This may include pregnant women, people with unusually high or low blood pressure, epilepsy, and those taking stimulants, tranquilizers, or psychoactive substances. Saunas have also been linked to a temporary decrease in fertility , as high temperatures impair sperm production.
The main danger of a sauna is the possibility of overheating or dehydration; both severe heatstroke and dehydration can be life-threatening, and people have died in saunas. Alcohol makes you more susceptible to this; according to a Finnish study , half of people who died in saunas were intoxicated. (The authors argue that the greatest danger lies not in the alcohol itself, but in allowing an intoxicated person to be in a sauna alone.) So, if you decide to spend time in a sauna, do so wisely. Drink enough water, don’t go alone, and don’t expect more from a sauna than it can offer.