In the ever-evolving landscape of weight loss strategies, people are continually seeking new ways to shed those stubborn pounds and achieve their fitness goals. One trend that is gaining traction in the health space might seem unconventional: using saunas. But can using a sauna really help you lose weight? Let's explore the science behind sauna weight loss, including what studies say, how the process works, and whether it’s worth adding to your health routine.
What is a Sauna?
A sauna is a small room or space designed to expose you to heat, whether it’s using a dry heat or infrared technology. Saunas are commonly found in fitness centers, spas, and wellness centers. Saunas have been used for millennia, incorporated into cultural and social traditions. But as time has passed, more and more people have integrated sauna into their wellness routine. And for some advocates, sauna has another effect -on the scale.
Saunas are typically heated between 110 and 195 degrees, depending on the type, per the Cleveland Clinic.
Types of Saunas
Different types of saunas include:
- Wood-burning saunas: The most traditional type of sauna and use fire to heat up the space. "These saunas are typically fueled by dry, seasoned hardwoods like birch, oak, or maple-woods that burn hot, clean, and long, creating a soft, humid heat and a subtle, earthy aroma that many people find grounding," says functional medicine physician Jaclyn Tolentino, DO. Wood-burning stoves are used to heat sauna rocks. Temperatures are high and humidity is low.
- Electric saunas: Produce heat with electricity, “usually through built-in heating elements that warm up rocks or panels," Dr. Tolentino says. An electric heater mounted on the floor or wall is used to heat the room. Temperatures are high and humidity is low.
- Infrared saunas: Utilize infrared light waves to warm your body up directly without raising the temperature of the air around you, says Dr. Tolentino. They supposedly spark the same effects in your body as a traditional sauna but at a lower temp, she says. This type of sauna uses infrared lamps and electromagnetic magic to create heat that’s typically a lower temperature than traditional saunas. The benefits are similar to more conventional saunas.
- Steam rooms: You might also know these as “Turkish bath houses.” Temperatures are low and humidity is high, at 100 percent. Steam room uses humidity. When it comes to dry heat versus wet heat, there’s no clear indication that one is better than another,” clarifies Dr. Zack. “With infrared saunas, there is no external heat that’s generated, only heat that’s generated in the body from the infrared light.”
The Science Behind Sauna Weight Loss
One of the immediate effects of using a sauna is water weight loss. When you spend time in a sauna, your body sweats - a lot - to regulate its temperature. This significant sweating leads to fluid loss. Researchers found that four 10-minute sauna sessions, with a 5-minute break in between, resulted in body mass loss. The people whose body weight was within a normal range lost less. But before you get too excited, fluid loss in a sauna is not a path to permanent weight loss.
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Increased Caloric Burn
Several sources suggest that a session in a sauna may help you burn a significant number of calories. According to a study published in the Journal of the American Medical Association, a 30-minute sauna session can burn as many as 600 calories. The reason? As your body works to cool itself, your heart rate, cardiac output, and metabolic rate increase-similar to moderate exercise. This effect mimics what happens during aerobic workouts, making sauna weight loss an appealing option for those with limited mobility or recovering from injuries.
Water Weight and Sweating
Sweating helps your body eliminate excess water and salt. A single session in a sauna can make you sweat profusely, leading to temporary weight loss. However, it’s essential to note that this is mostly water weight, not fat loss. Once you rehydrate, that weight typically returns. Still, regular use may help with overall body composition when combined with a healthy lifestyle, as shown in this 2019 study from Complementary Therapies in Medicine.
Improved Circulation and Metabolism
Heat increases circulation, which can improve oxygen delivery and nutrient transport throughout the body. A faster metabolism means your body burns more calories even at rest. One study in Alternative Medicine Review found that subjects who used saunas regularly experienced improvements in cardiovascular health and basal metabolic rate. This provides another mechanism through which sauna weight loss might be possible over time.
Are there any other weight loss benefits?
Using a sauna for weight loss isn't completely useless, as it does burn calories (more on that shortly), and it can have other health benefits that can contribute to your efforts to lose weight. With that being said, using a sauna for weight loss is unlikely to help you lose weight on any significant level unless you're also eating a balanced, nutrient-rich diet and engaging in regular exercise.
How long should you be in a sauna to lose weight?
While sauna use is not thought to lead to significant or sustainable weight loss - as the weight lost is primarily water weight from sweating - it does have other health benefits that can increase your other weight loss efforts, like getting regular exercise.
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For post-exercise recovery and other general health benefits, sauna sessions are typically recommended to last between 15 and 20 minutes.
If you decide to use a sauna for weight loss or as a part of your healthy lifestyle, it's important to start slowly. Begin with shorter sessions, and increase the duration as your body becomes accustomed to regular dry sauna bathing. It's also important to stay hydrated and drink plenty of water before, during and after your sauna therapy session in order to prevent dehydration. Finally, make sure to listen to your body. If you find yourself feeling dizzy, lightheaded or otherwise unwell, leave the sauna and seek assistance if necessary.
Can saunas help burn fat?
Saunas themselves do not directly burn fat. The weight loss observed after a sauna session is primarily due to water loss through sweating, which is temporary and regained upon rehydration. With that being said, there are a few ways that saunas can have indirect benefits that may support weight loss or body mass loss.
The primary way that sauna therapy can help your body burn fat is by helping your post-exercise recovery. This is because sauna therapy can help with muscle relaxation and recovery after exercise, and in turn, this may make your workout routine more sustainable. By keeping up the consistency in your exercise regime, you may find that losing weight becomes easier.
The heat from the sauna bath can also increase your heart rate in a way that is similar to moderate exercise. This can have some cardiovascular benefits, and help to control high blood pressure. In turn, this can help to improve your exercise abilities.
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Finally, saunas are a great way to reduce stress and improve the quality of your sleep. Just as exercise is important for weight loss, rest and recovery are crucial to your overall healthy lifestyle, and this can support weight management.
How many calories can you burn during a sauna session?
There are many variables specific to each individual that will affect how many calories a person can burn in a sauna bath. Each person will burn calories at a different rate, depending on factors like their weight, the temperature of the sauna, and how long their session goes for.
On average, a person might burn approximately 100-300 calories during a 30-minute sauna session, but it's important to keep in mind that the primary purpose of a sauna is relaxation and recovery, not calorie burning or weight loss. The calorie expenditure in a sauna is modest compared to activities like running, cycling, or strength training.
Sauna Benefits
Saunas offer a variety of health benefits while also providing relaxation and rejuvenation. But do saunas help you lose weight? In short - yes! However, there’s much more to how it works, and there are several things you need to know to ensure safe weight loss. While using a sauna shouldn’t be your only weight loss effort, it can complement a healthy lifestyle. It does provide some weight loss benefits, but it’s best when used in combination with other elements, like a healthy diet and a consistent workout routine.
Here are some more potential benefits of sauna use:
Muscle recovery
The heat helps relax muscles and relieve soreness, which can aid in recovery after intense physical activity. Sauna baths are most often practiced for recovery after exercise. A single visit to a Finnish sauna (three sessions of 10 min each at 90°C and 10% relative air humidity) directly after 30 minutes of aerobic exercise reduces oxidative stress. Heat increases the effectiveness of muscle restitution processes; it improves the flexibility and extensibility of connective tissue structures, which increases overall flexibility levels. Sauna is used in sports to maximize the athletes' physical and psychological recovery.
Using a sauna can benefit your overall skin health because it helps bring blood flow to the surface of your skin before you start sweating. Regular sauna use makes the skin more robust-meaning it sort of firms it up-and makes it more elastic, which is good for aesthetic reasons, but also because the skin acts like a general health barrier.
Stress reduction
Saunas promote relaxation and reduce stress levels, contributing to overall mental well-being. Sauna bathing is a regular part of Scandinavian culture as a way to destress and relax, says Dr. Millstine. According to 2024 research in Frontiers in Public Health, women who sat for sporadic 20-minute sessions in a sauna with a temperature of 80 degrees Celsius, or 176 degrees Fahrenheit, experienced less tension, depression, anger, and fatigue when it came to their mental health. If you can easily and frequently integrate sauna sessions into your schedule (bonus points if you can socialize while using it!), the sauna “likely will reduce your stress levels,” Dr. Millstine adds.
Detoxification
Sweating in a sauna can help remove toxins from the body through the skin.
Improved skin health
Increased blood circulation and sweating can help cleanse the skin and improve its elasticity and texture. The steam our skin is exposed to in a sauna has been shown to have two major benefits: improve the hydration of skin and reduce the acne-causing sebum content of our skin," Dr. Ilyas says. That said, more research is needed on the sauna’s exact scientific benefits on skin.
Improved sleep
The relaxation effect of saunas can lead to better sleep quality and help address insomnia.
Enhanced mood
The release of endorphins during a sauna session can improve mood and promote a sense of well-being.
Improve cardiovascular health
Research shows that people who regularly use a sauna at least four times a week for 20 minutes have a significantly lower risk of heart attack, stroke, and dementia, notes Dr. Parikh. Sauna bathing may also help increase cardiovascular fitness, per 2022 research in the American Journal of Physiology.
“In those with no underlying cardiovascular disease, sauna bathing may be helpful to modulate the autonomic nervous system and reduce blood pressure," says Dr. Li. It may also be helpful to improve dilation of the smooth muscles and reduce arterial stiffness, he adds.
Improves lung function
If you have asthma and chronic obstructive pulmonary disease (COPD), research shows that regular sauna use may help with your lung function. Wet sauna use likely hydrates the respiratory tract, improving the ability to move mucus from the respiratory tract more easily with coughing. However, those sensitive to temperature changes may not tolerate sauna use and all patients should consult their primary care physician or specialist.
Improves immune system
Saunas may also help prevent the common cold and other viral infections, research shows. Further research is needed to substantiate claims of improvement in the immune system.
Lowers risk of dementia and Alzheimer’s disease
While a study shows that regular sauna use may help reduce the risk of neurocognitive diseases like dementia and Alzheimer’s disease, Dr. Zack says that more research is needed. There may also be benefits that include improved cognition, however, the physiological reasons for these benefits are not yet known.
Sauna use and BMI
The main aim of the study was to evaluate the relationship between BMI and BML induced by thermal stress in a dry sauna in young sedentary women and men. It must be noted that for a person with a sedentary to active lifestyle, the average daily water demand is 2-4 L in a temperate climate and 4-10 L in a hot climate.
In humans, the most effective method of heat elimination is sweating and evaporation of water from the skin. The inhabitants of desert areas perspire 0.3-1.2 L of water per hour when performing routine daily tasks. Persons performing light exercise in protective clothing generally lose 1.0-2.5 L of water per hour. The risks and benefits of sauna bathing have been researched extensively, but most studies were conducted on a small number of participants. During sauna bathing, precipitation is intensified to maintain body temperature at a fairly constant level, which can lead to significant loss of bodily fluids. The magnitude of increase in core temperature ranges from 0.1 to 0.25°C for every percent BML.
BML cannot be entirely attributed to dehydration, and it also results from the utilization of energy stores (glycogen, triglycerides) [34]. Both dehydration and overheating can negatively affect basic physiological functions. Fluid replenishment is recommended during and directly after sauna bathing. Incomplete fluid replacement decreases total body water levels. During sauna bathing, sweating begins quickly and reaches its maximum at approximately 15 minutes, with average total secretion of 0.5 kg. The quantity and quality of ingested fluids should be precisely determined. According to experts, sauna-goers should drink 400-800 mL/h of fluids containing 60-80 g of simple sugars and 400-1100 g of sodium during every bathing session.
A statistical analysis of the results revealed significant correlations between BMI and BML induced by heat stress in a dry sauna. BML caused by a 20-minute visit to the sauna was determined in the range of 0.24 kg for women with BMI <18.5 and of 0.82 kg for men with BMI >24.99. The noted correlations between BMI and BML values were not linear. Percentage BML in women with BMI >25 was nearly twofold higher than in the group of women with BMI <18.5. Similar correlations were observed in men. The relationship between BMI and BML is directly proportional, which implies that BML increases with a rise in BMI values. The above can probably be attributed to an increase in body surface area, which promotes heat loss through radiation. Our results suggest that persons with a high BMI are more susceptible to dehydration; therefore, they should always replenish fluids during and directly after sauna bathing.
The results of our study and the findings of other authors indicate that sauna bathing has a significant effect on BML. BML is determined by the severity of heat stress (temperature, humidity, exposure time, breaks between sessions, and quantity and quality of ingested fluids), anthropometric parameters, and proportions (BMI).
Risks of Using a Sauna
Sauna use can have some risks, especially if proper precautions are not taken.
Dehydration
Excessive sweating can lead to severe dehydration if you don't drink enough water before, during, and after your sauna session.
Overheating
Prolonged exposure to high temperatures can cause overheating, leading to heat exhaustion or heat stroke. Symptoms include dizziness, nausea, headache, and confusion.
Skin burns
Direct contact with hot surfaces inside the sauna can cause burns.
Pregnancy risks
Pregnant women should consult their healthcare provider before using a sauna, as high temperatures can pose risks to the developing foetus.
How to Use a Sauna Safely
There are several ways to ensure that you're using the sauna room safely and minimising any potential risks. If you have any health concerns or pre-existing medical conditions, your best bet will be to consult with your doctor before starting a regular sauna routine.
Before you begin your sauna session, make sure to drink plenty of water, and avoid alcohol or eating a heavy meal, as these can increase your risk of dehydration and overheating.
It's a good idea to start with shorter sessions of 10-15 minutes a few times a week and build your tolerance from there. Gradually increase the length of your sessions as you get used to the heat, but try not to exceed 20 minutes.
Keep the sauna temperature between 65-90°C - higher temperatures and increase the risk of overheating. Sit on a towel for your sessions, both for hygiene and to avoid direct contact with hot surfaces.
Most importantly, listen to your body! If you find that you're feeling dizzy, lightheaded, nauseous, or uncomfortable, leave the sauna immediately. It's not worth risking a medical emergency.
After your session, let your body cool down naturally, either with a cool shower or resting in a cooler environment. Drink plenty of water to replenish the water your body sweat out during the session.
Some additional tips
- Avoid saunas if you’re unwell: Do not use a sauna if you have a fever, infection, or feel generally unwell.
- Sauna attire: Wear a swimsuit or go naked, depending on the sauna's rules and cultural norms. Always sit on a towel if you are naked.
Experts say you should avoid the sauna if:
- You’re sick or have a fever, “as the heat can increase your body temperature, ultimately making it worse,” says Raj Dasgupta, MD, the chief medical advisor for Sleep Advisor.
- You have drugs or alcohol in your system
- You have a cardiovascular condition like a heart condition or high blood pressure, since "the heat can put more stress on the cardiovascular system, leading to more complications,” Dr. Dasgupta says. You may also be at risk if you've recently had a heart attack, adds Dr. Parikh.
- If you're pregnant, be sure to consult your doctor first as "excessive heat can potentially harm the fetus," says Dr. Dasgupta.
Realistic Expectations: What Saunas Can and Can’t Do
Let’s be clear-sauna weight loss is not a magic bullet. If your lifestyle includes poor diet choices and a sedentary routine, a sauna alone won’t lead to dramatic weight loss. However, as part of a holistic approach that includes exercise, healthy eating, and hydration, it can be a valuable complementary tool.
What You Can Expect: