Using the sauna is helpful when losing weight, but perhaps not for the reasons that would be presumed. Following use of the sauna, the loss in weight experienced is primarily related to a loss of water and not the burning of fat. In reality, the main advantages of using the sauna on a regular basis are the indirect results. These include improved sleep, lowering of cortisol levels, increased muscle recovery, and improved cardiovascular health.

If you’re considering incorporating sauna sessions into a weight loss plan, it is essential to consider what the research says and how best to implement them. Our programs at TH7 Body Labs have been developed with this in mind.

The short answer

In an average sauna experience, you will see your weight fall by between one and two kilograms. This is not due to burning fat but because of profuse perspiration. When you drink water, you will regain the lost weight almost instantly.

Although heat treatment is not capable of melting fat directly, there are some aspects of heat treatment that may help with weight loss. This treatment can speed up your recovery process, help you get a good night’s sleep, and help you reduce stress. Heat treatment can also make your training more productive.

What happens to your body in a sauna?

Upon entering a sauna set at 70°C to 90°C, your body will not just rest there. Rather, your body will undergo a series of physiological changes due to the heat, which can make the whole process much more beneficial if fully understood.

Heart rate and circulation

When relaxing in the sauna, the heart rate will go up significantly from a normal rate of 60 to 70 beats per minute to 100 to 150 beats per minute. This is due to the fact that the heart rate increases to match the physiological changes brought about by physical exercises like walking at a fast pace or biking at an easy pace. The blood vessels become wider to allow more warm blood to flow into the skin surface, leading to improved circulation in the body.

Core temperature and metabolic response

During a 15 to 20-minute sauna session, your core temperature can increase by one to two degrees Celsius. Your body works diligently to manage this rise, engaging in activities such as sweating, redirecting blood flow, and increasing metabolic activity while maintaining electrolyte balance. The energy expended during this process contributes to calorie burning, not because the heat directly burns fat, but due to the body’s efforts to regulate its temperature.

Hormonal changes during heat exposure

Exposure to heat initiates a series of hormonal responses. Growth hormone levels may rise significantly with repeated sauna use, aiding muscle recovery and influencing body composition. During the session, norepinephrine levels spike, enhancing focus and supporting fat metabolism in the subsequent hours. Regular sauna users often experience a shift in cortisol levels, with a tendency for these stress-related hormones to decrease over time. This can be particularly beneficial if stress eating is a challenge for you.

How many calories does a sauna session actually burn?

Curious about how many calories you can burn in a sauna session? The answer varies, influenced by factors like your body size, the duration of the session, temperature, and how used you are to the heat. 

In 2019, a study focused on overweight, sedentary men revealed some interesting findings. During a 60-minute sauna session, their calorie burn increased from about 73 calories in the first 10 minutes to roughly 131 calories by the fourth session. They also experienced a body mass loss of 0.65 kg, mainly due to fluid loss.

Calories burned in a traditional sauna

On average, a person who sits in a traditional sauna heated from 80°C to 90°C for 20 to 30 minutes may lose between 300 and 600 calories. The intense heat causes your body to be challenged by the conditions, which helps increase calorie consumption.

Infrared sauna calorie burn

Infrared saunas, on the other hand, operate at cooler temperatures, usually between 45°C and 60°C. Unlike the traditional method, the infrared rays penetrate the body tissues without heating up the surrounding air. When using infrared for 30 to 45 minutes, you could burn anything ranging from 200 to 600 calories. The lower heat makes these sessions more comfortable and often longer. If you’re deciding between infrared and traditional saunas, you should think about differences like heat source, temperature range, and your personal preferences.

Steam room calorie burn

As steam rooms have their temperature between 40°C to 50°C with high humidity levels, it leads to intense sweating. Within 20 minutes of using a steam room, a person will lose anywhere from 300 to 500 calories. The humidity prevents sweat from evaporating, too, making the heat feel more intense.

Why your body size changes the numbers

The bigger the person’s body weight, the greater the calories burned. A person who weighs 90 kilograms will burn more calories in the sauna than a person who weighs 60 kilograms under the same conditions. That is because the larger amount of body mass consumes additional energy when maintaining thermal homeostasis. Moreover, an efficient circulatory system helps tolerate the heat better, though burning fewer calories.

Water weight vs fat loss: what the scale is really showing you

When you step on the scale after spending some time in a sauna, you might notice a drop of one to two kilograms. This change is mostly due to the loss of sweat. However, once you drink enough water, your weight will likely return to its previous level within a few hours. It’s important to understand that losing water weight doesn’t mean you’re reducing body fat. In fact, excessive dehydration can lead to serious issues such as low blood pressure, dizziness, heat exhaustion, and an imbalance of electrolytes.

Studies focusing on athletes who rapidly lose weight through sauna sessions reveal that three 20-minute sessions can result in a body mass reduction of about 1.4 to 1.8%. Yet, this weight change isn’t easily undone just by rehydrating.

If you’re aiming for actual fat loss, maintaining a consistent calorie deficit is essential. While a single sauna session might help you burn around 400 calories, this is roughly the same as a 45-minute run or skipping a heavy meal. Saunas can complement your weight loss efforts, but they shouldn’t replace the core strategies of diet and exercise.

The Binghamton study and what infrared saunas can actually do for body fat

In 2009, researchers at Binghamton University explored how infrared saunas might influence body fat. Over 16 weeks, participants spent 45 minutes in a far infrared sauna three times a week. Compared to those who didn’t use the sauna, the group experienced noticeable decreases in body fat and waist size.

However, the study had a few limitations. With a small number of participants, some didn’t stick to their usual diets or exercise routines. While the findings hint at potential benefits from regular sauna use, the impact appears modest. Larger, more comprehensive studies have yet to prove that using an infrared sauna alone leads to significant fat loss without dietary and lifestyle changes. For now, think of the evidence as promising but not definitive.

Where saunas support a weight loss journey

When it comes to weight loss, saunas may not directly make the numbers on the scale drop overnight, but they do play an important part in your overall fitness journey. The benefits accumulate over time, working through indirect pathways.

Better muscle recovery between training sessions

Saunas improve blood circulation to your muscles, which helps clear away metabolic waste and delivers vital nutrients for repair. If you’re someone who trains intensely four or five times a week, muscle soreness can become a barrier to your next workout. Regular sauna sessions can ease this soreness, letting you keep up with your training schedule. This consistent activity is what truly drives changes in body composition. If you’re curious about maximising recovery with saunas, we have a detailed guide that covers sauna timing and protocols.

Lower cortisol and reduced stress eating

High stress levels often lead to elevated cortisol, a hormone that promotes belly fat and disrupts appetite control. Using a sauna activates the parasympathetic nervous system, helping your body relax. This practice can lower cortisol levels and curb those late-night cravings that come from a stressful day. For those whose weight loss efforts are thwarted by stress eating, managing stress is more crucial than burning calories during the sauna session. If stress is hindering your nutrition goals, our guide on reducing stress and anxiety offers insights into using heat therapy and other helpful techniques.

Improved sleep quality

A sauna session followed by cooling down mimics the natural drop in body temperature that signals it’s time to sleep. People who regularly use saunas often report falling asleep more easily and enjoying deeper rest, especially when sessions are held in the late afternoon or early evening. Poor sleep can harm insulin sensitivity, increase hunger hormones, and make sticking to a healthy diet challenging. Improve your sleep, and managing your weight becomes much simpler.

Cardiovascular conditioning that complements exercise

Frequent trips to the sauna can yield cardiovascular benefits equivalent to those obtained from moderate physical exercise. The sauna is an “exercise mimetic,” which means that it works on biological pathways like AMPK. Finnish studies have found that frequent sauna use is linked to lower rates of cardiovascular disease and better blood pressure management. Those individuals who cannot tolerate rigorous exercise sessions can benefit from a sauna session as a complement to their exercise and fitness regime. Sauna sessions can help you lose weight in an effective and sustainable manner.

Why saunas alone will never replace a calorie deficit

Using only saunas to lose weight can never eliminate the necessity of consuming fewer calories than your body expends. Weight loss is achieved through burning more calories than you consume. Although using a sauna can enable a person to burn up to 300-600 calories, this will come to an end as soon as you exit the sauna. If there is no modification in the individual’s eating habits or physical activities, they will not lose any considerable weight.

There are occasions when the wellness sector promotes the idea that you can easily shed pounds by visiting a sauna. Such claims aren’t true. Whenever anyone tells you that you can drop those extra pounds without making any significant changes in your diet and lifestyle apart from going to the sauna regularly, then chances are that they are trying to make a sale.

How to use a sauna as part of a body composition strategy

To effectively incorporate a sauna into your body composition plan, view it as a tool for recovery and adaptation rather than a primary method for burning fat. 

Session length and frequency that delivers results

Research suggests that attending a sauna three to four times a week provides the best results. Traditional saunas are most effective with sessions lasting 20 to 30 minutes, while infrared saunas work well within a 30 to 45-minute timeframe. Attending less than twice a week may not create enough heat stress for your body to adapt, whereas more than five sessions can hinder recovery, especially if you’re engaged in intensive training. For a more detailed guide on adjusting the duration according to your experience and specific goals, check out our detailed article on how long you should sit in an infrared sauna.

When to sauna around your training

The timing of your sauna session can significantly influence its effects. Using a sauna immediately after a strength workout can interfere with muscle growth, as heat shock proteins can clash with the inflammation signals necessary for hypertrophy. If building muscle is your main goal, consider using the sauna on rest days or at least four to six hours after lifting weights.

Endurance athletes might benefit from a pre-workout sauna to build heat tolerance. However, it’s not recommended before strength training, as it may leave you dehydrated and your nervous system unprepared for peak performance. A post-cardio sauna session can enhance cardiovascular stress without compromising recovery, like it might after weightlifting.

On rest days, the sauna serves as an excellent tool for parasympathetic recovery, aiding sleep, reducing stress, and supporting overall adaptation.

Hydration protocol around your sessions

Proper hydration is crucial when using a sauna. Drink 500 millilitres of water an hour before your session, and bring another 500 millilitres to sip during it. Afterwards, replenish with 750 millilitres to one litre of water. If you sweat heavily or use the sauna often, consider adding electrolytes to one of your drinks. Losing sodium, potassium, magnesium, and chloride through sweat can lead to headaches and fatigue post-sauna.

Pairing sauna with strength training and nutrition

Remember, the sauna complements but does not replace the foundations of fitness. Continue strength training two to four times a week, consume adequate protein (around 1.6 to 2.2 grams per kilogram of body weight), maintain a calorie deficit if you’re aiming for fat loss, and ensure you get seven to nine hours of sleep. When you add sauna sessions to this solid base, the benefits will accumulate over time. Without this foundation, sauna use alone offers minimal returns.

Who should be cautious or avoid saunas?

Using a sauna can be a relaxing experience for many, but it’s important to consider safety, especially for certain groups of people. The heat can put a strain on the heart and circulatory system, so if you fall into any of the following categories, you should take extra care.

Pre-existing health conditions

If you have health conditions like low or uncontrolled high blood pressure, recently experienced heart problems, severe aortic stenosis, unstable angina, or epilepsy, it’s crucial to consult your doctor before using a sauna. For those with conditions that affect how your body manages heat, such as multiple sclerosis, the sauna’s high temperatures might worsen your symptoms. Also, if you’re taking medications that influence blood pressure, hydration, heart rate, or how your body regulates heat, a chat with your healthcare provider is wise.

Pregnant women

Pregnancy requires special attention when it comes to heat exposure. Spending time in a sauna, especially during the first trimester, can increase the risk of neural tube defects and other complications. Most health guidelines suggest avoiding saunas during this time. If you’re pregnant or planning to become pregnant, it’s best to discuss sauna use with your doctor.

Signs you need to exit immediately

Be on the lookout for symptoms that indicate you should exit the sauna immediately. These include feeling dizzy, nauseous, experiencing a fast or irregular heartbeat, a sudden drop in energy, confusion, or feeling cold despite the heat. These signals shouldn’t be ignored, as they may lead to heat exhaustion or even heat stroke. Remember, it’s better to be safe and step out than to push your limits.

Sauna types compared for weight management goals

Choosing the right sauna can significantly impact your weight management and overall wellness goals. If you focus on muscle recovery after intense workouts, an infrared sauna offers a gentler experience. Its lower temperatures allow for longer, more comfortable sessions, aiding in deep tissue recovery without overwhelming your heart.

For anyone aiming to boost cardiovascular health, a traditional sauna might be more effective. With temperatures ranging from 80 to 90 degrees Celsius, it provides a greater cardiovascular challenge, which can enhance your fitness routine.

When it comes to managing stress and improving sleep, both sauna types are beneficial. Steam rooms, however, might be preferable if you find dry heat uncomfortable. Their humid environments offer a soothing, enveloping experience. Our detailed comparison of infrared saunas and steam rooms can help you decide based on your preferences.

If burning calories is your main goal, a traditional sauna slightly outperforms others at higher temperatures. Nonetheless, this difference is minimal and shouldn’t be the sole factor in your choice. Consistency is key, so select the option that you will use regularly; aim for three to four sessions a week for optimal benefits.

Try heat therapy with a structured approach

TH7 Body Labs offers a variety of wellness treatments in Brisbane, Cleveland, and on the Sunshine Coast. We provide traditional saunas, infrared saunas, contrast therapy, and dedicated recovery spaces at each studio. Schedule a session with us, and we’ll guide you toward the best options for achieving your goals.

FAQs

How much weight can you lose in a single sauna session?

Most people end up losing anywhere from 0.5 to 2 kilograms in just one session inside the sauna. This weight loss consists entirely of water due to excessive sweating. When you rehydrate yourself, you will find that your body weight comes back. The number on the scale isn’t fat loss.

Is infrared better than a traditional sauna for fat loss?

According to the research conducted at Binghamton University, infrared sauna use may have slight benefits for body fat loss, but it is not sufficient to conclude that infrared saunas are superior. However, both options can help your weight loss efforts by improving recovery, enhancing sleep quality, lowering stress levels, and boosting heart health.

Can I lose belly fat from using a sauna?

It is impossible to spot reduce body fat in any type of sauna. Body fat reduction depends on creating a calorie deficit, and where the body reduces body fat is genetic. The sauna will help because of its ability to decrease cortisol, which contributes to the storage of abdominal body fat.

How often should I use a sauna to see results?

Between three and four times per week is the optimal frequency recommended by scientific studies in relation to cardiovascular benefits and recovery. Once or less than twice per week will not lead to adaptation. More than five times per week may impair recovery if you are overtraining.

Does sweating more mean burning more fat?

No. Sweating is a means to regulate body temperature rather than oxidising fat. You may sweat profusely but burn minimal amounts of energy, or you may sweat minimally but burn considerable amounts of energy. It all depends on your fitness level, body size, hydration, and heat intensity.

Can I sauna every day?

For most healthy adults, using a sauna every day is safe, as long as sessions last between 15 to 20 minutes and you stay well-hydrated. Finnish studies indicate that the best health benefits appear among those who use the sauna four to seven times weekly. If you’re engaged in intense training, think about whether frequent sauna use aids your recovery or slows it down. It’s wise to start with a few sessions a week and gradually increase rather than diving into daily use immediately.