What Does Science Says?
Do Saunas Really Burn Fat?
You’ve likely heard someone who’s wanting to lose weight say something like, “I’m going to the sauna to burn fat and lean out.” The act of sitting in a heated room and increasing your heart rate while sweating profusely actually tends to burn fat; after all, you typically walk away feeling “lighter.” But does sweating actually make you lose fat?
Saunas make you sweat and that can most definitely alter your weight temporarily but that can change due to more than just fat loss. Let’s investigate the science behind saunas, body fat, and changes in weight.
What Does Research Tell Us About Saunas And Weight Loss?
When you enter the sauna your core temperature rises and your sweat glands become activated to begin sweating. According to research, sweat rates are between 0.6 to 1.0 kg per hour, at temperatures ranging from 80°C to 90°C, with average total sweating of about 0.5 kg for the sauna session (This varies person to person and temperature dependent).
Fluid loss measurement reduces body weight temporarily, and that’s the operative term: temporary. The weight lost is primarily related to sweating and is likely just water weight and not fat loss. And, once the individual is rehydrated, body weight will return to baseline.
So, while the feeling of “lightness” makes sauna-goers feel good afterwards, it does not contribute to racimally burning stored body fat.
Is There Evidence That Saunas Cause Fat Loss?
There have been very few studies relating sauna use to real fat reduction. Some studies have noted a minor drop in body weight changes in subjects with cardiovascular issues or heart failure, although their weight measures were more related to fluid shifts and polyurination than actual fat metabolism.
Also, research has indicated that claims of “weight loss due to sauna” are often not well substantiated. One 2021 review even went so far to say that the medical evidence for sauna weight loss was “scant and incomplete.” In other words, sure your weight may drop a little after a session, but your body has not utilized stored fat to produce energy.
In contrast, a physically intense exercise program has consistently been shown to produce meaningful fat loss through caloric expenditure improvement and better metabolic efficiency. Sauna bathing may have great benefits in many ways, but cannot reproduce those effects.
So, What's The Basis For This Confusion In Beliefs?
The thought that the sauna burns fat is often from visible, short-term changes: sweating, feeling lighter, and having the feeling of exertion. Dehydration can easily be compared to fat loss. However, in physiology, fat oxidation requires prolonged caloric deficit and caloric needs, neither of which occur by sitting in heat.
That said, a sauna could provide a nice addition to a healthy lifestyle. Regular sauna exposure is good for health benefits by assisting circulation, recovery, and decreasing stress levels, all of which may indirectly help with fitness and well-being.The sauna is likely better treated more like a wellness promotion, than a weight loss shortcut.
Conclusion
There is a little truth to “weight loss” through sauna, but as the science indicates, this is primarily water loss and not fat loss. Real, proper fat reduction comes from daily exercise, eating right, and staying hydrated.
Use your sauna for what it’s really good at, which is aiding in recovery from exercise, relaxing the mind, and improving circulation. That’s the real pathway to wellness.
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Sauna Health Benefits Research Resources
We asked, what research is actually out there? How do we know what is sales words, and what is grounded research. Through that, we decided to compile a library of all the literature on the health benefits of sauna.
Sauna & Heart Health
Sauna benefits to vascular endothelial cardiac function
Vascular endothelial function improved: Sauna therapy significantly increased flow-mediated dilation (%FMD), showing better blood vessel function.
Cardiac stress decreased: Levels of BNP (a marker of heart failure severity) dropped after two weeks of sauna treatment.
Clinical symptoms improved: 17 out of 20 patients reported better symptoms and overall cardiac function after repeated sauna sessions.
Sauna & Heart Health
Sauna effect on heart rate variability
Significant plasma volume increase: Post-exercise sauna use expanded plasma volume by about 18% after just four sessions.
Heart rate and HRV changes were small or unclear: Only minor reductions in resting heart rate and small shifts in HRV markers were observed, with unclear correlations to plasma volume.
Sauna enhanced training adaptation: Adding sauna to normal training improved physiological capacity in trained cyclists beyond training alone.
Sauna & Arthritis
Infrared Sauna in Arthritis and Spondylitis
Pain and stiffness significantly reduced: During IR sauna sessions, both RA and AS patients showed marked decreases in pain and stiffness (p < 0.05 and p < 0.001, respectively).
No adverse effects or disease flare-ups: Treatments were well tolerated, with no signs of increased disease activity or other side effects.
Short-term comfort, modest long-term benefit: Patients reported feeling comfortable and relaxed during and after sessions. Clinical improvements persisted during treatment but faded post-therapy.
Sauna & Heart Health
Advertising in Saunas and Positioning
Digital promotion gained momentum: Social media emerged as a powerful channel for business growth, offering wide reach and precise audience targeting for tailored advertising.
Marketing strategies adapted post-crisis: The health crisis reshaped the economy and reduced ad spending, pushing companies—including sauna brands—to prioritize customer acquisition through focused advertising efforts.
Medicinal benefits reinforced: Positioning centered on health advantages, with studies showing that 2–3 or ≥4 weekly sauna sessions significantly reduced the risk of respiratory diseases compared to ≤1 session per week.
Sauna & Exercise Recovery
Effects of Thermal Modalities on Exercise Recovery
- Effectiveness depends on participant type: Warm Water Immersion (WWI) was found to be more effective for athletes in increasing recovery and preventing muscle cell damage. Conversely, Infrared Sauna (IRS) and Traditional Sauna (TRS) were more effective for recovery in nonathletes.
- Significant reduction in fatigue markers: All recovery modalities played a role in reducing the blood lactate level (BLL) after physical activity, and all modalities were effective in significantly reducing heart rate (HR) in both groups after exercise.
- WWI minimized perceived pain: The WWI modality resulted in the least amount of pain in both athletes and nonathletes. Passive recovery (PAS), in contrast, tended to cause severe pain.
Sauna & Mortality
Sauna Use and Mortality Reduction
- High frequency reduces overall and cardiovascular death: Increased frequency of sauna bathing is associated with a reduced risk of sudden cardiac death (SCD), fatal coronary heart disease (CHD), fatal cardiovascular disease (CVD), and all-cause mortality.
- Maximum protective effect seen in frequent users: Compared with men bathing once per week, those reporting 4 to 7 sauna sessions per week had a significantly lower adjusted hazard ratio for SCD (0.37) and experienced a 40% reduction in all-cause mortality.
- Longer duration also lowers SCD risk: Longer sauna sessions were inversely associated with fatal cardiac events; sessions lasting more than 19 minutes were linked to a 52% lower risk of SCD compared to sessions lasting less than 11 minutes.
Sauna & Therapies
Benefits and Scope of Passive Heat Therapies
- Finnish Sauna is the most studied modality: Finnish saunas are the most widely studied passive heat therapy, characterized by high temperatures (80–100°C) and dry air (10–20% relative humidity).
- Demonstrated health benefits and disease prevention: Finnish saunas have robust evidence showing they decrease the risk of hypertension, cardiovascular disease (CVD), dementia, and respiratory conditions. They may also improve sleep, mental well-being, and longevity.
- Potential for synergistic effects and mechanism: Passive heat therapies may augment the beneficial effects of physical activity and their positive effects are linked to anti-inflammatory, cytoprotective, and anti-oxidant properties.
Sauna & Respiratory Diseases
Sauna Reduces Respiratory Diseases
- Lower respiratory disease risk: Men taking 2–3 sauna sessions per week showed a 27% reduction in respiratory disease incidence compared to ≤1 session.
- Stronger benefits with higher frequency: Those bathing ≥4 times weekly had up to a 41% lower risk, indicating a dose-response relationship.
- Pneumonia risk reduced: Frequent sauna users experienced 28–37% lower pneumonia incidence after long-term follow-up and risk adjustment.
Sauna & Health Benefits
Finnish Sauna Health Benefits
- Offers vascular and nonvascular benefits: Traditional Finnish sauna bathing, characterized by high temperatures (80°C–100°C) for brief periods, is linked to reduced risk of vascular diseases like high blood pressure and cardiovascular disease (CVD), as well as nonvascular conditions such as pulmonary diseases.
- Physiological effects mimic moderate physical activity: The physiological responses during an ordinary sauna bath correspond to those produced by moderate- or high-intensity physical activity, such as walking. This is linked to mechanisms like reduction in systemic blood pressure, improvement in endothelial function, and beneficial modulation of the autonomic nervous system.
- Sauna is generally safe, even for stable CVD patients: Sauna bathing is a safe activity and can be used in patients with stable CVD, provided it is used sensibly, though patients with unstable disease conditions like recent myocardial infarction or uncontrolled hypertension should exercise caution.
Sauna & Dementia Risk
Sauna Bathing Frequency and Dementia Risk
- Frequent use suggests reduced dementia risk: A long-term prospective cohort study suggests that frequent sauna bathing may be associated with a reduced subsequent risk of dementia in both men and women.
- Highest protection seen in moderate users: Individuals reporting 9–12 sauna sessions per month (approximately three times per week) had a significantly lower adjusted hazard ratio for dementia (HR=0.47) during the first 20 years of follow-up, compared to those bathing 0–4 times per month.
- Temperature influences protective effects: The most favorable sauna temperature range for dementia protection was 80–99 ◦C. Bathing at temperatures higher than 100 ◦C, however, was associated with an elevated risk during the initial 20 years of follow-up.
Dry Sauna & Clinical Effects
Clinical Effects of Regular Dry Sauna
- Review found benefits across multiple conditions, but studies were heterogeneous: The systematic review included 40 clinical studies involving regular dry sauna bathing (Finnish-style and infrared) and concluded there is potential evidence of health benefits across cardiovascular disease (CVD), rheumatological, pain, and respiratory conditions.
- Frequent sauna use linked to lower CVD and mortality risks: Frequent Finnish sauna use (4–7 sessions per week) was strongly associated with a reduced risk of sudden cardiac death (63% reduction), dementia (66% reduction), and a 40% reduction in all-cause mortality over a 20-year period in middle-aged men.
- Generally safe, though reversible spermatogenesis impairment noted: Regular dry sauna bathing appears to be safe and generally well-tolerated in clinical settings, but one study showed reversible reduction in sperm count and motility in healthy men after repeated sessions, with all effects reverting to normal six months after cessation.
Sauna & Health Benefits
Cardiovascular and Other Health Benefits of Sauna
- Focus on Traditional Finnish Sauna: This passive heat therapy is characterized by exposure to high environmental temperatures (80°C–100°C) and dry air (10%–20% relative humidity), traditionally used for pleasure and relaxation.
- Linked to Reduced Risk of Vascular Disease and Mortality: Emerging evidence suggests sauna bathing reduces the risk of vascular diseases such as high blood pressure and cardiovascular disease (CVD). Frequent use (4–7 sessions/wk) was associated with a reduced risk of sudden cardiac death and all-cause mortality.
- Physiological Effects and Safety Profile: The physiological responses produced during a sauna bath correspond to those of moderate- or high-intensity physical activity (like walking). Sauna bathing is generally safe for patients with stable CVD, but those with unstable conditions (e.g., uncontrolled hypertension) or those combining it with alcohol should exercise caution.
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