Inside Your Heart
Sauna Bathing and Cardiovascular Health
While many of us associate the sauna with relaxation or clearing our minds, there is much more happening inside our bodies, especially for our hearts. Traditional sauna bathing is growing in focus in research on cardiovascular health, and rightly so. From improved blood pressure to reduced stroke risk over time, clearly there is something good happening for your heart with the heat.
Let’s explore what the science is revealing.
The Cardiovascular Chain Reaction
Entering a sauna is an entirely new physiological experience that initiates a chain of effective physiological reactions. As one’s body heats, core temperature increases, heart rate increases, and blood vessels dilate. All of this is similar to the effect of a bout of moderate to vigorous exercise without moving a single muscle.
In fact, a heart rate of 120-150 BPM can be achieved during a typical sauna session, driven by heat stress. Blood flow is diverted to the skin, stroke volume increases, and sweat glands become extraordinarily active. While this all sounds like a stressful experience, it is important to know the degree of heat stress is a positive change for the cardiovascular system over time.
Blood Pressure: Immediate and Long-Term Changes
There is a compelling indication that sauna bathing has an impact on blood pressure in both the immediate and long-term.
Immediate Changes
There is evidence that both systolic and diastolic blood pressure is decreased after sauna use for 30 minutes. Example: Dropped systolic from 137 to 130 mm Hg, and diastolic dropped from 82 to 75 mm Hg. Importantly, the benefits of lower blood pressure were shown for at least a couple of hours after sauna use.
Long-Term Changes
Here is where it gets even more interesting: Sauna bathing may help to mitigate the onset of high blood pressure altogether. A long-term cohort study in Finland over nearly 25 years and almost 1,600 men found that the men who had 4-7 sauna baths per week had a 47% reduced risk of developing hypertension than men bathing once per week, even after accounting for other lifestyle factors like alcohol consumption and fitness.
Cardiovascular Disease & Longevity
Multiple large scale studies now show a SIGNIFICANT reduction in cardiovascular events and early death where sauna use is frequent.
One important study, the Kuopio Ischemic Heart Disease Risk Factor Study, tracked 2,300+ Finnish men for 20 years. The results were astonishing:
- 63% lower risk of sudden cardiac death
- 50% lower risk of fatal cardiovascular disease
- 48% lower risk of coronary heart disease
- 40% lower risk of all-cause mortality
And this isn’t just due to the frequency of sauna use, it is also due to the duration.
People who used saunas for more than 19 minutes had much greater benefits relative to those whose sauna session lasted less than 11 minutes.
In addition, if you regularly exercise, this effect multiplies. Research suggests that frequent sauna use combined with regular activity provides even more protection against heart disease and premature death.
Sauna and Stroke: A Surprising Link
Sauna bathing may also significantly reduce your risk of stroke.
In a 15-year study involving over 1,600 Finnish adults, sauna users had a 62% reduced risk of stroke when they used the sauna 4-7 times per week, as compared to users who used the sauna once per week. This protective effect encompasses all types of stroke, both ischemic and hemorrhagic.
What is happening at the cellular level?
So how does a heat bath provide protection for your cardiovascular system? While we continue to study the specifics, there are likely several cellular processes involved:
- Heat Shock Proteins (HSPs): HSPs are proteins activated during heat stress, and serve the cell by stabilizing and repairing proteins. Because misfolded proteins play a role in numerous neurological and cardiovascular conditions, HSPs may be a significant mechanism for long-term cellular protection.
- Reduced Inflammation: Sauna use has been associated with lower levels of inflammatory markers (e.g. C-reactive protein, fibrinogen, and white blood cells). Reduced inflammation may mean less cardiovascular workload and also a healthier brain.
- Enhanced Immune Function: Another consideration as to why regular sauna bathers seem to be sick less often is a stronger immune response. Some may argue that this immune resilience indirectly supports heart and brain health.
- Oxidative Stress: Although results are mixed, sauna exposure (over time) may decrease oxidative stress or increase antioxidant defenses—both can protect the integrity of blood vessels and heart.
What We Still Don't Know
Despite all of these exciting findings, there are still things we don’t know. For example, if these same effects apply to lower-temperature saunas, infrared saunas. Future randomized controlled trials with diverse participants will be critical for confirming these findings, and figuring out how saunas are delivering this broad range of benefits.
Final Thoughts
Although it might not be the first thing that comes to mind when you enter a sauna, your heart could be the largest beneficiary. Among other cardiovascular benefits, saunas may reduce blood pressure, lessen the risk of stroke, and improve heart function. Saunas are a useful passive intervention for cardiovascular health, according to the study.
And this is only scratching the surface.
If you want to learn more about what heat does inside your body, continue reading the Health Benefits of Sauna series, there is so much more to learn.
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
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Vascular endothelial function improved: Sauna therapy significantly increased flow-mediated dilation (%FMD), showing better blood vessel function.
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Cardiac stress decreased: Levels of BNP (a marker of heart failure severity) dropped after two weeks of sauna treatment.
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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.
