Are saunas good for you? What the evidence shows and what it doesn’t

What the Finnish cohort found

A later analysis that added women found the same pattern for cardiovascular death². The findings are associations, not proof that sauna caused the difference, which is why the rating is Moderate rather than Strong².

In randomized trials, the effect on blood pressure is uncertain, though people with heart failure saw short-term gains in some heart-function markers^{5, 6}. Evidence for infrared cabins is thinner and comes mainly from people with heart conditions^5–7. None of the trials in the reviews cited here is described as testing a sauna blanket^{5, 6, 8}.

The strongest health signal for sauna comes from the Kuopio Ischemic Heart Disease Risk Factor (KIHD) study in eastern Finland. It enrolled 2,315 men aged 42 to 60 between 1984 and 1989. They were followed for a median of 20.7 years¹.

Compared with once-a-week users, men who used a sauna four to seven times a week had a lower adjusted risk of sudden cardiac death. The hazard ratio was 0.37 (95% CI 0.18 to 0.75). At two to three sessions a week, the estimate was smaller and statistically uncertain (0.78, 0.57 to 1.07). The authors reported similar links between more frequent use and lower risk for fatal coronary heart disease, fatal cardiovascular disease and death from any cause¹.

Later KIHD analyses pointed the same way. The 2018 analysis added women, following 1,688 men and women with a mean age of 63 for a median of 15 years. There were 181 cardiovascular deaths in that time. Four to seven sessions a week was linked to a fully adjusted hazard ratio of 0.23 (0.08 to 0.65) for cardiovascular death. Two to three sessions gave 0.75 (0.52 to 1.08), which wasn’t statistically significant².

In the original male cohort, four to seven sessions a week was also associated with lower rates of dementia (204 cases) and Alzheimer’s disease (123 cases)³. A review by the KIHD investigators summarizes other analyses that linked frequent sauna use with lower rates of new high blood pressure and stroke⁴.

The cohort also looked at session length. In men, sessions longer than 19 minutes were linked with a lower risk of sudden cardiac death than sessions under 11 minutes (0.48, 0.31 to 0.75). Session length wasn’t significantly linked with death from any cause¹.

What trials of repeated heat show

Randomized trials can’t run for decades, so they measure blood pressure, blood vessel function and blood markers instead of deaths or dementia. A 2025 meta-analysis pooled 20 randomized trials of repeated passive heating. They lasted 2 to 15 weeks and ranged from 15 to 188 participants. Most enrolled older adults, including people with heart failure, peripheral artery disease, coronary disease or coronary risk factors, obesity and other conditions. Three enrolled young healthy adults⁵.

Six trials tested Japanese Waon therapy, a far-infrared dry sauna kept at 60 °C and used for 15 minutes. Three tested Finnish sauna. The rest used another dry sauna, hot-water or spa bathing, hot yoga or heating of the legs⁵.

Overall, systolic blood pressure fell by 2.46 mmHg (95% CI -5.02 to 0.10). Diastolic pressure fell by 1.08 mmHg (-2.79 to 0.63). Neither change was statistically significant. With whole-body heating alone (11 trials), systolic pressure fell by 4.11 mmHg (-7.36 to -0.86)⁵.

There was no clear effect on artery dilation (flow-mediated dilation), arterial stiffness (pulse wave velocity), resting heart rate, fasting glucose, HbA1c or cholesterol. Most trials had a moderate to high risk of bias. The authors said the blood pressure finding should be interpreted with caution. They pointed to wide variation between trials (high heterogeneity) and limitations in the included studies⁵.

For heart failure, a 2018 systematic review found nine randomized or nonrandomized controlled studies and pooled seven. Only infrared sauna studies qualified. Sessions were typically 60 °C for 15 minutes, followed by 30 minutes of warm rest, five times a week for two to four weeks⁶.

In these studies, infrared sauna was associated with lower B-type natriuretic peptide (a heart-strain marker), a smaller heart on chest X-ray and better left ventricular ejection fraction. Blood pressure didn’t change significantly. The authors rated the strength of evidence as moderate to insufficient. They called the improvement short term and said more evidence is needed on long-term effects⁶.

Single sessions also change circulation temporarily. In one study, 100 men and women aged 32 to 75 with at least one cardiovascular risk factor had a 30-minute sauna. Measured afterward, systolic blood pressure fell from 137 to 130 mmHg and diastolic from 82 to 75 mmHg. Pulse wave velocity, a measure of arterial stiffness, fell from 9.8 to 8.6 m/s⁴. Short-term changes like these don’t show a lasting benefit.

What the evidence doesn’t show

The cohort findings are consistent and come from long follow-up, but they can’t settle cause and effect. Sauna habits, health and lifestyle travel together. The gaps below are why we rate the evidence moderate rather than strong.

• Association isn’t causation. The KIHD authors list several limitations: residual confounding, reverse causation (illness changing sauna habits), self-reported sauna use and sauna habits changing over time².
• There’s almost no comparison with non-users. Only 43 people in the 2018 analysis never used a sauna, and the authors note they couldn’t compare sauna users with non-users. So the results compare frequent users with once-a-week users².
• The top group is small. Only 201 of the 2,315 men reported four to seven sessions a week. That group had 10 sudden cardiac deaths, so the confidence intervals are wide¹.
• The population is narrow. All of these analyses come from one long-running study in eastern Finland, and several included only men. In the 2018 analysis, the estimates for women alone weren’t statistically significant. The 2018 authors say their results can be generalized to Northern European populations. They call for studies in populations not accustomed to regular sauna bathing^{1, 2}.
• Trials haven’t tested hard outcomes. The trials pooled in the reviews cited here measured blood pressure, vessel function, blood markers, heart function or exercise performance. They didn’t measure heart attacks, strokes, dementia or deaths. Pooled effects on blood pressure, vessel function, glucose and cholesterol were small or uncertain^{5, 6, 8}.
• Infrared-specific evidence is thin. A 2009 review of far-infrared sauna research found limited published evidence behind manufacturers’ health claims. Evidence for obesity was weak and came from a single study, and there was fair evidence against cholesterol lowering⁷.

Do infrared saunas and sauna blankets work?

The cohort evidence is about traditional Finnish sauna: dry air at 80 to 100 °C at head level and 10 to 20% humidity. Sessions last 5 to 20 minutes⁴. The 2018 KIHD analysis reported a mean sauna temperature of 75.9 °C. Its authors say their findings can’t be directly applied to other types of steam rooms or warm-water therapy². The investigators’ review adds that it’s unknown whether saunas at lower temperatures or other passive heat therapies have similar effects⁴.

The infrared research used cooler heat. Most of the infrared trials pooled in the reviews above tested Waon therapy at about 60 °C. They were run largely in people with heart failure or other cardiovascular conditions^{5, 6}. An earlier review of far-infrared sauna research found limited, moderate evidence for blood pressure and heart failure. It found fair evidence from a single study for chronic pain, and weak single-study evidence for chronic fatigue syndrome and obesity⁷.

None of the trials in these reviews is described as testing a sauna blanket. The passive heating meta-analysis covered dry and Finnish saunas, hot-water bathing, hot yoga and local leg heating⁵. The heart failure review covered infrared sauna⁶. The exercise studies used traditional or infrared sauna and hot-water immersion⁸. So any health benefit claimed for a blanket is an extrapolation from different devices at different temperatures.

Sauna after exercise: recovery and heat acclimation

A 2025 systematic review looked at heat after exercise (sauna or hot-water immersion) in healthy adults. It found 14 studies with 194 participants, mostly men. Some studies had fewer than 10 people per group⁸.

For short-term recovery, results were mixed: four studies found no effect, four found a benefit and one found harm. Over weeks of training, post-exercise heat may improve running performance, at least in hot conditions. But repeated heating didn’t improve cycling performance or VO2max. None of the studies was rated at low risk of bias, and the authors judged the evidence low to moderate quality⁸.

The proposed mechanism is heat acclimation, the body’s adjustment to repeated heat stress. The review’s authors say regular post-exercise heat may help endurance if acclimation occurs. But they found the evidence too uncertain for firm conclusions⁸.

Sauna safety: who should be careful

A sauna session is a real cardiovascular load. Heart rate can climb to about 120 to 150 beats a minute, and blood pressure usually falls⁴. The KIHD investigators’ review warns that sudden drops can occur during or after a session, especially in people with orthostatic hypotension or severe valve disease⁴. The safety points below come from published reviews and federal guidance. They’re not a substitute for advice from a clinician who knows your health.

• Alcohol: the KIHD investigators’ review says combining sauna and alcohol raises the risk of low blood pressure, heart complications and injury. It says sauna-related sudden deaths were at least partly linked to alcohol, and that about 40% of sauna-related burns happened under the influence⁴. CDC guidance notes that alcohol increases sweating and urination and impairs heat perception¹⁰.
• Heart conditions: this page’s cohort findings and short trials do not establish that sauna is safe for an individual with heart disease, arrhythmia or a recent change in symptoms^{1, 2, 5, 6}. The accessible review source for a more specific contraindication list could not be independently checked in this release, so this page does not present that list as verified guidance. Do not use the cohort association to make a personal safety decision; ask a clinician who knows your health.
• Dehydration and medicines: CDC guidance for hot weather lists several kinds of medicine that raise heat risk. They include diuretics (volume depletion and dehydration, with fainting and fall risk) and beta blockers (less sweating and lower blood pressure). ACE inhibitors and ARBs (lower blood pressure, reduced thirst) are on the list, as are several psychiatric and anticholinergic drugs (impaired sweating or temperature control). The guidance covers heat exposure in general, not saunas specifically, and reflects expert opinion¹⁰.
• Pregnancy: a 2019 systematic review covered 12 studies in 347 pregnant women. No participant exceeded the 39.0 °C core-temperature threshold linked to fetal risk. Its sauna finding (up to 20 minutes at 70 °C and 15% humidity) rests on a single study of women who were used to saunas. That finding received a low evidence grade (grade D)⁹.
• Other contraindications: the KIHD investigators’ review also lists fever, acute infection or inflammation, and skin conditions such as abrasions and urticaria (hives). In one Finnish hospital, about 26% of 598 burn patients over seven years had sauna-related burns. Most came from touching the stove or from steam⁴.
• Children: in a Finnish laboratory study, 61 children and 20 adolescents and young adults sat for 10 minutes in heat set to match an ordinary Finnish sauna. Heart rate and rectal temperature rose in everyone. Blood pressure fell right afterward in children under 10, and stroke volume fell by 32.9% in children under 5. There were two vasovagal collapses (fainting). The authors concluded that sauna strains children’s circulation considerably and that very young children should be closely supervised¹¹. The cohort analyses above studied middle-aged and older adults^{1, 2}. The pooled trials mostly enrolled older adults⁵. So neither says much about children. CDC guidance notes that some medicines raise heat risk in children and adolescents, including certain antihistamines, stimulants such as methylphenidate, antidepressants and diuretics¹⁰.

What to look for when buying a home sauna

If you want something close to the saunas behind the cohort findings, look at a traditional sauna. The KIHD saunas averaged about 76 °C². Traditional Finnish saunas run at 80 to 100 °C at head level⁴. Infrared cabins are a different, cooler experience, and their best evidence comes from sessions at about 60 °C in people with heart conditions^{5, 6}. Blankets have no direct trial evidence in the reviews cited here.

The lowest risks in the cohort were seen in men who used a sauna four to seven times a week, compared with once a week¹. That’s an association, not proof of benefit. But it does mean the cohort findings describe frequent use. So weigh how often you’d realistically use a sauna alongside the heater specifications.

• Check the stated maximum temperature and how it’s measured. The Finnish cohort evidence comes from saunas at roughly 75 to 100 °C^{2, 4}. It’s unknown whether lower temperatures or other passive heat give similar effects⁴.
• Read health claims skeptically. A review of far-infrared sauna research found limited published evidence behind manufacturers’ health claims. It found weak evidence for obesity and fair evidence against cholesterol lowering⁷. The 2025 meta-analysis of passive heating trials included no sauna-blanket trials⁵.
• Look for a guard around the heater or stove, and follow the manufacturer’s clearance distances. Most sauna burns in the Finnish hospital series came from accidental contact with the hot stove or from steam⁴.
• Think about session length and cooling off. Traditional sessions usually last 5 to 20 minutes, alternating with cooling-off periods such as a shower, a swim or rest at room temperature⁴. The KIHD investigators’ review warns that rapid cooling may trigger arrhythmias in people with heart disease⁴.
• Before ordering, confirm the electrical requirements, delivery route, floor space and return policy for the exact model.

Sources

1. Association between sauna bathing and fatal cardiovascular and all-cause mortality events JAMA Internal Medicine (Laukkanen T, Khan H, Zaccardi F, Laukkanen JA), 2015 · cohort study
2. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study BMC Medicine (Laukkanen T, Kunutsor SK, Khan H, et al.), 2018 · cohort study
3. Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men Age and Ageing (Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA), 2017 · cohort study
4. Cardiovascular and other health benefits of sauna bathing: a review of the evidence (author manuscript) Mayo Clinic Proceedings (Laukkanen JA, Laukkanen T, Kunutsor SK), 2018
5. Non-acute effects of passive heating interventions on cardiometabolic risk and vascular health: systematic review and meta-analysis of randomized controlled trials American Journal of Preventive Cardiology (Hamaya R, et al.), 2025 · meta-analysis
6. Effects of sauna bath on heart failure: a systematic review and meta-analysis Clinical Cardiology (Källström M, et al.), 2018 · meta-analysis
7. Far-infrared saunas for treatment of cardiovascular risk factors: summary of published evidence Canadian Family Physician (Beever R), 2009 · systematic review
8. Effects of post-exercise heat exposure on acute recovery and training-induced performance adaptations: a systematic review Sports Medicine - Open (Ahokas EK, et al.), 2025 · systematic review
9. Heat stress and fetal risk. Environmental limits for exercise and passive heat stress during pregnancy: a systematic review with best evidence synthesis British Journal of Sports Medicine (Ravanelli N, et al.), 2019 · systematic review
10. Heat and Medications – Guidance for Clinicians US Centers for Disease Control and Prevention, 2025 · guideline
11. Children in sauna: cardiovascular adjustment Pediatrics (Jokinen E, Välimäki I, Antila K, Seppänen A, Tuominen J), 1990