AumniVIDA

Sauna

PromisingUpdated October 31, 2026 · 23 studies · Written by the AumniVIDA teamUnits

What is sauna?

Sauna bathing means sitting in dry heat, usually 176 to 212 °F (80 to 100 °C)80 to 100 °C (176 to 212 °F), for 5 to 20 minutes or more. Finnish cohorts link 4 to 7 sessions a week to 63% lower sudden cardiac death, and trials show blood pressure falls 4 to 8 mmHg, but long-term benefits rest on observational data.

Wooden benches in a softly lit Finnish sauna with a stone heater, a wooden bucket and ladle, and faint steam.
The sauna in the Finnish studies ran at about 79°C (174°F) or hotter, with steam from water on hot stones.

Sauna is safe for most healthy adults and has consistent evidence that it lowers blood pressure and improves blood vessel function in the short term. The striking mortality and dementia figures come from observational cohorts, almost all from one Finnish research group, so cause and effect are not proven. Mainstream cardiology treats it as a reasonable addition to exercise, not a substitute.

The rules

The rules ofSauna

Promising in mainstream science5 rules
  1. 1Sit in a heated room at about 176 to 212 °F (80 to 100 °C)80 to 100 °C (176 to 212 °F) for a Finnish sauna, or 113 to 140 °F (45 to 60 °C)45 to 60 °C (113 to 140 °F) for an infrared sauna.
  2. 2Stay for a planned time, commonly 5 to 20 minutes per round, with 1 to 3 rounds per visit.
  3. 3Cool down between rounds with air, a shower or cold water.
  4. 4Repeat on a weekly schedule; the Finnish data compare 1, 2 to 3, and 4 to 7 sessions a week.
  5. 5Rehydrate during and after, and never use a sauna after alcohol.

Share these rules as an image or a link.

Common variants
Finnish dry saunaAbout 176 to 212 °F (80 to 100 °C)80 to 100 °C (176 to 212 °F) with low humidity and occasional steam from water on hot stones; the version studied in KIHD.
Infrared saunaInfrared panels heat the body directly at 113 to 140 °F (45 to 60 °C)45 to 60 °C (113 to 140 °F) air temperature, usually for longer sessions.
Waon therapyA Japanese medical protocol: 140 °F (60 °C)60 °C (140 °F) infrared sauna for 15 minutes, then 30 minutes resting under a blanket, daily.
Post-exercise saunaA 15 to 30 minute sauna straight after a workout, as tested in an 8 week randomized trial.
Hot tub or hot bathImmersion in water at about 104 °F (40 °C)40 °C (104 °F), as in Japanese daily bathing or lab heat therapy trials.
Contrast therapyAlternating sauna with cold water immersion, often ending on cold.

What it aims to do

  • Lower blood pressure and improve blood vessel function.
  • Reduce the risk of cardiovascular disease and death.
  • Add a cardiovascular stimulus that complements exercise.
  • Relax, lower stress and improve mood.
  • Trigger heat shock proteins and other stress responses linked to healthy aging.

What it claims, and what the evidence shows

Grades reflect evidence in people. Animal and cell results alone never earn more than limited.

  • Heart and blood vessels

    Moderate evidence

    Lowers blood pressure and cardiovascular risk

    A meta-analysis and randomized trials show blood pressure falls of about 4 to 8 mmHg, and large cohorts link frequent sauna to lower cardiovascular death and stroke. [1][2][3][4][5]

  • Lifespan and mortality

    Limited evidence

    Lowers all-cause mortality

    KIHD found lower all-cause mortality with more frequent sauna, but the evidence is observational and comes mostly from one Finnish cohort. [3][6]

  • Brain and cognition

    Limited evidence

    Lowers dementia and Alzheimer's risk

    One cohort of 2,315 Finnish men linked 4 to 7 weekly sessions with a 66% lower dementia risk; no trials exist. [7]

  • Cardiorespiratory fitness

    Limited evidence

    Improves cardiorespiratory fitness

    One 8 week randomized trial found sauna after exercise raised fitness by 2.7 mL/kg/min more than exercise alone. [2]

  • Mood and stress

    Limited evidence

    Improves mood and depression

    One small sham-controlled trial of whole-body hyperthermia reduced depression scores for up to six weeks. [8][9]

  • Inflammation

    Limited evidence

    Lowers chronic inflammation

    Frequent sauna users had lower C-reactive protein in a cross-sectional analysis, and a session raises heat shock proteins, but no trial has tested inflammation directly. [10][11]

  • Blood sugar and insulin

    Not enough evidence

    Improves insulin sensitivity through heat shock proteins

    Heat therapy protected mice from diet-induced insulin resistance via HSP72; human trials are lacking. [12]

  • Hormones

    Evidence against

    Safe for male fertility

    Regular sauna at 80 to 90°C reversibly reduced sperm count and motility in a small study. [13]

Key takeaways

  1. 1

    Finnish men using a sauna 4 to 7 times a week had a 63% lower risk of sudden cardiac death than once-weekly users; the data are observational.

  2. 2

    Sessions over 19 minutes were linked to lower risk than sessions under 11 minutes.

  3. 3

    Controlled studies show systolic blood pressure falls of about 4 to 8 mmHg with regular heat.

  4. 4

    Most outcome data come from dry Finnish saunas at about 174 °F (79 °C)79 °C (174 °F) or hotter, not infrared cabins.

  5. 5

    Alcohol is the main factor in sauna deaths; unstable heart disease, pregnancy and male fertility need care.

  6. 6

    Detox and longevity gene claims go beyond the human evidence.

What are the proven benefits of sauna?

The best evidence links regular Finnish sauna to lower blood pressure and lower cardiovascular death. Short trials show blood pressure falls by about 4 to 8 mmHg; long-term benefits for death, dementia and stroke come from observational cohorts, mostly in one Finnish region.

Sauna evidence comes in three layers, and it helps to keep them apart:

  1. Large observational cohorts in eastern Finland link frequent sauna to lower risk of sudden cardiac death, cardiovascular death, dementia, stroke and high blood pressure [3] [7] [4] [5]. These show association, not cause.
  2. Short controlled trials show that repeated heat lowers blood pressure and improves blood vessel function [1] [2] [14].
  3. Mechanistic studies show what a session does: heart rate rises to the level of moderate exercise, blood pressure and arterial stiffness fall, and heat shock proteins rise [15] [11]. The KIHD group's own review proposes that these changes, plus better endothelial function, explain the cohort findings [16].

A 2018 systematic review of 40 clinical studies found mostly positive results, but only 13 were randomized and most had fewer than 40 participants [9]. So the direction is consistent, while the size of the long-term benefit is uncertain.

What happens in the body during a 30 minute sauna

Core temperature
Before: Baseline
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): About 0.8°C higher
Heart rate
Before: 65 beats per minute
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): 81 beats per minute; about 131 in a heat chamber study
Systolic blood pressure
Before: 137 mmHg
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): 130 mmHg
Arterial stiffness (pulse wave velocity)
Before: 9.8 m/s
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): 8.6 m/s
Heat shock protein HSP72
Before: Baseline
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): About 49% higher
Fluid
Before: Drink water before
After 30 minutes at 163 °F (73 °C)73 °C (163 °F): Sweat loss: drink water after

Averages from two studies: one session in 102 adults and a heat chamber study in 25 young adults. Individual responses vary.

Heart rate climbs to the level of moderate exercise while blood pressure and arterial stiffness fall during and after the session.

What did the Finnish KIHD study find about sauna frequency and duration?

In 2,315 Finnish men followed for 20.7 years, 4 to 7 sessions a week was linked to a 63% lower risk of sudden cardiac death than one session, and sessions over 19 minutes to a 52% lower risk than sessions under 11 minutes.

The Kuopio Ischemic Heart Disease Risk Factor Study (KIHD) recruited men aged 42 to 60 in eastern Finland between 1984 and 1989 and asked about their sauna habits [3]. Compared with once-weekly users, after adjusting for cardiovascular risk factors:

Outcome2 to 3 sessions a week4 to 7 sessions a week
Sudden cardiac deathHR 0.78 (0.57 to 1.07)HR 0.37 (0.18 to 0.75)
DementiaHR 0.78 (0.57 to 1.06)HR 0.34 (0.16 to 0.71)
Alzheimer's diseaseHR 0.80 (0.53 to 1.20)HR 0.35 (0.14 to 0.90)
Incident high blood pressureHR 0.76 (0.57 to 1.02)HR 0.54 (0.32 to 0.91)

Sources: [3] [7] [5].

Duration mattered too. Compared with sessions under 11 minutes, sessions of 11 to 19 minutes had a hazard ratio for sudden cardiac death of 0.93, and sessions over 19 minutes of 0.48 [3]. A later cohort that was half women found 4 to 7 weekly sessions linked to a 70 to 77% lower risk of cardiovascular death [6].

What the study cannot show. Only 201 men used the sauna 4 to 7 times a week. Men healthy enough to sit in a hot sauna daily may differ in ways the adjustments miss, and almost all results come from one research group and one region.

Sudden cardiac death risk by sauna sessions per week (KIHD)

Show the data
Sudden cardiac death risk by sauna sessions per week (KIHD)
ItemValue (hazard ratio)LowHighNote
1 session a week (reference)1
2 to 3 sessions a week0.780.571.07Confidence interval crosses 1
4 to 7 sessions a week0.370.180.75
Hazard ratios compared with one session a week, adjusted for cardiovascular risk factors, in 2,315 Finnish men followed for 20.7 years. This is an association, not proof of cause.

How hot, how long and how often should you use a sauna?

The Finnish data come from dry saunas of about 174 °F (79 °C)79 °C (174 °F) or hotter, used 2 to 7 times a week for 11 to 20 or more minutes. Trials that lowered blood pressure used 15 to 30 minutes per session.

The protocols with outcome data look like this:

ProtocolTemperatureTimeFrequencySource
KIHD lowest risk groupFinnish sauna, about 174 °F (79 °C)79 °C (174 °F)Over 19 minutes4 to 7 a week[3]
Sauna after exercise trialFinnish sauna15 minutesAfter each workout, 8 weeks[2]
Single session study163 °F (73 °C)73 °C (163 °F), 10 to 20% humidity30 minutesOnce[15]
Waon therapy for heart failure140 °F (60 °C)60 °C (140 °F) infrared15 minutes plus 30 minutes restDaily for 10 days[17]
Hot water immersion105 °F (40.5 °C)40.5 °C (105 °F) bathEnough to hold core temperature at 101.3 °F (38.5 °C)38.5 °C (101.3 °F) or more for 60 minutes4 to 5 a week, 8 weeks[14]

The average KIHD sauna temperature of about 79°C comes from Jari Laukkanen's interview on FoundMyFitness (FoundMyFitness). Huberman's public protocol suggests 176 to 212 °F (80 to 100 °C)80 to 100 °C (176 to 212 °F) for 5 to 20 minutes, 2 to 7 times a week, or about 1 hour a week in total (Huberman Lab).

If you are new to sauna, start at the lower bench, 5 to 10 minutes, and build up over weeks. Heat tolerance improves with use.

Does sauna lower blood pressure?

Yes, modestly. A meta-analysis of heat therapy found systolic blood pressure about 4 mmHg lower than control, and an 8 week trial found a 15 minute sauna after exercise lowered systolic pressure 8 mmHg more than exercise alone.

A single 30 minute session at 163 °F (73 °C)73 °C (163 °F) lowered systolic pressure from 137 to 130 mmHg and the effect lasted through 30 minutes of recovery [15]. Repeated use seems to carry over:

  • A meta-analysis of controlled studies found heat therapy lowered systolic pressure by about 3.9 mmHg and diastolic by about 3.9 mmHg, and improved flow-mediated dilation [1].
  • In a randomized trial of 47 inactive adults with a cardiovascular risk factor, exercise plus a 15 minute sauna for 8 weeks lowered systolic pressure by 8 mmHg more than exercise alone, and raised fitness by 2.7 mL/kg/min more [2].
  • Eight weeks of hot baths at 40.5°C lowered mean arterial pressure from 83 to 78 mmHg and reduced arterial stiffness compared with a sham [14].

Not every measure moved. The same research group found that adding sauna to exercise did not improve heart rate variability [18]. In advanced heart failure, 10 days of infrared sauna improved walking distance, but the main blood marker endpoint did not differ from control [17].

If you track blood pressure, LDL cholesterol and hs-CRP, sauna is one of the few lifestyle habits with data on all three [2] [10].

Blood pressure changes from heat in controlled studies

Show the data
Blood pressure changes from heat in controlled studies
ItemValue (mmHg lower systolic)LowHighNote
Heat therapy vs control, meta-analysis of 10 studies3.90.77.2
Exercise plus 15 minute sauna vs exercise alone, 8 weeks81.414.6Lee 2022
Drops in systolic blood pressure from a meta-analysis of heat therapy and from an 8 week randomized trial of sauna added to exercise.

What are heat shock proteins, and does sauna raise them?

Heat shock proteins are chaperones that help other proteins keep their shape under stress. Thirty minutes at 73°C raised blood levels of HSP72 by about 49%, but no human study links that rise to longer life.

When cells heat up, they make more heat shock proteins. In a randomized crossover study, 30 minutes in a 163 °F (73 °C)73 °C (163 °F) chamber raised core temperature by 0.8°C, norepinephrine by 58% and HSP72 by about 49% [11].

Why that might matter comes mostly from animals. In mice, raising HSP72 by heat therapy, genes or a drug protected against insulin resistance on a high-fat diet [12]. Advocates also connect heat shock proteins to long life; the FoundMyFitness sauna page cites HSP70 gene variants linked to longevity in a Danish cohort (FoundMyFitness).

The chain from "sauna raises HSP72" to "sauna slows aging" has not been tested in people. Treat it as a plausible mechanism, not an established benefit.

Illustration of a barrel-shaped chaperone protein complex holding an unfolded protein chain and releasing it folded.
Heat shock proteins help other proteins keep or regain their shape under stress; sauna raises one of them, HSP72, in the blood.

Is sauna good for the brain and mood?

Possibly. KIHD men using a sauna 4 to 7 times a week had a 66% lower dementia risk than once-weekly users, and one session of whole-body hyperthermia eased depression in a small sham-controlled trial. Neither finding has been widely replicated.

The dementia finding comes from the same Finnish cohort: 4 to 7 sessions a week was linked to a hazard ratio of 0.34 for dementia and 0.35 for Alzheimer's disease, compared with one session [7]. Because people in early cognitive decline may stop using the sauna, some of that link could run backwards.

For mood, a double-blind trial gave 30 adults with major depression either one session of whole-body hyperthermia or a sham. Depression scores fell about 6 points more with heat at one week, and about 4 points more at six weeks [8]. Whole-body hyperthermia uses a medical device rather than a sauna, and the trial was small.

Who should not use a sauna, and what are the risks?

Sauna is safe for most healthy adults. The main dangers are alcohol, dehydration, unstable heart disease and medicines that cause low blood pressure. Pregnant people and men trying to conceive should talk to a clinician first.

  • Alcohol. Deaths in Finnish saunas are rare, under 2 per 100,000 people a year, but half of those who died were under the influence of alcohol [19].
  • Heart disease. A review found sauna well tolerated by people with treated, stable high blood pressure, coronary disease and heart failure. Blood pressure medicines can cause dizziness on standing after a session [20]. Unstable angina, a recent heart attack or severe aortic stenosis are reasons to ask a cardiologist first. Laukkanen warns that moving from heat straight into cold water can trigger coronary spasm in unstable heart disease (FoundMyFitness).
  • Pregnancy. A core temperature of 102.2 °F (39.0 °C)39.0 °C (102.2 °F) is the threshold linked to birth defects. In a systematic review, no pregnant woman reached it, and dry sauna at 158 °F (70 °C)70 °C (158 °F) for up to 20 minutes kept core temperature below it [21]. Some public protocols still advise pregnant people to avoid saunas altogether (Huberman Lab); this is a decision for you and your clinician.
  • Male fertility. Two 15 minute sessions a week at 80 to 90°C for 3 months sharply reduced sperm count and motility in 10 men; it fully recovered 6 months after stopping [13].
  • Dehydration and heat illness. You can lose a lot of fluid in a session. Drink water before and after, and get out if you feel dizzy, nauseous or confused.

Who should check before using a sauna

Do not

Half of the people who died in Finnish saunas had been drinking.

  • Use a sauna after drinking alcohol
  • Stay in if you feel dizzy, nauseous or confused

Ask a clinician first

Treated, stable heart disease is usually well tolerated.

  • Unstable angina or a recent heart attack
  • Severe aortic stenosis
  • Blood pressure medicines that cause dizziness on standing
  • Pregnancy: 158 °F (70 °C)70 °C (158 °F) for up to 20 minutes kept core temperature under 102.2 °F (39.0 °C)39.0 °C (102.2 °F)

Know the trade-off

Effects that are temporary but real.

  • Trying to conceive: sperm count fell after 3 months of twice-weekly sessions and recovered by 6 months
  • Fever, an acute illness or dehydration: wait until it passes

Sauna is safe for most healthy adults. If you have a heart condition or are pregnant, decide with your clinician.

Most sauna deaths in Finland involved alcohol; heart disease, pregnancy and male fertility need specific care.

Infrared sauna vs Finnish sauna vs steam room vs hot tub: which is best?

Most outcome data come from Finnish dry saunas at about 176 °F (80 °C)80 °C (176 °F). Infrared saunas run cooler, at about 45 to 60°C, and have small trials in heart failure. Daily hot tub bathing has its own cohort data from Japan.

  • Finnish sauna (dry heat, 80 to 100°C or 176 to 212°F, with occasional steam from water on the stones) is the version behind the KIHD findings [3].
  • Infrared sauna heats the body directly at lower air temperatures. Japanese Waon therapy uses 140 °F (60 °C)60 °C (140 °F) for 15 minutes; it improved symptoms and endothelial function in heart failure in small studies [22] [17]. No long-term mortality data exist for home infrared cabins.
  • Hot water immersion at 105 °F (40.5 °C)40.5 °C (105 °F) improved vascular function in a controlled trial [14], and Japanese adults who bathed in a hot tub almost daily had a 28% lower risk of cardiovascular disease [23].
  • Steam rooms run cooler, at high humidity, and have little outcome data.

Detox claims are the weakest. Neurologist Steven Novella argues that sweat removes negligible amounts of toxins and that the liver and kidneys do that work (Science-Based Medicine). Bryan Johnson's Blueprint reports drops in some urinary toxins after 15 sessions, but that is one person's before-and-after data (Blueprint).

People who also cold plunge can read the cold plunge guide; the Danish winter swimmers who inspired the "11 minutes" figure also logged about 57 minutes of sauna a week.

The studies, by type

Strongest designs first. Scroll each row; every card links to the paper and says whether it supports the protocol.

Systematic reviews and meta-analyses (3)

  • Exp Physiol · 2021

    [1]

    The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta-analysis

    Systematic review and meta-analysis of 15 studies

    Across controlled studies of repeated heat therapy, systolic pressure fell by about 4 mmHg, diastolic by about 4 mmHg and flow-mediated dilation improved by about 2 percentage points.

    SupportsRead

  • Evid Based Complement Alternat Med · 2018

    [9]

    Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review

    Systematic review of 40 clinical studies · 3,855 participants

    Forty clinical studies with 3,855 participants mostly reported benefits, but only 13 were randomized and most had fewer than 40 people.

    Mixed resultRead

  • Br J Sports Med · 2019

    [21]

    Heat stress and fetal risk. Environmental limits for exercise and passive heat stress during pregnancy: a systematic review with best evidence synthesis

    Systematic review with best evidence synthesis of 12 studies · 347 pregnant women

    No pregnant woman in 12 studies reached the 39.0°C core temperature linked to birth defects; dry sauna at 70°C for up to 20 minutes kept core temperature below that threshold.

    No clear effectRead

Randomized controlled trials (4)

  • Am J Physiol Regul Integr Comp Physiol · 2022

    [2]

    Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial

    Three-arm randomized controlled trial, 8 weeks · 47 inactive adults aged about 49 with a cardiovascular risk factor

    Adding a 15 minute sauna after exercise for 8 weeks lowered systolic blood pressure by 8 mmHg and raised fitness by 2.7 mL/kg/min more than exercise alone.

    SupportsRead

  • Physiol Rep · 2025

    [18]

    Regular postexercise sauna bathing does not improve heart rate variability: A multi-arm randomized controlled trial

    Three-arm randomized controlled trial, 8 weeks · 38 sedentary adults aged about 49

    Adding a 15 minute post-exercise sauna for 8 weeks gave no extra improvement in heart rate variability over exercise alone.

    Finds againstRead

  • JAMA Psychiatry · 2016

    [8]

    Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder: A Randomized Clinical Trial

    Double-blind sham-controlled randomized trial, 6 weeks · 30 adults with major depressive disorder

    A single session of whole-body hyperthermia lowered depression scores by about 6 points more than a sham at one week, with a smaller benefit lasting to six weeks.

    SupportsRead

  • Circ J · 2016

    [17]

    Waon Therapy for Managing Chronic Heart Failure - Results From a Multicenter Prospective Randomized WAON-CHF Study

    Multicenter randomized controlled trial, 10 days · 149 hospitalized adults with advanced heart failure in Japan

    Ten days of 60°C infrared sauna therapy in advanced heart failure improved walking distance and symptom class, but its primary endpoint, the change in BNP, was not significantly different from control.

    Mixed resultRead

Large observational studies in people (8)

  • JAMA Intern Med · 2015

    [3]

    Association between sauna bathing and fatal cardiovascular and all-cause mortality events

    Prospective cohort (KIHD), median follow-up 20.7 years · 2,315 men aged 42 to 60 in eastern Finland

    Over a median 20.7 years, men who used a sauna 4 to 7 times a week had a 63% lower risk of sudden cardiac death than once-weekly users, and sessions over 19 minutes were linked to lower risk than sessions under 11 minutes.

    SupportsRead

  • Age Ageing · 2017

    [7]

    Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men

    Prospective cohort (KIHD), median follow-up 20.7 years · 2,315 men aged 42 to 60 in eastern Finland

    Men using a sauna 4 to 7 times a week had a 66% lower risk of dementia and a 65% lower risk of Alzheimer's disease than once-weekly users over about 20 years.

    SupportsRead

  • Am J Hypertens · 2017

    [5]

    Sauna Bathing and Incident Hypertension: A Prospective Cohort Study

    Prospective cohort (KIHD), median follow-up 24.7 years · 1,621 Finnish men without hypertension at baseline

    Men who used a sauna 4 to 7 times a week had about half the risk of developing high blood pressure over 24.7 years compared with once-weekly users.

    SupportsRead

  • Neurology · 2018

    [4]

    Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study

    Prospective cohort, median follow-up 14.9 years · 1,628 Finnish men and women aged 53 to 74

    Men and women using a sauna 4 to 7 times a week had a 61% lower risk of stroke over 14.9 years than once-weekly users.

    SupportsRead

  • BMC Med · 2018

    [6]

    Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study

    Prospective cohort, median follow-up 15 years · 1,688 Finnish adults, 51% women, mean age 63

    In a cohort that was half women, 4 to 7 weekly sessions were linked to a 70 to 77% lower risk of cardiovascular death over 15 years than one weekly session, depending on adjustment.

    SupportsRead

  • Eur J Epidemiol · 2018

    [10]

    Sauna bathing and systemic inflammation

    Cross-sectional analysis of a cohort · 2,084 Finnish men aged 42 to 60

    C-reactive protein was lower at each step up in sauna frequency, about a third lower in men using it 4 to 7 times a week than in once-weekly users.

    SupportsRead

  • Heart · 2020

    [23]

    Habitual tub bathing and risks of incident coronary heart disease and stroke

    Prospective cohort, 1990 to 2009 · 30,076 Japanese adults aged 40 to 59

    Japanese adults who took a hot tub bath almost daily had a 28% lower risk of cardiovascular disease over about 20 years than those bathing 0 to 2 times a week.

    SupportsRead

  • J Forensic Sci · 2008

    [19]

    Death in sauna

    Forensic review of national death records, 1990 to 2002 · Finland

    Deaths in Finnish saunas from 1990 to 2002 occurred at under 2 per 100,000 people a year, and half of those who died were under the influence of alcohol.

    Finds againstRead

Mechanistic studies in people (5)

  • J Physiol · 2016

    [14]

    Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans

    Sham-controlled trial of hot water immersion, 8 weeks · 20 young sedentary adults

    Eight weeks of hot water immersion at 40.5°C, 4 to 5 times a week with core temperature held at 38.5°C or more for 60 minutes, improved flow-mediated dilation, lowered arterial stiffness and cut mean arterial pressure from 83 to 78 mmHg compared with a sham.

    SupportsRead

  • Eur J Prev Cardiol · 2018

    [15]

    Sauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental study

    Non-randomized before-and-after experiment, single session · 102 adults, mean age 52

    A single 30 minute session at 73°C lowered systolic blood pressure from 137 to 130 mmHg and pulse wave velocity from 9.8 to 8.6 m/s, while heart rate rose from 65 to 81 beats per minute.

    SupportsRead

  • J Athl Train · 2012

    [11]

    Heat stress and cardiovascular, hormonal, and heat shock proteins in humans

    Randomized crossover laboratory study · 25 young healthy adults

    Thirty minutes in a 73°C heat chamber raised core temperature by 0.8°C, heart rate to about 131 beats per minute, norepinephrine by 58% and the heat shock protein HSP72 by about 49%.

    SupportsRead

  • J Am Coll Cardiol · 2002

    [22]

    Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure

    Controlled clinical study, 2 weeks · 30 adults with chronic heart failure

    Two weeks of daily 60°C sauna for 15 minutes improved endothelial function, BNP and symptoms in 17 of 20 people with chronic heart failure.

    SupportsRead

  • Hum Reprod · 2013

    [13]

    Seminal and molecular evidence that sauna exposure affects human spermatogenesis

    Longitudinal before-and-after study, 3 months plus 6 months follow-up · 10 men with normal sperm

    Two 15 minute sessions a week at 80 to 90°C for 3 months sharply reduced sperm count and motility, which fully recovered 6 months after stopping.

    Finds againstRead

Animal and cell studies (1)

  • Proc Natl Acad Sci U S A · 2008

    [12]

    HSP72 protects against obesity-induced insulin resistance

    Mouse study with heat therapy, transgenic and drug arms

    Raising the heat shock protein HSP72 in mice, by heat therapy, genetics or a drug, protected them from insulin resistance on a high-fat diet.

    SupportsRead

Hypotheses and expert reviews (2)

  • Mayo Clin Proc · 2018

    [16]

    Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence

    Narrative review

    Summarizes evidence linking Finnish sauna to lower blood pressure, cardiovascular and neurocognitive disease, and proposes mechanisms such as better endothelial function and lower arterial stiffness.

    SupportsRead

  • Int J Circumpolar Health · 2006

    [20]

    Health effects and risks of sauna bathing

    Literature review

    Sauna at 80 to 90°C was well tolerated by healthy people and by stable, treated heart patients, with antihypertensive drugs the main risk through low blood pressure on standing.

    No clear effectRead

Who follows it, who backs it, who doubts it

Public positions summarized in our words. Follow each link for the full context.

Follow it

  • Rhonda PatrickBiomedical scientist and host of FoundMyFitness

    Uses a traditional sauna at about 186 °F (86 °C)86 °C (186 °F) for 20 to 30 minutes roughly four times a week, usually after exercise, and replaces lost electrolytes afterwards.

    FoundMyFitness: How Dr. Rhonda Patrick Uses Sauna and Heat

  • Bryan JohnsonEntrepreneur, founder of Blueprint

    Uses a dry sauna at 175 °F (about 79 °C)about 79 °C (175 °F) for 20 minutes daily with an ice pack on the groin to protect fertility, and reports personal drops in blood pressure and urinary toxins that have not been tested in trials.

    Bryan Johnson's Blueprint protocol

Support it

Oppose or doubt it

  • Steven NovellaNeurologist at Yale School of Medicine and founder of Science-Based Medicine

    Argues that infrared sauna detox claims have no basis, that short-term blood pressure changes may reflect dehydration, and that the evidence for lasting benefit is sparse and inconsistent.

    Science-Based Medicine: Infrared Saunas for Detoxification

Public examples

How to follow it

  1. Check with a clinician first if you have heart disease, low blood pressure, take blood pressure medicines, are pregnant or are trying to conceive.
  2. Drink a glass of water beforehand and skip the sauna after alcohol or when ill.
  3. Start with 5 to 10 minutes on a lower bench at about 158 to 176 °F (70 to 80 °C)70 to 80 °C (158 to 176 °F).
  4. Cool off for a few minutes between rounds, and stand up slowly when you leave.
  5. Build toward 15 to 20 minutes per session, 2 to 4 times a week, adding sessions as tolerance grows.
  6. Rehydrate afterwards with water and, after long sweaty sessions, some electrolytes.

How to know you are following it

Log each session with sauna type, temperature (°C or °F), minutes in the heat and rounds. Adherence is sessions per week and minutes per session against your target, for example 3 sessions of 15 to 20 minutes at about 80°C.

Common mistakes

  • Drinking alcohol before or during a sauna.
  • Staying in past dizziness, nausea or a pounding headache.
  • Standing up quickly after a session, which can cause fainting.
  • Assuming infrared cabins at 45 to 60°C deliver the same effects as the Finnish saunas in the cohort studies.
  • Using a sauna as a substitute for exercise rather than an addition.
  • Expecting sweat to detoxify the body.

Who should be careful

Check with a clinician first if you

  • You have unstable angina, a recent heart attack, severe aortic stenosis or uncontrolled heart failure, unless a cardiologist approves it.
  • You have been drinking alcohol.
  • You have a fever, an acute illness or are dehydrated.
  • You are pregnant, unless your clinician agrees and you keep sessions short and cooler.
  • You take medicines that lower blood pressure or affect sweating, unless your clinician agrees.
  • You are a man trying to conceive, since sperm counts can fall for months.

Possible side effects

  • Dizziness or fainting from low blood pressure, especially on standing.
  • Dehydration and, rarely, heat exhaustion or heat stroke.
  • Temporary, reversible reduction in sperm count and motility.
  • Skin irritation in people with some skin conditions.
  • Rarely, sudden cardiac events in people with unstable heart disease, most often with alcohol.

Watch

Talks and explainers worth your time. Nothing loads from YouTube until you press play.

  • Dr. Jari Laukkanen on Sauna Use for the Prevention of Cardiovascular & Alzheimer's Disease

    FoundMyFitnessOpen on YouTube

    The lead KIHD investigator explains the cohort, the frequency and duration findings, and their limits.

  • The Science & Health Benefits of Deliberate Heat Exposure

    Andrew HubermanOpen on YouTube

    A long walkthrough of heat physiology, heat shock proteins and published sauna protocols.

  • Does regular sauna use provide health benefits? | The Peter Attia Drive Podcast

    Peter Attia MDOpen on YouTube

    A physician's short take on how much weight to give the sauna studies.

  • Sauna Benefits Deep Dive and Optimal Use with Dr. Rhonda Patrick & MedCram

    MedCram - Medical Lectures Explained CLEARLYOpen on YouTube

    A physician and a biomedical scientist discuss the research and how Finnish and infrared saunas differ.

  • How to Use Cold & Heat Exposure to Improve Your Health | Dr. Susanna Søberg

    Andrew HubermanOpen on YouTube

    Covers how sauna and cold water are combined in Scandinavian contrast practice.

Biomarkers it can move

Common questions

How long should you stay in a sauna to get benefits?

In the Finnish KIHD study, sessions over 19 minutes were linked to the lowest risk of sudden cardiac death. Trials that lowered blood pressure used 15 to 30 minutes. Beginners should start with 5 to 10 minutes.

How often should you use a sauna?

The KIHD data compared 1, 2 to 3 and 4 to 7 sessions a week, and risk was lowest at 4 to 7. Two to three sessions a week is a common, practical target.

What is the best sauna temperature for health benefits?

The Finnish studies used dry saunas averaging about 174 °F (79 °C)79 °C (174 °F). Most protocols use 176 to 212 °F (80 to 100 °C)80 to 100 °C (176 to 212 °F). Infrared saunas run at 113 to 140 °F (45 to 60 °C)45 to 60 °C (113 to 140 °F) and have less outcome data.

Is it safe to use a sauna every day?

For healthy adults who stay hydrated and avoid alcohol, daily use appears well tolerated; 4 to 7 sessions a week was the most frequent group in the Finnish studies. People with heart disease or who are pregnant should ask a clinician first.

Are sauna benefits scientifically proven?

The short-term effects on blood pressure and blood vessel function are shown in trials. The large drops in death and dementia risk come from observational studies, so they show association, not proof of cause.

Does sauna help with weight loss?

Weight lost in a sauna is mostly water and returns when you drink. No trial shows sauna causes fat loss.

Is sauna or cold plunge better?

Sauna has stronger evidence for blood pressure and cardiovascular outcomes. Cold plunging has better evidence for post-exercise soreness. Many people use both, often alternating them.

Does sauna affect fertility?

Yes, in men. Two 15 minute sessions a week at 80 to 90°C for 3 months sharply reduced sperm count and motility in a small study, with full recovery about 6 months after stopping.

Can you use a sauna when pregnant?

A systematic review found that dry sauna at 158 °F (70 °C)70 °C (158 °F) for up to 20 minutes kept core temperature below the 39.0°C threshold linked to birth defects, but some guidance still advises avoiding it. Decide with your clinician.

Should you sauna before or after a workout?

The randomized trial that lowered blood pressure used a 15 minute sauna after exercise. Using it afterwards also avoids starting a workout dehydrated.

Sources

  1. 1.Pizzey FK, Smith EC, Ruediger SL, et al. The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta-analysis. Exp Physiol, 2021. doi:10.1113/EP089424
  2. 2.Lee E, Kolunsarka I, Kostensalo J, et al. Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. Am J Physiol Regul Integr Comp Physiol, 2022. doi:10.1152/ajpregu.00076.2022
  3. 3.Laukkanen T, Khan H, Zaccardi F, et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med, 2015. doi:10.1001/jamainternmed.2014.8187
  4. 4.Kunutsor SK, Khan H, Zaccardi F, et al. Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study. Neurology, 2018. doi:10.1212/WNL.0000000000005606
  5. 5.Zaccardi F, Laukkanen T, Willeit P, et al. Sauna Bathing and Incident Hypertension: A Prospective Cohort Study. Am J Hypertens, 2017. doi:10.1093/ajh/hpx102
  6. 6.Laukkanen T, Kunutsor SK, Khan H, et al. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study. BMC Med, 2018. doi:10.1186/s12916-018-1198-0
  7. 7.Laukkanen T, Kunutsor S, Kauhanen J, et al. Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men. Age Ageing, 2017. doi:10.1093/ageing/afw212
  8. 8.Janssen CW, Lowry CA, Mehl MR, et al. Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry, 2016. doi:10.1001/jamapsychiatry.2016.1031
  9. 9.Hussain J, Cohen M. Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review. Evid Based Complement Alternat Med, 2018. doi:10.1155/2018/1857413
  10. 10.Laukkanen JA, Laukkanen T. Sauna bathing and systemic inflammation. Eur J Epidemiol, 2018. doi:10.1007/s10654-017-0335-y
  11. 11.Iguchi M, Littmann AE, Chang SH, et al. Heat stress and cardiovascular, hormonal, and heat shock proteins in humans. J Athl Train, 2012. doi:10.4085/1062-6050-47.2.184
  12. 12.Chung J, Nguyen AK, Henstridge DC, et al. HSP72 protects against obesity-induced insulin resistance. Proc Natl Acad Sci U S A, 2008. doi:10.1073/pnas.0705799105
  13. 13.Garolla A, Torino M, Sartini B, et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Hum Reprod, 2013. doi:10.1093/humrep/det020
  14. 14.Brunt VE, Howard MJ, Francisco MA, et al. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. J Physiol, 2016. doi:10.1113/JP272453
  15. 15.Lee E, Laukkanen T, Kunutsor SK, et al. Sauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental study. Eur J Prev Cardiol, 2018. doi:10.1177/2047487317737629
  16. 16.Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clin Proc, 2018. doi:10.1016/j.mayocp.2018.04.008
  17. 17.Tei C, Imamura T, Kinugawa K, et al. Waon Therapy for Managing Chronic Heart Failure - Results From a Multicenter Prospective Randomized WAON-CHF Study. Circ J, 2016. doi:10.1253/circj.CJ-16-0051
  18. 18.Lee E, Ketelhut S, Wiklund P, et al. Regular postexercise sauna bathing does not improve heart rate variability: A multi-arm randomized controlled trial. Physiol Rep, 2025. doi:10.14814/phy2.70449
  19. 19.Kenttämies A, Karkola K. Death in sauna. J Forensic Sci, 2008. doi:10.1111/j.1556-4029.2008.00703.x
  20. 20.Kukkonen-Harjula K, Kauppinen K. Health effects and risks of sauna bathing. Int J Circumpolar Health, 2006. doi:10.3402/ijch.v65i3.18102
  21. 21.Ravanelli N, Casasola W, English T, et al. Heat stress and fetal risk. Environmental limits for exercise and passive heat stress during pregnancy: a systematic review with best evidence synthesis. Br J Sports Med, 2019. doi:10.1136/bjsports-2017-097914
  22. 22.Kihara T, Biro S, Imamura M, et al. Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure. J Am Coll Cardiol, 2002. doi:10.1016/s0735-1097(01)01824-1
  23. 23.Ukai T, Iso H, Yamagishi K, et al. Habitual tub bathing and risks of incident coronary heart disease and stroke. Heart, 2020. doi:10.1136/heartjnl-2019-315752

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