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Sauna Hype

The claim

“Sauna makes your arteries more flexible.”

Stretched. Arteries measured less stiff right after a 30-minute sauna in a study without a control group, and the change was already fading half an hour later. Randomized trials that ran for weeks, one of them in Finnish saunas, found no lasting change.

Updated Sep 24, 2026 · 3 studies reviewed

A real finding has been pulled well past what the study showed.

People say it in places like these

  • Journal titles

    A sauna session improves how well your arteries stretch.

    See an example ↗

  • Wellness sites

    Regular saunas train your blood vessels the way exercise does.

  • Podcasts

    Sauna makes your arteries more elastic, so your heart works less.

The research found this

The claim traces to a Kuopio experiment in which 102 adults with at least one heart risk factor sat in a 73°C sauna for 30 minutes. The researchers measured pulse wave velocity, which rises as the big arteries stiffen. It fell from 9.8 to 8.6 meters a second right after the sauna and stood at 9.0 after half an hour of rest.Source 1 · Clinical trialSauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental studyLee E, Laukkanen T, Kunutsor SK, et al.. European Journal of Preventive Cardiology, 2018.Read the paper ↗PubMed ↗ The experiment had no control condition.Source 2 · Clinical trialAcute effects of sauna bathing on cardiovascular functionLaukkanen T, Kunutsor SK, Zaccardi F, et al.. Journal of Human Hypertension, 2018.Read the paper ↗PubMed ↗

Another measure of blood vessel health didn't budge. In a randomized crossover study of 21 healthy adults in their sixties, one or two 10-minute bouts at 80°C didn't improve flow-mediated dilation.Source 3 · Crossover trialAcute effect of Finnish sauna bathing on brachial artery flow‐mediated dilation and reactive hyperemia in healthy middle‐aged and older adultsGravel H, Coombs GB, Behzadi P, et al.. Physiological Reports, 2019.Read the paper ↗PubMed ↗ That test measures how well an arm artery widens when blood flow rises.

The biggest reported change came from hot water in Oregon. Ten sedentary young adults soaked in 40.5°C water four or five times a week for eight weeks, and each time they held their core temperature at 38.5°C or higher for an hour. Their aortic pulse wave velocity fell from 7.1 to 6.1 meters a second and their flow-mediated dilation nearly doubled, while a comparison group in 36°C water showed no change.Source 4 · Clinical trialPassive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humansBrunt VE, Howard MJ, Francisco MA, et al.. The Journal of Physiology, 2016.Read the paper ↗PubMed ↗ The investigators assigned people to the groups by matching them on sex, age, body mass index and time of year, and there was no randomization.

Randomized trials at more ordinary doses found no such gains. Forty-one adults with stable coronary artery disease used a 79°C sauna four times a week for eight weeks, and neither flow-mediated dilation nor pulse wave velocity changed against a control group, even though their bodies had adapted to the heat.Source 5 · Randomized trialFinnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trialDebray A, Gravel H, Garceau L, et al.. Journal of Applied Physiology, 2023.Read the paper ↗PubMed ↗ Pooling 20 randomized trials of passive heating found no effect on flow-mediated dilation or pulse wave velocity, and a separate analysis of 51 controlled studies found artery stiffness unchanged.Source 6 · Meta-analysisNon-acute effects of passive heating interventions on cardiometabolic risk and vascular health: systematic review and meta-analysis of randomized controlled trialsHamaya R, Joyama Y, Miyata T, et al.. American Journal of Preventive Cardiology, 2025.Read the paper ↗PubMed ↗Source 7 · Meta-analysisHeat thermotherapy to improve cardiovascular function and cardiometabolic health: A systematic review and meta‐analysisPrice BS, Lucas SJE, Akerman AP, et al.. Experimental Physiology, 2025.Read the paper ↗PubMed ↗

A few results lean the other way. An earlier pooled analysis found a 1.95-point gain in flow-mediated dilation across five studies, and its authors rated the certainty low.Source 8 · Meta-analysisThe effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta‐analysisPizzey FK, Smith EC, Ruediger SL, et al.. Experimental Physiology, 2021.Read the paper ↗PubMed ↗ In Japan, people who took hot baths at least five times a week had less stiff arteries than people who bathed less. That was a survey, so it can't say which came first.Source 9 · Cross-sectional studyHabitual hot water bathing protects cardiovascular function in middle-aged to elderly Japanese subjectsKohara K, Tabara Y, Ochi M, et al.. Scientific Reports, 2018.Read the paper ↗PubMed ↗

The dial reads 61°H for four reasons

How the reading adds up

16 + 20 + 15 + 10 = 61°H

  1. EvidenceWhat kind of evidence exists in people?

    16/25

    Randomized trials have measured artery stiffness directly and mostly found nothing, including a pooled analysis of 20 trials and an eight-week trial of Finnish sauna.Source 6 · Meta-analysisNon-acute effects of passive heating interventions on cardiometabolic risk and vascular health: systematic review and meta-analysis of randomized controlled trialsHamaya R, Joyama Y, Miyata T, et al.. American Journal of Preventive Cardiology, 2025.Read the paper ↗PubMed ↗Source 5 · Randomized trialFinnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trialDebray A, Gravel H, Garceau L, et al.. Journal of Applied Physiology, 2023.Read the paper ↗PubMed ↗ The positive data come from a single session without a control group and a small hot-tub study that didn't randomize.Source 1 · Clinical trialSauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental studyLee E, Laukkanen T, Kunutsor SK, et al.. European Journal of Preventive Cardiology, 2018.Read the paper ↗PubMed ↗Source 4 · Clinical trialPassive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humansBrunt VE, Howard MJ, Francisco MA, et al.. The Journal of Physiology, 2016.Read the paper ↗PubMed ↗

  2. ConsistencyHas the finding held up?

    20/25

    Better-controlled studies contradict a lasting effect. A 2025 pooling of 51 controlled studies found artery stiffness unchanged after single or repeated bouts of heat.Source 7 · Meta-analysisHeat thermotherapy to improve cardiovascular function and cardiometabolic health: A systematic review and meta‐analysisPrice BS, Lucas SJE, Akerman AP, et al.. Experimental Physiology, 2025.Read the paper ↗PubMed ↗

  3. MagnitudeDoes the claim match the size of the effect?

    15/25

    The popular figure is pulse wave velocity falling from 9.8 to 8.6 meters a second right after a session and sitting at 9.0 after 30 minutes.Source 1 · Clinical trialSauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental studyLee E, Laukkanen T, Kunutsor SK, et al.. European Journal of Preventive Cardiology, 2018.Read the paper ↗PubMed ↗ The claim suggests a lasting change that trials of weeks didn't find.

  4. DoseDoes the studied protocol match how people use it?

    10/25

    The single-session study used a normal 30-minute sauna at 73°C.Source 2 · Clinical trialAcute effects of sauna bathing on cardiovascular functionLaukkanen T, Kunutsor SK, Zaccardi F, et al.. Journal of Human Hypertension, 2018.Read the paper ↗PubMed ↗ The one long study with a big result held people's core temperature at 38.5°C or higher for an hour at a time in hot water, and they did it four or five times a week.Source 4 · Clinical trialPassive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humansBrunt VE, Howard MJ, Francisco MA, et al.. The Journal of Physiology, 2016.Read the paper ↗PubMed ↗

The claim drifts from the data here

A reading taken minutes after a sauna captures the heat's short-term effect. In the Kuopio study a third of the drop had gone after 30 minutes, and there was no control condition to compare against.Source 1 · Clinical trialSauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental studyLee E, Laukkanen T, Kunutsor SK, et al.. European Journal of Preventive Cardiology, 2018.Read the paper ↗PubMed ↗

The hot-tub result that people cite held core temperature at 38.5°C or more for an hour at a time. Three 10-minute sauna bouts raised core temperature by 0.4°C in a head-to-head test.Source 4 · Clinical trialPassive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humansBrunt VE, Howard MJ, Francisco MA, et al.. The Journal of Physiology, 2016.Read the paper ↗PubMed ↗Source 10 · Crossover trialComparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalitiesAtencio JK, Reed EL, Wiedenfeld Needham K, et al.. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2025.Read the paper ↗PubMed ↗

Put it to use

If you want heat to help your blood vessels, the best evidence pairs it with exercise. After eight weeks, hot-water soaks that followed cycling improved flow-mediated dilation more than lukewarm soaks did, though aortic stiffness didn't change.Source 11 · Randomized trialPost‐exercise hot water immersion enhances haemodynamic and vascular benefits of exercise without further improving cardiorespiratory fitness, glucose, lipids or inflammationSteward CJ, Hill M, Menzies C, et al.. The Journal of Physiology, 2025.Read the paper ↗PubMed ↗

From our sister magazine

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Sauna Monthly compares barrels and cabins that run hot-rock heaters.

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Sauna Monthly · Guide

Choose between a wood stove and an electric heater

Sauna Monthly compares the two ways to heat a backyard sauna.

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People also ask

Does sauna reduce arterial stiffness?

Right after a 30-minute session, pulse wave velocity fell from 9.8 to 8.6 meters a second in 102 adults. That study had no control group.Source 1 · Clinical trialSauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental studyLee E, Laukkanen T, Kunutsor SK, et al.. European Journal of Preventive Cardiology, 2018.Read the paper ↗PubMed ↗ Trials lasting weeks have found no lasting change, and one of them gave eight weeks of Finnish sauna to people with coronary disease.Source 5 · Randomized trialFinnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trialDebray A, Gravel H, Garceau L, et al.. Journal of Applied Physiology, 2023.Read the paper ↗PubMed ↗Source 7 · Meta-analysisHeat thermotherapy to improve cardiovascular function and cardiometabolic health: A systematic review and meta‐analysisPrice BS, Lucas SJE, Akerman AP, et al.. Experimental Physiology, 2025.Read the paper ↗PubMed ↗

Is a hot tub or a sauna better for your arteries?

Neither has shown a lasting benefit at a normal dose. The strongest positive result came from a small, non-randomized study in which people held their core temperature at 38.5°C or higher for an hour in a hot tub on four or five days a week.Source 4 · Clinical trialPassive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humansBrunt VE, Howard MJ, Francisco MA, et al.. The Journal of Physiology, 2016.Read the paper ↗PubMed ↗

Check these claims next

44°H

Early

Heat

“Sauna lowers your blood pressure.”

Blood pressure falls for a while after a sauna, and that short dip is what the popular numbers measure. Trials lasting weeks found little or no lasting drop from heat on its own, while one small trial found a clear drop when the sauna followed exercise.

62°H

Stretched

Heat

“A sauna session is as good as a workout.”

A hot sauna raises your heart rate about as much as moderate cycling, which is where the idea comes from. The heart speeds up without pumping more blood per beat, and no trial has shown that sauna alone builds fitness the way exercise does.

36°H

Likely

Heat

“Using a sauna four to seven times a week halves your risk of dying from heart disease.”

In one Finnish cohort, men who took four to seven saunas a week died of heart disease at about half the rate of men who went once a week. Later analyses of the same men found a smaller gap, and the link was missing in the fittest men and in women who went two or three times a week.

We cited these sources

  1. 01Lee E, Laukkanen T, Kunutsor SK, Khan H, Willeit P, Zaccardi F, et al.. Sauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental study. European Journal of Preventive Cardiology. 2018;25(2):130-138. doi:10.1177/2047487317737629 PMID 29048215
  2. 02Laukkanen T, Kunutsor SK, Zaccardi F, Lee E, Willeit P, Khan H, et al.. Acute effects of sauna bathing on cardiovascular function. Journal of Human Hypertension. 2018;32(2):129-138. doi:10.1038/s41371-017-0008-z PMID 29269746
  3. 03Gravel H, Coombs GB, Behzadi P, Marcoux‐Clément V, Barry H, Juneau M, et al.. Acute effect of Finnish sauna bathing on brachial artery flow‐mediated dilation and reactive hyperemia in healthy middle‐aged and older adults. Physiological Reports. 2019;7(13):e14166. doi:10.14814/phy2.14166 PMID 31293098
  4. 04Brunt VE, Howard MJ, Francisco MA, Ely BR, Minson CT. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. The Journal of Physiology. 2016;594(18):5329-5342. doi:10.1113/JP272453 PMID 27270841
  5. 05Debray A, Gravel H, Garceau L, Bartlett AA, Chaseling GK, Barry H, et al.. Finnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trial. Journal of Applied Physiology. 2023;135(4):795-804. doi:10.1152/japplphysiol.00322.2023 PMID 37650138
  6. 06Hamaya R, Joyama Y, Miyata T, Fuse SI, Yamane N, Maruyama N, et al.. 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. 2025;23:101082. doi:10.1016/j.ajpc.2025.101082 PMID 41049507
  7. 07Price BS, Lucas SJE, Akerman AP, Gilworth RE, Lucas RAI. Heat thermotherapy to improve cardiovascular function and cardiometabolic health: A systematic review and meta‐analysis. Experimental Physiology. 2025:EP092404. doi:10.1113/EP092404 PMID 41166412
  8. 08Pizzey FK, Smith EC, Ruediger SL, Keating SE, Askew CD, Coombes JS, et al.. The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta‐analysis. Experimental Physiology. 2021;106(6):1317-1334. doi:10.1113/EP089424 PMID 33866630
  9. 09Kohara K, Tabara Y, Ochi M, Okada Y, Ohara M, Nagai T, et al.. Habitual hot water bathing protects cardiovascular function in middle-aged to elderly Japanese subjects. Scientific Reports. 2018;8(1):8687. doi:10.1038/s41598-018-26908-1 PMID 29930309
  10. 10Atencio JK, Reed EL, Wiedenfeld Needham K, Lucernoni KM, Comrada LN, Halliwill JR, et al.. Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 2025;329(1):R20-R35. doi:10.1152/ajpregu.00012.2025 PMID 40332494
  11. 11Steward CJ, Hill M, Menzies C, Russell SL, Thake CD, Pugh CJA, et al.. Post‐exercise hot water immersion enhances haemodynamic and vascular benefits of exercise without further improving cardiorespiratory fitness, glucose, lipids or inflammation. The Journal of Physiology. 2025;603(16):4515-4533. doi:10.1113/JP288873 PMID 40719540