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Sauna Hype

Blood pressure and artery stiffness fell right after one 30-minute sauna

Researchers measured 102 Finnish adults before and after one sauna session and got the popular 137-to-130 blood pressure figure. Their 2018 paper in the Journal of Human Hypertension had no comparison group.

The paper

Acute effects of sauna bathing on cardiovascular function

Laukkanen T, Kunutsor SK, Zaccardi F, Lee E, et al.. Journal of Human Hypertension, 2018;32(2):129-138.

Read the paper ↗PubMed 29269746 ↗

See the study at a glance

Design
Single-group before-and-after experiment
People
102 adults
Who they were
The volunteers were Kuopio adults who were used to saunas and had at least one cardiovascular risk factor. Their average age was 51.9, and 56% were men.
What they did
Each person took one 30-minute session at 73°C (heater set to 80°C) and 10–20% humidity. A two-minute shower broke it up after the first 15 minutes. Measurements came before the session, straight after it and after 30 minutes of recovery.
How long
One session

These numbers came out of it

137 → 130

Systolic blood pressure (the top number, in mmHg) dropped between the reading before the sauna and the one right after.

82 → 75

Diastolic pressure (the bottom number) fell over the same stretch.

9.8 → 8.6

Carotid-femoral pulse wave velocity (meters a second) tracks how stiff the big arteries are. It fell right after the sauna and was back up to 9.0 after 30 minutes of rest.

+12%

The heart-strain marker NT-proBNP rose this much in the 20 people tested right after the sauna.

The researchers did this

Researchers in Kuopio recruited 102 adults who each had at least one cardiovascular risk factor and who were used to saunas. Each sat through one 30-minute session in a 73°C sauna with a short shower halfway and was measured before the session and twice afterward.Source 1 · 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 ↗Source 2 · Clinical trialShort-term effects of Finnish sauna bathing on blood-based markers of cardiovascular function in non-naive sauna usersKunutsor SK, Häkkinen A, Zaccardi F, et al.. Heart and Vessels, 2018.Read the paper ↗PubMed ↗

Right after the sauna, systolic pressure had fallen from 137 to 130 mmHg and diastolic from 82 to 75. Systolic pressure was still below its starting level after 30 minutes of recovery.Source 1 · 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 ↗ Pulse wave velocity fell from 9.8 to 8.6 meters a second and had climbed back to 9.0 by the end of recovery.Source 3 · 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 ↗

Heart rate rose from 65 to 81 beats a minute, and the heart spent less time pushing blood out with each beat.Source 3 · 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 ↗ In 20 of the volunteers, NT-proBNP rose 12% and was still up 13.9% at 30 minutes. Troponin and other markers of heart muscle damage stayed flat.Source 2 · Clinical trialShort-term effects of Finnish sauna bathing on blood-based markers of cardiovascular function in non-naive sauna usersKunutsor SK, Häkkinen A, Zaccardi F, et al.. Heart and Vessels, 2018.Read the paper ↗PubMed ↗

At least three companion papers came out of the same volunteers. For largely the same people, two of them put the resting heart rate before the sauna at 65 and at 77 beats a minute.Source 3 · 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 trialRecovery from sauna bathing favorably modulates cardiac autonomic nervous systemLaukkanen T, Lipponen J, Kunutsor SK, et al.. Complementary Therapies in Medicine, 2019.Read the paper ↗PubMed ↗

The study can't tell you these things

  • There was no comparison condition, so the changes can't be separated from the effects of resting and drinking water.
  • Every reading was taken after people left the sauna. Another study found blood pressure rising steadily during a very hot session.Source 5 · Clinical trialThe blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exerciseKetelhut S, Ketelhut R. Complementary Therapies in Medicine, 2019.Read the paper ↗PubMed ↗
  • The participants were habitual sauna users with risk factors, so the results can't speak for newcomers or for healthy young people.
  • One session can't show what regular use does over weeks, and trials that ran for weeks found little or no lasting change in blood pressure or artery stiffness.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 · 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 ↗

People quote it like this

The finding circulates as proof that a sauna session lowers blood pressure and softens arteries. Few retellings mention that every reading came after people left the sauna or that the study had no comparison group. The authors' 2018 review lists it among the benefits of sauna.Source 8 · ReviewCardiovascular and Other Health Benefits of Sauna Bathing: A Review of the EvidenceLaukkanen JA, Laukkanen T, Kunutsor SK. Mayo Clinic Proceedings, 2018.Read the paper ↗PubMed ↗

We cited these sources

  1. 01Laukkanen 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
  2. 02Kunutsor SK, Häkkinen A, Zaccardi F, Laukkanen T, Lee E, Willeit P, et al.. Short-term effects of Finnish sauna bathing on blood-based markers of cardiovascular function in non-naive sauna users. Heart and Vessels. 2018;33(12):1515-1524. doi:10.1007/s00380-018-1202-9 PMID 29971466
  3. 03Lee 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
  4. 04Laukkanen T, Lipponen J, Kunutsor SK, Zaccardi F, Araújo CGS, Mäkikallio TH, et al.. Recovery from sauna bathing favorably modulates cardiac autonomic nervous system. Complementary Therapies in Medicine. 2019;45:190-197. doi:10.1016/j.ctim.2019.06.011 PMID 31331560
  5. 05Ketelhut S, Ketelhut R. The blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exercise. Complementary Therapies in Medicine. 2019;44:218-222. doi:10.1016/j.ctim.2019.05.002 PMID 31126559
  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. 07Debray 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
  8. 08Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clinic Proceedings. 2018;93(8):1111-1121. doi:10.1016/j.mayocp.2018.04.008 PMID 30077204