Eight weeks of Finnish sauna left blood vessel health unchanged in heart patients
In this 2023 Journal of Applied Physiology trial, 41 adults with stable coronary artery disease were randomly assigned to four sauna sessions a week or their usual routine.
The paper
Finnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trial
Debray A, Gravel H, Garceau L, Bartlett AA, et al.. Journal of Applied Physiology, 2023;135(4):795-804.
See the study at a glance
- Design
- Randomized controlled trial
- People
- 41 adults (33 men, 8 women)
- Who they were
- Adults with stable coronary artery disease took part, and their average age was 62.
- What they did
- The sauna group took four unsupervised sessions a week of 20 to 30 minutes in a 79°C Finnish sauna at 13% humidity. The control group kept to their usual lifestyle.
- How long
- 8 weeks
These numbers came out of it
+0.15
With sauna, flow-mediated dilation (how well an artery widens, in percentage points) changed this much. Controls changed by +0.07.
0.909
A P value this close to 1 means the difference in flow-mediated dilation between the groups could easily be chance.
−0.27°C
Resting core temperature fell this much in the sauna group. That shows their bodies had adapted to the heat.
+0.3 L/h
The sauna group's sweat rate rose this much, as it does when a body gets used to heat.
The researchers did this
Researchers randomly assigned 41 adults with stable coronary artery disease to eight weeks of Finnish sauna or to their usual lifestyle. The sauna group bathed unsupervised four times a week for 20 to 30 minutes at 79°C.Source 1 · 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 trial measured how well the upper-arm (brachial) artery widened when blood flow increased, how strongly forearm blood flow rushed back after a brief blockage, carotid-femoral pulse wave velocity and blood pressure. Flow-mediated dilation changed by +0.15 points with sauna and +0.07 with the usual routine, and the P value for the difference was 0.909.Source 1 · 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 ↗
Pulse wave velocity and blood pressure didn't differ between the groups either. The forearm blood flow measure did differ, because it fell slightly with sauna and rose in controls. Taken separately, neither change was significant.Source 1 · 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 sauna group's bodies adapted to the heat. Their resting core temperature dropped 0.27°C and their sweat rate rose by 0.3 liters an hour, while the vascular measures stayed where they were.Source 1 · 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 study can't tell you these things
- With 41 people, the trial could miss a small effect.
- People took their sessions without supervision, so how much heat each one got was up to them.
- Participants were taking heart medicines.
- The abstract doesn't say which outcome was the primary one.
- Men made up 33 of the 41 participants.
People quote it like this
Popular accounts of sauna and arteries mostly cite the one-session Kuopio experiment.Source 2 · 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 ↗ This trial ran a home-style routine for weeks in heart patients and found no change in their blood vessels.
We cited these sources
- 01Debray 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
- 02Lee 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