Finnish sauna bathing and vascular health of adults with coronary artery disease: a randomized controlled trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 37650138 · doi:10.1152/japplphysiol.00322.2023
What was done
Forty-one adults (mean age 62 years, 33 men and 8 women) with stable coronary artery disease were randomized to 8 weeks of Finnish sauna use (n = 21; 4 sessions per week, 20-30 minutes per session at 79°C and 13% relative humidity) or a control group maintaining their normal lifestyle (n = 20). Investigators measured resting core temperature, sweat rate during heat exposure, brachial artery flow-mediated dilation, carotid-femoral pulse wave velocity, forearm reactive hyperemia (total area under the curve and peak), and automated blood pressure before and after the 8-week intervention.
What was found
The sauna intervention produced markers of heat acclimation: resting core temperature decreased (-0.27°C [95% CI: -0.54, -0.01], P = 0.046) and sweat rate increased (0.3 L/h [95% CI: 0.1, 0.5], P = 0.003). However, vascular markers showed no benefit. Change in brachial artery flow-mediated dilation did not differ between control (0.07% [-0.99, +1.14]) and sauna (0.15% [-0.89, +1.19], interaction P = 0.909). There were no significant differences between groups for changes in carotid-femoral pulse wave velocity (P = 0.816), systolic blood pressure (P = 0.951), or diastolic blood pressure (P = 0.292). Differences in total (P = 0.031) and peak (P = 0.024) reactive hyperemia were driven by a nonsignificant decrease in the sauna group alongside an increase in controls.
Why it matters
While observational studies link regular sauna use to reduced cardiovascular mortality, this trial shows that 8 weeks of frequent sauna bathing does not improve resting endothelial function, arterial stiffness, or blood pressure in stable coronary artery disease.
Limits
The study was small (n = 41), predominantly male (80.5%), limited to an 8-week duration, and utilized unsupervised sauna sessions. It evaluated surrogate vascular markers rather than clinical cardiovascular events.
Cited by
- contradicts Sauna exposure improves endothelial function and arterial compliance.