Acute effects of sauna bathing on cardiovascular function.
Level 4 - case-series / case-control
Uncontrolled single-group before-and-after experimental study without a control group.
PubMed 29269746 · doi:10.1038/s41371-017-0008-z
What was done
An experimental pre-post study evaluated 102 adults (mean age 51.9 ± 9.2 years, 56% male) with at least one cardiovascular risk factor. Participants underwent a single 30-minute sauna session at 73 °C and 10–20% humidity. Arterial stiffness (carotid-femoral pulse wave velocity), blood pressure, and blood-based biomarkers were measured before, immediately after, and after a 30-minute recovery period.
What was found
Carotid-femoral pulse wave velocity decreased from 9.8 (2.4) m/s before sauna to 8.6 (1.6) m/s immediately after (p < 0.0001). Mean systolic blood pressure decreased from 137 (16) to 130 (14) mmHg (p < 0.0001) and remained lower after 30 minutes of recovery. Mean diastolic blood pressure decreased from 82 (10) to 75 (9) mmHg (p < 0.0001). Plasma creatinine increased slightly from sauna until recovery, while sodium and potassium levels remained constant.
Why it matters
This study documents acute reductions in arterial stiffness and blood pressure following heat exposure, illustrating potential hemodynamic mechanisms behind observed cardiovascular associations with sauna bathing.
Limits
The study lacked a control or sham comparison group, meaning changes cannot be isolated from non-specific rest or time effects. Follow-up was limited to 30 minutes, leaving long-term adaptations unmeasured.
Cited by
- supports Exposure to a single sauna session improves blood pressure.
- context Finnish saunas typically operate at temperatures between 174°F and 179°F with 20% to 30% humidity.