The blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exercise.
Level 4 - case-series / case-control
Single-arm within-subject physiological study comparing sauna to exercise testing without a randomized control group.
PubMed 31126559 · doi:10.1016/j.ctim.2019.05.002
What was done
Nineteen healthy adult volunteers (7 women; mean age 46.4 ± 10.2 years; BMI 24.4 ± 2 kg/m²) underwent blood pressure and heart rate monitoring during a 25-minute sauna session (93°C, 13% humidity) and during a subsequent 30-minute rest period. Hemodynamic parameters were compared with responses during submaximal dynamic exercise testing.
What was found
Sauna exposure caused a significant progressive increase in systolic and diastolic blood pressure (p < 0.01) and heart rate (p < 0.001), significantly increasing systolic blood pressure × heart rate (rate-pressure product, p < 0.001). In the post-sauna rest period, blood pressure and heart rate decreased steadily (p < 0.001), with blood pressure dropping significantly below baseline (p < 0.001). The abstract reports no absolute numerical values for blood pressure or heart rate, but indicates the cardiac load was equivalent to dynamic exercise at 60–100 watts.
Why it matters
Acute sauna bathing places a cardiovascular load on the heart equivalent to moderate submaximal exercise, contradicting the assumption that heat exposure induces an immediate drop in cardiac workload and blood pressure.
Limits
The study is limited by a small sample size (n = 19) of healthy adults, so responses in populations with cardiovascular disease were not assessed. The abstract does not provide absolute numerical values, confidence intervals, or baseline readings, and the study lacked a separate non-heat control arm.
Cited by
- supports Spending 15 minutes in a hot sauna produces acute and post-exposure cardiovascular changes (heart rate, blood pressure) identical to 15 minutes of cycling at 100 watts on a stationary bike.
- supports Exposure to a single sauna session improves blood pressure.
- supports Infrared saunas max out at around 145°F and do not mimic moderate-intensity cardiovascular exercise for the same duration as traditional hot saunas.