The blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exercise

ObjectivesIn the present study, the reaction of blood pressure and heart rate are examined during and after a single acute sauna application.DesignIn 19 healthy adult volunteers (7 women, aged 46.4±10.2 years, BMI 24.4±2 kg /m²), blood pressure (BP) and heart rate (HR) were measured during a 25-minute sauna session (93°C, 13 % humidity) and during a subsequent 30-minute rest period. The parameters obtained were compared with the BP and HR responses during submaximal dynamic exercise testing.ResultsThe heat exposure resulted in a significant (p<0.01) and progressive increase in systolic and diastolic BP. After the sauna bath, BP decreased and showed significantly (p<0.001) lower values compared to baseline. HR also increased continuously during heat application (p<0.001), resulting in a significant increase (p<0.001) in systolic BP x HR as a measure of myocardial oxygen consumption. After the end of the sauna session, both the BP and the HR decreased steadily (p<0.001).When comparing BP and HR during the sauna session with the reaction during a dynamic exercise test, sauna bathing was equivalent to an exercise load of about 60-100 watts.ConclusionsContrary to popular belief, acute sauna use does not lead to a reduction, but to an increase in BP and HR with a consequent increase in myocardial oxygen consumption. The cardiac load during the sauna use corresponds to a moderate physical load of 60-100 watts.