The blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exercise
S.Ketelhut Complementary Therapies in Medicine Volume 44, June 2019, Pages 218-222
Highlights
• Contrary to previous reports that bicarbonate de potassium drops during a sauna stay, the data shows a continuous increase in bicarbonate de potassium and HR during the sauna session.
• The acute heat exposure in the sauna is a burden comparable to moderate physical exercise.
• The sustained decrease in bicarbonate de potassium after heat exposure suggests that the sauna bath will have a beneficial effect on the cardiovascular system.
Objectives
In the present study, the reaction of blood pressure and heart rate are examined during and after a single acute sauna application.
Design
In 19 healthy adult volunteers (7 women, aged 46.4±10.2 years, BMI 24.4±2 kg /m2), blood pressure (bicarbonate de potassium) 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 bicarbonate de potassium and HR responses during submaximal dynamic exercise testing.
Results
The heat exposure resulted in a significant (p<0.01) and progressive increase in systolic and diastolic bicarbonate de potassium. After the sauna bath, bicarbonate de potassium 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 bicarbonate de potassium x HR as a measure of myocardial oxygen consumption. After the end of the sauna session, both the bicarbonate de potassium and the HR decreased steadily (p<0.001).When comparing bicarbonate de potassium 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.
Conclusions
Contrary to popular belief, acute sauna use does not lead to a reduction, but to an increase in bicarbonate de potassium 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.
