A moderate sauna session after a workout or spa treatment can be quite relaxing. A new study from Germany's Martin Luther University Halle-Wittenberg (MLU) and Medical Center Berlin (MCB) has demonstrated that a sauna session is also equivalent to a short, moderate workout.
The study was recently published in Complementary Therapies in Medicine and aimed to provide evidence about the widespread assumption that sauna use causes blood pressure declines. In a press release from MLU regarding the study Dr. Sascha Ketelhut, lead author and sport scientist at MCB, stated that "it was thought that the heat dilates the blood vessels and that this lowers the blood pressure." In fact, many saunas feature an advisory to warn those with low blood pressure or cardiovascular disease of the risks involved with their use.
The study used 19 healthy, adult volunteers and consisted of two parts. In the first part of the study, participants spent 25-minutes in a sauna at 93°C (199.4°F) with 13% humidity. Blood pressure and heart rate were measured both during the session and during a 20-minute rest period after the session. In the second part of the study, participants were asked to complete an exercise program on an exercise bike, during which their blood pressure and heart rate were measured.
The results, simply stated, showed that a sauna session is equivalent to a short, moderate workout. Both blood pressure and heart rate increased during the sauna session. Dr. Ketelhut reported, "Comparing the two conditions, the participants' blood pressure and heart rate reached the same levels during the sauna session as they did with a load of about 100 watts during the exercise test."
Although sauna sessions can have positive effects on the cardiovascular system and are physically straining, they will not contribute to weight loss. Ketelhut clarified that "the effect is too low as there is no muscle activity. Although we lose weight in the sauna, but these are just the fluids that we sweat out." She also advised those with low blood pressure to use caution after a sauna session, as their blood pressure may drop significantly afterward.