BACKGROUND: Recently, thermal therapy such as sauna and sweating room is popular as a health behavior. In patients with heart failure, sauna treatment improves hemodynamic data and clinical symptoms by restoring endothelial function. The purpose of this study was to investigate that sauna bath could decrease pulse wave velocity reflecting vascular function of people in the community. METHODS: A total of 43 volunteers (11 male, 32 female) older than 40 years old were kept in 60 degrees C dry sauna for 15 to 20 minutes. We measured the brachial-ankle pulse wave velocity (baPWV), blood pressure, heart rate, body weight and body temperature before and, 30 and 60 minutes after sauna bath and assessed the differences of the means of these measurements with repeated measures of ANOVA. Then, we peformed multiple regression analysis to find out the factors independently associated with the amount of baPWV change. RESULTS: The BaPWV and systolic and diastolic blood pressure decreased significantly 30 and 60 minutes after sauna bath comparing to those before (P<0.001, P=0.003, P=0.011, respectively). Multiple regression analysis showed that baseline baPWV and history of hypercholesterolemia independently influenced on the amount of baPWV change (beta=-0.47, P=0.002; beta=-0.36, P=0.013, respectively). CONCLUSION: We studied the acute reduction of pulse wave velocity after sauna bath in adults over 40 years old. This change was striking in the subjects with faster baseline baPWV. This result suggests that sauna bath can improve vascular function in the high risk group of cardiovascular diseases.