Effective treatment of hypertension includes decrease of blood pressure at rest, dynamic and isometric exercise. Therefore, we investigated the hemodynamic changes by radiocardiography (central hemodynamic) and Xenon-133-muscle clearance (peripheral hemodynamic) before and after a sauna treatment during a period of 3 months. 46 hypertensive men (WHO I-II, aged 41 +/- 11 years) participated in the study. Systolic and diastolic blood pressure at rest and during dynamic exercise were decreased significantly (p < or = 0.01) by sauna therapy. Change of blood pressure at isometric exercise was not significant (from 157.5 +/- 16.5 mmHg to 155.0 +/- 15.4 mmHg). The changes of cardiac output and total peripheral resistance were also not significant. Half-time of muscle clearance decreased significantly (from 4.4 +/- 1.9 min to 3.2 +/- 1.2 min, p < or = 0.01) and functional cross-section A increased significantly (from 3.8 +/- 0.9 mm2.c to 4.4 +/- 0.9 mm2.c, p < or = 0.01) after the sauna therapy at dynamic exercise, but not at isometric exercise. These results show the changes between isometric and dynamic exercise, which can only be explained well by a study of peripheral hemodynamic. Contrary to dynamic exercise, sauna therapy did not significantly decrease blood pressure at isometric exercise.