[Central and regional hemodynamics in long space flights].

This paper presents the results of studying central and regional hemodynamics in short-term (7 days) and long-term (65-237 days) space mission onboard Salyut-6--Soyuz and Salyut-7--Soyuz using the method of tetrapolar rheography. During space flights circulation changes were observed: variations in pulse blood filling and tone of regional vessels (head, forearm, leg) and insignificant changes of stroke volume and cardiac output. In response to exercise tests the contribution of stroke volume to cardiac output decreased and that of the chronotropic function of the heart increased. These changes were induced by variations in the hemodynamic status of the human body and were, to a certain extent, dependent on flight duration and position of the vascular area relative to the heart. The changes suggested that the circulation system retained its adaptive capabilities in flights of 237 days in duration.