PERIPHERAL HEMODYNAMICS IN CHANGING BODY POSITION IN MEN

Changing the pose of the human body in the conditions of Earth gravity is accompanied by the initiation of adaptive reactions of the visceral systems of the body, primarily the circulatory system. The manifestation of adaptive effects largely depends on the level of reactivity of the centers of the autonomic nervous system. The purpose of this work was to study the features of blood flow in the shoulder-forearm segment during postural changes in men, taking into account the excitability of the centers of the sympathetic nervous system. The study was performed on 50 practically healthy male students who underwent rheovasography using the Rheo-spectrum computer rheographic complex for 5 minutes in the supine position, then 5 minutes with passive orthostasis and passive antiorthostasis. The excitability of sympathetic vegetative centers was assessed by the nature of changes in heart rate during the active orthostatic test. It has been shown that passive orthostasis causes a decrease in the degree of blood filling of arterial and venous vessels in the shoulder-forearm segment, and also leads to an increase in blood flow velocity, which is a consequence of increased vascular tone and narrowing. The revealed changes are more pronounced in men with increased excitability of sympathetic nerve centers. The passive transition to an antiorthostatic position in men with increased sympathetic excitability causes an increase in the duration of blood vessel filling associated with their expansion. At the same time, in men with normal excitability of the sympathetic nervous system, there is a decrease in vascular wall tone without a significant change in blood flow velocity.