RESUMO
The extention and intensification of space exploration the influence of weightlessness on human organism and the formation of a new level of adaptation. The studies of blood circulation is very important because of frequent occurrence of cardiovascular disorders in the middle age subjects. In connection with extension and intensification of space exploration the influence of weightlessness on human organism and the formation of a new level of adaptation mechanisms acquires a special significance. The data obtained in recently undertaken model experiments and also during space flights indicate that weightlessness in many ways affects various physiological systems of organism, and first of all cardiovascular system with the development of reflex, humeral and metabolic reactions. It also indicates, that the changes in functioning of cardiovascular system brings about the disruption of its regular responses, which is foremost expressed in decreased antigravitational response, which manifests itself in lowered orthostatic stability. It is worth mentioning, that the changes during previous investigations of haemodynamics were mainly carried out with the subjects under forty, therefore age related specific features of blood circulation system response are described in a few articles. The studies of the kind are especially important because of frequent occurrence of cardiovascular disorders such as heart and brain vessels atherosclerosis, hypertension in the middle age, which can to a great extent complicate and affect the "acute" period of adaptation to weightlessness and readaptation process.
