Effects of hypoxic hypoxia, statokinetic stimuli, breathing O2 at excessive pressure, hypodynamia, and loads on the human body were studied with rheoencephalographic, rheovasographic and rheopneumographic techniques. The data obtained allows to conclude that rheography is an adequate and highly informative method for assessment of systemic hemodynamics in humans. More pronounced shifts in the circulation system in response to air and space flight factors occurred in head-down position and when breathing O2 at excessive pressure. The key mechanism controlling hemodynamics in altered environment was modulation of tone in cerebral and peripheral vessels. Rheographic, amplitude rate, dicrotic and diastolic indices can be referred to as parameters which most fully describe systemic hemodynamics.