[Antiorthostatic hypokinesia as an approximate model of weightlessness].

Eight test subjects were exposed to a five-day bed rest experiment in the recumbent and head-down position (at an angle of 0 degrees,--4 degrees,--8 degrees, and--12 degrees) to study the physiological effects of the exposure. The head-down tilting at--4 degrees and--12 degrees was shown to simulate physiological effects of real space flight better than bed rest at 0 degrees. The results made it possible to model an acute stage of weightlessness adaptation and to assay the contribution of gravity-induced blood redistribution to the physiological reactions.