[Postural reactions in cosmonauts after long flights aboard Salyut-6]

Tilt tests were used to study changes in cardiovascular responses to ortho- and antiorthostasis of four cosmonauts after their 96- and 140-day flights onboard Salyut-6. Preflight the cosmonauts were exposed to head-up and head-down tests in order to facilitate their readaptation to weightlessness. Postflight all cosmonauts exhibited a better cardiovascular capability to counteract cranial blood redistribution during antiorthostatic tilt tests. This can be considered as a result of their adaptation to weightlessness. After flight every crewmember showed a significant decrease of orthostatic tolerance. One of the factors responsible for the lower orthostatic tolerance is assumed to be inactivity of the vascular tone mechanisms. It is suggested that their better stimulation before reentry may improve the efficacy of countermeasures against postflight orthostatic disorders.