[Acid-base equilibrium, blood gases and glycolysis during modeling of the factors of extravehicular activities].

The effect of factors simulating extravehicular activities (lower barometric pressure, 100% oxygen breathing, physical load on the upper body, head-down body position) on blood gas composition, acid-base equilibrium, and glycolysis end-products was investigated in 17 test subjects. It was found that 5-hour exposure did not change physiological responses to test workloads, when compared to the baseline studies. In the simulation studies, changes in acid-base equilibrium of venous blood were more significant than those of mixed capillary blood. The variations of the parameters under study reflected primarily the effect of hyperoxia on metabolic processes. The head-down position affected the level of variations in gas composition and acid-base equilibrium of venous blood. These changes were transient and rapidly returned to the norm after termination of the exposure.