Mechanisms of natural variability during adaptation of human physiological systems to space flight conditions

Physiological data have been analyzed using the principle of invariant relationships to reveal the mechanisms of adaptive variability. The physicochemical, biochemical, and hormonal blood parameter of the cosmonauts who performed short- and long-term space flights have been used. It has been shown that the application of the methods of fractal geometry to the quantitative estimates of homeostasis allows us to identify the processes depending on the adaptive variability increase/decrease and to determine the state of stability or instability of certain physiological regulatory subsystems, whose mobility and reduction of the level of stability maintain a stable internal structure of relationships throughout the body.