Effect of Total Duration and Amount of Performed Space Flights on the Human Plasma Hemostasis System

This study involved 27 cosmonauts aged from 37 to 59 years. First, we carried out a correlation analysis of hemostatic parameters and the total duration of space flights. No statistically significant correlation was found for any parameters at any terms of the survey. Then, the sample of cosmonauts was divided into three groups according to the amount of performed flights. We studied the dynamics of parameters within the groups and observed an increase in the coagulation contact phase potential in the dynamics of post-flight studies on the basis of the shortened activated partial thromboplastin time with a tendency of this parameter to restore to the baseline level. This tendency was weakening after three space flights. The observed changes appear to be due to the cumulative effect of space flight factors and the stress of readaptation to terrestrial conditions.