Assessment of individual adaptation to microgravity during long term space flight based on stepwise discriminant analysis of heart rate variability parameters

► Adaptation to microgravity may manifest not in functional but in regulatory changes. ► HRV analysis is useful for detecting of early changes in the regulatory systems. ► We developed a classification system for evaluation of adaptive shifts in cosmonauts. ► They can transit from normal to prenosological functional state during space flight. ► The individual patterns depend in great degree on the pre-flight functional state.