[Modification of plasma blood coagulation factor activity by physical stress].

The influence of physical stress (bicycle ergometer and track) on 13 parameters of the plasmatic coagulation system was investigated in trained and untrained test persons. Shortenings of the coagulation times as well as distinct increases of the activity or concentration were observed in the partial thromboplastin time (PTT), the factor VIII activity (VIII:C) and the factor VIII-associated antigen (VIIIR:Ag). The results are discussed with regard to their causes and their clinical importance.