Thrombin generation after physical exercise.

Many investigators have studied the influence of physical exercise on hemostatic system and it is well accepted that exercise causes an activation of coagulation as indicated by a shortening of aPTT and by an increase in plasma factor VIII activity and levels. A controversial point remains whether this clotting activation leads to a significant thrombin generation and fibrin formation. The type of physical exercise performed and the methods used to study blood coagulation may be two major sources of discrepancies in different studies. In the last years sensitive and reliable methods became available to evaluate prothrombin activation and thrombin generation. Thus in this study we have investigated the influence of a well standardized treadmill stress test, controlled by the measurement of cardiorespiratory and metabolic parameters, on plasma concentration of different markers of clotting activation in healthy untrained young subjects. Blood samples were also withdrawn just before anaerobic threshold to investigate a possible role of metabolic acidosis in changes of clotting system.