BALANCED ACTIVATION OF COAGULATION AND FIBRINOLYSIS AFTER A 2-H TRIATHLON

To examine whether exercise-induced thrombin formation is accompanied by increased in vivo plasmin formation, we measured molecular markers and neoantigens of the hemostatic system in 10 male subjects (mean 29 yr, range 19-38) before, immediately after, and 2, 8, and 21 h after a triathlon lasting 128-163 min. Thrombin-antithrombin (TAT) complexes, fibrinopeptide A (FPA), and tissue plasminogen activator (t-PA) antigen were maximally increased immediately after exercise and decreased thereafter rapidly. Prothrombin fragment 1 + 2 (PTF1 + 2), fibrin degradation products (FbDP) and plasmin-antiplasmin (PAP) complexes rose to a similar extent 0 and 2 h after exercise and decreased thereafter. The maximal levels of PTF1 + 2, TAT, FPA, and FbDP were 1.5-, 2.1-, 1.8-, and 1.9-fold above baseline values, respectively, while t-PA antigen and PAP rose 9.9- and 10.6-fold above baseline, respectively. This investigation shows that strenuous prolonged exercise leads to a moderate activation of blood coagulation resulting in thrombin and fibrin formation which is accompanied by a greatly enhanced plasmin generation. It is concluded that the hemostatic system of healthy individuals is well kept in balance when stimulated by prolonged strenuous exercise.