Effect of prolonged physical exercise on the fibrinolytic system

Summary The effect of a test marathon race on plasma fibrinolytic activity (FA) was studied in 16 endurance athletes before, immediately after, 3 h, and 31 h after the run. Tissue plasminogen activator (t-PA) activity increased about 31-fold immediately after the run. Similar increases were found in t-PA antigen concentration. Plasminogen activator inhibitor (PAI) was not detectable immediately after the race and was significantly decreased 3 h (P < 0.05) and 31 h (P < 0.01) later. B_15–42 peptide increased by 0.63 pmol · ml^–1 (P<0.001),d-dimer by 68.3 ng · ml^–1 (P< 0.05). Euglobulin lysis time (ELT) was reduced from 109 to 18 min (P<0.001). The increased t-PA activity and t-PA antigen concentration disappeared in the course of the first 3 h after exertion. ELT also reached its pre-exercise levels at this time. Thirty-one hours after the race ELT and t-PA antigen levels were slightly but significantly reduced (P<0.05), whereas B_15–42 peptide remained increased (P<0.05). t-PA activity was unchanged compared with pre-exercise values. It seems that the exercise-induced FA is mainly caused by the marked increase of t-PA antigen and t-PA activity.