COAGULATION AND FIBRINOLYSIS AFTER MODERATE AND VERY HEAVY EXERCISE IN HEALTHY MALE-SUBJECTS

To examine the relationship between exercise intensity and activation of coagulation and fibrinolysis, we measured markers of thrombin, fibr in and plasmin formation in 12 male subjects (mean 24 +/- 4 yr (SD)) b efore and after running on a treadmill for 1 h at two different intens ities corresponding to moderate (82% maximal heart rate (HR), 68% (V) over dotO(2max)) and very heavy (94% maximal HR, 83% (V) over dot)(2ma x)) exercise. During moderate exercise plasma levels of tissue plasmin ogen activator (t-PA) antigen rose from 3.7 +/- 0.5 (mean +/- SE) to 1 4.6 +/- 1.8 ng.mL(-1) (P < 0.01) and of plasmin-alpha-antiplasmin (PAP ) complexes from 2.1 +/- 0.3 to 4.2 +/- 0.7 nmol.L-1 (P < 0.01), where as prothrombin fragment 1 + 2 (PTF1+2), thrombin-antithrombin III (TAT ) complexes and fibrinopeptide A (FPA) did not change significantly. I n response to very heavy exercise, mean plasma levels of t-PA antigen and PAP complexes exceeded the upper limit of normal values 2.5- (P < 0.01) and two-fold (P < 0.01) respectively, while significant increase s of plasma levels of PTF1+2 (P < 0.01), TAT (P < 0.05), and FPA (P < 0.01) occurred within the range of normal. We conclude that in healthy young individuals, exercise-induced activation of coagulation is well balanced by activation of the fibrinolytic system, since moderate exe rcise results in increased plasmin formation only, while at very heavy exercise generation of plasmin seems to exceed that of thrombin and f ibrin.