Abstract
Exercise increases clotting and fibrinolytic activity in humans. This has also been reported for oral contraceptive agents (OCA). We studied the effects of strenuous exercise and OCA on a number of hematological variables in 20 highly trained female athletes. Ten had been using OCA for more than a year (users). The other ten served as the control group (non-users). All subjects were exercised to exhaustion by means of a graded exercise test on a bicycle ergometer. Biochemical and cellular assays for the determination of plasma volume changes and used to standardize the intensity of exercise were performed in pre- and post-exercise blood samples. Procoagulant activity of factors XII, XI and VII were determined. High molecular weight kininogen (HMWK), α2 -macro-globulin, and C1 -esterase inhibitor were quantified by rocket Immunoelectrophoresis using monospecific antisera. Synthetic chromogenic peptide substrates were used for the determination of plasminogen, prekallikrein, α2,-antiplasmin, and antithrombin III. The two groups examined were anthropometrically and physically very well matched. The pre-exercise results of the groups of users demonstrated a significantly higher factor XII and plasminogen level, together with a significantly lower C1-esterase inhibitor level compared to the pre-exercise data of the group of non-users. No significant differences in pre-exercise values of factor XI, factor VII, HMWK, α2-macro-globulin, prekallikrein, α2-antiplasmin, and antithrombin III were observed between the groups. Exercise induced a significant decrease in all clotting and fibrinolytic variables, except factor VII and α2-antiplasmin in the group of users. In the group of non-users, significant post-exercise decreases were observed in factor XII, HMWK, prekallikrein, and α2-macro-globulin only. Results indicate a potentiating effect of OCA on post-exercise hemostatic and fibrinolytic changes.
Key words
oral contraceptives - exercise - clotting - fibrinolysis - training
