Effect of exercise and oral contraceptive agents on fibrinolytic potential in trained females.

It has been shown that physical exercise increases blood fibrinolytic potential, primarily by inducing a release of extrinsic plasminogen activator from the vessel wall. Synthetic estrogens have also been reported to influence fibrinolytic activity. The effect of exercise and the possible additional effect of oral contraceptive agents (OCA) on the fibronolytic system were studied in 20 competitive female rowers. Ten females used OCA (users), and 10 others did not (nonusers). All participants were subjected to standardized exhaustive exercise. Preexercise data revealed higher factor XII, total plasminogen, and free plasminogen levels together with a significantly lower C1-inactivator level in the group of users. No differences were observed in prekallikrein, high-molecular-weight kininogen, alpha 2-antiplasmin, alpha 2-macroglobulin, antithrombin III, and histidine-rich glycoprotein plasma levels. The factor XII-dependent fibrinolytic activator activity and the extrinsic (tissue-type) plasminogen activator were significantly higher; however, the urokinase-like fibrinolytic activator activity was significantly lower. These observations suggest a greater susceptibility to activation of the fibrinolytic pathways during OCA medication. Exercise resulted in a decrease of all factors under study but an increase in all fibrinolytic activities. No differences were observed between the two groups in the percentages of change that occurred with exercise.