Increase in endogenous fibrinolysis and platelet activity during exercise in young volunteers.

The influence of physical exercise and intake of oral contraceptives on endogenous fibrinolytic activity and platelet aggregation behaviour was studied in young healthy women and compared to an age matched group of male volunteers. Physical exercise beyond the anaerobic threshold significantly increased the activity of tissue-plasminogen activator (t-PA) in male and female volunteers from initial values of 1.6 +/- 0.1 and 1.8 +/- 0.2 IU/ml to 5.5 +/- 1.0 and 5.3 +/- 0.9 IU/ml (P less than 0.01), respectively. In women taking low-dose estrogen oral contraceptives t-PA increased from 1.5 +/- 0.2 to 3.8 +/- 0.5 (P less than 0.01). There were no major alterations in plasminogen activator inhibitor - I (PAI-I) plasma activities. Platelet activity during exercise was significantly enhanced in male test persons indicated by a significant decrease in the ED50 values for ADP. In contrast, in women ED50 values were basically unaltered, irrespective of the intake of oral contraceptives.