To study the long-term overall effect of habitual physical exercise on fibrinolysis, 20 sedentary males and 15 sedentary females were trained 3-4 times a week with increasing intensity during 9 months. After 24 and 36 weeks all subjects ran a 15 km and half marathon (21 km) race, respectively. Blood samples were drawn before the training programme, 5 days before both races and 5 days after the half marathon run. After the training period plasma tissue-plasminogen activator antigen concentration was slightly decreased in both the male and female population. Plasma plasminogen activator inhibitor activity decreased significantly (p<0.01) in both groups during the course of the training programme. No effect of increased fibrinolytic activity was observed, since plasma D-dimer concentrations were not changed after the test period. In summary, the results of this study demonstrate that long-term physical conditioning leads to a marked decrease in plasminogen activator inhibitor activity, without an actual increase of fibrinolytic end-products.
