ABSTRACT
The effect of exercise on both the blood coagulability and fibrinolytic activity, and the relation between the changes observed and the low incidence of atherosclerosis in atheletes, were investigated in 24 young male athletes. Blood coagulability and fibrinolytic activity were estimated by determination of the venous coagulation time and the euglobulin lysis time respectively, which were measured at rest and following an exhausting muscular exercise. After work performance, both the venous coagulation time and the euglobulin time were decreased. The decrease in the coagulation time was slight [5.13%] and of no statistical significance. On the other hand, the decrease which occurred in the euglobulin lysis time was much more marked [41.6%] and of a highly statistical significance. These changes suggest that physical activity alters the coagulation fibrinolytic equilibrium, favouring the blood fibrinolytic activity. According to the fibrin-deposit theory of atherosclerosis, this effect may be the possible mechanism by which work performance lowers the incidence of atherosclerosis and occlusive vascular diseases in atheletes. Since the exercise-induced fibrinolytic activity is transient and proportional to the intensity of work performance, it can be concluded that the greatest benefit would be obtained by daily strenuous exercise performance