Effects of exercise on hemostasis in sedentary adults and peripheral arterial disease patients

A balance between blood clot development (coagulation) and blood clot breakdown (fibrinolysis) is important for maintaining the integrity of the cardiovascular system. Regular exercise is thought to help maintain a balance between coagulation and fibrinolysis (i.e. hemostatic balance). However, acute exercise is considered to be potentially dangerous in individuals with an existing hemostatic imbalance. The overall purpose of this dissertation was to examine the effects of exercise on hemostasis in asymptomatic adults and peripheral arterial disease (PAD) patients. The first study examined the effects of short-term exercise training in sedentary asymptomatic adults on fibrinolysis and associated metabolic variables. The results indicated that there were no significant changes in plasminogen activator inhibitor, type 1 (PAI-1), tissue plasminogen activator (tPA) or associated metabolic variables during the intervention period. Interestingly, within the exercising subjects, those with higher body fatness had a significant decrease in insulin and triglyceride compared to those with lower body fatness. However, no change in PAI-1 was observed within the subgroups. These data suggest that decreases in PAI-1 with exercise training may require decreases in adiposity and/or marked changes in metabolic variables.;A second study examined the acute effects of a rehabilitative exercise session on measures of fibrinolysis, coagulation, and platelet aggregation in PAD patients. A significant increase in fibrinolytic activity was observed with the acute exercise but no changes were found in coagulative measures or for platelet aggregation. These results suggest that rehabilitative exercise does not appear to increase the thrombotic risk of symptomatic PAD patients despite their reduced fibrinolytic activity at rest.;A third study examined the effects of short-term exercise training on plasma leptin concentration in sedentary, asymptomatic men and women. Plasma leptin was found to be reduced in the exercise group compared to the control group following the short-term exercise training. There were no significant changes in body weight, caloric intake, plasma triglyceride, plasma glucose or plasma insulin concentration following the training. Short-term exercise training appears to reduce leptin concentration independent of changes in body weight. However, the mechanism and clinical implications) of this change are not yet known.