FIBRINOLYTIC RESPONSES TO MODERATE INTENSITY EXERCISE - COMPARISON OFPHYSICALLY ACTIVE AND INACTIVE MEN

The purposes of this study were to compare fibrinolytic responses to m oderate intensity exercise in physically active and inactive men and d uring morning and evening exercise. Fourteen physically inactive men ( mean age, 34.7+/-4.0 years) and 12 regularly active men (34.8+/-4.0 ye ars) performed two exercise sessions, morning and evening, at 50% of m aximal oxygen consumption. Tissue plasminogen activator (TPA) and plas minogen activator inhibitor-1 (PAI-1) activity were measured before an d after exercise. Data were analyzed using a three-way ANOVA with repe ated measures. TPA activity increased with exercise in both groups, al though the active group demonstrated greater increases than the inacti ve group. Postexercise TPA activity was greater with evening than morn ing exercise. The inactive group exhibited greater PAI-1 activity than the active group. PAI-1 activity was higher during the morning than e vening but did not change with exercise for either group. We conclude that moderate intensity exercise increases TPA activity in physically active and inactive men, with greater increases seen in active men, pa rticularly during evening exercise. Moderate intensity exercise does n ot appear to affect PAI-1 activity. The lower PAI-1 activity in active men may be one mechanism whereby regular physical activity lowers the risk for coronary artery disease.