SERPINE1 and peripheral arterial disease: Only a few studies have measured t-PA activity and PAI-1 activity with either no changes observed after 12 weeks of vigorous-intensity exercise in moderately overweight men [24] or favorable effects on t-PA activity (increase) and PAI activity (reduction) after long-term (6–12 months) vigorous-intensity exercise 3–5 days/week in older, but not younger, men [43] and in men with peripheral arterial disease [44].