Abstract Background and Aims. Previous studies have shown that aging is an important risk factor for insulin resistance and type 2 diabetes. The beneficial effects of exercise on glucose metabolism are well known. Our goal was to examine whether physical activity improves insulin levels in older individuals. Material and Methods. Plasma glucose and insulin were measured in fasting state and 2 h after a 75-g oral glucose tolerance test in young lean, sedentary, non-diabetic subjects (n=34, age 25±2 years, body mass index- BMI 24.4±0.7 kg/m2) and older, lean, sedentary, non-diabetic subjects (n=36, age 75±3 years, BMI 24.8±0.4 kg/m2), before and after 8 weeks of aerobic exercise. Training consisted of exercise (such as cycling or fast walking) 5 days/week for approximately 30 min/day. Results. Fasting plasma insulin and 2-h serum insulin levels at baseline were significantly higher in older than young subjects (11.6 μU/ml vs 10.0 μU/ml, p=0.0001, 46.3 μU/ml vs 34.0 μU/ml, p=0.0001). Fasting and 2h plasma insulin levels were reduced after 8 weeks of aerobic exercise in older subjects, with no change in body weight. Conclusion. In our study the hyperinsulinemia associated with aging can be blunted significantly by aerobic exercise in older individuals independent of any changes in body composition
Effect of Aging and Exercise Training on Plasma Insulin Concentration
