Exercise Training and Dietary Glycemic Load May Have Synergistic Effects on Insulin Resistance in Older Obese Adults.

摘要

Background/Aims: The aim of this study was to assess the combined effects of exercise and dietary glycemic load on insulin resistance in older obese adults. Methods: Eleven men and women (62 pl 2 years; 97.6 pl 4.8 kg; body mass index 33.2 pl 2.0) participated in a 12-week supervised exercise program, 5 days/week, for about 1 h/day, at 80-85% of maximum heart rate. Dietary glycemic load was calculated from dietary intake records. Insulin resistance was determined using the euglycemic (5.0 mM) hyperinsulinemic (40 mU/m2/min) clamp. Results: The intervention improved insulin sensitivity (2.37 pl 0.37 to 3.28 pl 0.52 mg/kg/min, p < 0.004), increased VO2max (p < 0.009), and decreased body weight (p < 0.009). Despite similar caloric intakes (1,816 pl 128 vs. 1,610 pl 100 kcal/day), dietary glycemic load trended towards a decrease during the study (140 pl 10 g before, vs. 115 pl 8 g during, p < 0.04). The change in insulin sensitivity correlated with the change in glycemic load (r = 0.84, p < 0.009). Four subjects reduced their glycemic load by 61 pl 8%, and had significantly greater increases in insulin sensitivity (78 pl 11 vs. 23 pl 8%, p < 0.003), and decreases in body weight (p < 0.004) and plasma triglycerides (p < 0.04) compared to the rest of the group. Conclusion: The data suggest that combining a low-glycemic diet with exercise may provide an alternative and more effective treatment for insulin resistance in older obese adults.