Progressive Improvement in Glucose Tolerance with Light Resistance TVaining in Older Women

Abstract

PURPOSE: To compare aerobic vs. light resistance training on serial improvements in glucose tolerance in aging. METHODS: Healthy, inactive older (74 ± 5 (SD) y) women (N=20) were randomized into either a high volume/moderate-intensity aerobic (ATM: 240 min-wk-1; 65–75% VO2peak or 4.3 METs; n=12) or a lower-intensity resistance training (RTL; 180 min-wk-1; 50% VO2peak or 2.5 METs; n=8) control group. Both groups exercised under supervision 4 times per week for 45–60 min sessions over 9 months. Measurements of plasma glucose, insulin, and free fatty acid (FFA) responses to an oral glucose tolerance test (OGTT) were performed at baseline and at 3-, 6-, and 9-months 48 h after the last exercise session. RESULTS: Surprisingly, we observed significant improvements in 2-h glucose concentrations at 3-, 6-, and 9-months among women in the RTL (152 ± 42 vs.134 ± 33 vs. 134 ± 24 vs. 130 ± 27mg-dL-1;p<0.05), butnot the ATM (151 ± 25 vs. 156 ± 37vs. 152 ± 40 vs. 155 ± 39 mg-dL-1) group. These improvements were accompanied by an 18% (p<0.07) decrease in basal FFA concentrations in the RTL group, whereas basal and 30-min FFA concentrations increased (p<0.05) after training in the ATM group. CONCLUSIONS: These findings suggest that the net physiological benefit-to-stress ratio from exercise may have been lower in the ATM, compared with the RTL group, indicated by higher circulating levels of FFA after a large volume of moderate-intensity aerobic exercise, which may have temporarily interfered with insulin action.