Insulin resistance associated with aging is well known. It is now well established that aerobic exercise training increases the decreased insulin action in the elderly. However, the effect of resistance exercise training on insulin action still remains unclear. The aim of this study was to assess the effect of resistance exercise training on insulin action in the elderly. Twelve healthy aged subjects (age: 68±1) were enrolled in the study. The aged subjects were divided into two groups, the resistance training (RT) group and the combination of aerobic and resistance training (CT) group. Subjects participated in each training program three times a week for 12 weeks. Before and after training insulin action (sensitivity / responsiveness) was determined using the euglycemic clamp technique at insulin infusion rates of 40 (L: physiological hyperinsulinemia; insulin sensitivity) and 400 (H: supraphysiological hyperinsulinemia; insulin responsiveness) mU/m²/min. The body composition was measured by dual-energy X-ray absorptiometry (DXA). In the CT group, glucose infusion rate (GIR) increased significantly at both insulin infusion rates (L: from 6.5±0.9 to 7.5±1.1, p＜0.05 H: from 10.5±0.7 to 12.9±0.9 mg/kg BW/min, p＜0.01). In the RT group, GIR at L tended to increase (from 6.1±0.6 to 6.9±0.6 mg/kg BW/min), but not statistically significant. GIR at H increased significantly (from 10.1±0.7 to 11.3±0.7 mg/kg BW/min, p＜0.05). When calculated per muscle mass, GIR increased significantly in the CT group. However, GIR per muscle mass in the RT group didn't change significantly at both insulin infusion rates. In conclusion, the combination of aerobic and resistance training is more effective for the improvement of the decreased insulin action in the elderly than the resistance training alone.

DESCENTE SPORTS SCIENCE Vol.22/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE