| Summary: | The purpose of this study was to evaluate changes in insulin sensitivity assessed by hyperinsulinemic-euglycemic clamp after 16 weeks of aerobic plus resistance training (Ae + RT), aerobic only training (Ae only), or usual care in a group of 28 randomly assigned postmenopausal women with type 2 diabetes (T2D). A second purpose was to relate improvements in insulin sensitivity to changes in abdominal subcutaneous and visceral AT (AT) cross-sectional area and thigh muscle cross-sectional area and density as assessed by single-image computed tomography (CT) scans. Glucose disposal during the hyperinsulinemic-euglycemic clamp was significantly increased by 77% after Ae + RT training (pre 2.36 ± 0.33, post 4.17 + 0.65 mg/kg/min, p=0.007), with no significant change seen in either the usual care group (pre 2.29 ± 0.46, post 2.36 + 0.46 mg/kg/min) or the Ae only group (pre 2.78 + 0.49, post 3.33 ± 0.64 mg/kg/min). The Ae + RT group demonstrated significant losses of 10.5% from the visceral AT area (pre 251.1 ± 22.9 cm², post 224.8 ± 20.0 cm², p<0.006), significant increases of 5.9% in muscle cross-sectional area (pre 207.7± 10.0 cm², post 213.6 ± 9.6 cm², p=0.017) and significant increases in average muscle density (pre 43.9 ± 1.7, post 46.4 + 1.2 HU, p<0.015) and the proportion of normal density muscle (pre 156.6 ± 12.8, post 167.1 ± 11.4 cm², p<0.001). The usual care group had a significant decrease in average muscle density (pre 47.1 + 1.1, post 46.0 ± 0.9 HU, p<0.004) and a significant increase in the proportion of low density muscle (pre 50.6 ± 4.2, post 53.8 ± 3.9 cm², p<0.015). Across all subjects, improved glucose disposal during the euglycemic clamp was significantly negatively associated with change in total abdominal AT area (r=-0.62, p<0.001), abdominal subcutaneous AT area (r=-0.64, p<0.001), visceral AT area (r=-0.32, p<0.047), and positively associated with muscle cross-sectional area (r=0.43, p<0.011), average muscle density (r=0.50 p=0.003) and normal density muscle (r=0.52, p<0.002). Significant associations remained between change in glucose disposal and change in muscle cross-sectional area (r=0.43, p<0.01), and area of normal density muscle (r=0.42, p<0.02) after controlling total abdominal AT area. These findings suggest that aerobic plus resistance training is an effective exercise strategy to improve insulin sensitivity in postmenopausal women with type 2 diabetes. The improved insulin sensitivity is related to loss of abdominal subcutaneous and visceral AT and to increased muscle cross-sectional area and density. === Education, Faculty of === Kinesiology, School of === Graduate
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