Exercise Alone Reduces Insulin Resistance in Obese Children Independently of Changes in Body Composition
Context: The number of obese children with insulin resistance and type 2 diabetes is increasing, but the best management strategy is not clear.
Objective: The objective of this study was to assess the effect of a structured 8-wk exercise training program on insulin resistance and changes in body composition in obese children.
Design: The study was 8 wk of structured supervised exercise intervention with outcome measures before and after the exercise period.
Subjects: Fourteen obese children (12.70 ± 2.32 yr; eight male, six female) with high fasting insulin levels were enrolled into the study.
Intervention: Intervention consisted of 8 wk of supervised circuit-based exercise training, composed of three fully supervised 1-h sessions per week.
Outcome Measures: Outcome measures were assessed pretraining program and posttraining program and included insulin sensitivity (euglycemic-hyperinsulinemic clamp studies), fasting insulin and glucose levels, body composition using dual energy x-ray absorptiometry scan, lipid profile, and liver function tests.
Results: Insulin sensitivity improved significantly after 8 wk of training (Mlbm 8.20 ± 3.44 to 10.03 ± 4.33 mg/kg·min, P < 0.05). Submaximal exercise heart rate responses were significantly lower following the training (P < 0.05), indicating an improvement in cardiorespiratory fitness. Dual energy x-ray absorptiometry scans revealed no differences in lean body mass or abdominal fat mass.
Conclusion: An 8-wk exercise training program increases insulin sensitivity in obese children, and this improvement occurred in the presence of increased cardiorespiratory fitness but is independent of measurable changes in body composition.
Bell, L. M., Watts, K., Siafarikas, A., Thompson, A., Ratnam, N., Bulsara, M., et al. (2007). Exercise alone reduces insulin resistance in obese children independently of changes in body composition. Journal of Clinical Endocrinology and Metabolism, 92(11), 4230-4235. doi: 10.1210/jc.2007-0779