Exercise reduces body fat and improves insulin sensitivity and pancreatic β-cell function in overweight and obese male Taiwanese adolescents

BACKGROUND: Improvements in insulin resistance and pancreatic β-cell function have been shown following exercise in adults with obesity; however, few adolescent-based studies have been conducted. This study examined the impact of exercise training on body fat and insulin sensitivity and secretion in overweight and obese adolescents. METHODS: The effects of a 12-week exercise program on the parameters of adiposity and glucose homeostasis were investigated in 47 overweight and obese male adolescents. RESULTS: After the exercise training program, body weight, body mass index, waist circumference, and body fat were significantly decreased (P < 0.001). Improvements in insulin sensitivity (HOMA-IR: 1.40 vs. 0.86, P < 0.001) and the disposition index (5.84 vs. 12.77, P < 0.001) were also observed. Compared to baseline, oral glucose tolerance tests showed reduced glucose and insulin levels at all time points following the exercise training (all P < 0.001). Subgroup analysis of overweight and obese adolescents with abnormal glucose tolerance revealed that there was no difference in plasma glucose levels as compared to the lean group. CONCLUSIONS: A 12-week exercise training is effective in reducing body fat and improving insulin sensitivity and secretion. In addition, the benefits of the exercise intervention were even experienced by those with impaired glucose tolerance.