Effects of Exercise Modality on Insulin Resistance and Ectopic Fat in Adolescents with Overweight and Obesity: A Randomized Clinical Trial

Abstract

To examine whether a combined aerobic exercise and resistance exercise is more effective than either aerobic exercise or resistance exercise alone in improving insulin sensitivity and reducing total adiposity and ectopic fat in adolescents. A total of 118 sedentary adolescents with overweight/obesity (body mass index >85th percentile, 12-17 years) were recruited from October 2013 through April 2017 at Children's Hospital of Pittsburgh. Participants were randomized to 1 of the following 6-month exercise groups (3 d/wk, 180 min/wk): aerobic exercise (n = 38), resistance exercise (n = 40), and combined aerobic exercise and resistance exercise (n = 40). The primary outcome was the change in insulin-stimulated glucose disposal by a 3-hour hyperinsulinemic-euglycemic clamp. The secondary outcomes were changes in liver fat by proton magnetic resonance spectroscopy and intermuscular adipose tissue by computed tomography. Of the 118 participants randomized, 85 participants (72%) completed the study with 90% exercise attendance. Total adiposity reduced similarly in all groups (-2%, P < .05). After adjusting for age and sex, insulin-stimulated glucose disposal increased (P < .05) in all groups, with the increase in the aerobic exercise group being greater than the resistance exercise group (1.7 ± 0.1 vs 0.7 ± 0.1 mg/kg/min, P < .05) but not different from the combined group (1.2 ± 0.1 mg/kg/min). Liver fat was reduced (P < .05) in the aerobic exercise (-0.6%) and combined (-0.6%) groups but not in the resistance exercise group (-0.3%, P > .05). Intermuscular adipose tissue decreased (P < .05) similarly in all groups. Combined aerobic exercise and resistance exercise and aerobic exercise alone are similarly beneficial in improving insulin sensitivity and reducing ectopic fat in adolescents with obesity. ClinicalTrials.gov: NCT01938950.