Role of regular exercise in the treatment of abdominal obesity in adolescent boys

Background. Abdominal obesity is a strong risk factor for cardiovascular disease (CVD) and insulin resistance. Currently, the role of regular exercise alone in the treatment of abdominal obesity is unknown in adolescent boys.;Objective. The aim of this study was to examine the effect of a 3-month regular exercise alone without calorie restriction on total and abdominal adiposity in overweight adolescent boys. More specifically, the effects of different types of exercise training (aerobic vs. resistance exercise) on total fat, and visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) were compared.;Study design & methods. Thirty overweight adolescent boys (BMI ≥ 95th percentile, 12-18 years, Tanner stage III-V) were randomly assigned to one of three intervention groups: aerobic training (AE, n = 10, 60 min/session, 3 days/week), resistance training (RE, n = 13, 60 min/session, 3 days/week) and no-exercise control group (n = 7). Outcome measurements included waist circumference (WC), total body fat, abdominal AT (VAT and ASAT), cardiorespiratory fitness (CRF) and muscular strength.;Results. Body weight and BMI did not change in both exercise groups (P > 0.1), but significantly (P < 0.05) increased in the control group. Compared with the control group, a significant (P < 0.05) reduction in total fat (kg) was observed in both AE (-2.3 kg) and RE groups (-1.4 kg). Both VAT (kg) and ASAT (kg) were significantly (P < 0.05) reduced in the AE (-9.7% and -6.5%, respectively) and RE groups (-14.5% and -5.2%, respectively). By contrast, both VAT (17.0%) and ASAT (6.2%) were significantly (P < 0.05) increased in the control group. Compared with the control group, a significant (P < 0.05) improvement in CRF was observed in both exercise groups, and the improvement was greater (P < 0.05) in the AE (36.5%) vs. RE (25.8%) groups. Upper and lower body muscular strength were significantly (P < 0.01) increased in the RE group (>30% and 43-50%, respectively) compared with the AE and control groups.;Conclusions. Regular exercise without calorie restriction, independent of exercise modality, is associated with significant reductions in total and abdominal adiposity and improvements in CRF and muscular strength in previously sedentary overweight adolescent boys.;Keywords. Exercise, abdominal obesity, visceral adipose tissue, subcutaneous adipose tissue, cardiorespiratory fitness, muscular strength, adolescents.