Sustained improvements in fitness and exercise tolerance in obese adolescents after a 12 week exercise intervention

A 12 week exercise program was evaluated for its effect on aerobic fitness, anaerobic threshold, physical activity and sedentary behavior levels in obese insulin resistant adolescents post intervention and at follow up. 111 obese insulin resistant 10-17 year olds were recruited to a 12 month lifestyle intervention, known as RESIST. From months 4 to 6, adolescents participated in supervised exercise sessions twice per week (45-60min/session). Aerobic fitness and anaerobic threshold were measured by gas analysis at baseline, 6 months (post intervention) and 12 months (follow up). Self-reported physical activity and sedentary behavior was measured using the CLASS questionnaire. At 6 months aerobic fitness and time to reach the anaerobic threshold had improved by 5.8% [95% CI: 0.8-11.3] and 19.7% [95% CI: 10.4-29.0], respectively compared with baseline. These improvements were maintained at 12 months. Compared to baseline, 6 month physical activity levels increased by 19min/day [95% CI: 5-33] and screen time decreased by 49min/day [95% CI: 23-74] but returned to baseline levels by 12 months. Improved fitness and anaerobic threshold can be sustained up to 6 months following completion of an exercise program possibly enhancing capacity to perform daily functional tasks.