Benefits of physical activity in obese adolescents and children

Physical activity creates many positive benefits for children and young people, and provides an opportunity for play activity and pleasure, and allows the child to explore the environment. Physical activity also facilitates the development of motor skills and increases energy expenditure. The level and patterns of physical activity of children change as they age, with the physical activity patterns of children tending to be of short duration with high intensity. Adolescent patterns of physical activity more closely resemble those of adults. Although physical activity is recognized as having many potential health benefits, the optimal physical activity (e.g. intensity and type of activity) for obese children and adolescents remains to be established. In addition, the optimal environment for physical activity (e.g. home, school or other setting) remains to be determined. Riley and McDowall have reviewed physical activity interventions in the prevention and treatment of paediatric obesity. 1 Beneficial effects have been demonstrated by targeting reductions in sedentary behaviour as well as targeting increases in physical activity in obese children. Epstein et al. performed a 10-year longitudinal followup study of obese children, with a variety of physical activity interventions, including structured aerobic exercise and lifestyle physical activity. 2 Over a 10-year follow-up period, the change in percentage overweight was superior following a lifestyle physical activity intervention (e.g. walking to school, cycling, using the stairs, doing chores around the home), compared to structured aerobic exercise or callisthenics. Although regular physical activity has been shown to improve insulin sensitivity and other components of the insulin resistance syndrome in adults, there is as yet limited evidence for a beneficial effect of regular physical activity on the same parameters in obese adolescents. Small but significant reductions in per cent body fat and fasting insulin levels have been demonstrated in obese children who exercised at high intensity for a 4-month period. In addition, moderate–high intensity supervised training in obese adolescents has been shown to result in improvements in lipids and blood pressure. Physical activity interventions have traditionally been conducted in hospitals, exercise laboratories and gymnasiums. Although these programmes may be effective, they are resource intensive and have limited applicability for community intervention. In addition, overweight and obese adolescents are unlikely to participate in high intensity physical activity interventions over prolonged periods. For this reason, lifestyle moderate intensity physical activity interventions need to be explored to determine if community or home-based physical activity programmes can provide beneficial effects for obese children and adolescents. Although there is limited evidence demonstrating that increasing physical activity improves weight loss outcomes in children and adolescents, clear evidence for the benefits of physical activity in obese children and adolescents is currently limited. Large scale longitudinal studies exploring a range of strategies designed to limit sedentary behaviour and promote physical activity in children and young people are required to determine the most appropriate cost-effective methods of preventing and treating overweight and obesity in children and young people. In the interim, it would be appropriate to encourage children and young people to be active every day in as many ways as possible (e.g. non-competitive inclusive play, walking, cycling, using the stairs instead of lifts). Structured moderate to vigorous intensity physical activity sessions (e.g. sport, physical education) on three or more occasions per week, may give additional benefits. Families should be encouraged to develop an active lifestyle, and to decrease sedentary activity such as TV viewing and other screen-based behaviours (e.g. computer, video games).