Effect of Exercise on Hepatic Fat in Overweight Children

The objective of the present study is to evaluate the effect of 6 months exercise intervention program on hepatic fat fraction in overweight children. Methodology: A total of 160 children, 9-11 years old, will be randomly assigned to control (N=80) or intervention (N=80) groups. Training sessions will include 90 minutes of exercise, comprising warm-up and skill development. The control group will attend a healthy lifestyle education program (2 days/month) and the intervention group an exercise (3 days/week) and healthy lifestyle education (2 days/month) combined program. Before and after the intervention (6 months) hepatic fat fraction, body composition, , and cardiometabolic risk factors will be measured. Furthermore, dietary habits and physical activity, blood pressure and pubertal development will be evaluated before and after the intervention.

The control group will attend a healthy lifestyle education program (2 days/month) and supportive therapy and behavioral advice for both children and parents to improve nutrition and physical activity (nutritionists and psychologists). The intervention group will attend an exercise (3 days/week) and healthy lifestyle education (2 days/month) combined program. Training sessions will include 90 minutes of exercise, comprising warm-up and skill development, moderate to vigorous aerobic activities, flexibility and strength exercises. Before (baseline) and after the intervention (6 months) total and abdominal adiposity, lean tissue mass and bone mass density (dual-X-ray-absorptiometry), abdominal visceral and hepatic adiposity (magnetic resonance imaging), and blood insulin, glucose, C-reactive protein, alanine aminotransferase, aspartate aminotransferase, gamma-glutamil transpeptidase and lipid profile will be measured. Furthermore, cardiorespiratory fitness (treadmill test) and blood pressure will be measured before and after the intervention. Changes (6 months - baseline) in dietary habits will be estimated by using two repeated 24h recalls and food frequency questionnaires and changes (6 months - baseline) in physical activity by accelerometry.