Developmental Changes in Energy Expenditure and Physical Activity in Children: Evidence for a Decline in Physical Activity in Girls Before Puberty

• Published in: Pediatrics (Evanston) 1998-05, Vol.101 (5), p.887-891
• Main Authors: Goran, Michael I, Gower, Barbara A, Nagy, Tim R, Johnson, Rachel K
• Format: Article
• Language: English
• Subjects: Basal Metabolism; Behavior; Biological and medical sciences; Boys; Child; Child behavior; Child development; Child Development - physiology; Child, Preschool; Childhood obesity; Children; Demographic aspects; Energy Intake; Energy Metabolism; Energy metabolism in children; Exercise; Exercise for children; Female; Fundamental and applied biological sciences. Psychology; Girls; Humans; Intermediate and energetic metabolism; Longitudinal Studies; Male; Metabolism; Metabolisms and neurohumoral controls; Obesity in children; Pediatrics; Physical Exertion; Physiological aspects; Puberty; Risk factors; Sex Factors; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0031-4005; 1098-4275
• DOI: 10.1542/peds.101.5.887

To examine individual changes in energy expenditure and physical activity during prepubertal growth in boys and girls. Total energy expenditure (TEE), resting energy expenditure, physical activity-related energy expenditure, reported physical activity, and fat and fat-free mass were measured three times over 5 years in 11 boys (5.3 +/- 0.9 years at baseline) and 11 girls (5.5 +/- 0.9 years at baseline). Four-year increases in fat ( approximately 6 kg) and fat-free mass ( approximately 10 kg) and resting energy expenditure ( approximately 200 kcal/day) were similar in boys and girls. In boys, TEE increased at each measurement year, whereas in girls, there was an initial increase from age 5.5 (1365 +/- 330 kcal/day) to age 6.5 (1815 +/- 392 kcal/day); however, by age 9.5, TEE was reduced significantly (1608 +/- 284 kcal/day) with no change in energy intake. The gender difference in TEE changes over time was explained by a 50% reduction in physical activity (kcal/day and hours/week) in girls between the ages of 6.5 and 9.5. These data suggest a gender dimorphism in the developmental changes in energy expenditure before adolescence, with a conservation of energy use in girls achieved through a marked reduction in physical activity.