Changes in physical activity over the lifespan: impact on body composition and sarcopenic obesity.

Physical activity and body composition show a typical pattern over the lifecycle. Fat-free mass and physical performance generally peak in early adulthood. Here, evidence for a relation between physical activity changes over the life span and the development of sarcopenic obesity is presented. Activity-induced energy expenditure increases with body size and physical activity during growth. The physical activity level, calculated by expressing total energy expenditure as a multiple of resting energy expenditure, gradually increases from early age to adulthood to decrease again in old age. Habitual physical activity has a significant effect on growth of fat-free mass during adolescence and thus on peak fat-free mass and physical performance in early adulthood. Older subjects have a lower fat-free mass and lower physical activity levels but there is no association, suggesting physical activity does not protect against loss of lean body mass at higher age. Prevention of sarcopenic obesity starts with a physically active lifestyle to develop a healthy peak fat-free mass and subsequent prevention of excess fat gain. The change from a physically active to a more sedentary routine in later life requires restriction of energy intake to maintain energy balance.