Assessing the influence of physical activity on health and fitness

Increasing rates obesity and related chronic diseases in the United States and other parts of the world appear to be partly attributable to declining levels of physical activity. Given that adult obesity and chronic diseases often have their origins in childhood, there is a critical need to better understand how activity and fitness levels in childhood and adolescence shape health status in adulthood. The four papers in this series on physical activity draw on several longitudinal studies to examine the relationships between levels of physical activity and health-related fitness in childhood and adolescence to those in adulthood. These studies consistently demonstrate that adult activity levels and associated health outcomes are only modestly correlated with activity and fitness measures from childhood and adolescence. However, it appears that the methodological limitations in measuring activity levels may result in an underestimation of the importance of the influence of physical activity on health. Newer methods of measuring activity and energy expenditure offer to substantially improve our understanding of the influence of activity patterns on human health and fitness. Such information is necessary for promoting lifestyle changes that will reduce the risks of obesity and other chronic diseases.