Abstract

Regular moderate-to-vigorous physical activity confers numerous health-enhancing benefits that contribute to reductions in the risks for numerous chronic diseases and disabling conditions (Bouchard, Shephard & Stephens, 1994; US Department of Health and Human Services, 1996). Within the past 25 years, recommendations have been published for an optimal dose of physical activity and/or energy expenditure to minimise morbidity and mortality from chronic diseases (Paffenbarger, Wing & Hyde, 1978; Pate, Pratt, Blair et al., 1995) minimise risks for obesity (Institute of Medicine, 2002); and enhance cardiorespiratory fitness (American College of Sports Medicine, 1998) in adults and youth (Health Education Authority, 1998; Sallis & Patrick, 1994). Evidence for such recommendations arise from epidemiological and clinical studies that evaluate various combinations of frequency, duration, and intensity of physical activity and energy expenditures associated with the lowest risk for adverse health outcomes. However, methods used to measure physical activity and energy expenditure vary in terms of precision and feasibility. Thus, the recommendations for the optimal health-enhancing doses of physical activity and energy expenditure often are more global than specific in their definitions. This chapter is designed to provide an overview of the methods of assessing physical activity and energy expenditure and identify methodological issues that may impact on the feasibility of their use in research and practice settings. Einleitung