strong
consistent
evidence
observational
physical inactivity
poor
cardiorespiratory fitness (ie, fitness) are associated with higher morbidity and mortality from all causes, including cardiovascular disease (CVD) and cancer.1 United States population reports describe an increasingly less physically active society, with marked downturns in reported physical activity during adolescence and young adulthood.1- 3 Physical activity has been described in the population and in relation to health outcomes; however, prior to the current National Health and Nutrition Examination Survey (NHANES),4 data were not available to quantify objectively determined cardiorespiratory fitness in the US population.