Approximately 60 years ago, the observations of Jeremy Morris and colleagues1 showed that the incidence of coronary heart disease in bus conductors who climbed the stairs of double-deck buses collecting tickets was lower than that of the relatively inactive bus drivers who were sedentary during most of their occupational time. Since then, numerous studies have confirmed the strong association between physical activity and health in diverse populations. The accumulated evidence linking physical inactivity to health prompted the American Heart Association (AHA) to include physical inactivity as a major risk factor for coronary heart disease in 1992.2 More recently, the AHA included physically active lifestyles as 1 of the 7 goals for ideal cardiovascular health for children as well as for adults.3Underscoring the importance of physical activity as a key health indicator, the Global Cardiovascular Disease Task Force, an international panel of experts in cardiovascular and noncommunicable disease, set a goal of 10% relative reduction in the prevalence of insufficient physical activity, 1 of the top 4 evidence-based global targets to reduce noncommunicable diseases.4