The physical activity paradox: six reasons why occupational physical activity (OPA) does not confer the cardiovascular health benefits that leisure time physical activity does

Physical activity (PA) is well documented to improve health. However, this documentation is restricted to leisure time physical activity (LTPA; eg, sports, recreation and transportation). Increasing evidence shows that occupational physical activity (OPA) does not improve health.1 Actually, OPA can be detrimental. These contrasting health effects of LTPA and OPA constitute the so-called PA health paradox.2 For a considerable fraction of the adult population, work constitutes the main setting for PA. Workers in many occupations, such as construction, cleaning, refuse collection, elderly care, farming and manufacturing, are physically active for large parts of their working days, for most of the year. Despite this PA at work, these and other manual workers have relatively poor health. Many epidemiological studies document that high OPA increases the risk for cardiovascular disease (CVD) and mortality outcomes, even after extensive adjustments for other risk factors including socioeconomic status, LTPA and other health behaviours.1 This increased risk from high OPA has been shown to be particularly pronounced among workers with low job resources, low cardiorespiratory fitness3 or pre-existing …