Employment and Daily Physical Activity in America

Abstract

Physical inactivity is a risk factor for obesity, cardiovascular disease, hypertension, and many other chronic diseases. In America, unemployment rates have risen drastically since 2007, and there has been a steady shift away from physically demanding jobs towards more sedentary occupations since the 1950s. Time at work represents a major portion of the day for most adults, so these employment trends could have an important effect on physical activity at the population level. PURPOSE: To provide objective data on daily physical activity levels between workers and non-workers in a nationally representative sample of American adults, and to quantify the effect of highly active vs. sedentary occupations on daily activity. METHODS: The study population was adults aged 20-60 not retired or in school (n = 1826; 892 men, 934 women) from the 2003-2004 National Health and Nutrition Examination Survey (NHANES). Employment groups were defined as full-time (? 35 hrs/wk), part-time (1-34 hrs/wk), non-working for a reason other than a health problem or disability (NWABLE), and non-working because of a health problem or disability (NWSICK). Job activity levels were active, unclassified, and sedentary. Objective daily physical activity was assessed using uniaxial accelerometers for 7 days. The primary outcome variable was average counts/min during weartime (CPM). RESULTS: CPM averages for full-time, part-time, NWABLE, and NWSICK were 416.9±12.2, 394.2±35.1, 339.1±41.4, and 281.9±39.8 in men and 311.1±10.1, 327.3±17.2, 295.1±16.7, and 229.3±27.8 in women. In men, differences were significant between NWSICK and all other groups (all p <.001), and NWABLE had lower CPM than full-time (p <.001); this latter difference was maintained even after removing workers with active jobs (p =.008). In women, NWSICK was significantly less active than the other groups (all p <.001), but there were no differences among full-time, part-time, and NWABLE. Full-time workers with active jobs had significantly higher CPM than those with sedentary jobs in both men (489.0±36.1 vs. 405.3±24.1, p <.001) and women (383.1±55.7 vs. 287.0±15.7, p <.001). CONCLUSIONS: Compared to not working, full-time employment is associated with greater daily activity levels in men but not in women. Fulltime workers with active jobs have greater total daily activity than those in sedentary occupations. These results show that sedentary work results in lower levels of daily activity in both men and women, and that, in men, unemployment contributes to lower daily activity. These data call attention to work-related daily activity as a contributing factor to overweight and metabolic diseases.