Income, physical activity, sedentary behavior, and the 'weekend warrior' among U.S. adults.

The present study examines the association between income and physical activity intensity along the entire continuum using accelerometry in a nationally representative sample of U.S. adults. Specifically, we assessed the relationship between annual household income, sedentary behavior, light, and moderate-vigorous intensity physical activity, and meeting physical activity guidelines over a brief, 2-day period ('weekend warrior'), and during the entire week. The sample consisted of 5206 National Health and Examination Survey adult participants (2003-2006) who wore accelerometers and completed pertinent survey questions. Ordinary Least Square models were computed to examine the relationship between income and the dependent variables (sedentary behavior, light, and moderate to vigorous intensity activity) adjusting for covariates. Logistic regression was employed to examine the association between income and meeting physical activity guidelines during a 2-day and 7-day time-period. Results indicate that individuals with an annual income of ≥$75,000 engaged in 4.6 more daily minutes of moderate to vigorous activity (p-value<0.01), in comparison to the reference group (<$20,000 annual income). Those in the high-income strata were 1.6 and 1.9 times more likely to meet physical activity guidelines during a 2 and 7-day period (respectively) than their lower income counterparts (p<0.05 for both). Further, those in the high-income strata spent 11.8 more minutes daily being sedentary than their lower income counterparts (p-value<0.01). In conclusion, higher annual household income is related to more intense, less frequent (per week) patterns of physical activity and more daily sedentary time.