Purpose: Research demonstrates that moderate-to-vigorous physical activity (MVPA) is associated with a reduced risk of all-cause mortality. Few studies have examined the effects of light-intensity physical activity on mortality. Therefore, the purpose of this study was to examine the association between objectively measured light-intensity physical activity and all-cause mortality risk.
Design: Longitudinal.
Setting: National Health and Nutrition Examination Survey 2003-2006 with follow-up through December 31, 2011.
Subjects: Five thousand five hundred seventy-five U.S. adults.
Measures: Participants wore an accelerometer for at least 4 days and completed questionnaires to assess sociodemographics and chronic disease information, with blood samples taken to assess biological markers. Follow-up mortality status was assessed via death certificate data from the National Death Index.
Analysis: Cox proportional hazard model.
Results: After adjusting for accelerometer-determined MVPA, age, gender, race-ethnicity, cotinine, weight status, poverty level, C-reactive protein, and comorbid illness, for every 60-minute increase in accelerometer-determined light-intensity physical activity, participants had a 16% reduced hazard of all-cause mortality (hazard ratio = .84; 95% confidence interval: .78-.91; p < .001).
Conclusion: In this national sample of U.S. adults, light-intensity physical activity was inversely associated with all-cause mortality risk, independent of age, MVPA, and other potential confounders. In addition to MVPA, promotion of light-intensity physical activity is warranted.
Keywords: Accelerometry, Chronic Disease, Epidemiology, Exercise, Mortality, National Health and Nutrition Examination Survey (NHANES), Prevention Research. Manuscript format: research; Health focus: physical activity; Outcome measure: mortality; Research purpose: modeling/relationship testing; Setting: national; Strategy: education, behavior change; Study design: longitudinal; Target population age: adults; Target population circumstances: education.