Associations between physical activity, sedentary time, sleep duration and daytime sleepiness in US adults

Objective: To examine the associations between objectively measured physical activity (PA) or sedentary behavior and self-reported sleep duration or daytime sleepiness in a nationally representative sample of healthy US adults (N=2128).

Methods: We report analyses of four aspects of sedentary behavior and PA derived from accelerometry data (minutes of sedentary time, activity counts/minute, Minutes of Moderate and Vigorous PA [MVPA], and MVPA in 10-minute bouts) versus self-report of sleep duration and frequency of daytime sleepiness from the 2005-2006 National Health and Nutrition Examination Survey.

Results: Age and sex dependence of associations between PA and sleep were observed. Aspects of PA were significantly lower in adults reporting more frequent daytime sleepiness in younger (20-39) and older (≥ 60) age groups, but not in middle-aged (40-59), respondents. In younger respondents, PA increased with sleep duration, but in middle aged and older respondents PA was either unrelated to sleep duration or lower in those reporting ≥ 8 h of sleep. Objectively measured sedentary time showed limited evidence of associations with sleep duration.

Conclusions: Further research delineating the relationships between sleep and PA is important because both activities have been implicated in diverse health outcomes as well as in the etiology of obesity.