No Evidence of Reciprocal Associations between Daily Sleep and Physical Activity.
This study aimed to determine whether physical activity patterns are associated with sleep later at night and if nighttime sleep is associated with physical activity patterns the next day among adult women.



Women (N = 353) living throughout the United States wore a wrist and a hip accelerometer for 7 d. Total sleep time (TST, hours per night) and sleep efficiency (SE, %) were estimated from the wrist accelerometer, and moderate to vigorous physical activity (MVPA, >1040 counts per minute, h·d) and sedentary behavior (SB, <100 counts per minute, h·d) were estimated from the hip accelerometer. Mixed-effects models adjusted for age, race, body mass index, education, employment, marital status, health status, and hip accelerometer wear time were used to analyze the data. Follow-up analyses using quantile regression were used to investigate associations among women with below average TST and MVPA and above average SB.



The average age of our sample was 55.5 yr (SD = 10.2 yr). The majority of participants were White (79%) and married (72%), and half were employed full time (49%). The participants spent on average 8.9 and 1.1 h·d in SB and MVPA, respectively, and 6.8 h per night asleep. No associations were observed between MVPA and SB with nighttime TST or SE. There were no associations between nighttime TST and SE with MVPA or SB the next day. The findings were the same in the quantile regression analyses.



In free-living adult women, accelerometry-estimated nighttime sleep and physical activity patterns were not associated with one another. On the basis of our observational study involving a sample of adult women, higher physical activity will not necessarily improve sleep at night on a day-to-day basis (and vice versa).
1Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA; 2Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; 3Department of Family Medicine and Public Health, University of California, San Diego, San Diego, CA; 4Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL; 5School of Psychology and Counseling, Queensland University of Technology, Brisbane, AUSTRALIA; 6Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; 7Department of Environmental Health and Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA; 8Department of Parks, Recreation, and Tourism Management and Center for Geospatial Analytics, NC State University, Raleigh, NC; 9Perelman School of Medicine and School of Nursing, University of Pennsylvania, Philadelphia, PA.
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D061725:Accelerometry / Q000379:methods; D015444:Exercise / Q000502:physiology*; D005260:Female; D006615:Hip; D006801:Humans; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D014953:Wrist