Abstract P159: Sedentary Behavior During the Weekend, Rather Than Weekdays, Affects Body Composition in Young Adults
Background: High sedentary time has been considered an important chronic disease risk factor but there remains limited evidence on the differential effects of sedentary behaviors during weekdays versus the weekend on body composition. The purpose of the study was to examine the prospective association between objectively measured sedentary time and self-reported sedentary behaviors during weekdays and the weekend with body composition in young, healthy adults.
Methods: Measurements were taken every 3 months in a sample of 430 young adults (49% male) between 20 and 35 years of age over a period of 1 year. Energy Expenditure, time spent sedentary excluding sleep (SED) was objectively assessed with a multi-sensor device over a period of 10 days at every measurement time. In addition, participants reported sitting time, TV time and non-work related time spent at the computer separately for weekdays and the weekend. Body weight was measured in a fasted state with participants wearing surgical scrubs and in bare feet. Fat mass and fat free mass were assessed via dual x-ray absorptiometry and used to calculate percent body fat (BF). Further, energy intake (EI) was calculated based on change in body composition and objectively measured energy expenditure.
Results: A total of 332 (50% male) participants provided valid data over the 12-month observation period. At baseline SED was associated with sitting time (r=0.20), TV time (r=0.23) and non-work computer time (r=0.24) during the weekend (p<0.01) but not during weekdays. Body weight and BF at baseline were directly associated with SED during weekdays and the weekend (0.23 < r < 0.30, p<0.01). In addition, TV time during weekdays was associated with BF (r=0.16, p<0.01). Linear mixed models, adjusted for EI, did not show a significant association between change in SED during weekdays and body composition at 12 months. Change in SED during weekends, however, was directly associated body body composition at 12 months follow up (βweight=0.05, βBF=0.08; p<0.01). As for self-reported sedentary behaviors, only change in sitting time during the weekend was directly associated with BF at 12 months but not with body weight. No significant associations were observed between sedentary behaviors during weekdays and body composition at 12 months.
Conclusions: Total sedentary time, rather than specific sedentary behaviors, appears to influence subsequent body composition, particularly during the weekend. These findings suggest that a reduction in leisure time sedentary behaviors should be emphasized in addition to strategies aiming at a reduction in occupational sedentary time when addressing weight management.
Author Disclosures: C. Drenowatz: B. Research Grant; Modest; The Coca Cola Company. M.M. DeMello: None. R.P. Shook: B. Research Grant; Modest; The Coca Cola Company. G.A. Hand: B. Research Grant; Modest; The Coca Cola Company, NIH, CDC, HRSA, American Heart Association. S.N. Blair: B. Research Grant; Modest; The Coca Cola Company, NIH, DoD, Body Media. G. Consultant/Advisory Board; Modest; Technogym, Santech, Clarity, International Council on Active Aging, Cancer Fit Steps for Life.
- © 2016 by American Heart Association, Inc.