Is Sitting Time Related To Moderate And Vigorous Physical Activity Among Middle-aged Women? Observations From The Win Study

Abstract

The health benefits of physical activity are well established. The association between sedentary behavior and duration and intensity of physical activity has not been sufficiently explored. PURPOSE: In the present study, we utilize data from the Women's Injury Study (WIN) to investigate the cross-sectional relation between women's sedentary behavior and physical activity (PA) level. METHODS: The WIN study was a prospective observational study of women's PA behavior and risk of musculoskeletal injury. Women (n=918) were age 52 ± 13 years at baseline, including 75% Caucasian, 4% Hispanic, and 18% African American. Women self-reported PA weekly for up to 3 years. At the end of the study, women were asked to complete a survey including assessment of their time spent sitting during a typical day. Women who responded to the post-study survey with complete data were included for analysis (n=584; 80% of those initially enrolled). During the study, participants were reminded weekly to log their frequency and duration spent in moderate and vigorous physical activities (MVPA) on the WIN study web site. For the present analysis, the final 3 months of PA surveillance was averaged for each woman as an assessment of their MVPA. Women were classified as meeting PA guidelines (≥150 minutes of MVPA) or not. Two categories of sitting time were created for analysis: sitting ≥half the time or sitting <half the time on a typical day. A logistic regression model was used to assess the odds of meeting PA guidelines if reportedly sedentary when adjusting for age, weight, and sitting time. RESULTS: Women who sat <half the time were more likely to meet PA guidelines (OR=2.0, 95%CI: 1.4, 2.9). CONCLUSION: These results suggest that typical sedentary behavior relates to meeting PA guidelines and is an important public health target for modifying PA behaviors. Supported by NIH NIAMS 1R01AR052459-05.