Reduce Your Sit and Be More Fit: An Examination of Sedentary Behavior

Abstract

Sedentary behavior is associated with negative health and should be accurately assessed. Due to the amount of time spent at work and the growing number of sedentary jobs, the workplace offers a natural setting to reduce sedentary behavior. The purpose of the first study in this dissertation was to validate the SWA as an instrument to measure sedentary behavior. The purpose of the second study was to use the SWA to monitor the feasibility of behavioral strategies to reduce sedentary time in the workplace. The validity of the SWA in measuring the energy expenditure of sedentary behavior and light physical activity was determined by comparing energy expenditure measurements from the SWA to indirect calorimetry (Oxycon). The feasibility of behavioral strategies to reduce sedentary time in the workplace was assessed by implementing a 1-week behavioral strategy program among sedentary female office workers titled, Reduce Your Sit and Be More Fit. This program included one-on-one counseling, goal setting, and self-monitoring of goals to reduce sedentary behavior.

Sedentary behavior and light physical activity energy expenditure measures from the SWA were strongly correlated with the Oxycon, r(20) = .90, p < .001, ICC = .90, 95% CI [.699, .966]. The SWA significantly under predicted energy expenditure while standing with no movement (p = .002), performing office work while sitting (p < .001), and performing office work while standing (p < .001). In addition, the SWA correctly classified sedentary, light, and moderate physical activity 88.6% of the time. Overall, these results demonstrated the SWA is a valid instrument to measure sedentary behavior and light activity. In the second study, office workers who received the intervention to reduce sedentary behavior had a greater decrease in sedentary behavior (p = .023), a greater increase in light physical activity (p = .027), a greater increase in average occupational energy expenditure, (p = .032), and a greater increase in average occupational MET level (p = .036) compared to the control group. Based on these results, it was feasible to reduce sedentary time in the workplace by implementing behavioral strategies.