Changes in activity spaces, life spaces, and exposures to physical activity-promoting environments among women with overweight or obesity.

Understanding factors associated with successful adherence and maintenance of weight loss interventions is important to potentially increase efficacy. Activity spaces and environmental exposures are two understudied factors that may be associated with intervention adherence and outcomes. Women with overweight or obesity (n = 498) from two weight loss intervention studies, Reach for Health and Metabolic, Exercise, and Nutrition at University of California San Diego, wore accelerometer and Global Positioning System (GPS) devices for 1 week at baseline and at 6-month follow up. Changes in activity spaces and time spent in three life space domains (Home, Neighborhood, and Beyond Neighborhood) were assessed at the two timepoints for total time and the subset of time in physical activity (PA). Relationships between repeated GPS-measured exposure to PA promoting environments (walkability; recreation; and greenness) were assessed with linear mixed effects models with an interaction between intervention and timepoint. There was no significant change in the average total or PA-related activity space size. There was no significant change in the amount of total time spent in life space domains by intervention group. However, for PA time in life spaces, the Intervention group increased percent of PA time in the Neighborhood (1.49 %-1.71 %; p = 0.011) and Beyond Neighborhood domains (from 5.85 %-6.60 %; p < 0.0001), whereas PA time at Home was not significantly different (p = 0.755). For the mixed effects models with PA-related time, being in the Intervention group was associated with (-0.06, 95 % CI: -0.19, -0.07; p < 0.01) less exposure to walkability and this was attenuated at time 2, compared to controls. Results suggest that PA-focused interventions did not increase the size of participants' total and PA-related activity spaces but were associated with a higher percent of PA-related time outside of the home. There were not consistent associations between the Intervention group and increased exposure to PA-supportive environments.