Patterns of Change in Device-Based Physical Activity and Sedentary Time Following Bariatric Surgery: a Longitudinal Observational Study.

PURPOSE The aim of this study is to investigate changes in physical activity (PA) and sedentary time (ST) over 12 months following bariatric surgery. METHODS Pre-surgery and at 3, 6, 9, and 12 months post-surgery, wearable devices were used to measure PA at different intensities, grouped according to energy expenditure and daily step count, and ST. Measures were also collected of weight and self-efficacy for exercise. Pre- and 12 months post-surgery, measures were collected of body composition and cardiovascular fitness. RESULTS Thirty adults scheduled for bariatric surgery were recruited (20 females, 44.1 [range, 22.0 to 65.0] years, body mass index 39.6 [range, 30.9 to 50.9] kg/m2). When compared to pre-surgery measures, over the 12 months post-surgery, there were no changes in the percentage of waking hours (mean [95% CI]) spent in ST (- 2% [- 6 to 3]), light intensity PA (1% [- 3 to 5]), and moderate-to-vigorous intensity PA (1% [- 1 to 3]). At all time points, participants spent most (> 70%) of their waking hours accumulating ST, with little time spent in light intensity PA (~ 21%) and almost no time in moderate-to-vigorous intensity PA (~ 5%). Step count and cardiovascular fitness were also unchanged. There were significant changes in weight, self-efficacy for exercise, and body composition. CONCLUSIONS Although bariatric surgery resulted in substantial weight loss and improved self-efficacy for exercise, it was insufficient to effect change in PA, ST or cardiovascular fitness. Complementing surgical intervention with behavioral interventions may optimize change in PA and ST.