In this two-phase pilot, we will first test in a controlled setting whether an acceptance-based intervention can modify the relationship between Heart Rate and perceived exertion/negative affect during moderate intensity physical activity among individuals high in internalized weight bias (Phase 1) and then evaluate these mechanisms in real-time during uptake of a two-week physical activity prescription (Phase 2). Using a 2x2 factorial design, we will randomize individuals with Body Mass Index (BMI) ≥25, high and low internalized weight bias, and insufficient activity (<60 min of moderate physical activity/week) to receive a 90-minute acceptance-based intervention workshop versus a multi-health behavior education condition prior to completing a 30-minute session of supervised, moderate intensity treadmill walking. Heart rate, self-reported perceived exertion and affect will be assessed throughout physical activity.~For Phase 2, all participants from Phase 1 will receive a two-week physical activity prescription consistent with National Guidelines (150 minutes moderate intensity aerobic physical activity, recommended in 30-minute bouts) to determine the effect of treatment condition on subsequent adherence to physical activity. Physical activity adherence will be monitored with Actigraphy and Ecological Momentary Assessment (repeated daily surveys via smartphone) will be used to evaluate participant self-efficacy, intention, motivation for physical activity in near real-time.
The goal of this study is to test whether an acceptance based intervention can modify the relationship between heart rate and perceived exertion/negative during physical activity among individuals who have a high degree of internalized weight bias.