Framing physical activity as a distinct and uniquely valuable behavior independent of weight management: a pilot randomized controlled trial for overweight and obese sedentary persons.

PURPOSE: Promoting benefits of physical activity independent of weight management may help overweight/obese persons. DESIGN: Pilot randomized-controlled-trial. SUBJECTS: Twenty-six sedentary, overweight/obese persons receiving health-care at Stanford Medical Center, no contraindications for exercise. CONTROL/INTERVENTION GROUPS: Usual medical care and community weight-management/fitness resources versus same plus a brief intervention derived from behavioral-economic and evolutionary psychological theory highlighting benefits of activity independent of weight-management. ANALYSIS: Intent-to-treat. Cohen's d effect-sizes and 95% confidence intervals (95%CI) for changes in moderate-intensity-equivalent physical activity/week, cardiorespiratory fitness, and depression at 3 months relative to baseline. RESULTS: Intervention group participants demonstrated 3.76 hour/week of increased physical activity at study endpoint, controls only 0.7 hours/week (Cohen's d=0.74, 95% CI -0.06 to +1.5). They also improved cardiorespiratory fitness (Cohen's d=0.51, 95% CI -0.3 to +1.3) and reduced depression relative to controls (Cohen's d=0.66, 95% CI -0.1 to +1.4). CONCLUSION: Promoting activity independent of weight-management appears promising for further study.