Amount and intensity effects of exercise training alone versus a combined diet and exercise lifestyle intervention on health-related quality of life in the STRRIDE-PD randomized trial

Introduction To determine the relative contributions of various amounts and intensities of exercise alone to a combined lifestyle intervention on health-related quality of life (HrQoL) measures. Research design and methods Participants (n=162) were sedentary, overweight/obese, with pre-diabetes, and randomized to one of four 6-month interventions: (1) high amount/moderate intensity exercise-energy expenditure of 16 kcal/kg of body weight/week (KKW) at 50% oxygen consumption ((V) over dotO(2)) reserve; (2) high/vigorous-16 KKW at 75% (V)over dotO(2) reserve; (3) low/moderate-10 KKW at 50% (V) over dotO(2) reserve; (4) low/moderate plus diet-10 KKW at 50% (V) over dotO(2) reserve plus a calorically restricted diet. The 36-Item Short-Form Survey (SF-36) and Satisfaction with Physical Function and Appearance (SPF/SPA) survey were assessed at baseline and post-intervention. Analyses of covariance determined differences in change scores among groups (p<0.05). Paired t-tests determined significant pre-intervention versus post-intervention scores within groups (p<0.05). Results Across the intervention, all groups (p<0.05) improved the physical component, SPF, and SPA scores. Only the low/moderate/diet group (p<0.001) significantly improved the mental component score. The high/vigorous group achieved 84.5% of the low/moderate/diet group effect for change in physical component score, and the low/moderate group achieved 83.7% of the low/moderate/diet group effect for change in mental component score. Conclusions In general, a low amount of moderate intensity exercise combined with diet was the most effective intervention for improving HrQoL. Of the exercise-only interventions, vigorous intensity exercise provided the greatest impact on changes in physical function. On the other hand, low amounts of moderate intensity exercise provided the greatest impact on mental well-being, potentially being a more attainable exercise dose for previously sedentary individuals with pre-diabetes to achieve.