Association of physical activity intensity levels with overweight and obesity in a population-based sample of adults

Background. Clarify the association between physical activity intensity and overweight/obesity. Methods. Population-based 1997–2001 survey in Geneva, Switzerland (n = 5,757, ages 35 to 74). Intensity of physical activity energy expenditure (EE) defined as percentage of total EE in moderate activities [3–3.9 × basal metabolism rate (BMR), e.g., normal walking, household chores] and high-intensity activities (≥4 × BMR, e.g., brisk walking, sports). Overweight or obesity based on measured body mass index (BMI). Results. Comparing participants in the lowest vs. the highest tertile of the percentage of high-intensity EE, the odds ratios (ORs) were, for obesity vs. normal weight, 2.8 (95% confidence interval: 2.0–3.8, P < 0.0001) in men and 2.4 (1.7–3.4, P < 0.0001) in women. For obese vs. overweight, the men/women ORs were 1.9 (1.4–2.6, P < 0.0001)/1.5 (1.0–2.2, P < 0.05). For overweight vs. normal weight, the men/women ORs were 1.4 (1.1–1.7, P < 0.002)/1.7 (1.3–2.1, P < 0.0001). Less or no relationship was found for the percentage of moderate-intensity EE. Conclusions. This cross-sectional study cannot determine whether exercise is an effective strategy for weight control or whether overweight or obese people exercise less. However, clear dose–response associations in both genders between obesity or overweight and energy expenditure in high (but not in moderate)-intensity activities are findings with potentially major public health implications meriting validation in an experimental intervention study.