Factors associated with physical activity in adults in Brasília, Central-West Brazil

Objective: To describe physical activity practice in adults and to identify associated factors. Methods: A cross-sectional study was performed with cluster sampling from the four areas of the city of Brasília, Central-West Brazil, in 2006-2007. A sample comprised of 469 adults was obtained from 250 randomly selected households. Sociodemographic data, weight and height were obtained during a household interview. The short version of the International Physical Activity Questionnaire (IPAQ) was used to measure physical activity. A multivariate linear regression analysis was made to assess the effect of sex, body mass index (BMI), socioeconomic classification and marital status on physical activity scores. Results: The majority of the sample was comprised of women (57%). The percentage of individuals who achieved 150 minutes of weekly physical activity practice was 52% (95% CI: 47; 56), while that of inactive individuals was 21.5% (95% CI: 17.8; 25.3). An inverse association between physical activity and BMI was only found in men. Types of physical activity reported differed between sexes: walking and doing household chores among women; cycling, running, swimming and weight-lifting among men. There was a strong interaction between male sex and BMI in terms of the association with physical activity scores: the higher the BMI, the lower the physical activity score. Conclusions: The portion of inactive individuals in Brasília can be considered low, when compared to estimates from other Brazilian cities. Differences in BMI and physical activity score found between sexes are associated with the type of physical activity practiced.