Measuring physical activity with the behavioral risk factor surveillance system

Purpose and Methods: Because regular physical activity reduces the risk of premature death and disability, accurate methods of population-based measur ement are important for public health surveillance efforts such as those ba sed on the Behavioral Risk Factor Surveillance System (BRFSS). The present study: 1) briefly reviews and compares currently available methods to measu re physical activity using BRFSS data, 2) describes physical activity patte rns in the United States using these state-aggregated measures, and 3) prov ides suggestions on future directions for practitioners and researchers. Us ing a random-digit dialing, telephone survey, we collected data for noninst itutionalized adults aged 18 yr and older. We analyzed BRFSS data for 1996 from 50 states and the District of Columbia and Puerto Rico (N = 124,085). Based on recent literature and public health priorities, we developed eight different physical activity indices (one vigorous and seven moderate). The se varied in their threshold for duration, kcal expenditure, and in frequen cy and intensity of activity. Results: Using different algorithms, the popu lation prevalence of moderate physical activity ranged from about 20% to 38 %. Only 20% of adults met the Healthy People 2000 definition for regular, s ustained activity (greater than or equal to 30 min of moderate activity per day for at least 5 d.wk(-1)). Conclusions: Considerable progress is needed if the United States is to reach the current public health goal for regula r physical activity. Standardized approaches to analyzing and collecting ph ysical activity data are essential for public health surveillance, policy m aking, and communication to the public.