Since 2001, BRFSS has used six survey questions about physical activity in three domains (household work, transportation, and discretionary/leisure time) to quantify its frequency, duration, and intensity. These questions are asked in all states once every 2 years. Respondents are asked to provide information on overall frequency and duration of time spent in bouts of 10 minutes or more of physical activity of moderate intensity (e.g., brisk walking or gardening) and vigorous intensity (e.g., heavy yard work, running, or aerobics) during a usual week. Moderate-intensity activity is described to respondents as any activity “that causes small increases in breathing and heart rate,” and vigorous-intensity activity is described as any activity “that causes large increases in breathing or heart rate.” Respondents are classified as active at the minimum recommended level if they report moderate-intensity activity at least 30 minutes per day, 5 or more days per week, or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week. Respondents are classified as inactive if they report no activity of 10 minutes or more per week of moderate or vigorous intensity. For this analysis, prevalence estimates were age-adjusted to the 2000 U.S. standard population. Pairwise comparisons for changes in prevalence from 2001 to 2003 were performed for each state and territory to calculate t-statistics. Differences were considered statistically significant at p<0.05. Statistical analysis software was used to account for the complex sampling design.