Regular physical activity helps prevent obesity, heart disease, hypertension, diabetes, colon cancer, and premature mortality. During 1986--2000, the Behavioral Risk Factor Surveillance System (BRFSS) included questions that measured leisure-time physical activity (primarily exercise or sports-related activities). Previous guidelines for appropriate physical activity to increase cardiorespiratory fitness included participating in vigorous-intensity activity (i.e., > or =20 minutes per day, > or =3 days per week). BRFSS questions used to measure this level of activity were developed a decade before CDC and the American College of Sports Medicine concluded that health-related benefits could accrue from a minimum of 30 minutes of moderate-intensity activity on most days of the week. Various household and transportation-related physical activities and some leisure-time activities, therefore, can be important to measure. In response to expanded activity recommendations designed to include health-related lifestyle activities, new BRFSS physical activity questions have been developed. After cognitive, validity, and reliability testing, the new lifestyle activity questions were used in the 2001 BRFSS. A separate question allowed tracking of physical inactivity during leisure time across years and was used in the 2000 and 2001 BRFSS questionnaires. This report presents data from responses to the 2000 BRFSS leisure-time activity questions and the updated lifestyle activity questions of the 2001 BRFSS to compare overall U.S. and state-specific prevalence estimates for adults who engaged in physical activities consistent with recommendations from both survey years. The findings indicate that even with a more complete measure of physical activity than used previously, the majority of U.S. adults are not physically active at levels that can promote health.