The updated Physical Activity Guidelines for Americans (2nd edition) removes the requirement that physical activity should occur in bouts lasting 10 minutes or more to count toward the minimum aerobic guideline. Using self-reported data from the 2017 Behavioral Risk Factor Surveillance System (N = 386,960), we examined differences in national physical activity estimates with and without this requirement. Overall, 1.9% of adults reported activities in short bouts (<10 minutes). When excluding short bouts, 29.9% were inactive, 20.7% were insufficiently active, and 49.4% were active. When including short bouts, 29.1% were inactive, 21.4% were insufficiently active, and 49.5% were active. Eliminating the 10-minute-bout requirement had little effect on physical activity estimates.