Technical Abstract: Analysis of the 2005-2006 National Health and Nutrition Examination Survey (NHANES) accelerometer data provides the descriptive epidemiology of peak 30-minute cadence (defined as the average steps/min recorded for the 30 highest, but not necessarily consecutive, minutes in a day) and peak 1-minute cadence (defined as the steps/min recorded for the highest single minute in a day) by sex, age, and body mass index (BMI). Minute-by-minute step data were rank ordered each day to identify the peak 30-minute and 1-minute cadences for 3,522 adults (20+ years of age) with complete sex, age, and BMI data and at least 1 valid day (i.e., 10/24 hours of accelerometer wear) of accelerometer data. Peak values were averaged across days within participants by sex, age, and BMI-defined categories. U.S. adults average a peak 30-minute cadence of 71.1 (Men: 73.7, Women: 69.6, p<0.0001) steps/min and a peak 1-minute cadence of 100.7 (Men: 100.9, Women: 100.5, p=0.54) steps/min. Both peak cadence indicators displayed significant and consistent declines with age and increasing levels of obesity. Peak cadence indicators capture the highest intensity execution of naturally occurring ambulatory activity. Future examination of their relationship with health parameters using cross-sectional, longitudinal, and intervention designs is warranted.