Accelerometer-Determined Lifestyle Activities in U.S. Adults

Background: Objective physical activity data analyses focus on moderate-to-vigorous physical activity (MVPA) without considering lower intensity lifestyle-type activities (LA). We describe 1) quantity of LA (minutes and steps per day) across demographic groups, 2) proportion of LA to total physical activity, and 3) relationships between LA and MVPA using NHANES 2005-2006 accelerometer adult data (n = 3744). Methods: LA was defined as 760 to 2019 counts per minute (cpm) and MVPA as >= 2020 cpm. LA was compared within gender, ethnicity, age, and BMI groups. Regression analyses examined independent effects. Correlations were evaluated between LA and MVPA. All analyses incorporated sampling weights to represent national estimates. Results: Adults spent 110.4 +/- 1.6 minutes and took 3476 +/- 54 steps per day in LA. Similar to MVPA, LA was highest in men, Mexican Americans, lowest in adults >= 60 years or obese. When LA was held constant, ethnic differences no longer predicted MVPA minutes, and age no longer predicted MVPA steps. LA and MVPA minutes (r = .84) and steps per day (r = .72) were significantly correlated, but attenuated with MVPA modified bouts (>= 10 minutes sustained activity). Conclusions: LA accumulation differs between demographic subgroups and is related to MVPA: adults who spend more minutes and steps in MVPA also spend them in LA.