Accelerometer steps/day translation of moderate-to-vigorous activity.

Abstract

Physical activity (PA) guidelines are typically communicated in terms of duration, frequency and intensity, e.g., 30 min/day of moderate-to-vigorous physical activity (MVPA) on at least 5 days/week. Step counters can be used to collect objective PA expressed as steps/day, however the association between steps/day and recommended PA levels is unclear. We determined a direct steps/day translation of 30 min/day accumulated MVPA, using concurrently detected ActiGraph accelerometer-defined step and activity count data collected as part of the 2005-2006 National Health and Nutrition Examination Survey (NHANES). We employed statistical models to analyze data from 3523 participants 20+years of age who wore the accelerometer for at least one valid day (i.e., at least 10/24h) over 7 days. 30 min/day of MVPA translated to approximately 7900 steps/day for males and 8300 steps/day for females. In a subsample of participants (n=1197) with valid data on all 7 days, we found 150 min/week of MVPA translated to approximately 7000 steps/day (or 49,000 steps/week). Accumulating approximately 8000 steps/day is a good proxy for 30 min of daily MVPA, while accumulating 7000 steps/day every day of the week is consistent with obtaining 150 min of weekly MVPA.