Step Counts and Stepping Intensity among U.S. Adults: National Health and Nutrition Examination Survey 2011-2014.

Abstract

To characterize stepping in a nationally representative sample of U.S. adults by age, sex, and race and ethnicity. Step counts are a simple, scalable metric of physical activity associated with lower mortality and chronic disease risks. However, nationally representative estimates of step volume and intensity across demographic groups remain limited. We analyzed data from U.S. adults aged ≥20 yr in National Health and Nutrition Examination Survey 2011-2014 who wore a wrist accelerometer for 7 d. Stepping metrics derived from the OxWearables machine-learning algorithm, including daily steps, peak 30-min cadence, and self-selected cadence. We estimated survey-weighted means and the prevalence of meeting age-specific thresholds associated with substantial reductions in mortality risk (≥9000 steps/d for adults <60 yr; ≥7000 steps/d for adults ≥60 yr) from previous meta-analyses. Adults ( N = 8,762, mean age 48 yr [SD = 17]; 52% female) averaged 8818 steps/d (95% CI: 8676-8961). Fifty-one percent of steps were accumulated from <2-min bouts and 28% from ≥5-min bouts. Males took more steps than females. Hispanics had higher step counts than other racial and ethnic subgroups. Peak and self-selected cadence converged in older adults; 48.6% of adults <60 yr obtained ≥9000 steps/d, and 44.8% of ≥60 yr obtained ≥7000 steps/d. Nearly half of U.S. adults achieved step counts associated with substantially lower mortality risk, with differences by age, sex, race, and ethnic groups. These findings provide benchmarks for population surveillance and can help shape strategies to encourage step-based activity. They may also guide future initiatives aimed at promoting stepping as a form of physical activity among the least active adults.