Daily steps and life expectancy: a life table analysis of NHANES 2005-2006 and 2011-2014

The association between daily steps, an accessible and comprehensible metric of physical activity, and life expectancy remains unclear. This study aims to quantify the dose-response relationship between daily steps and life expectancy in a nationally representative sample of U.S. adults. This cohort study included 8317 adults aged ≥ 40 from the 2005–2006 and 2011–2014 NHANES cycles. Steps were objectively measured using accelerometers over seven consecutive days. Mortality through December 2019 was ascertained via the National Death Index. Life expectancy was estimated by converting hazard ratios (HRs) into differences of life years using life tables from the 2018 National Vital Statistics, rescaled with HRs and population prevalences from NHANES. Over 8.7 years, 1281 deaths occurred. Compared with < 4000 steps/d, life expectancy at age 40 was greater by 5.4 (95% CI: 4.4–6.5), 9.0 (7.6–10.7), 11.9 (10.0–14), 13.6 (11.4–15.9), and 14.8 (12.7–17.1) years for individuals walking 4000–5999, 6000–7999, 8000–9999, 10000–11999, and ≥ 12000 steps/d, respectively. On average, each additional 1000 steps/d at age 40 corresponded to a 1.4-year (1.0-1.8) gain. If all insufficiently active individuals (< 8000 steps/d) increased to 8000 steps/d, life expectancy could theoretically rise by 4.8 years. In conclusion, higher daily steps associated with extended life expectancy among U.S. adults.