Daily Steps and Life Expectancy: A Life Table Analysis of a Population-Representative Sample

The association between daily steps, an accessible and comprehensible metric of physical activity, and life expectancy remains unclear. This study aimed to quantify the dose-response relationship between daily steps and life expectancy in a nationally representative sample of US adults.

This cohort study included 8570 adults aged ≥40 from the 2005 to 2006 and 2011 to 2014 National Health and Nutrition Examination Survey (NHANES) cycles. Steps were objectively measured using accelerometers over 7 consecutive days. Mortality through December 2019 was ascertained via the National Death Index. Life expectancy was estimated by converting hazard ratios into differences in life years, using life tables from the 2018 National Vital Statistics rescaled with hazard ratios and population prevalence from NHANES.

During a mean follow-up of 8.5 years, 1534 deaths occurred. Compared with those walking <4000 steps/d, life expectancy at age 40 increased by 7.4 (95% CI, 6.6-8.4), 12.2 (11.0-13.7), 15.7 (14.3-17.4), 17.8 (16.2-19.7), and 19.2 (17.7-21.1) years for individuals walking 4000 to 5999, 6000 to 7999, 8000 to 9999, 10,000 to 11,999, and ≥12,000 steps/d, respectively. Each additional 1000 steps/d corresponded to a 1.5-year (1.1-1.9) increase in life expectancy at age 40. If all insufficiently active individuals (<8000 steps/d) increased to 8000 steps/d, life expectancy could theoretically rise by 6.1 years.

Higher daily steps were associated with substantial gains in life expectancy among US adults, with the most pronounced benefits observed among the least active individuals and tended to plateau at approximately 8000 steps/d.