A US prospective cohort study in older women showed that more steps taken per day are associated with lower mortality rates until approximately 7500 steps/day. The study included 18 289 women by wearing an accelerometer during waking hours for 7 days between 2011 and 2015. 16 741 (mean age 72.0) were compliant wearers (≥10 h/day of wear on ≥4 days) and included in the analyses. Mean step count was 5499/day, with 51.4%, 45.5%, and 3.1% of time spent at 0, 1 to 39 (incidental steps), and 40 steps/min or greater (purposeful steps), respectively. During a mean follow-up of 4.3 years, 504 women died. Median steps/day across low-to-high quartiles of distribution were 2718, 4363, 5905, and 8442, respectively. The corresponding quartile hazard ratios (HRs) associated with mortality and adjusted for potential confounders were 1.00 (reference), 0.59, 0.54, and 0.42, respectively. In spline analysis, HRs were observed to decline progressively with higher mean steps/day until approximately 7500 steps/day, after which they leveled. For measures of stepping intensity, higher intensities were associated with significantly lower mortality rates; however, after adjusting for steps/day, all associations were attenuated, and most were no longer significant. The findings suggest that number of steps, rather than stepping intensity, was the step metric consistently related to lower mortality rates. Source: https://jamanetwork.com/
