Step intensity not linked to significantly lower mortality risk after adjusting for total steps per day
TUESDAY, March 24, 2020 (HealthDay News) — A greater number of daily steps — 8,000 or more — is associated with a significantly lower risk for all-cause mortality, according to a study conducted in U.S. adults published in the March 24/31 issue of the Journal of the American Medical Association.
Pedro F. Saint-Maurice, Ph.D., from the National Cancer Institute in Bethesda, Maryland, and colleagues analyzed data from 4,840 participants (mean age, 56.8 years; 54 percent women) of the National Health and Nutrition Examination Survey (2003 to 2006) who wore an accelerometer (mean of 5.7 days for a mean of 14.4 hours per day). Mortality data were followed through December 2015.
The researchers found that the mean number of steps per day was 9,124. For individuals who took <4,000 steps per day, the unadjusted incidence density for all-cause mortality was 76.7 per 1,000 person-years compared with 21.4 per 1,000 person-years for individuals who took 4,000 to 7,999 steps per day, 6.9 per 1,000 person-years for individuals who took 8,000 to 11,999 steps per day, and 4.8 per 1,000 person-years for individuals who took ≥12,000 steps per day. Taking 8,000 steps per day and taking 12,000 steps per day were associated with significantly lower all-cause mortality (hazard ratios, 0.49 [95 percent confidence interval, 0.44 to 0.55] and 0.35 [95 percent confidence interval, 0.28 to 0.45], respectively) compared with taking 4,000 steps per day. However, greater step intensity was not significantly associated with lower mortality after adjustment for total steps per day (highest versus lowest quartile of peak 30 cadence: hazard ratio, 0.90; 95 percent confidence interval, 0.65 to 1.27; P value for trend = 0.34).
“While we knew physical activity is good for you, we didn’t know how many steps per day you need to take to lower your mortality risk or whether stepping at a higher intensity makes a difference,” Saint-Maurice said in a statement. “We wanted to investigate this question to provide new insights that could help people better understand the health implications of the step counts they get from fitness trackers and phone apps.”
One author disclosed financial ties to ActiGraph, the device used in the study.
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