Can’t find the hours in a day to log your daily 10,000 steps for good health? Good news: A new study shows that walking as few as 4,400 steps per day was significantly related to lower mortality and that those rates continued to decrease with more steps, leveling off at approximately 7,500 steps per day. The study, “Association of Step Volume and Intensity With All-Cause Mortality in Older Women,” was recently published in JAMA Internal Medicine (2019;179:1105-1112).
Explore This IssueFebruary 2020
So where did that magic 10,000-steps-per-day recommendation come from? The study’s lead author, I-Min Lee, MD, MPH, ScD, a professor in the department of epidemiology at the Harvard T.H. Chan School of Public Health, said that while we often hear the number 10,000 cited as a daily step goal, the basis for this number is unclear.
“It likely originated as a marketing tool,” she said, noting that in 1965 the Yamasa Clock and Instrument Company in Japan sold a pedometer called “Manpo-kei,” which in Japanese means “10,000 step meter.”
Dr. Lee said that for many older people, 10,000 steps per day can be a daunting goal, which is why she and her colleagues wanted to investigate whether this was necessary for lower mortality rates in older women.
The researchers set out to examine the associations of number of steps per day and stepping intensity with all-cause mortality, and the prospective cohort study included 18,289 U.S. women from the Women’s Health Study who agreed to participate by wearing an accelerometer during waking hours for seven days between 2011 and 2015. Of these women, 16,741 were compliant wearers (≤10 h/d of wear on ≤4 days). Their results were analyzed between 2018 and 2019.
The study’s limitations, according to Dr. Lee, are two-fold: Only mortality was studied, and there are other health outcomes they will examine in the future; also, the participants were older women, although she says the findings likely apply to older men. For younger individuals, Dr. Lee said that while they know ‘some is good; more is better,’ it is unclear that maximum risk reduction for mortality occurs at 7,500 steps per day.
As for the concern that seven days of wear is a limitation, Dr. Lee doesn’t believe it is. “In a subgroup of women, we asked participants to wear the device for multiple observation periods over three years,” she said, “and only seven days of wear is a good representation for the longer period.”