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When it comes to physical activity, taking 10,000 steps per day may sound like a familiar goal. The idea was popularized decades ago by a marketing campaign in Japan for a pedometer. But as NPR's Allison Aubrey reports, a new study published in JAMA Internal Medicine finds a far fewer number of steps reduce the risk of premature death.
ALLISON AUBREY, BYLINE: Researchers suspected there was nothing magical about 10,000 steps. To find out, I-Min Lee of Brigham and Women's Hospital and her collaborators studied a group of about 17,000 women. Their average age was 72, and they all agreed to clip on a wearable device to count their steps.
I-MIN LEE: They wore it during all waking hours for seven days.
AUBREY: And then, for the next four to five years, the researchers kept up with the women. It turns out 4,400 steps a day seemed enough to boost longevity. Women who walked that amount were 40% less likely to die during the study, compared to women who took just 2,700 steps a day, on average. I asked Lee if she was surprised by the results.
LEE: It was sort of surprising because this was below the 10,000 steps a day.
AUBREY: In general, the more the women walked, the greater the benefit. But here's another surprise. There was a point of diminishing returns. The benefits leveled off at about 7,500 steps a day, meaning the women who got more than that got no additional boost in longevity. So much for that goal of 10,000 steps.
LEE: Yes, I think the original basis of the number really was not scientifically determined.
AUBREY: Kathleen Janz of the University of Iowa studies how exercise influences health outcomes.
KATHLEEN JANZ: I love this study. I think this is really good news for women who may not be particularly active.
AUBREY: Janz helped to shape the federal exercise recommendations. She says the message from this study is that for older women, just light walking is really beneficial.
JANZ: They didn't need to go to the gym. They didn't need to invest in a personal trainer or exercise equipment.
AUBREY: All they had to do was walk.
JANZ: To me, the study suggests that there's probably more benefit in terms of light activity than we were previously thinking that there might be.
AUBREY: And Janz says that's encouraging. Allison Aubrey, NPR News.
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