There's nothing magical about the number 10,000.
In fact, the idea of walking at least 10,000 steps a day for health goes back decades to a marketing campaign launched in Japan to promote a pedometer. And, in subsequent years, it was adopted in the U.S. as a goal to promote good health. It's often the default setting on fitness trackers, but what's it really based on?
"The original basis of the number was not scientifically determined," says researcher I-Min Lee of Brigham and Women's Hospital.
She was curious to know how many steps you need to take a day to maintain good health and live a long life, so she and her colleagues designed a study that included about 17,000 older women. Their average age was 72. The women all agreed to clip on wearable devices to track their steps as they went about their day-to-day activities.
It turns out that women who took about 4,000 steps per day got a boost in longevity, compared with women who took fewer steps. "It was sort of surprising," Lee says.
In fact, women who took 4,400 steps per day, on average, were about 40 percent less likely to die during the follow-up period of about four years compared with women who took 2,700 steps. The findings were published Wednesday in JAMA Internal Medicine.
Another surprise: The benefits of walking maxed out at about 7,500 steps. In other words, women who walked more than 7,500 steps per day saw no additional boost in longevity.
"I love this study. I think it's really good news for women who may not be particularly active," says Kathleen Janz, who studies how physical activity influences health at the University of Iowa. She was not involved in this study.
Janz, who helped shape the new federal exercise recommendations released last November, says the message that comes from this study is that older women can benefit from just light walking.
"They didn't need to go the gym or invest in a personal trainer or exercise equipment," she says. All they had to do was walk.
And Janz says that's encouraging.
"To me, this study suggests there's more benefit to light activity than we were previously thinking there might be," she says.
Of course, the researchers point out, they would like to know much more about how walking may affect other health parameters such as quality of life and memory and cognitive function. It's possible that walking a greater number of steps each day could influence these outcomes.
Another thing Janz notes is that this study only measures walking. It didn't measure things that many of us do that don't require steps, things like gardening, swimming or biking. And it's safe to assume some women in the study were doing these other things that can influence health as well.
And Janz says to remember the federal exercise guidelines call for 150 minutes per week of moderate physical activity, which includes all kinds of daily movement, not just steps.
So, if 10,000 steps has been feeling out of reach to you, it may be time reset those factory settings on your fitness tracker. Instead, try to hit at least 4,400 a day, along with daily activities that you enjoy. And stick to it.
AUDIE CORNISH, HOST:
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. Transcript provided by NPR, Copyright NPR.