AILSA CHANG, HOST:
How many steps should you take in one day? I mean, many of us have heard 10,000 is the number to aim for, but that was never based on solid science. Researchers have combed through the data and they've come up with a more accurate target. NPR's Will Stone has more.
WILL STONE, BYLINE: Scientists have made big strides in the science of step taking in recent years. Melody Ding is an epidemiologist at the University of Sydney. She says the technology for counting is everywhere.
MELODY DING: It's hard not to track it because there are so many devices, you know, like wearables, our phone. It all tells us, you know, roughly how many steps we take every day.
STONE: So when Ding set out to update the physical activity guidelines for Australia, she ended up taking on a massive review of the evidence, analyzing data from 160,000 adults on the link between their daily step count and the risk of dying, cancer, cardiovascular disease, Type 2 diabetes and dementia. Ding says they found the sweet spot hovers around 7,000 steps.
DING: The 7,000 steps tend to be the range where there seems to be diminishing return on investment for increasing more steps.
STONE: In other words, 10,000 or even 12,000 steps did not significantly reduce your health risk beyond what you'd already get from reaching 7,000.
DING: So the risk will still continue to go down for some of the outcomes beyond 7,000, but the added benefits become smaller and smaller.
STONE: Another big takeaway - they found sizable benefits for any steps above the bare minimum of 2,000. For example, doubling that to 4,000 was associated with a 36% lower risk of dying.
DING: That's message No. 1 from the study - any steps is good, even when you're at low levels.
STONE: They also checked if speed made a difference, but Ding says, here, they couldn't make any definitive conclusions. The study was published in the journal Lancet Public Health, and it echoes what Amanda Paluch has seen in her own research. Paluch is a physical activity epidemiologist at UMass Amherst. She says they've noticed age makes a difference, too.
AMANDA PALUCH: We were seeing that older adults did not seem to need as many steps compared to younger adults. So older adults older than 60, the kind of the range where we started to see that plateau was six to eight for an older adult versus eight to 10 for a younger adult.
STONE: Paluch likes this new research in the Lancet, but cautions some of the findings are preliminary because they're not yet based on many studies. Dr. William Kraus, a cardiologist and researcher at Duke, worked on the 2018 U.S. Physical Activity Guidelines. He'd love to see step count targets be included one day.
WILLIAM KRAUS: Because they're objective measures, right? Everybody has a phone now.
STONE: The current guidelines recommend at least 150 to 300 minutes of moderate-intensity exercise a week for adults. Kraus says time spent exercising or taking steps ultimately reflects the same thing - the link between health and energy expenditure.
KRAUS: Because anything is better than nothing, more is better than less. That's what the evidence says, right? So everybody wants to know how little I need to do. That is the wrong question.
STONE: Because if you aim for the high end, you will maximize your chances of getting the most benefits, even if those are incremental. And there's another reason to do extra - all that time spent in a chair. While it wasn't part of this new study, Kraus says past research shows you need to aim higher than 7,000 or even 10,000 if you spend eight hours a day sitting.
KRAUS: If you get 13,000 steps, you get the same thing as somebody who doesn't sit. Which if they don't sit, that means they're getting steps, right? If you're not sitting, you're doing something.
STONE: Though Kraus says there's nothing magic about steps. You can convert miles to swimming or cycling. Melody Ding at the University of Sydney says she likes to think of movement in the same way as diet.
DING: Just like we need a balanced, healthy diet, it's important for us to have balanced physical activity, training throughout the week as well.
STONE: Get those steps, but also make time for mobility and strength training. All of it adds up.
Will Stone, NPR News. Transcript provided by NPR, Copyright NPR.
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