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Ten thousand steps a day. It's the default goal on many fitness trackers and smartphone apps — and the obsessive aim of many a self-quantifier. But a new study led by Brigham and Women's Hospital researchers finds there's nothing magical about the number.
In older women, at least, it appears that longevity benefits level off at around 7,500 steps a day. So if you've been aiming for 10,000 in hopes of living longer, you just got a 25% discount. And by the way, it appears that 10,000 number was never based on scientific evidence in the first place.
There may well be other health benefits of logging as many as 10,000 steps, of course. But for anyone who finds the 10,000 goal daunting, the study's point is that even adding just a couple of thousand steps a day can bring health benefits, says Harvard Medical School Professor I-Min Lee, lead author of the study in the journal JAMA Internal Medicine.
The researchers followed more than 16,000 women whose average age was 72, and found that those who took more steps did tend to live longer, but the effect leveled off at about 7,500 steps a day. Here are lightly edited excerpts of our conversation:
What's the take-home message here?
The main take-home message is that even a small amount of physical activity can significantly benefit your health. In this study, we found that stepping a very modest amount — 4,400 steps a day — significantly lowered mortality rates compared with stepping, say, 2,700 steps a day.
And the more women stepped, the lower their mortality rates were, until about 7,500 steps a day — beyond which mortality rates did not go down but leveled off at that point. So it seemed that women who stepped 10,000 steps a day had essentially the same mortality rates as women who stepped 7,500 steps a day.
So — don't let the perfect be the enemy of the good. Just doing a little bit is helpful. Of course, individuals who want to get to 10,000 steps a day, I'll say "Go for it!" But I think for many people who are not very active, that number can be very daunting. So it's important to know that stepping a little bit more — say, an additional 2,000 steps a day — is beneficial for your health.
And it's important to note that in this study, the stepping was stepping throughout the day. It wasn't steps that were part of an intentional exercise program or walking for exercise. It was just cumulative stepping throughout the day. So any steps you do during the day will count.
Is there any reason to believe that there are health benefits if you go over 7,500 steps though? Not mortality benefits but health benefits?
Great point. When we say that the benefits leveled at 7,500 steps a day, I have to add a couple of caveats. First, we found this in older women who are not very active and who didn't step a lot. So findings may differ in a younger population or a more active population.
Secondly, we only looked at mortality in this population, and clearly whether you die or whether you live is not the be-all and end-all of health. There are many other aspects to look at, and we hope to continue studies in these women to look at important things as you grow older: your functional health, your quality of life, your cognitive outcome, and also the development of other chronic diseases. So it's not clear that you would not get additional benefit beyond the 7,500 steps a day for these other endpoints.
What's our best understanding of how 10,000 steps became this iconic number that everybody aims for?
When I looked for the basis of this 10,000 steps goal, it's interesting to see that it originated not based on any scientific evidence. It appears it originated in 1965 in Japan from a company that made pedometers, and the trade name for that pedometer was "Manpo-kei," which in Japanese means "10,000 steps meter." So from that, I think, it sort of evolved into our popular use, our popular lore.
And clearly, if you can do 10,000 steps you will have benefits to health, but that number can seem so large for someone who is not active. So I'm very appreciative of this study's findings that very modest amounts, much less than the 10,000 steps, can be beneficial for health.
Is there any data that shows that the goal of 10,000 steps actually discourages people?
We don't have any formal studies showing that this 10,000 step number discourages people. But anecdotally, if you talk to people and if you look at the number of steps that individuals get in the U.S., we are actually not very active. The average number of steps in the U.S. is about 4,000 for women and 5,000 for men. So if you want to get to 10,000, that's more than doubling it for women. And I think for most people that idea can be very discouraging.
And you found that the health benefits seemed to start at around the average, right? So in effect, you're saying to all the average people, it looks like there are significant benefits from doing just somewhat more.
That's correct. The average in the U.S. is 4,000 to 5,000. And we found that this level significantly reduced mortality rates. But remember, there's another big pot of people who are far lower than that. So among the people who are below that, if you can just get up to that 4,000 or 5,000 level, that is great.
You're presenting these findings at the American College of Sports Medicine in Orlando. How do you anticipate your colleagues there will receive them?
At other conferences, you see people dressed in suits. Here, people come in running gear and biking gear. They're probably thinking, "Oh, 4,400 steps a day, that is nothing!" But I would say there is a significant group here whose job it is to promote physical activity, and I think these people will be very appreciative, because they work with individuals who might be very overweight, or very inactive. And to be able to tell these individuals that look, you can get health benefits, just do an additional 2,000 steps — they'll find that message very encouraging.
And in terms of the study itself, what sets it apart? Is it a first or a most?
This is one of the first studies that has looked at the actual number of steps rather than increasing physical activity. So I think it tells us that a modest number of steps can reduce your mortality rates.
The second thing is that it's the first study to look at the stepping intensity, meaning if you step faster versus if you step slower, does it matter? And we found that it didn't matter once you accounted for the total number of steps that they took during the day. Meaning if you looked at two individuals with the same number of steps, it didn't matter whether they stepped fast or stepped slow, it was the number of steps that drove the relation.
Having said that, I need to add the caveat that the women in this group were not very active, and there wasn't a lot of fast stepping in these women.
That does seem to contradict past findings that the speed of your walking could indicate the state of your health...
Good point. There are a lot of studies on walking pace, but walking pace is different from the step counts in this study. So walking pace is what you do when you're intentionally walking for exercise or walking for transportation. Here, the stepping intensity refers to your average best natural effort throughout the day. So it's what you do throughout the day. Not just when you're intentionally walking for exercise or transportation.
So more than anything it's just kind of a reflection of how active you are generally?
Correct. It's how much you move during the day.
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