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Does step count really matter? New study links number of steps to mortality

"Adults should aim to move more, sit less, and take more steps."

Physical activity is undeniably good for your health, and plain old walking remains to be one of the easiest and cheapest ways to keep fit. Exactly just how much walking is thought to be optimal for your health, however, has been a point of contention for years.

New research published Tuesday in the Journal of the American Medical Association may help guide the way — and dismisses “10,000 steps” as a hard-and-fast rule. This study found that walking between 8,000 to 12,000 steps per day is a smart choice for your health — a finding that suggests that it's generally being active that induces positive effects.

The infamous “10,000 steps” rule is often touted as the gold standard for exercise, but it’s also a ripe source of debate. The decree upholds that the optimal number of steps to hit every day is 10,000 – but the science that backs it up is little-to-none.

Its conception can be traced back to the 1960s in Japan when it was devised as a marketing tool to promote the release of a new pedometer. Since then, it remains the default setting on the majority of fitness trackers — despite the criticism over its one-size-fits-all approach, and the dearth of evidence to support 10,000 steps specifically.

Debates over what exact number of steps is best aside, studies have consistently shown that walking more is better for your health and wellbeing. This study provides further support — and associates higher daily step counts with lower all-cause mortality.

Walk more, live longer

The researchers used a sample of 4,850 US adults aged 40 years and over in the National Health and Nutrition Examination Survey who wore accelerometers for up to 7 days between the years of 2003 and 2006. Using something called the National Death Index, they then tracked the participants for mortality through 2015.

Across the board, higher step counts were tied to a longer life, says study author Pedro Saint-Maurice, a researcher at the National Cancer Institute’s Division of Cancer Epidemiology and Genetics. He tells Inverse that the benefits associated with higher step counts were maintained across demographics, sexes, and age groups.

In turn, the researchers found that taking 8,000 steps a day was associated with a 51 percent reduction in risk of all-cause mortality when compared with hitting just half that number. When the step count was stretched to 12,000 steps, the risk decrease shot down a further 14 percent when compared against 4,000 steps. The research team also found a link to lower rates of death from cancer, as well as cardiovascular disease.

The research was a joint effort by the National Cancer Institute (NCI), National Institute on Aging (NIA), and Centers for Disease Control and Prevention (CDC).

Why there is no perfect number of steps

The team also controlled for some potential confounding factors — mainly sociodemographic and lifestyle — that may have swayed the results, such as age, race, ethnicity, diet, smoking, BMI, and education. Regardless, their findings held.

An interesting – and surprising – finding of the study is that the researchers didn’t find a link between step intensity (how fast you’re walking) and a decrease in mortality.

This suggests that there’s a chance that power walking isn’t going to extend your lifespan – something that has long been thought to be the case. The authors do acknowledge, however, that more studies exploring this relationship are needed to conclusively disprove this.

"It's important to emphasize that optimal activity is not 'one size fits all.'"

One thing to note is that this study relied on observational data only, Saint-Maurice cautions, and that association doesn’t prove causation. These results should be taken with a grain of salt, for now, Saint-Maurice says.

He also makes clear that there is no perfect number of steps.

It’s important to emphasize that optimal physical activity is not ‘one size fits all’ — different people may have different needs depending on their age, chronic disease status, or other factors, and may need to consult their primary care doctor for further guidance,” Saint-Maurice explains.

Boiled down, Saint-Maurice advocates that “as their health allows, adults should aim to move more, sit less, and take more steps per day.”

More studies are needed to establish a formal recommendation about how many steps a person should aim to get each day, Saint-Maurice says. Until then, he and his colleagues hope this study gives people a helpful frame-work for their health. This new study is another addition to the mountain of research that indicates walking is a surefire way of improving your health — and perhaps, extending your life.

Partial abstract:
Importance: It is unclear whether the number of steps per day and the intensity of stepping are associated with lower mortality.
Design, setting, and participants: Representative sample of US adults aged at least 40 years in the National Health and Nutrition Examination Survey who wore an accelerometer for up to 7 days ( from 2003-2006). Mortality was ascertained through December 2015.
Conclusions and relevance: Based on a representative sample of US adults, a greater number of daily steps was significantly associated with lower all-cause mortality. There was no significant association between step intensity and mortality after adjusting for total steps per day
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