The coronavirus pandemic may have us stuck at home, but it’s still important for our long-term health that we stay physically active, including going outside for daily walks or runs when and where possible (staying at least six feet away from others, of course).
The study reports that the more steps people aged 40 and older take each day, the less likely they are to die from heart disease, cancer or any other cause over the next 10 years.
Compared to people who walked 4,000 steps per day (the equivalent of about 2 miles), those who walked 8,000 steps per day were half as likely to die within the decade, the study found.
And those who walked even more — 12,000 steps per day — were two-thirds less likely to die.
Interestingly, the intensity with which people walked — the number of steps taken per minute — did not appear to be linked to a longer life, the study also found.
“While we knew physical activity is good for you, we didn’t know how many steps per day you need to take to lower your mortality risk or whether stepping at a higher intensity makes a difference,” says Pedro Saint-Maurice, the study’s lead author and a researcher at the National Cancer Institute, in a released statement.
“We wanted to investigate this question to provide new insights that could help people better understand the health implications of the step counts they get from fitness trackers and phone apps,” he adds.
As background information in the study points out, exactly how much walking we need to optimize our health has been a matter of debate. In recent years, we’re often told that 10,000 steps (about five miles of walking for most people) should be our daily goal. That number, however, is totally arbitrary, established decades ago as a marketing ploy to help a Japanese company sell pedometers.
Still, most studies have found that higher daily step counts — just not necessarily 10,000 steps — are associated with a lower risk of early death. The current study offers further support to that idea.
How the study was done
Saint-Maurice and his colleagues used data collected from a sample of 4,850 adults, aged 40 and older (average age: 57 years), who participated in the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2006. As part of that survey, the participants had worn accelerometers — devices that track their physical activity — for up to seven days.
According to the accelerometer data, 13 percent of the participants walked less than 4,000 steps per day, 35 percent walked 4,000 to 7,999 steps, 31 percent walked 8,000 to 11,999 steps and 18 percent walked more than 12,000 steps.
The study’s participants averaged 9,124 steps per day — far above the average 3,000 to 4,000 steps most Americans achieve, according to the Mayo Clinic.
The researchers also used the National Death Index, a database of death record information, to determine which of those participants had died by the end of 2015 (an average of 10 years after the accelerometer data had been collected). That data revealed that 1,164 of the participants had died during the follow-up period. Of those, 406 had died of cancer and 283 of heart disease.
The researchers then looked to see if any associations could be found between the number of daily steps people averaged at the start of the study and their risk of death by the end of it.
Such associations were found. Compared to walking 4,000 steps per day, walking 8,000 steps per day was linked to a 51 percent lower risk of death from all causes, including deaths from heart disease and cancer.
And walking even more — 12,000 steps per day — was associated with a 65 percent lower risk of early death.
Here’s another way of looking at those findings: The mortality rate was 76.7 per 1,000 people per year for those who took fewer than 4,000 steps per day, compared to 21.4 per 1,000 for those who took 4,000 to 7,999 steps per day and 6.9 per 1,000 for those who took 8,000 to 12,000 steps per day.
These findings held even after adjusting for a long list of other factors associated with early death, such as age, diet, smoking status, body mass index, education level, mobility limitations and diabetes, heart disease, cancer, chronic bronchitis and other chronic illnesses.
In addition, the findings were consistent in men and women, younger and older adults, and across all racial and ethnic groups.
What the study didn’t find — to the researchers’ surprise — was a link between the pace at which people walked and the risk of early death. What mattered was how much the participants walked, not how fast they did it.
Limitations and implications
This was an observational study, so it can’t prove a causal relationship between the numbers of steps people take each day and their risk of premature death. Factors not adjusted for in the study might have affected the results.
Still, the findings are in line with other research on this topic — and with current public health recommendations that urge adults to move more and sit less throughout the day. Indeed, plenty of research has found that any amount of physical activity can lead to better health. A study published in 2019 reported, for example, that as little as 4,400 steps per day was associated with lower death rates — at least among women over the age of 62.
So, although the current study suggests that more steps are better, we shouldn’t lose sight of the fact that any increase in our daily physical activity is likely to be good for our health.
“Being physical active has many benefits, including reducing a person’s risk of obesity, heart disease, type 2 diabetes, and some cancers,” says Janet Fulton, one of the study’s co-authors and a researcher at the Center for Disease Control and Prevention (CDC), in a released statement.
“The main thing is to get moving for better overall health as we age,” adds co-author Eric Shiroma of the National Institute of Aging.
FMI: You’ll find an abstract of the study on the JAMA website, but the full paper is behind a paywall.