Many people with activity trackers strive for 10 000 steps a day. But does it really take nearly five miles (nearly 8km) daily to make a difference in longevity?
Maybe not, says new research.
The study looked at nearly 17 000 older women - average age 72. It found that women reduced their risk of dying by 41% when they got just 4 400 steps daily compared to women who only clocked 2 700 steps. The women had additional benefit up to around 7 500 steps a day, but then the risk of dying leveled off.
"Our message is not a new message: Physical activity is good for you. What's new and striking is how little you need to do to make a difference," said the study's lead author, Dr. I-Min Lee. She's a professor of medicine at Harvard Medical School and a professor of epidemiology at Harvard's School of Public Health.
Lee said the researchers don't know if the same benefits would be seen in men or younger people. But she said it's clear that people benefit from physical activity.
The average American walks about 4 000 or 5 000 steps a day, Lee said.
Lee said the researchers aren't sure where that 1 000-step daily goal came from. They suspect it was from a pedometer made by a Japanese company in the 1960s. The name of the device was Manpo-kei. Translated into English, that means 10 000-step meter.
Step fast or step slow
To get a better idea of how much activity could make a difference in life span, the researchers looked back at a large study of older women. All wore a device that measured their activity for seven days during their waking hours. The device counted steps, and also measured the pace of each activity.
Since the gold standard for number of steps is not clear, the researchers divided the women into four groups based on their average number of daily steps: 2 700, 4 400, 5 900 and 8 500.
The study's average follow-up time was just over four years. During that time, 500 women died.
The risk of dying during follow-up dropped by 46% for women in the 5 900-step group compared to the least active group.
The most active group (8 500 steps daily) had a 58% lower risk of dying during follow-up. But the benefit appeared to top off around 7 500 steps, the researchers said.
The researchers also found that the intensity of activity didn't make a statistically significant difference.
"You can step fast or you can step slow. It didn't matter," Lee said.
The study didn't look specifically at how extra physical activity might lower the risk of death since it only found an association, but Lee said that daily physical activity can improve blood pressure, blood sugar processing and cholesterol levels. Regular physical activity has also been linked to better thinking and memory skills and improved quality of life.
"I can't beat home enough the point that physical activity is good for you. Just moving around is so good for your health," Lee said.
That doesn't mean you have to go to the gym. She suggested parking your car farther away, taking stairs, getting up and moving during commercial breaks on TV, playing with your grandkids or walking a pet.
Intensity doesn't matter
Dr Traci Marquis-Eydman, an associate professor of medical sciences at Quinnipiac University's School of Medicine in North Haven, Conn. She wasn't involved with the study, but reviewed the findings, and called them encouraging.
"At least in this subset of the population, you don't have to shoot for this number that feels overwhelming. We also saw that intensity didn't matter. If you just stay active, you can reduce your mortality risk," Marquis-Eydman said. She added it would be helpful to see this research in different age groups and in men, too.
Marquis-Eydman said a step goal is easy to measure with a wearable activity tracker or a counter in your smartphone. She said future versions of physical activity guidelines might have a daily step goal instead of minutes per day.
Plus, she said, physicians could write an activity prescription for adding 1 000 steps a day each week or month. "Steps are easy to quantify," she said.
The study was published May 29 in JAMA Internal Medicine.
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