�����ƽ��

How many steps for better health?

Research has found that walking can bring many health benefits. FatCamera / E+ via Getty Images

Walking is one of the most popular ways to get more physical activity as an adult. It’s free, easy to get started, and you can fit it into your day any time you want.

Wearable technologies like smartphones and watches can help you track how may steps you take each day. Many of these devices recommend a goal of 10,000 steps for better health. But that goal may sound like a lot to some people. The average number of steps for the U.S. population is between 4,000 and 5,000 steps a day. Inactive people may get only 2,000 steps a day or less.

To investigate how many steps are needed to gain health benefits, a team led by Dr. I-Min Lee at Brigham and Women’s Hospital and Harvard Medical School analyzed the daily activity of almost 17,000 women with an average age of 72 years. They then tracked deaths among the women from any cause for more than four years. The research was supported by NIH’s National Cancer Institutes (NCI) and National Heart, Lung, and Blood Institute (NHLBI). Results were published online on May 29, 2019, in JAMA Internal Medicine.

Participants wore a device that measures acceleration, called an accelerometer, on their hip while they were awake for seven days. Researchers measured the number of steps the women took each day and how fast these steps were (steps/min).

More than 500 of the women died over the course of the study. Those who took around 4,400 steps per day had a 41% lower risk of death (mortality) during the study than those who took 2,700 steps. This risk continued to decrease until about 7,500 steps, when the effect leveled off.

Step intensity wasn’t linked to lower mortality. In fact, most of the women walked slower than what’s considered moderately intense walking.

“Taking 10,000 steps a day can sound daunting. But we find that even a modest increase in steps taken is tied to significantly lower mortality in older women,” Lee says. “Our study adds to a growing understanding of the importance of physical activity for health, clarifies the number of steps related to lower mortality, and amplifies the message: Step more—even a little more is helpful.”

The design of the study couldn’t rule out the possibility that the women’s stepping patterns were affected by other health factors that also influenced mortality—although the researchers did adjust for many of these. Additional studies are also needed, with more diverse participants, to explore how widely applicable these findings are and how step patterns affect specific health conditions.

—Tianna Hicklin, Ph.D.