viernes, 3 de abril de 2020

Number of steps per day more important than step intensity | National Institutes of Health (NIH)

Number of steps per day more important than step intensity

At a Glance

Adults who took 8,000 or more steps a day had a reduced risk of death over the following decade than those who only walked 4,000 steps a day.
Step intensity (number of steps per minute) didn’t influence the risk of death, suggesting that the total number of steps per day is more important than intensity.

Walking is a free or low-cost way of getting physical activity. You don’t need special equipment, clothing, facilities, or training. gradyreese / E+ via Getty Images

Doctors often recommend walking as an easy way for inactive people to ease into better health. Taking 4,000 or fewer steps a day is considered a low level of physical activity. A goal of 10,000 steps a day is commonly cited, but recent studies have shown that health benefits accrue even if fewer than 10,000 steps are taken daily.

Past studies have mostly been done in older adults. It hasn’t been clear what number of steps or intensity are needed to benefit adults of other ages.

A research team with investigators from NIH’s National Cancer Institute (NCI) and National Institute on Aging (NIA) and the Centers for Disease Control and Prevention (CDC) looked at the association between step count, intensity, and risk of death in a broader range of the U.S. population. They used data on physical activity collected by a national health survey, the National Health and Nutrition Examination Survey (NHANES), between 2003-2006. The study was published on March 24, 2020, in JAMA.

The team used data from people aged 40 or older who wore an accelerometer—a device that measures step number and cadence (steps per minute)—during their waking hours for a week. Researchers then collected information on deaths for about a decade. They also tracked deaths specifically from cancer and heart disease.

In their analysis, the researchers compared the risk of death over the follow-up period among people who took fewer than 4,000, up to 8,000, or 12,000 or more steps a day. They also tested whether step intensity, measured by cadence, was associated with better health.

During the decade of follow-up, 1,165 out of the 4,840 participants died from any cause. Of these, 406 died from heart disease and 283 died of cancer.

Compared with people who took 4,000 steps a day, those who took 8,000 steps a day at the start of the study had a 50% lower risk of dying from any cause during follow-up. People who took 12,000 steps a day had a 65% lower risk of dying than those who took only 4,000.

Higher step counts were also associated with lower rates of death from heart disease and cancer. These benefits were consistent across age, sex, and race groups.

Step intensity did not seem to impact the risk of mortality once the total number of steps per day was considered. Only an increased number of steps per day was associated with a reduced risk of death.

“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,” says first author Dr. Pedro Saint-Maurice of NCI.

The findings are consistent with current recommendations that adults should move more and sit less throughout the day. But because this study was observational, it could not prove that increased physical activity caused a reduced risk of death. Higher step counts also may reflect people who were in better health to begin with, which could potentially influence the results.

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viernes, 3 de abril de 2020