How Much Do Step Counts Matter?

Women who averaged about 4,400 steps each day (around 2 miles, the second quartile) had 41% lower mortality rates than those who averaged only about 2,700 steps each day (a little over a mile, the lowest quartile) over the mean follow-up period of 4.3 years, reported I-Min Lee, MBBS, of Brigham and Women’s Hospital in Boston, and colleague in JAMA Internal Medicine.

Additional steps added to the mortality effect until it leveled off at about 7,500 steps per day, according to the study which was published in conjunction with a presentation at the American College of Sports Medicine Annual Meeting in Orlando.

Intensity of the activity was not clearly associated with decreased mortality rates after considering the total number of steps each day. All the step-adjusted associations were attenuated and the majority were no longer significant:

• Time spent at a stepping rate of ≥40 steps/min: (HR 1.27, 95% CI 0.96-1.68)
• Maximum 5-minute cadence: (HR 0.80, 95% CI 0.62-1.05)
• Peak 30-minute cadence: (HR 0.86, 95% CI 0.65-1.13)
• 1-minute cadence: (HR 0.87, 95% CI 0.68-1.11)

The public is often advised to take 10,000 steps each day for health, but the origin of this figure remains unclear.

The 2018 Physical Activity Guidelines promote activity of any intensity to get people at all degrees of fitness and ages moving. The guidelines also suggest step counts can be useful for public health initiatives, recommendations, and policies.

Physicians should continue to encourage their patients to become more active as patients may benefit significantly from even modest increases in the number of steps they take each day, Lee told MedPage Today.

The steps that the study participants took were largely in daily activity rather than exercise, noted Lee. “So just step more in whatever you are doing, I’m not asking you to exercise, just step more during your day.”

This data “may serve as encouragement to the many sedentary individuals for whom 10,000 steps [per day] pose an unattainable goal,” the researchers wrote.

Beyond the long-recognized role of physical activity in reducing all-cause mortality, this investigation “basically showed that the total volume of physical activity is important rather than pattern,” commented Deepa Iyengar, MD, MPH, of McGovern Medical School at UTHealth in Houston, who was not involved in the study.

This study “needs to be replicated in larger samples, but it seems to actually go with some of the recommendations that we give, basically which is that elderly people in general need to keep themselves more active to preserve their muscle mass,” Iyengar told MedPage Today.

Lee’s group evaluated 16,741 women from the Women’s Health Study with a mean age of 72.0 years. Participants wore an accelerometer for 1 week, at least 10 hours a day, and sent it in for central analysis.

Women were excluded if they had BMIs under 18.5 kg/m², prevalent diabetes, cardiovascular disease, or cancer, or self-reported health status less than “good.”

Lee’s group admitted the limitations of the study as it only assessed all-cause mortality and was observational. “It is unclear whether our results apply to other populations who are less or more active,” they added.

Future research will assess other health outcomes using longer follow-up and larger numbers of other clinical endpoints like cancer and cardiovascular disease, the researchers indicated.