24 September 2021

Just Keep Walking

Welcome back. As important as it was, perhaps last week’s blog post endorsing exercise was too much for some, especially referencing the 2016 European Guideline of at least 150 minutes/week of moderate intensity or 75 minutes/week of vigorous activity, or some combination (Time to Get Active). By the way, that’s also the current guideline of the American Heart Association.

If it was too much, you could just take a walk.

How Many Steps?
If you were following this blog in 2015, you might recall a two-part, guest blog post on walking to stay fit by a then-recently retired elementary school principal in Ontario, Canada (Stepping into Fitness, Part 1, Stepping into Fitness, Part 2).

When her fitness began to ebb with retirement, and her entire wardrobe seemed to have mysteriously shrunk, she was ready for a change. For Christmas, her son gave her a wristband monitor to encourage her to walk regularly and record the number of steps on her computer or smartphone.

The newly retired school principal (in red) with members of a local walking club (from Stepping into Fitness, Part 1).

She adopted the goal of 10,000 steps per day, roughly 5 miles. In the 1960s, Japan’s pedometer companies and walking clubs were promoting 10,000 steps daily as a way to achieve fitness. At the time of her writing, the American Heart Association was also recommending 10,000 steps for improved health and decreased risk of heart disease. Should 10,000 steps be your goal?

Recent Findings on Steps and Intensity
To help you decide, I’ll summarize the findings of three studies.

National Cancer Institute researchers led a study published in 2020 that assessed the associations of daily step counts and intensity (cadence) with all-cause mortality.

A representative sample of 4840 U.S. adults (mean age 56.8; 54% female) wore accelerometers to count steps for a mean of 5.7 days. Over a mean follow-up of 10.1 years, there were 1165 all-cause mortality deaths. The rate of deaths fell with increased steps--64% of those who took fewer than 4000 steps/day, 28% of those who took 4000 to 7999 steps/day, 11% of those who took 8000 to 11,999 steps/day, and 9% of those who took at least 12,000 steps/day.

All-cause mortality vs steps per day among U.S. adults age 40 or older (from jamanetwork.com/journals/jama/fullarticle/2763292).
There was no significant association between step intensity and mortality after adjusting for total steps per day.

All-cause mortality vs steps per day among U.S. adults by age (from jamanetwork.com/journals/jama/fullarticle/2763292).
University of North Carolina investigators led a team that conducted a study presented at a 2021 American Heart Association Conference.

The researchers analyzed daily steps, walking patterns and all-cause mortality of 16,732 women (mean age 72; mostly white, non-Hispanic) who had worn a waist step counter for 4 to 7 days. Each participant’s steps were divided into: (1) bouts of walking 10 minutes or longer with few interruptions and (2) short spurts of walking during regular daily activities. Over a mean follow-up of 6 years, there were 804 deaths.

The researchers found:
- Each initial increase of 1000 steps/day over no daily steps had 28% fewer deaths.
- Exceeding 2000 steps/day in uninterrupted bouts had 32% fewer deaths.
- Participants who took more steps in short spurts lived longer regardless of how many steps they took in longer, uninterrupted bouts; however, the short-spurt benefits leveled off at about 4500 steps/day.

A University of Massachusetts investigator led a research team in the most recent assessment of steps/day and all-cause mortality.

Steps and intensity of 2110 participants (mean age 45.2, 57.1% female, 42.1% Black) were monitored with an accelerometer for 7 days; 72 participants died during the mean follow-up of 10.8 years.

Grouping steps/day as low (fewer than 7000), moderate (7000-9999) and high (10,000 or more), the team found the risk of all-cause mortality associated with low steps/day to be 28% greater than with moderate steps/day and 45% greater than with high steps/day. There was no association of step intensity with mortality.

Wrap Up
I was surprised that step intensity--how fast one walks--is not associated with mortality; but other studies have also found that any level of physical activity, regardless of intensity, is associated with a substantially lower risk of death.

How many steps should you walk? Do what you can, knowing that more steps per day, all at once or in shorter spurts, could improve your health and help you live longer. Be well and thanks for stopping by.

American Heart Assoc. fitness guidelines: www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults
National Cancer Institute led study in JAMA Network Open: jamanetwork.com/journals/jama/fullarticle/2763292
Univ. of North Carolina led study presented at American Heart Assoc. Conference: newsroom.heart.org/news/taking-more-steps-daily-may-lead-to-a-longer-life
Univ. of Massachusetts led study in Jama Network Open: jamanetwork.com/journals/jamanetworkopen/fullarticle/2783711

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