A Step Too Far?

Summer has, unofficially, arrived here in the United States, and as a result, there are more opportunities to be more active. For those of us who wear step trackers — FitBits, Apple Watches, etc. — that means it’ll be easier to hit that daily goal of 10,000 steps. That number has permeated public consciousness; as the Guardian points out, “in recent years, the 10,000-steps-a-day regime has become entrenched in popular culture” and as a result, “an entire industry has been built on the claim that 10,000 steps a day were necessary to be healthy.”

But: the 10,000 step goal isn’t really based in science — at least, not to that specificity. So where’d the 10,000 step goal come from? Perhaps it’s a visual pun.

In 2019, Dr. I-Min Lee, an epidemiologist and professor at the Harvard School of Medicine, led a team of researchers hoping to determine where one’s step goal should really be set. Dr. Lee’s paper, available here, address the question somewhat narrowly, asking “if increased numbers of steps per day associated with lower mortality rates among older women.” The results suggested, as you’d expect, that the more steps, the better. But the 10,000 number didn’t make an appearance:

In this cohort study of 16,741 women with a mean age of 72 years, steps per day were measured over 7 days. Women who averaged approximately 4,400 steps/d had significantly lower mortality rates during a follow-up of 4.3 years compared with the least active women who took approximately 2,700 steps/d; as more steps per day were accrued, mortality rates progressively decreased before leveling at approximately 7,500 steps/d.

While not core to her research, Dr. Lee also wanted to know where that 10,000 steps-per-day number came from. There wasn’t much, at least from the world of scientific research, to help answer that question. Other studies have shown similar results — more exercise is better (obviously!) but there’s nothing remotely magical about that 10,000th step according to research reviewed by the American Council on Science and Health.

But Dr. Lee discovered another source — the number almost certainly came from a team created one of the first personal pedometers. “It turns out the original basis for this 10,000-step guideline was really a marketing strategy,” she told the Atlantic. “In 1965, a Japanese company was selling pedometers, and they gave it a name that, in Japanese, means ‘the 10,000-step meter.’”

Why 10,000 though? The fact that it’s a nice, round number, of course, had a lot to do with the appeal of the number — but there’s likely more to the story than that, according to Dr. Lee. As Marketwatch explains, in 1965, the Yamasa Clock and Instrument Company “wanted a snappy name for a new pedometer and hit on ‘Manpo-kei.’ [ . . . ] which “translates, literally, as ‘10,000-steps meter.'” And the Japanese character (pronounced “man”) for the number 10,000, looks like this:

If that looks to you a little bit like a pair of legs moving forward, you’re not alone. The Atlantic continues: “based on conversations she’s had with Japanese researchers, Lee believes that name was chosen for the product because the character for 10,000 looks sort of like a man walking.” For Yamasa Clock, the number 10,000 wasn’t just a round number-goal — it was a literal, but imprecise, picture of health.

Bonus fact: Earlier this year, a Connecticut judge allowed for Fitbit data to be used as evidence in a murder trial. Slate explained why: “Connecticut resident Richard Dabate was charged this month with the felony murder of his wife, Connie. One day in December 2015, Richard called 911 and told police that a man had broken into the couple’s home, shot Connie, and tied Richard to a chair. The only problem was, at a time when Richard claimed Connie had already been shot by the intruder, her Fitbit was tracking her movements.” Connie, according to the Fitbit data and “local surveillance footage” was at the gym when her husband claimed she was dead in their home; she later turned up dead in their home. 

From the Archives: Walk This Way: Synchronized walking.