A recent study suggests the 10,000 steps a day for better health advice may not be based in research:

I-Min Lee, a professor of epidemiology at the Harvard University T. H. Chan School of Public Health and the lead author of a new study published this week in the Journal of the American Medical Association, began looking into the step rule because she was curious about where it came from. “It turns out the original basis for this 10,000-step guideline was really a marketing strategy,” she explains. “In 1965, a Japanese company was selling pedometers, and they gave it a name that, in Japanese, means ‘the 10,000-step meter.’”

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. As far as she knows, the actual health merits of that number have never been validated by research.

Scientific or not, this bit of branding ingenuity transmogrified into a pearl of wisdom that traveled around the globe over the next half century, and eventually found its way onto the wrists and into the pockets of millions of Americans. In her research, Lee put it to the test by observing the step totals and mortality rates of more than 16,000 elderly American women. The study’s results paint a more nuanced picture of the value of physical activity.

“The basic finding was that at 4,400 steps per day, these women had significantly lower mortality rates compared to the least active women,” Lee explains. If they did more, their mortality rates continued to drop, until they reached about 7,500 steps, at which point the rates leveled out. Ultimately, increasing daily physical activity by as little as 2,000 steps—less than a mile of walking—was associated with positive health outcomes for the elderly women.

This sounds like a “mutant statistic” like sociologist Joel Best describes. The study suggests the figure originally arose for marketing purposes and was less about the actual numeric quantity and more about a particular cultural reference. From there, the figure spread until it became a normal part of cultural life and organizational behavior as people and groups aimed to walk 10,000 steps. Few people likely stopped to think about whether 10,000 was an accurate figure or an empirical finding. As a marketing ploy, it seems to have worked.

This should raise larger questions about how many other publicly known figures are more fabrication than empirically based. Do these figures tend to pop up in health statistics more than in other fields? Does countering the figures with an academic study stem the tide of their usage?