Wearable devices are pre-programmed with 10,000 steps as the daily goal. Picture: 123RF/MARIDAV
Wearable devices are pre-programmed with 10,000 steps as the daily goal. Picture: 123RF/MARIDAV

It’s a number that has entered the mythology and lexicon of fitness advice: the idea that you should take 10,000 steps daily for optimum health. It has become the benchmark of wearable devices that are preprogrammed with 10,000 steps as the daily goal.

Discovery Health gives 50 Vitality rewards points for anything from 5,000 to 9,999 steps. Points double to 100 — and stop — once your wearable shows that you hit 10,000.

But is there any science behind it?

New US research in the Journal of the American Medical Association (Jama) suggests that it’s most likely a thumb-suck.

The researchers at the Harvard Medical School affiliate, Brigham and Women’s Hospital, trawled through data from the enormous Women’s Health Study. They found a more likely “sweet spot” for the number of steps to take for your health’s sake. Their data showed that for older women, as few as 4,400 steps daily was significantly associated with lower risk of death compared with 2,700 steps. Benefits appeared to “plateau” at about 7,500 steps daily.

But just where did 10,000 spring from?

The researchers suggest its origins are in the 1960s, when a Japanese clock company started marketing a pedometer called Manpo-kei. In Japanese, that translates to “10,000 steps meter”.

In other words, 10,000 is a nice, round number but not scientific.

The same applies to the “10,000-hours rule”: that to become an elite athlete you must do 10,000 hours of dedicated practice.

Dr Habib Noorbhai, senior lecturer and biokineticist at the University of Johannesburg, talks about that rule in his memoir, Heart (self-published, 2017). Whoever dreamt it up did so on the basis of 2,000 hours a year for five years, 170 hours a month or about 40 hours a week, says Noorbhai, a former Mr SA (2017).

Other precedents

He says it’s just another example of experts quantifying one aspect (duration, in this case) without “meticulously considering the many factors and determinants that contribute to the uniqueness of the individual and success”.

There are other precedents for mixing marketing and semantics instead of solid science to produce lifestyle advice.

The “five a day” fruit and vegetable exhortation is also plucked out of thin air. British public health researcher Dr Zoë Harcombe once told me that whoever thought it up probably did so because five is a “memorable number — the same as the digits on one hand”.

Presumably, five makes it easy for people to count and remember portions of fruit and veg daily.

Another sign that five a day is hopelessly unscientific is its variability across more than 25 countries. A Canadian study suggested that three daily servings are sufficient. The US National Cancer Institute advises five a day but wants Americans to eat nine a day. The Japanese government tops that with a 13 a day recommendation.

The Jama study is limited and looked only at older women. And the researchers aren’t saying you shouldn’t do 10,000 steps. They just don’t want you to think the number is written in scientific stone.

Noorbhai reminds us that there’s no one-size-fits-all prescription for fitness or any other kind of success.