What’s so sacrosanct about the 10,000-step goal?

 What’s so sacrosanct about the 10,000-step goal?

 

Of late, I have been thinking about this popular exhortation to achieve the 10,000 step daily goal. Maybe it is the coming together of multiple sporting events (the Olympic Games begin today), or maybe it’s just my idle mind, deprived of social stimuli. In any case, what bothers me most is the apparent precision of the goal. Why not 7,500 (which in any case is well beyond an average person’s activity level), or 8,000? Is it our collective preference for round numbers? (10,000 is considered more “round” than 8,000). Is it okay to take a few steps below this magic number? What about a few thousand steps more? The lay press, citing reputed researchers, would have us believe that between 7,000 and 8,000 steps a day lies the proverbial “sweet spot”. The implication being that anything more or less than this, can cause you harm. And conveniently, this also plays nicely into that popular trope, of “moderation” being the best thing in life. So, where does the truth lie? In order to arrive at this, let’s first delve into the origins of the “10,000-step” goal. I am certain that you’ll find it both entertaining and revealing. At least, I did.

 

Lost in translation

My first instinct was to link the number to Malcolm Gladwell’s popular 10.000-hour prescription for developing expertise, which he popularised in his 2008 book Outliers. (https://en.wikipedia.org/wiki/Outliers_(book)) I thought that perhaps the 10,000-step goal was an apophenic extrapolation from the realm of prescriptions for success. Never mind that Gladwell may have actually got it wrong, but that is a story for another post. Or maybe, unbeknown to me, there are 10,000 steps to Shaolin glory, like the fabled 36 chambers. But my brief foray into the exercise literature revealed something far more interesting. In a 2004 paper, one of the leading researchers on physical activity, Catrine Tudor-Locke, throws light on the possible origins of the 10,000 figure. (https://doi.org/10.2165/00007256-200434010-00001) It seems that walking clubs became popular in Japan, around the time of the 1964 Olympic Games in Tokyo. And in 1965, the Yamasa Corporation (Tokyo, Japan) marketed a pedometer under the name of manpo-kei. When literally translated into English, it was taken to mean “10,000 step meter”. But anyone, who has watched Bill Murray’s struggles in Lost in translation, will realise that literal translations from the Japanese can be quite misleading. It seems that the character man (万), in manpo-kei can mean “10,000”, “a million”, “lots”, “myriad”, etc. depending on the context. For example, it is used in the Japanese word for a fountain pen (man’nenhitsu), which literally translated reads, “a 10,000 (or million) year writing brush”. Readers who know Japanese may correct me if I am wrong, but my own feeling is that the character man (万) in manpo-kei, carries the same connotation as the “100” in the phrase “May you live a 100 years”. I am sure everyone will agree that here the intention is to wish for a long life in general, not a prescription for a precise 100-year life-span. It simply amazes me that at least a whole generation of researchers (lay persons can be forgiven) have uncritically taken up the “10,000-step” goal as a starting point representing optimal physical activity. Round number preference aside, our tacit endorsement of the 10,000 figure highlights the perils of a world view that is so singularly Anglo-centric.

 

How many steps to salvation?

That brings us to the question of how many steps a day bestows health benefits. It gets tricky here because, we have to rely on the differences observed among a wide range of people, who go through their (equally wide range of) daily activities, and draw inferences from how they fare in the long-run. Epidemiologists call these observational studies. Ideally, researchers would perform randomised experiments that allocate people to different activity levels, and see what happens in the long-run. But that is only possible with mice, other small animals, and college students (it seems they can be convinced to go to a lot of trouble for surprisingly little cash; college students, not the mice!). And these experiments can only be run for very short periods of time, for obvious reasons. So we are stuck to drawing conclusions from observational studies, with all their inherent biases. It’s easy to understand that left to their own devices, people would be active to different extents, influenced by several well-known factors (such as wealth, health-consciousness, education level, and health state), and a number of other unknown ones. Unhealthy individuals, for instance, would be less active, and would also be more likely to die. But they exercise less (and unfortunately die) because they are unhealthy, not the other way around. The other knotty issue relates to when and how the quantum of activity should be measured. If we were to measure activity levels at the beginning, would it hold true for the entire duration of a study, which may often run for years? Now, it is possible, to an extent, to correct for the effects of some of these known issues, and most studies do so. But it would of course be impossible to “adjust” for the effects of factors and influences that we don’t know about. Different studies may therefore yield different results. And hence we have this surfeit of mixed messages.

 

Reports in the lay press, citing recent research, tell us that 8,000 steps (or even 5,000) a day may be enough to substantially reduce our risk of dying. Anything beyond that, we are told produces little added benefit (and may even cause harm), and by implication, not worth the effort. (https://www.nytimes.com/2021/07/06/well/move/10000-steps-health.html) While I understand that the idea is to encourage the very sedentary to become just a little more active, it runs the risk of lulling a sizeable proportion of active people into curtailing their activity in the interests of that lazy generalisation called “moderation”. The “harm” with greater activity is possibly an artefact of measurement. In general (you’ll have to trust me on this), the more activity you accumulate over your lifetime, the better-off you will be in the long run. With no (practically breachable) upper limit. (https://doi.org/10.1007/s10654-020-00707-3) That of course doesn’t mean that everyone should start training for a marathon from tomorrow. Some may be comfortable just walking for half an hour a day, and some others may enjoy a 10 kilometre run.

 

So, dear reader, the 10,000-step goal is simply a misunderstanding, the result of an egregious translation error. It has no scientific basis. The truth is, the more active you are, the better off you will be. You don’t have to surpass some arbitrary threshold of activity to start reaping benefits. But that doesn’t mean that you should not push yourself just that little bit, get out of your comfort zone. Just as you would, to get better at something you love to do. In keeping with the spirit of the Japanese manpo-kei, may you endeavour to take many, many steps in your day!