Sunday, November 23, 2014

10,000 Steps a Day: Where Did That Number Originate?

Image by Giovanni. Creative Commons. 
Ten thousand steps a day.

If you've used a modern activity tracker from companies like Fitbit or Jawbone, you probably noticed that the default goal is 10,000 steps per day. I've been curious about the history of this recommended number because I test and write about fitness trackers as part of my job.

Why 10K?
While I haven't pinpointed the source exactly, an abstract of a paper published in the journal Sports Medicine in 2004 points to popularity of the number in Japan since the mid-1970s.

Pedometers in the U.S. at that time probably also promoted 10,000 steps as the goal. But it wasn't until the mid 1990s when a non-profit organization called Shape Up America! suggested making 10,000 steps a benchmark in the U.S. That's the same time the U.S. Surgeon General issued a report on the nation's health and our lack of activity.

Since then, it seems as if more and more studies have tried to quantify a ballpark figure for the minimum amount of activity a person needs to get in a day to maintain general health and wellness. I wonder how much the public is now primed toward 10,000 steps.

How Many Steps Make a Mile?
Another popular estimate or benchmark that you'll find is the number of steps an average person takes in a mile: 2,000. In other words, the recommended minimum activity translates to walking five miles cumulatively in a day. I've used a click counter to see whether the estimate is correct. I walked on a treadmill for one mile at a natural pace a little more than 3 mph (I've done this experiment more than a dozen times). I register one click once for every other step so that at the end of the mile, I double the number to see how many total steps it takes me to walk one mile. I learned that I take between 1,930 and 2,100 steps, which closely lines up to the average.

Note that all the recommendations that cite 10,000 steps aren't saying you must walk five miles, but rather take a minimum of 10,000 steps in the course of the day. That means you can count all the puttering you do around the kitchen, walking from your desk at work to the bathroom, and so forth. In other words, the message isn't to try and reach some far-flung goal like going for a five-mile jog or walk each day, which would be very difficult for unfit people, but rather to be up and on your feet more frequently and for longer stretches of time. The idea is that all that little activity adds up.

What Should We Really Be Measuring?
I'd love to see other variations on this same number, such as the percent of time in a day spent sitting or standing still, versus being up and moving. Would it be 80 percent to 20 percent?

Or what would it be if we thought about the total number of minutes a day we should be moving? I imagine 10,000 steps came about in part because it is an easy number to remember, but also because it came of age in the era of pedometers when steps is the metric that was measurable.

What I like about modern "pedometers" or fitness trackers is that they collect more data and allow you to become more intimate with your personal readings. I think a better way to find a goal is to look at your own activity on your worst day of the week and set a goal to beat that number consistently, based on other information you know about yourself. For example, if your data say your least active day saw only 3,000 steps, but your average day has you at 8,000 steps, a good goal might be to first his 8,000 consistently, and then eventually exceed it by 15 percent.

Really smart activity trackers either adjust this goal for you automatically or provide some guidance to help you do it, but the important thing is for the user to start to become aware of how much she or he walks.

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