Is 10,000 steps a day good for you?

My guilty pleasure is Quora, which I dip into if a question intrigues me. Sometimes I “archive” the more interesting topics here.

Is reaching a daily target of 10,000 steps good for you health-wise?

Sure – one of the largest studies to look at this question (using accelerometry-monitored activity) just added some evidence to this pile. Accelerometer measured physical activity and the incidence of cardiovascular disease: Evidence from the UK Biobank cohort study

The number 10,000, however, is completely artificial, as is the idea that it should be steps. Almost any amount of daily activity improves health outcomes – not just walking, not just over an hour a day. I have read that 10,000 became popular because it was part of the marketing for a pedometer in the Japanese market (where the number 10,000 is sort of a visual pun in that context). What 10,000 Steps Will Really Get You

It is common to see people try to tear down this number, or insist that it is an inadequate guideline because people should also be doing resistance exercise, or claim the “real” number is higher or lower, but it’s important to look at what question they think they’re answering when they say that.

Studies that try to address this have to choose an outcome to test – in the case of the new accelerometer-based study, that outcome was association with heart disease, and others have simply used all-cause mortality. It’s very unlikely that any of these study designs is directly measuring the “causal” element for those outcomes. For example, if runners are more likely to be hit by a car, does that mean running is dangerous? In the PLOS-published study above, did the exercise prevent heart disease, or were people who were less likely to get heart disease also more likely to enjoy exercise?

But the outcomes they test might not be the most relevant for recommending exercise in general, which can help regulate moods and sleep. No matter what you’re going to die of, you might as well be happier and better rested, right? Also, fairly modest amounts of physical ability are associated with living independently (in the sense of not needing direct assistance for activity of daily living) for longer. Prevention in Older Adults – Fundamentals – Merck Manuals Consumer Version Staying active throughout life is the best way to address this, because older adults who have already lost muscle mass have a particularly hard time adding exercise into their lives.

It is possible that there is truly an ideal, optimal exercise plan that would maximize the potential benefit of exercise in every person who followed it, but it’s more likely that individuals can benefit more than enough from any number of activities as long as they are practiced regularly, ideally daily. In meantime, the good news is that even though many studies show “more is better,” benefits are usually visible with modest amounts, too.

My answer at Quora