T he idea that we need to walk 10,000 steps a day originated not in medical research but in a 1960s marketing campaign for a pedometer, says Jack McNamara, senior lecturer in clinical exercise physiology at the University of East London. The round number was easy to remember and the idea caught on, despite there being no scientific evidence for 10,000 steps as a specific threshold for health.

“When the research community looked into it, they found that there were health benefits, so it didn’t necessarily get thrown out as pseudoscience,” says McNamara.

Walking has been shown to benefit cardiovascular and cardiorespiratory health, as well as reducing the likelihood of some cancers. It also breaks up sedentary time, which is hugely harmful to health. “But when we look into it with systematic reviews and large-scale studies , there start to be diminishing returns the more steps you do.”

McNamara says the health improvement is huge when someone goes from a sedentary lifestyle, or 2,000 steps a day to 4,000.…