The fitness benchmark has surprisingly unscientific origins – yet it does contain more than a kernel of truth

The 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.

If you take a break from the gym you may lose muscle and gain fat, but it isn’t as simple as one turning into the other

‘This is not true,” says Prof Leigh Breen, a specialist in muscle physiology at the University of Leicester. But it’s a statement he hears a lot, particularly from people who have taken a long break from exercise. “They’ll often refer to the notion that their muscles have ‘softened’ or don’t feel as toned.”

The reality is that there’s no biochemistry linking the two types of tissue. Muscle and fat are distinct. “There’s no known process in the human body that would support muscle turning into fat, or vice versa,” says Breen.