Fitness trackers and step counting apps that advise people to walk 10,000 steps daily may be doing more harm than good, an expert has claimed. Dr Greg Hager, professor of computer science at John Hopkins University, said many apps and devices often use a one-size-fits-all approach in encouraging users to reach 10,000 steps, but few are actually based on scientific evidence and provide reasoning for the minimum limit.

"Some of you might wear Fitbits or something equivalent, and I bet every now and then it gives you that cool little message 'you did 10,000 steps today'," Hager said at the American Association for the Advancement of Science annual meeting in Boston, The Independent reports. "But why is 10,000 steps important? What's big about 10,000?"

Hager said the figure came from the 1960s in Japan when they found an average Japanese man walking 10,000 steps burnt about 3,000 calories.

"But is that the right number for any of you in this room? Who knows?" Hager argued. "It's just a number that's now built into the apps."

Among the roughly 165,000 healthcare apps that promise to improve mental health, fitness, disease diagnosis, etc, Hagar said "very few are science-based".

"We have an incredible number of apps in the wild basically being downloaded by people who may or may not understand what they are actually telling them or what the context for that is," Hager said. "Until we have evidence-based apps you could amplify issues.

"I mean, imagine everyone thinks they have to do 10,000 steps but you are not actually physically capable of doing that, you could actually cause harm or damage by doing so. Without any scientific evidence base, how do you know that any of these apps are good for you? They may even be harmful."

In September last year, a study by the University of Pittsburgh published in the Journal of the American Medical Association (JAMA) found that fitness trackers did not help users help people lose weight. Lead author John Jakicic said these trackers "may give people somewhat of a false sense of security that they don't pay attention to some of the key behaviours that they otherwise might to pay attention it".

Hagar said that in many ways the 10,000 steps example "typifies" the problem.

"We all know that probably the more you exercise, the better it is for you," he said. "But if you are elderly or infirm then this is not going to be good for you."