Fitness apps are 'doing more harm than good'
Devices and health apps that advise people to walk 10,000 steps a day could be doing more harm than good, experts warn.
Millions of fitness trackers have been sold worldwide, with the promise of monitoring and improving activity levels.
However, Dr Greg Hager, of Johns Hopkins University in the US, said many had no real evidence base and that a one-size-fits-all approach could be harmful for some people.
Dr Hager told an American Association for the Advancement of Science meeting in Boston, that the 10,000 steps doctrine was based on just one study of Japanese men in 1960.
"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'," he said.
"Is that the right number for any of you in this room? It's just a number built into the apps. I think apps could definitely be doing more harm than good."
In 2013, the UK's NHS established a Health Apps Library to provide patients with a choice of software and GPs were encouraged to recommend apps to their patients.
The University of Liverpool found just 15pc of those listed for depression were effective.
Dr Steve Flatt, of the university's psychological therapies unit, said: "This field is in its infancy and can currently be likened to the snake oil salesmen of the 1860s.
"There is every likelihood that apps will actually be very useful but unfortunately the designing and testing stages seem to have been largely missed out in the race for profits."
Simon Leigh, a health economist, said: "A GP, endocrinologist or other fitness specialist would unlikely recommend 10,000 steps for most people."
Research by the University of Pittsburgh concluded that people who used a wearable technology device lost less weight than those undertaking standard weight-loss techniques.
Dr John Jakicic said not everyone was capable of doing 10,000 steps. "If you are elderly or infirm, then this is not going to be good for you," he said.
"However, there is a place for these and so we need to be careful not to throw the baby out with the bathwater."