It can be difficult to stay motivated when trying to get fit or lose weight, but being rewarded for every step you take could make things a little easier.
That's the thinking behind the Sweatcoin app.
It tracks the number of steps using the iPhone's built-in sensors and uses 'complex software' to make sure people aren't cheating.
It then rewards them with a digital currency called 'sweatcoins' that can be redeemed with select retailers.