Fitness trackers, from Apple Watches to Fitbits, are everywhere now. And a lot of those trackers sing a magical little song when you hit 10,000 steps on a given day. But this number is totally made up! The number was devised by a Japanese pedometer company as a marketing stunt to promote their device, and the number has since become canon. If you believed you need to walk 10,000 steps a day, don’t worry. There are plenty of other health and diet myths out there.