>>38708380It depends on the brand. I've had two, Jawbone and a Garmin watch one. The former was incredibly accurate, you couldn't fool it. You DID have to press a button in order to tell it "hey, I'll be sleeping soon", but it would accurately know when, no matter how still you were, it'd detect when you actually fell asleep, also when you wake up. It would know you were sleeping because of your heartbeat and breathing, I think. It'd differentiate (and then show you) how long/when you were in a deep sleep and a light sleep, how much you moved, if you woke up in the middle of the night (and maybe you didn't even realize), etc.
The Garmin one was a bit shitty in comparison, it would only tell you for how long you slept and.. nothing much, really. And I think if you were REALLY still you could cheat that one. So yeah, it depends, and if anything I hope the Pokemon one is more like Jawbone.
