My doctor has me wearing one of these things to track my sleep as part of my insomnia treatment. It hasn’t been explicitly said that I won’t get this or that med if I’m sleeping too much, or so little that the med isn’t working, but I’m pretty sure some of that is going on.
The thing is, the Fitbit jibes fairly well with my subjective experience, and I’ve even learned some things-- for example, stretches of sleep, even relatively short ones that are accompanied by vivid dreaming are the most restful, which is counter-intuitive, but it works that way.
I assume it measures sleep partly by movement, and partly by pulse rate-- and I am a very still sleeper, to the point of sleeping very safely on top bunks in the middle of a room without safety bars, or even on the third tier of narrow train sleepers; but awake, I’m fidgety. So I suppose my wearing the Fitbit all the time allows it to collect information on differences between me awake and me asleep, which is how it’s not fooled by my lying down awake.
Still, there are times I’ve been lying down tired, and I startle, and am not sure whether I’ve been actually asleep. If I check my phone (ie, the Fitbit app), it’ll tell me one way or another.
Judging also by how tired I am during the day, and how I feel at bedtime the next night, the Fitbit seems to be pretty accurate.
Can it really be as simple as motion and pulse rate? I guess sleep seems like such a profound change (especially to an insomniac), that using such simple things to measure it feels too easy. What else is going on that I haven’t figured out?
Google is failing me here-- all I get are more guesses on third party websites. Fitbit seems to be guarding its secrets.