How does fitbit know when we are asleep?

[Chayah]

How does fitbit know how much we sleep?  Or when we are sleeping and when we are just laying still?  How accurate is it?

[SunsetRunner]

If you have basic fitbit, you tap it 3 times to get the lights to flash that you're putting it into sleep mode...if you're lying still, asleep or not, I don't think it can tell the difference...

[Mcore]

Welcome aboard @Chayah @SunsetRunner! I was able to find a very cool help article that will help resolved any questions you might have about sleep and how it works. Click here so you can have further information.

Have a great day! 

[Nannette]

Mine is usually right on---BUT--las night I was in bed, and hubby started snoring (he does not do to this very often) and getting to the point, I did NOT get to sleep until maybe 6:30 in the morning! Slept  only 4 and a half hours (what I say), but Fit Bit HR said I went to bed and slept 1 hour and 53 minutes the first time----and then 6:15 A.M. I went to sleep and slept for over 5 hours (almost 6). What's up with that?

Moderator edit: Format

[Mcore]

Welcome to the community @Nannette! I've seen this happening to other users and what I was able to find out is that the syncing process might take a few hours to update your sleep data. Can you confirm if this is the case? Do you see your correct sleep hours from that day on your Dashboard now?

Looking forward to your reply.