This feature is a total waste of time. It does not track sleep. I go to bed at the same time. I read for 15 minutes until my eyes get sleepy, then I drop off to sleep. Fitbit, however, does not BEGIN to track my sleep until an hour after I stop moving. Then, whether or not I awaken, if i move AT ALL, It logs no sleep. I often get 3 hrs of sleep period for a night, because If I should happen to roll over before midnite, it ends my sleep for the entire night. It is a waste to use this feature for any information on your sleep quality, as Fitbit has no idea whatsoever. I used to have a Fitbit one back in 2010. That device did track actual sleep.