isMainSleep = false characteristics

[sieberts]

It was my understanding that Fitbit only captured naps (here I'm assuming isMainSleep = false is a nap) that were at least 1 hour in length and not the longest sleep period of the day. It was also my understanding that sleeps > 3 hours in length would be scored as Stages, while those 1-3 hours would be reported as Classic.

However, some of our data conflicts with this understanding. Could you clarify why we would be seeing naps as short as 10 minutes and some > 20 hours?

 

[Gordon-C]

Hi @sieberts 

The Fitbit devices will record all sleep records from the main sleep to naps throughout the day.  Sleep is detected through heart rate and movement.   If a user is awake but not moving and has a low heart rate, the device could think the person is asleep.  See How do I track my sleep with my Fitbit device? for more information. 

Stages sleep logs are typically recorded for sleep periods > 3 hours, while classic sleep logs are typically recorded for sleep periods < 3 hours.  In order to calculate sleep stages, we need to have enough heart rate data to determine when the user is in the various sleep stages.   The infoCode value in the sleep log response might give you more information for the reason why the type of sleep log was generated.  The logType value will also let you know why the type of log was generated.   All manual logs will always create classic sleep logs, while auto_detected logs could be classic or stages.

Naps of 10 minutes could be created.   However, I don't understand why a sleep log of 20 hours would be generated.   Was this sleep log manually created?   Was the sleep log "classic" or "stages"?   Can you match up any activity that occurred during the same time as the sleep period?