Can Someone Explain The Sleep Stages?

[RobDude16]

My FitBit shows the following sleep 'stages':

* Deep 

* Light

* Rem

But the American Sleep Association defines:

https://www.sleepassociation.org/about-sleep/stages-of-sleep/

* Stage 1 (N1)

* Stage 2 (N2)

* Stage 3/4 (N3)

* Stage 5 or REM

Similarly - WebMD lists:

* Stage 1

* Stage 2

* Stage 3

* REM

Does anyone know how FitBit's Light/Deep sleep map to the generally accepted stages of sleep?

I tried to figure it out myself.  Wikipedia states that order should be N1->N2->N3->N2->REM

(https://en.wikipedia.org/wiki/Sleep#Non-REM_and_REM_sleep)

So I looked at my charts but they seem to largely random.  I found a sequence of

Deep->Light->Deep->Light->REM

Which seems to match Wikipedia, but I only found that pattern once in several days of sleep...and I see other patterns far more often.

REM->Light->REM

Awake->Light->REM

Light->Deep->Light->REM

Does anyone know how these map to the stages, and why FitBit has fewer stages of sleep than the medical community?

[SteveH]

I can't answer your questions but thought you might be interested in fitbit's explanation for their use of sleep stages at https://help.fitbit.com/articles/en_US/Help_article/2163/