Peaks

Peaks are the times where a particular sleep stage is either the only one that can appear, or is more likely to appear in higher quantities. Reducing schedules make use of this to increase sleep efficiency.

REM

During REM peak, sleep phases are extremely efficient and so one should be placed here. Read more at REM.

SWS

Napping is very hard during this peak due to difficulty waking up; read more at SWS.