Each cycle of non - REM / REM sleep lasts about 90 minutes, and these cycles are repeated five or six times during the night, with the last one occurring just before we awake.
Iga aeglase / REM - une tsükli kestus on umbes 90 minutit ning need tsüklid korduvad öö jooksul viis — kuus korda, kusjuures viimane saabub just enne ärkamist.