Healthy sleep is divided into five stage cycles.
Stages 1 through 4 are known as non-REM and stage five is classified as REM sleep (rapid eye movement). Sleep stage and type depends on your physiological and behavioural changes occurring within your body during sleep to determine sleep stage progression and
During REM sleep the brain processes and synthesises memories, emotions and activities that are crucial for learning and higher level thought.
It is important to get REM sleep. A lack of REM sleep results in slower cognitive and social processing, problems with memory, and difficulty concentrating.
REM sleep is not deep sleep. But in order to improve memory, concentration and cognition, it is important to get 90 mins of REM sleep a night.