You’ll typically complete 4 to 6 cycles per night. The first 3 stages, part of the first phase, are called non-REM sleep (N1 through N3). The final stage and second phase is REM. Stage N1 is the ...

A sleep cycle starts with N1, which is the first stage of light sleep and only lasts a few minutes. This is the stage when ...

But there are also subsets of non-REM sleep (N1, N2 and N3) as we move from light to deep slumber. It's within the NREM stage that the scientists made their discovery. “Non-REM sleep is when the ...

Three independent experts examined the recordings and scored five separate sleep stages (waking, N1, N2, N3 and REM sleep), whose different staging models were then trained for automated scoring.