PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -Approximately 75% of sleep is spent in the NREM stages, with the majority spent in the N2 stage.[14] A typical night’s sleep consists of 4 to 5 sleep cycles, with the progression of sleep stages in the following order: N1, N2, N3, N2, REM.[15] A complete sleep cycle takes roughly 90 to 110 minutes.

Detailed explanation-2: -In a typical night, a person goes through four to six sleep cycles. View Source . Not all sleep cycles are the same length, but on average they last about 90 minutes each.

Detailed explanation-3: -Sleep cycles across the night are only approximately 90 minutes in length. There are lots of individual differences in cycle length and the variation may be from around 60 to 110 minutes.