PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -The average length of the first NREM-REM sleep cycle is 70 to 100 minutes. The second, and later, cycles are longer lasting-approximately 90 to 120 minutes (Carskadon and Dement, 2005). In normal adults, REM sleep increases as the night progresses and is longest in the last one-third of the sleep episode.

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: -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.