AP PSYCHOLOGY

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: -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.

Detailed explanation-3: -An average sleep cycle lasts about 90 minutes. Ideally, you need four to six cycles of sleep every 24 hours to feel fresh and rested. Each cycle contains four individual stages: three that form non-rapid eye movement (NREM) sleep and one rapid eye movement (REM) sleep.

Detailed explanation-4: -During sleep, we experience two alternating types or states of sleep over an 8-hour time period: NREM sleep and REM sleep. The cycle repeats itself every 90 minutes. NREM or Non-Rapid Eye Movement includes 4 stages of sleep.

Detailed explanation-5: -A full sleep cycle takes about 90 to 110 minutes. Your first REM period is short. As the night goes on, you’ll have longer REM sleep and less deep sleep.