AP PSYCHOLOGY

Detailed explanation-1: -What Is REM Sleep? Usually, REM sleep happens 90 minutes after you fall asleep. The first period of REM typically lasts 10 minutes. Each of your later REM stages gets longer, and the final one may last up to an hour.

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: -The 90-minute snooze rule is based on timing the bedtime in a way that we wake up at the end of a sleep cycle-which has 90 minutes of proper REM sleep. When you wake up in the middle of a deep sleep, we end up feeling exhausted, tired and grumpy-because we feel we did not get proper sleep.

Detailed explanation-4: -On average you’ll go through 3-5 REM cycles per night, with each episode getting longer as the night progresses. The final one may last roughly an hour. For healthy adults, spending 20-25% of your time asleep in the REM stage is a good goal. If you get 7-8 hours of sleep, around 90 minutes of that should be REM.