Sleep is composed of natural sleep cycles of brain activity, and is made up of two basic phases with individual stages within. These include rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep.
What is Non REM Sleep?
Non REM sleep occurs during the first four sleep phases, and before REM sleep, which is the final stage before the sleep cycle repeats itself. On average each stage lasts from five to 15 minutes. A typical night’s sleep is comprised of 75% non-REM sleep and 25% REM sleep.