Everyone sleeps. All humans, all mammals, almost every living creature experiences a state of solitude and rest. Sleep is divided into two distinct states known as non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM). These two states occur in a roughly 90 minute cycle which is repeated 5 to 6 times a night and include four stages of NREM and REM. NREM sleep is the sleep from which REM sleep emerges. There are stages that introduce our psyche into the dream state which we begin to dream. There are approximately 5 stages of sleep that you slowly develop into, with the first stage taking only a couple of minutes to enter, and kick starts the first sleep cycle. Stage 2 is the main gateway that allows our brain to process into the next three stages and our brain waves become very active that they eventually reach REM sleep.
Before reaching REM cycle, you most commonly reach stage 3 and 4 which can be also called Delta sleep, where the brain dramatically slows down activity. This is achieved after the first 15-20 minutes of a person falling asleep and is considered the “deepest” sleep cycle. After sleeping within the delta sleep, the brain begins to pick up movement and engagement again which caused REM sleep. REM sleep or Rapid Eye Movement is when there is rapid eye movement, accelerated heart rate and respiration, and muscle relaxation. REM sleep is the fifth and last stage of sleep that occurs in the sleep cycle, which repeats itself about five times throughout a period of sleep REM sleep is the stage of sleep in which dreaming takes place and is thought to allow for the organization of memories and the retention of learning.