Usually we go through four stages of sleep: 1, 2, 3, Non Rapid Eye Movement (NREM) and Rapid Eye Movement (REM). These stages typically begin at 1 through to REM, then starts again at Stage 1. Each of these different stages serve a different purpose and understanding why each one is important, can help you identify how to deal with any sleep-related issues. Below is a breakdown of each stage.
This is the lightest stage of the NREM sleep, where you drift from being awake to being asleep and can easily be disrupted causing awakenings. It doesn’t last very long at all, and you may start to relax, dream or even twitch. You are still hearing things and have a sense of awareness; your brain thinks it is asleep but it’s actually not, it’s just making the transition into Stage 2.
Oh yeah, and you know that thing that happens when you think you’re about to fall and suddenly jerk yourself awake? This is a muscle spasm (they tend to happen more often when your body is tired) and happens while you’re drifting from Stage 1 to Stage 2.
This is a more defined stage of NREM sleep, where you are still in a light sleep but drifting into a steadier sleep and where awakenings aren’t as easy as Stage 1 and the slow moving eye rolls start to discontinue. Your body temperature begins to decrease, your muscles relax, and your breathing and heart rate slows down. This is the part where there’s a lot of body maintenance going on, and where your brain waves are less active.
Actually, although stage 2 is just light sleep, it is very important to the sleep cycle as it takes up more than half the night.
This stage is also known as NREM sleep. It is quite difficult to awaken someone in this stage, and random awakenings or arousals are rare. During deep sleep, your breathing, heartbeat, body temperature, and brain waves reach their lowest levels and your muscles are extremely relaxed.
The thinking parts of the brain are mainly offline, and your body goes through healing, where tissue growths and repairs take place; hormone growths and cellular energy is restored and the body does a lot of rebuilding, repairing and strengthening of the immune system. You are most likely not dreaming at all during this stage, as your body is working.
Also known as Rapid Eye Movement, is most commonly known as the dreaming stage. Your first REM cycle of the night usually begins around 90 minutes after you fall asleep and then recurs every 90 minutes after this. REM sleep is quite the opposite to Stage 3. During REM sleep, the brain does more work and the body is pretty much inactive, almost paralyzed to prevent you from actually acting out your dreams.
You are most likely to dream at this stage, and your eyes move rapidly behind your eyelids from side to side, and your brain waves are more active than stages 2 and 3. Heart rate increases and your breathing becomes more irregular. You are more easily awaken during this stage, but being woken up can leave you feeling overly sleepy or moody.
Your body goes through multiple cycles of these stages throughout the night, and how long it stays in each stage, varies. Each cycle lasts an average of 90 minutes, but this again varies from person to person.