The different stages of sleep

What goes on when you shut your eyes.

Going to sleep seems such a simple thing, but it's actually a complex and vital part of our lives.

We spend a third of our lives sleeping, yet we put such little effort into understanding what we are doing while we sleep through the night. So let us delve a little deeper into the stages of sleep and how these stages will affect you. 

There are four different stages to our sleep. 

The first 3 Stages of sleep are NREM sleep. NREM means non-rapid eye movement. 

Dozing off

Stage 1: The first step to sleep, more commonly known as "Dozing off", typically takes 1-5 minutes. During this stage, your body won't be fully relaxed. It is easy to wake someone in this stage of sleep, but if left undisturbed, they quickly move into stage 2. The brain's activity starts to slow a little in this stage and shows light changes inactivity.

Slowing down

Stage 2: During the first sleep cycle, this typically lasts 10-25 minutes. Each stage 2 can last up to 60 minutes and typically gets longer every time you enter this stage. Around half of our sleep time is spent in the second stage. During this stage, the heart rate and breathing slow, muscles relax, and body temperature drop. Brain activity slows down and shows a new pattern. Eye movement also stops.

Going deeper, getting creative

Stage 3: This stage is known as the deep sleep stage. It is hard to wake you up at this stage during the early start of sleep. We spend approximately 20-40 minutes in stage 3 sleep. This time gets shorter as sleep continues as more time you spend in REM sleep. The body relaxes further in this stage, meaning muscle tone, breathing and heart rate decrease. Studies show this stage of sleep is vital for restoration, allowing growth and recovery of the body. The current thinking is that stage 3 sleep may strengthen the immune system and other crucial processes in the body. During stage 3 sleep, your brain activity reduces; however, evidence shows that this stage of sleep contributes to memory, creativity, and insightful thinking. This stage of sleep is also known as SWS (short-wave sleep) sleep because the brain has an identifiable delta wave pattern.

Rapid eye movement

The final stage of sleep is known as REM sleep. During sleep, you won't typically enter REM sleep until 90 minutes after you enter sleep. The REM stage gets longer as the night's sleep goes on. First, REM sleep can only last a few minutes, but this stage can last up to an hour as the night goes on. REM sleep makes up around a quarter of sleep time. During this stage of sleep, dreams are often more intense, and although dreams can occur at any stage, they are more common and vivid. Studies believe that REM sleep is essential to things such as learning, creativity and other cognitive functions. Brain activity picks up during this stage and is close to the level of being awake. The body experiences a temporary paralysis of the muscles, other than the muscles for breathing and the eyes. Even though your eyes are closed during stage 4 sleep, your eyes will move quickly hence why stage 4 sleep is known as REM.

Why are the stages of sleep so important?

So, why are these sleep stages critical? They are essential because they allow the brain and body to develop and recover. Failure to obtain the last two stages can show adverse effects on thinking, emotions and physical health. People with insomnia may not get enough time in each stage, and those who wake often will not have the chance to cycle through these sleep stages fully. Insomnia results in sleep that does not leave the body feeling refreshed.  The lack of proper sleep will not give the body the time needed to recuperate.

Many things could affect sleep stages, such as:

• Age: as our age changes, so does our time in each stage. Babies spend more time in REM sleep than adults; however, older people spend a lot less time in REM sleep.
• Alcohol: Alcohol can mess with our body and not allow us to sleep in REM sleep early on into the night. As the alcohol wears off, the body has a REM sleep rebound, trying to make up for the lack of REM sleep at the start of the night.
• Sleep disorders: Those such as Restless Leg Syndrome and Sleep apnea can affect the cycle because they cause wakeups and disturbances during the night. 
• Recent patterns: If someone lacks sleep for many days, this will negatively affect the cycle. 
• Light, if your environment is too light. Try a sleep mask (affiliate link) to improve your sleep quality.

In conclusion, the sleep stages are critical because the body can repair and recover from the day. The mind also has time for cognitive growth, creativity and memory. To have a disturbed night means the body and mind aren't at its full potential.`