Importance of Sleep and Its Stages

When we shut down for the day and go to sleep, a lot is going on in the body and brain from physical restoration to memory consolidation to dreaming.

Once you sleep, your brain cycles through four sleep stages which play an important role in ensuring a restful night's sleep. Spending hours tossing and turning at night while attempting to sleep is unpleasant, disruptive, and utterly frustrating. Along with sleep quantity, sleep quality is also essential. The ability to progress through different stages of sleep defines whether you are getting enough rest or not.

Before jumping to the sleep cycle stages let's understand.

What is the sleep cycle?

Sleep is not consistent. Instead, your total sleep during the night is made up of several rounds of the sleep cycle, which is made up of four individual stages. On a typical night, a person goes through 4-6 sleep cycles. All sleep cycles may not have the same length but last for approximately 90 minutes. Nighttime eye ice masks, Neck Pillow are the best choice for a good sleep when you are traveling, Pick the suitable one for you from the Apollo Pharmacy, online or in-store. 

Sleep Types:

Our brain repeatedly cycles through distinct types of REM and non-REM sleep in a specific order. Of course, I will explain what it means further.

REM sleep represents rapid eye movement and is associated with dreams and the body’s reactions and responses to them. It lasts for 90 minutes to 2 hours.

Non-REM sleep represents non-rapid eye movement and consists of three phases, from getting drowsy to the period of deep sleep that is needed to replenish energy for the next day. It consists of 3 stages based on the analysis of brain activity during sleep, which shows distinct patterns that characterize each stage. Each stage lasts for around 5-15 minutes.

4 Stages of the Sleep Cycle:

Stage 1: It is also called N1, which is essentially when a person first falls asleep. This stage normally lasts only for 1-7 minutes.

In this stage, your body and brain activities start to slow down with periods of brief movements. There are slight changes in brain activity linked with sleep. It is easy to wake up someone during this sleep stage. As the night unfolds, an uninterrupted sleeper may not spend much more time in this stage.

Stage 2: It is also known as N2 when the body enters a more subdued state. The first sleep lasts for 10-25 minutes and becomes longer with each sleep cycle during the night.

You will observe a drop in temperature, relaxed muscles, and slowed breathing and heart rate during this stage. Your brain slows down activity and stops eye movement.

Stage 3: During the N3 stage, it is harder to wake someone up if they are in this phase. It commonly lasts for 20 to 40 minutes during early sleep cycles and as you continue sleeping, this stage gets shorter.

This stage is also known as deep sleep where muscle tone, pulse, and breathing rate decrease as the body relaxes even further. The brain activity during this period shows an identifiable pattern. Experts believe that this phase is essential for restful sleep, and allows the body to recover and grow. It also supports the immune system and other important bodily processes.

After this stage, you slowly set forth into REM sleep and start dreaming.

Stage 4: During the REM stage, your brain activity speeds up so much that brain scans make it appear like you're awake. Your heart rate, blood pressure, and breathing also speed up. As your eyes dart from side to side, your muscles and body are paralyzed. The most vivid, and story-like dreams occur during REM sleep as if the brain is thought to be replaying emotional content.

What affects sleep stages?

Age: Newborns usually enter in REM stage as soon as they fall asleep for a longer period while adults tend to spend less time in REM sleep.

Drug Abuse: Antidepressants, sleeping pills, and alcohol damage your regular sleeping pattern. It decreases REM sleep early in the night.

Disorders: Sleep apnea, restless legs syndrome, neurodegenerative disorders like Parkinson’s disease and other conditions cause multiple awakenings that interrupt a healthy sleep cycle.

Though you cannot control your sleep cycle, improve your chances of making healthy progress through each sleep stage. And the important step is to focus on improving your sleep hygiene which is associated with your sleep environment and sleep-related habits.

References:

1. Stages of Sleep available at https://www.sleepfoundation.org/stages-of-sleep
2. Does Melatonin Cause Vivid Dreams? available at https://ur.life/article/does-melatonin-cause-vivid-dream
3. What are REM and Non-REM Sleep? Does it cause nightmares? available at https://healthlibrary.askapollo.com/what-are-rem-and-non-rem-sleep-does-it-cause-nightmares/