Sleep Stages you need to know

Have you ever experienced that sometimes you wake up easily during sleep, and at other times you don't wake up even if someone calls you?
It’s related to your sleep stage.
What is Sleep Stage?
There are two basic types of sleep: rapid eye movement (REM) sleep and non-REM sleep (NREM). Each one is associated with specific brain waves and neuronal activity. You cycle through all stages of non-REM and REM sleep several times during a typical night.

-NREM sleep is composed of three different stages. The higher the stage of NREM sleep, the harder it is to wake a person up from their slumber. In the NREM phase, your heartbeat and breathing slow down and your muscles get relaxed. Brain waves become slower.

-REM sleep first occurs about 90 minutes after falling asleep. Your eyes move rapidly from side to side behind closed eyelids. Mixed frequency brain wave activity becomes closer to that seen in wakefulness. Your breathing becomes faster and irregular, and your heart rate and blood pressure increase to near waking levels.

How important the sleep stages are?
“Why do I not feel well rested after sleep?” Some people may have this doubt.
This problem also lies in your sleep stage. The important restorative work happens during deep sleep (stage 3 of NREM) and REM sleep.

Deep sleep is crucial for physical renewal, hormonal regulation, and growth. Without deep sleep, you’re more likely to get sick, feel depressed, and gain an unhealthy amount of weight.

In REM sleep, the brain processes and synthesizes memories and emotions, which is crucial for learning and higher-level thought. A lack of REM sleep results in slower cognitive and social processing, problems with memory, and difficulty concentrating.

Sleepers who are frequently awoken during earlier stages, such as people with sleep apnea, may struggle to properly cycle into these deeper sleep stages. People with insomnia may not get enough total sleep to accumulate the needed time in each stage.

What Affects Sleep Stages?
Since sleep stages are so important to us, is this possible to have longer deep sleep and REM?
There may be significant individual differences based on a number of factors:
  • Age: Time in each stage changes dramatically over a person’s life. Newborns spend around 50% time of their sleep in REM sleep. And elderly people tend to spend less time in REM sleep.
  • Exercise: Vigorous exercise can increase or consolidate deep sleep. Some sleep specialists recommend aerobic activities like jogging, running, and swimming.
  • Recent sleep patterns: If a person gets irregular or insufficient sleep over a period of days or more, it can cause an abnormal sleep cycle
  • Alcohol and some other drugs: Alcohol decreases REM sleep early in the night.
  • Sleep disorders: Sleep apnea, restless leg syndrome (RLS), and other conditions that cause multiple awakenings may interrupt a healthy sleep cycle.

So due to objective reasons such as age, sleep cycles are difficult to control, but for the sake of our health, you can take steps to improve your healthy progress through each sleep stage, such as achieving a more consistent sleep schedule, avoiding alcohol before bed, and eliminating noise and light distractions.
Besides, if you find that you have excessive daytime sleepiness or suspect that you may have a sleep disorder, such as sleep apnea, it is important to talk to your doctor who can most appropriately direct your care.

1., National Institute of Neurological Disorders and Stroke (NINDS). (2019, August 13). Brain Basics: Understanding Sleep, September 27, 2020
2., Why Sleep Is So Important, Anne Field, Harvard Business, Review, January 14, 2009
3,, How do dream affect sleep, Danielle Pacheco, Sleep Foundation, March 18, 2022
4., Stages of Sleep, Eric Suni, Sleep Foundation, July 8, 2022
5., Sleep Doctor: Sleep Disorder Specialist, American Sleep Association

Copyright © 2022 BMC. All rights reserved.
>Legal Statement
>Cookies Notice
go top