May 2023 | Eurobio

Sleep is a critical part of our lives, and it is important for us to understand the sleep cycle to ensure that we are getting enough restful sleep. On average, every adult gets less than seven hours of sleep every night. Therefore, good sleep hygiene will ensure we feel refreshed and recharged and well rested for the next day. Poor sleep hygiene can lead to a range of negative health effects, such as daytime sleepiness, difficulty concentrating, and irritability. 

Getting enough sleep is essential for maintaining optimal health and well-being. Having good quality sleep may help to prevent a range of health issues, cope with stress and recover from illness, just like the benefits of regular exercise and a balanced diet. Even one night of short sleep can affect you the next day. Without sufficient rest, you are more likely to feel sleepy, be in a bad mood, be less productive at work and be involved in accidents. 

In this article, we will explore the different stages of the sleep cycle, what happens during each stage and how to develop a healthy sleep cycle. 

What is sleep cycle? 

A sleep cycle is a series of events that occur during the course of a night’s sleep. Over the course of the night, there are several rounds of the sleep cycle, which typically compose of four individual stages.  

What are the stages of sleep?

To understand how we sleep, first we have to understand the sleep cycle. Our body cycles through two phases of sleep: the rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. NREM is further divided into three stages, which are N1-N3 respectively. Each phase and stage of sleep includes variations in muscle tone, brain wave patterns and eye movements. The sleep cycle typically lasts around 90 minutes, and we go through four to six cycles of NREM and REM sleep each night. 

• Stage 1

  During the N1 stage, our brains begin to relax and everything starts to slow down, including your eye movement and muscle activity as we transit from wakefulness to sleep. This stage lasts for only 5-10 minutes. 

• Stage 2

  N2 stage is where we spend the majority of our sleep time. During this period of light sleep, our brain activity and heart rate slows down, eye movement stops and body temperature drops as our body prepares itself into the deep sleep phase. During this period our muscles are experiencing periods of muscle contraction and muscle relaxation.  

• Stage 3 

  This last stage of NREM sleep is also known as the deep sleep stage. During deep sleep, our brain produces very slow brain waves, with no eye movement and our muscles relax completely. It is very difficult to wake someone up while they are in the deep sleep stage, and if we are awoken, we may feel disoriented for a few minutes. This is the most restorative stage of sleep.
  During these three NREM sleep, our body repairs and regenerates tissues, builds muscle and bones and strengthens the immune system. 

• Stage 4 

  The final stage of the sleep cycle is REM sleep, which is characterized by rapid eye movements and vivid dreams. During this stage we will experience rapid eye movement, our brain activity increases again with less deeper sleep and is associated with intense dreams. Our major muscles that control our arms and legs become temporarily paralyzed to prevent us from acting out our dreams. REM sleep is believed to be important for memory consolidation and emotional regulation. 

What affects our sleep stages and sleep quality? 

Sleep is affected by both internal and external factors. Poor sleep quality will result in sleep deprivation and will have a negative impact on our health, even if we are getting long hours of sleep.  

Several factors can affect the different stages of our sleep cycle and also our sleep quality. These factors include: 

• Stress

  Stress is a common culprit in sleep deprivation as stress will cause people to worry and have difficulty relaxing which ultimately keep them awake throughout the night. 

• Mental health issues

  People with mental health issues will suffer from nighttime anxiety and these anxious thoughts can prevent them from falling asleep. Mental health issues might also lead to more disturbing dreams or nightmares, making it a problem for them to stay asleep as well. 

• Physical pain

  Pain, especially back pain and neck pain while lying down can be uncomfortable and disrupt sleep quality. The pain may also cause you to wake up at night.   

• Lighting

  Lights, either natural daylight or artificial lights can affect sleep quality because light signals our body that it is time to be awake while darkness signals that it is time for our body to rest. Exposure to lights at the wrong time will affect our normal circadian rhythm, which is our body’s internal clock, thus affecting sleep quality. 

• Poor sleeping environment

  Our sleep quality will be affected by poor sleeping environments such as noise, unfavorable temperature and lack of comfort. 

• Medications and substances 

  Certain medications that are used to treat illnesses may affect sleep quality as they may cause insomnia. Some substances such as caffeine, alcohol and nicotine, can interfere with sleep patterns and the different stages of our sleep cycle. 

How to have a healthier sleep cycle? 

To have a healthier sleep cycle, first we have to practice good sleep hygiene. Sleep hygiene refers to the practices and habits that promote healthy sleep patterns and help individuals to get a good night’s rest.  

Good sleep hygiene practices include: 

• Establishing consistent sleep patterns by going to bed and waking up at the same time every day, even on weekends. This can lead to a better sleeping quality as it helps to regulate our body’s internal clock. Plan bedtime and wake-up time and stick to that every day. 
• Creating a comfortable sleeping environment by ensuring the room is dark, cool and quiet can help reduce distractions and promote relaxation. 
• Avoid certain activities and substances that can interfere with sleep. Avoid taking caffeine and alcohol before bedtime, and avoid using electronic devices such as mobile phones and tablets to promote better sleep quality. 
• Regular exercise can help to reduce the time it takes to fall asleep. However we should avoid strenuous physical activity late in the evening. 
• Establishing a relaxing bedtime routine. Relaxing activities such as taking a warm bath, reading a book or listening to soft music can help in relaxation and prepares the body for sleep.

The sleep cycle is a complex series of events that occurs and repeats during the course of a night’s sleep. By understanding the different stages of the sleep cycle, we can prioritize good sleep hygiene habits to ensure that our body and mind receive the restorative benefits of a good night’s sleep. 

Sometimes, it may be difficult for you to fall asleep due to stress and worries about work, family or other issues.  There are some supplements that may help you to relax, to help you get better sleep.  It is best to get advice for a healthcare professional if you think you need help with improving your sleep quality, or if you continue to have trouble falling asleep or staying asleep that it has interfered with your daily activities and ability to perform tasks.  

A good quality sleep can have a positive impact on our physical and mental health. We can feel more energized, focused, and productive throughout the day when we get enough restful sleep each night. So prioritize having good quality sleep is very important for our overall well-being. 

Reference

• Centers for Disease Control and Prevention. (2022, September 19). Are you getting enough sleep? Centers for Disease Control and Prevention. Retrieved May 5, 2023, from https://www.cdc.gov/sleep/features/getting-enough-sleep.html  
• MediLexicon International. (n.d.). Why is sleep important? 9 reasons for getting a good night’s rest. Medical News Today. Retrieved May 8, 2023, from https://www.medicalnewstoday.com/articles/325353
• Zwarensteyn, J. (2022, December 16). 12 factors affecting sleep and your sleep quality. Sleep Advisor. Retrieved May 3, 2023, from https://www.sleepadvisor.org/sleep-factors/#:~:text=Sleep%20is%20affected%20by%20both,and%20alcohol%2C%20and%20certain%20foods.