Understanding the stages of sleep can reveal why some nights leave you feeling refreshed while others fall short. By exploring how each stage impacts your overall rest, you’ll gain insights into how to optimise your sleep quality and wake up truly restored.
When we sleep, it is normal to think about how long we sleep. Whilst this is an important factor, it is important to think about sleep quality and whether the sleep we’re having is truly restorative. The importance of getting high quality recovery whereby both mind and body wakes up refreshed is determined by our progression through separate sleep stages.
During a typical night of sleep, we oscillate through 90 minute cycles. For someone attempting to get 8 hours of sleep, this usually equates to about 5 to 6 cycles. Each cycle is composed of four individual stages: three stages of non-rapid eye movement (NREM) sleep followed by rapid eye movement (REM) sleep. [1]
What Occurs During Each Stage:
Stage 1 (NREM): This is the lightest stage of sleep, where your body and brain start to slow down with a period of movement. It’s the transition phase from wakefulness to sleep – our lightest stage of sleep.
Stage 2 (NREM): In this stage, brain waves, heart rate, and breathing slow down further as your body prepares for deeper sleep. This stage acts as a bridge to the more restorative stages of sleep.
Stage 3 (NREM): This is the deep sleep stage. This stage is critical for the restorative benefits including immune system bolstering, contributions to creativity, and enhancement of memory. In your early sleep cycles, this stage can last 20-40 minutes per cycle, but it shortens over the night as REM sleep periods increase..
Stage 4 (REM): Making up around 20% of the entirety of your sleep, this stage consists of the ‘dream state’ due to the significant uptick in brain activity. During this stage brain activity ramps up to levels similar to those seen when you’re awake. Your brain paralyses your body to let your mind dream safely and to protect you from acting out dreams. REM sleep stimulates areas of the brain involved in memory consolidation and learning. It helps repair the brain and processes emotional experiences. Arguably the most important stage of sleep, REM is also unfortunately the most easily disrupted stage of sleep. [1][2]
Why These Sleep Stages Matter – Importance for Recovery and Health
A balance between getting enough of both deep and REM sleep is important for your body and brain as this is the period most important for daily recuperation. Insufficient sleep can therefore have profound consequences on emotions, learning, thinking and physical recovery, particularly from bouts of physical work and exercise.
Some examples that commonly affect sleep stages are:
- Age: Although poorly understood, studies suggest that sleep efficiency declines as we age. Elderly people sleep on average 36% less than infants. Older individuals experience a decrease in melatonin levels – likely due to a deterioration of the hypothalamic nuclei.
- Alcohol/Cannabis: Seen to decrease REM sleep early in the sleep cycle.
- Sleep Disorders: insomnia, jet-lag or shift work sleep disorders, sleep-disordered breathing (sleep apnea), sleep-related movement disorders (restless leg syndrome) and other conditions can cause multiple awakenings.
- Poor sleep patterns [2][3]
How to Optimise Sleep – Sleep Hygiene for Sleep Quality
1. Consistent Sleep Schedule
Keep to a consistent sleep schedule. Sounds simple, but keeping to a consistent sleep and wake timing has a profound effect on your circadian rhythm – your body’s ‘internal clock’. A system controlled by your hypothalamus. Getting natural sunlight exposure within the first hour of awakening is an effective way to start this clock and has a profound effect on how you will sleep that night.
2. Artificial Light
Avoid artificial light before sleep. Artificial light has an effect on your body’s natural melatonin release (sleep hormone).
3. Bedtime Routine
Have a bedtime routine. We train our body throughout the day, but why not train our brain to prepare for the most important period of our 24hr window?
4. Limit Sedatives
Limit sedatives such as alcohol and cannabis due to their ability to inhibit your REM cycle
5. Sleep Hygiene
Improve your sleep hygiene through an optimal sleep environment (i.e., improve pillow and mattress quality and use of your bed for its supposed purpose)
In addition to a consistent sleep schedule and the other mentioned factors, building onto other habits can improve your sleep quality. Maintaining a balanced relationship with technology and incorporating regular physical activity are crucial for improving sleep, especially for individuals who have difficulty falling asleep despite feeling tired. Engaging in moderate physical activity earlier in the day can promote better sleep, as physical exertion helps regulate your body’s natural sleep-wake cycle. Additionally, taking a warm shower before bedtime can be beneficial. A warm shower helps lower your body temperature after you get out, which aligns with the body’s natural cooling process necessary for falling asleep. This combination of exercise and a pre-sleep routine can enhance your overall sleep quality.
Impact of Diet on Sleep
What you eat and drink can have a big impact on your sleep. Caffeine, found in coffee, tea, and some sodas, can make it hard to fall asleep and diminish sleep quality if consumed too close to bedtime. Similarly, heavy or rich meals, especially those high in fat or protein, can cause discomfort and disrupt your sleep.
To improve your chances of a restful night, it’s best to steer clear of sugary or caffeinated drinks in the hours before you go to bed. Instead, consider a cup of herbal tea, like chamomile or lavender, which can help you relax and prepare for sleep.
Another tip is to use calming scents as part of your bedtime routine. For instance, a lavender-scented pillow case might help signal to your brain that it’s time to wind down. Just make sure to use these scents consistently during relaxation times to avoid creating any negative associations that could interfere with your sleep.
About the Author:
Yuma Hemphill
Osteopathic Manual Practitioner
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References:
[1]. Sleep Doctor. Stages of Sleep: What Happens in a Sleep Cycle. Published December 8, 2023. Accessed August 30, 2024. https://www.sleepfoundation.org/stages-of-sleep
[2]. Institute of Medicine (US) Committee on Sleep Medicine and Research; Colten HR, Altevogt BM, editors. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington (DC): National Academies Press (US); 2006. 2, Sleep Physiology. Available from: https://www.ncbi.nlm.nih.gov/books/NBK19956/
[3]. Ancoli-Israel S. Sleep Research Society. SRS Basics of Sleep Guide. Westchester, IL: Sleep Research Society; 2005. Normal human sleep at different ages: Sleep in older adults; pp. 21–26.