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Sleep – The Science of Sleep and 10 tips to Sleep Longer and Deeper

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Sleep is an innate component of the human experience; we must spend approximately ⅓ of our time sleeping and restoring in order to live more fully during the other ⅔ that we are awake! 

Unfortunately, in today’s world driven by long hours, work pressure, social commitments, and ‘busy culture’, sleep is usually the first thing to go from our overflowing lives! Although this may seem like a time-efficient option, it is certainly not a healthy or productive option! Foregoing sufficient sleep considerably compromises the quality of the time we spend awake, with research indicating lower moods, energy and concentration, as well as higher risks of certain acute and chronic illnesses, and even a shorter lifespan in those who do not get enough sleep!

‘He that can take rest is greater than he that can take cities’ 
-Benjamin Franklin

 

More than one third (35.2%) of the adult population experience insufficient sleep, while research has found that 73% of high school students regularly do not get a healthy amount of sleep (1). Prevalence of obesity and certain chronic illnesses (such as diabetes, arthritis, depression) are also higher in those who do not achieve sufficient sleep (2). Let’s learn more about the science of sleep, why these increased risks occur, and what we can do to achieve a longer and deeper sleep for optimal health and happiness!

Science of sleep:

Two main processes are responsible for regulating our sleep: 

1. Circadian Rhythms: Controlled by a master clock in the brain, circadian rhythms are the 24 hour fluctuations in our hormones and bodily processes related to sleep. In response to certain environmental cues (light, temperature, food, stress), our circadian clocks either increase or decrease levels of melatonin – our sleep hormone. For optimal sleep and wake cycles, melatonin levels should be low during the day and high in the evening and at night while we sleep. As the evening rolls around and the sun goes down, our eyes sense the lack of light and send a signal to our circadian clocks in the brain. This signal ramps up melatonin production, which helps us feel tired and go to sleep. When the morning light comes (specifically blue-light wavelengths), melatonin levels are triggered to drop and we instead experience a healthy rise in cortisol, which promotes daytime energy and alertness (3).  

2. Sleep drive: As the day goes on and we spend more hours awake expending energy, our bodies craving for sleep continues to build. At the same time, a neurotransmitter known as adenosine is also gradually accumulating. When a certain point has been reached, we need to sleep. This is called ‘sleep drive’ (3). 

 

Side note: 3 Interesting facts about our sleep hormone Melatonin:

-Melatonin is an antioxidant: Melatonin is actually both a sleep hormone/neurotransmitter and an antioxidant. This is why people use the term ‘beauty sleep’, because antioxidants are known to fight free radical damage and improve the health of our skin, as well as our cardiovascular system and other bodily processes (4). 

-Happiness is needed for sleep: Serotonin (our ‘happy hormone’) is actually a precursor to Melatonin. Therefore, we need to experience a certain level of happiness in order to have the ability to accumulate enough melatonin for healthy sleep (5).

-Stress and sleep oppose each other: Our sleep hormone melatonin experiences an opposing rhythm to our ‘stress hormone’ cortisol. We can basically consider melatonin and cortisol to be on a seesaw: when one is high the other is low. Although we do need healthy levels of cortisol for energy, metabolism and other processes, excess cortisol is associated with stress. If we are still stressed in the evening, our cortisol levels remain unnaturally elevated, which means that our melatonin levels are unable to rise as needed for healthy sleep (6).

 

Sleep Cycles:

While we sleep, the brain continuously cycles through two major types of sleep: non-REM (non rapid-eye movement) sleep and REM sleep:

1. Non-REM sleep: This cycle is composed of four stages:

          -First stage: Between being awake and falling asleep

          -Second stage: Light sleep. During this time, heart rate and breathing regulate and body temperature drops. 

          -Third and fourth stages: Deep sleep. The more restful and restorative phase of sleep, and the most important stages for consolidating memory and learning. 

2. REM sleep: As we cycle into REM, brainwaves are most similar to being awake, the eyes move rapidly behind closed lids, respiratory rate increases and the body becomes temporarily paralysed as we dream.

This cycle takes about 90 minutes and continues to repeat  for about 4-5 rounds until we wake. However, we spend less time in the deeper stages of sleep (stages 3 and 4) and more time in REM sleep with each cycle. (7)

 

Importance of Sleep:

Throughout history, many believed sleep to be a passive activity during which the body and brain were inactive. We now know this couldn’t be further from the truth! Sleep is an essential function that allows our whole systems to recharge, heal and optimise. Sleep promotes waste removal from the brain by revitalising the function of the cerebral cortex and producing cerebrospinal fluid (CSF), which helps flush out toxins from the brain. Sleep is also essential for “brain plasticity”- the brain’s ability to adapt to input (8). In other words, if we don’t get enough sleep, we struggle to understand and remember new information. Sleep is vital to the rest of the body too; those who regularly don’t get enough sleep are at a higher risk of experiencing depression, obesity, seizures, high blood pressure, migraines, illness and infections. Lack of sleep also affects us in our short term day to day lives:

Memory and cognition: A lack of sleep significantly compromises learning, comprehension, focus, memory and work performance. 

Mental health: Sleep insufficiency can lead to damagingly high levels of stress hormone cortisol, which can negatively impact our mood, and lead to symptoms of depression, anger, anxiety, irritability and inability to cope with stress (9). 

Weight management: A lack of sleep disturbs the ‘discipline’ part of the brain, and also increases our hunger hormone ghrelin and decreases the satiety hormone leptin that tells our bodies we are full. Just one night of sleep deprivation has been shown to significantly impact our hunger and eating patterns! (10)

Ageing: Sleep deprivation has been shown to age us from both the inside and out (i.e. our physical appearance and brain function). Lack of sleep has been shown to age our skin by compromising collagen levels, which is the fibre needed to maintain skin integrity and health (low melatonin= high cortisol= less collagen) (4). Research also shows that the brain can age by as much as 7 years in middle aged people who regularly get less than 6 hours of sleep a night!

Others: Without sufficient sleep, we experience slower reflexes, lower immunity, hormonal disturbances, and certain physical symptoms such as general tiredness, sore eyes and headaches. 

 

10 tips to sleep deeper and longer: 

1. No screens before bed: Avoid looking at any electronic devices or artificial light (i.e. phone, laptop, TV etc.) 1-2 hours before bed in order to promote sufficient melatonin levels. Research has shown that as little as 1 hour of screen time at night can drop our levels of melatonin all the way down to those seen through the day, making it almost impossible to fall asleep and achieve deep sleep (11).

2. Reduce blue light exposure later in the day: Our melatonin levels begin rising in the evening, therefore reducing our exposure to blue-light in the afternoon will assist this process. Use blue light blocking glasses and change the settings on your computer/phone to automatically block blue light each evening. 

3. Sunlight in the morning: Exposure to sun (even just fresh air if it is cloudy) when we first wake up helps to support our natural rise in cortisol, which in turn promotes healthy circadian rhythms through the day, leading to high levels of melatonin at night (12). 

4. Go to sleep and wake up at roughly the same time each day: This technique provides us with the opportunity to significantly regulate our circadian rhythm, which then regulares and optimises both energy levels and sleep quality. Give yourself a window of about an hour for when you will wake up every day and when you will fall asleep every day. For example, wake between 6-7am every day and sleep between 10-11pm every day.

5. Do not eat after dark: Food is a major factor that influences circadian rhythms. Our pancreas (an organ that releases digestive enzymes) contains melatonin receptors and has its own smaller circadian clock. Therefore, eating after dark hinders not only our sleep, but also our ability to digest food and absorb nutrients.

6. Exercise: Physical activity helps to regulate cortisol (stress hormone), and therefore raises melatonin at night. It is best to exercise in the morning when we first wake up, as this is the time that cortisol naturally peaks. Ensure strenuous exercise is completed at least 4 hours before sleep- this allows cortisol levels enough time to drop so that we can experience optimal shut-eye. 

7. Have a bath: A bath is not only relaxing, it also mimics the natural body temperature changes that occur when we fall asleep. This therefore sends a signal to our brains that we are tired, promoting earlier sleep onset. 

8. Breathing exercises: Enjoy some breathing exercises (such as box breathing), a meditation practice, yoga flow, or something else of the like to promote a necessary drop in cortisol levels and a healthy rise in melatonin levels. 

9. Avoid the Booze: Although alcohol is a depressant that slows reflexes, reduces inhibitions, and can make us feel drowsy/sleepy, alcohol actually compromises sleep quality. Research shows that consuming alcohol significantly decreases time spent in restorative and REM sleep.

10. Herbal Medicine: A number of herbal medicines contain natural constituents that enhance sleep by targeting sleep hormone levels, stress, anxiety, sedation and more. These may be enjoyed as a tea or a supplement before bed. Some examples include: Passionflower, Valerian, Hops, Lavender and Melissa. It is best to speak to your Naturopath or Holistic Practitioner to determine which remedies best suit you. If taking medication, check with your doctor. 

BONUS TIP: If you wake through the night, spend about 20 minutes trying to fall back asleep. If unsuccessful, get out of bed and do an activity that involves your hands (such as colouring, knitting, construction, cooking, cleaning etc.). Research shows this to be the fastest and most effective way to fall back asleep. 

Sleep your way to better health, happier moods, higher productivity and a longer, more vibrant life!

 

References:

https://www.sleepfoundation.org/how-sleep-works/sleep-facts-statistics

https://www.cdc.gov/sleep/data_statistics.html

https://www.sciencedirect.com/science/article/pii/S0896627315001312

https://link.springer.com/article/10.1385/ENDO:27:2:137

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/otherendo/pineal.html

https://www.nature.com/articles/s41598-019-54806-7

https://www.sleepfoundation.org/how-sleep-works/stages-of-sleep

https://www.sciencedirect.com/science/article/pii/S0898656819302165

https://ajp.psychiatryonline.org/doi/abs/10.1176/appi.ajp.161.8.1404

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2869.2008.00662.x

https://journals.physiology.org/doi/abs/10.1152/japplphysiol.01413.2009?rss=1

https://journals.sagepub.com/doi/abs/10.1177/074873001129002178

https://onlinelibrary.wiley.com/doi/abs/10.1111/acer.12006

https://www.hopkinsmedicine.org/health/wellness-and-prevention/up-in-the-middle-of-the-night-how-to-get-back-to-sleep