Good night, sleep tight! - Part1/2

#worldsleepday #sleepawareness #mentalhealth

In commemoration of sleep awareness month in March, this post is intended to raise awareness about sleep! Generally speaking, we all spend approximately a third of our lives sleeping. Despite that, sleep is often misunderstood and/or misconceived as unproductive or over-rated.

In English language, there are phrases that hint at the potential benefits associated to having a good night’s sleep - e.g., “sleep on it”; “sleep it off” or “beauty sleep”. All of which suggest an individual’s ability to experience a shift in state and/or awareness following a night’s sleep. It is as if sleep can perform all kinds of wonder. And we are about to realise that this may actually not be far from the truth.

In my opinion, sleep is a non-negotiable bodily function that needs to be prioritised and fiercely protected in today’s day and age where productivity is pegged to what we can do or attain in physical /material sense. The next section, detailing the wonders of sleep, seeks to substantiate this view.

Illustration depicts a koala sleeping on a tree. Fun-fact: a koala sleeps for 18-22 hours a day! So it's considered a rarity to spot a koala in action.

Benefits of sleep

We tend to think of sleep as the final chapter of the day or as a “reward” for a day well spent. What if sleep is not the last chapter? What if it is the opening chapter to your deepest healing? Instead of your body shutting down, sleep may be a sacred and necessary cleanse for your body! It seeks to balance your hormonal levels, detoxify and give your organs a chance to breathe, repair, and recalibrate for the next day. What a restorative and healing process, and a reset of sorts. With the benefits that sleep brings, it can be likened to a (slumber) party of healing, rather than boring ol’ rest.

Restoration of bodily (cellular-level) processes

Sleep restores bodily processes by replenishing proteins used by body during waking state and by helping brain recover from daily wear and tear (Cai, 1995) as well as skin cell regeneration while we are in a slumber.

Energy conservation and replenishment

The lowering of body temperature during sleep may provide warm-blooded mammals, like us, more energy to maintain a higher body temperature during waking state (Berger & Phillips, 1995).

Facilitate learning and memory retention

While we sleep, our brain consolidates the skills and information learnt during the day, “sieve” through them, try to make sense of them, and “store” them for future retrieval.

In a way, it’s like hitting the “save” button for what was learnt today, into one’s long term memory.

Immunity Booster

Research evidence supports that sleep can bolster the body’s ability to defend itself against disease-causing agents (Colinge, 1999). Consistently, there is increasing evidence (e.g., Bryant et al, 2004) that suggests sleep deprivation has detrimental effects on the immune response, indicating that sleep should be considered a vital part of the immune system and that there is a reciprocal relationship between sleep and immunity.

Regulation of emotions and stress

According to study by Goldstein and Walker (2014), one’s  ability to adequately regulate and express emotions is compromised at both a brain and behavioural level for those who were sleep deprived. In fact, studies (e.g., Vandekerckhove & Wang, 2017) showed that healthy sleep repairs adaptive processing, functional brain activity, integrity of the medial prefrontal cortex-amygdala connections, and thus improves individuals’ capacity to regulate emotions as well as their well-being.

There is bi-directional relationship between sleep and mental health. Hence, the deprivation or disruption of sleep can present as both a common symptom of and risk factor for a range of psychiatric disorders including anxiety and mood disorders.

Regulation of weight and appetite

Adequate sleep can help to keep hormones, that regulates appetite, in check. There are two hormones in question. Leptin is called the “satiety hormone” because it signals our body to feel full after a meal. Ghrelin has the opposite effect. It stimulates our appetite and makes us feel hungry. When we are chronically sleep deprived, leptin levels decrease and ghrelin levels increase. This leads to us feeling more hungry before a meal and less satisfied after a meal which in turn results in overeating and/or more cravings.

As deep sleep facilitates release of hormones that support metabolism and repair muscles that aid in fat burning, poor sleep (which suggest less time in deep sleep stage) can slow down metabolism and fat burning process. Sleep deprivation also increases cortisol levels (stress hormones) which can result in storage of fat, especially in the abdomen areas. All these hormonal imbalance, resulting from poor sleep, can contribute to unhelpful eating patterns and weight gain.

Stages of sleep

Source: https://www.sleepfoundation.org/stages-of-sleep

In human beings, sleep is divided into two main categories: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep, with the latter being further subdivided into 3 stages. The stages correspond to the increasing depth of sleep. N3 (stage 3 non-REM sleep) is considered the deep sleep stage in which body and brain restoration, repair and rejuvenation works mostly occur. In addition, REM stage is vital for consolidation of more procedural memories (skills, habits) and emotional memory processing. Taken together, both REM sleep and deep sleep are touted as the brain’s memory boosters as well as body’s best medicine.

What constitutes healthy sleep?

Sleep is one of the bodily functions where not just its quantity matters, quality matters just as well.

Each sleep cycle lasts approximately 90-110 minutes, during which one progresses through light, to deep sleep and then finally, REM sleep. These cycles repeat throughout the night. Typically, it is recommended for adults to go through uninterrupted 4-6 sleep cycles per night (equivalent to 7-9 hours), maintaining an optimal balance between REM and deep sleep.

When we managed to optimise our REM and deep sleep for the night, our sleep is considered healthy. This is usually characterised by us waking up, and feeling all refreshed and rejuvenated, along with attainment of physical, mental and emotional wellness.

The below chart suggests the range of hours of sleep required for each age group. These are considered in light of individual differences e.g., personal circumstances, health status which inevitably affect how much sleep one needs or can have. For instance, if you are pregnant, you may need relatively more sleep during the first trimester.

Source: National Sleep Foundation. This shows varying number of hours needed by individuals, across different age groups.

Sleep-related concerns

Sleep disorders are sleep-related disturbances due to underlying medical problems, lifestyle and environmental factors which usually cause sleep disruption (to sleep cycles), leading to insufficient amount of sleep, or poor quality sleep.

Common types include insomnia (i.e., difficulty falling or staying asleep or perception of unrestful sleep), narcolepsy (i.e., sudden loss of muscle tone, hallucinations and muscle paralysis on waking), sleep apnea (i.e., cessation of breathing during sleep), or parasomnias (i.e., abnormal behaviours during sleep such as, sleep walking, sleep terrors). Causes are aplenty - they range from self-induced, lifestyle choices, to underlying medical and/or psychological illnesses.

It is essential for individuals to get deep, uninterrupted and adequate sleep of 7-9 hours of sleep to maintain good health and well-being. Relatedly, having sleep difficulties can have profound consequences on daily and potentially longer term basis for health as well as mental well-being. In the short term, lacking sleep can affect judgement, emotional regulation, ability to learn and retain information as well as increase one’s risk of accidents and injuries. In the long term (should sleep difficulties persist for weeks or even months), it may result in a host of physical health issues or psychological conditions.

Specifically, majority of individuals suffering from insomnia (about 75-90%) have an increased risk for co-morbid medical disorders such as gastroesophageal reflux disease, pain conditions and neurogenerative diseases (Katz & McHorney, 1998).  And 40% of those with insomnia have co-morbid psychiatric conditions (Ford & Kamerow, 1989), of which depression is the most common co-morbidity. In addition, insomnia is a diagnostic symptom for depression and anxiety disorders too.

In conclusion, sleep facilitates body and brain detoxification, repair and restoration processes. In order to ensure physical, mental and emotional health and well-being, we want to ensure we get both quantity and quality in terms of sleep. Healthy sleep refers to adequate and uninterrupted deep and REM sleep. The amount of sleep one needs can vary across age groups. When one struggles with sleep disturbances, resulting in insufficient and/or poor quality sleep, it may in turn undermine one’s health outcomes.

Hope this raises awareness on how important sleep can be for our health and well-being. And striving for and prioritising sleep is a caring and loving act that we can do for ourselves.

In the next part of the series, ways to improve sleep will be explored in further details.

Rooting for you,

Jeanice

References

Berger, R. J. & Phillips, N. H. (1995). Energy conservation and sleep. Behavioural Brain Research, 69, 65-73.

Bryant, P., Trinder, J. & Curtis, N.  (2004). Sick and tired: does sleep have a vital role in the immune system? Nat Rev Immunol, 4 , 457-467.

Cai, Z. J. (1995). An integrative analysis to sleep functions. Behavioural Brain Research, 69, 187-194.

Collinge, W. (1999, August 25). Sleep’s healing properties. Retrieved August 28, 1999, from http://www.cnn.com/HEALTH/alternative/9908/25/heal.sleep/

Ford, D. E., & Cameron, D. B. (1989). Epidemiologic study of sleep disturbances and psychiatric disorders. An opportunity for prevention? JAMA, 262: 1479-1484.

Goldstein, A. N. & Walker, M. P. (2014). The role of sleep in emotional brain function. Annual Rev Clinical Psychology, 10, 679-708.

Katz, D. A. & McHorney, C.A. (1998). Clinical correlates of insomnia in patients with chronic illness. Arch Intern Med, 158, 1099-1107.

Nevid, J. S. (2003). Psychology Concepts and Applications. New York: Houghton Mifflin Company.

Vandekerckhove, M. & Wang, Y. L. (2017). Emotion, emotion regulation and sleep: An intimate relationship. AIMS Neuroscience, 5 (1), 1-17.

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