Sleep Glorious Sleep! Understanding Sleep
How was your quality of sleep last night? Researchers have been ramping up sleep studies and associated health conditions in the last 15 years. Research has revealed the connection between poor sleep and a variety of disorders, including obesity, hypertension, impaired immune function, cardiovascular disease, arrhythmia, mood disorders, type-2 diabetes, neurodegeneration and dementia1.
Why do we need sleep?
Researchers have found sleep plays a critical role in many physiological functions including modulation of the immune system, cognition, performance, removal of brain waste, energy and metabolism 2. The most recent sleep research conducted in the UK analysed the cognitive function of 46 sleep subjects. The results found participants who achieved six-to-eight hours sleep had larger grey matter volume than those who had less sleep 3. Grey matter is involved in the regulation of memory, movement and emotions 4. Another study found participants who experienced insomnia had lower cognitive function as well as reduced grey matter. Additionally long term insomnia is associated with increased risk in Alzheimers Disease 7.
When it comes to our immune function, sleep plays a critical role in helping our immune system. When we sleep we experience a surge in blood and lymphatic fluids, this helps the distribution of oxygen, fatty acids, glucose and non-immune cells to lymphatic tissue, the spleen and lymph nodes. This process helps the removal of waste metabolites. Our immune is also regulated by the activation of cytokines, which are proteins released by cells that are anti-inflammatory and protective for our cells against disease and infection. Cytokines work with T helper cells in processing immune memory, beneficial for recovery from allergies and infection 5.
Sleep deficits have proven to affect mood and performance, increasing stress levels and emotional regulation. Athletes have been analysed through research for how sleep deficiency affects their performance. With studies conclusive that sleep greatly influences poor athletic performance as well reduced academic ability (most athletes are students) and low mood. Medication prescribed for athletes with poor sleep was shown only helpful short-term as long-term use was found to disrupt natural circadian rhythm 6.
Poor sleep can also affect the diet and lifestyle choices we make. Sleep also plays a vital role in regulating our hormones. This includes hormones that govern our appetite, such as leptin and Ghrelin. Ghrelin stimulates hunger, whilst leptin is related to satiety or feeling full. Insufficient sleep in research has shown the brain stimulates the production of more Ghrelin, which is linked to overeating and disruption of circadian rhythms worsening sleep further. Overeating is related to a variety of health problems such as obesity, sleep apnea, diabetes and cardiovascular disease. Studies have found participants who overeat generally have less motivation to participate in exercise, increasing their risk for cardio metabolic disease 8.
Circadian rhythms are natural cycles that initiate our body’s internal clock that influences essential bodily processes and functions. The cycles operate in a 24-hour period and are intricately synchronised with the master clock in our brain. Everything from our environment externally and internally, temperature, light exposure, timing of meals and what foods are eaten or not eaten at certain times all impact our natural healthy circadian rhythm. When our circadian cycle is balanced well and aligned it offers restorative and consistent sleep quality. However, if there is an imbalance, it can cause significant sleep problems such as, difficulty with sleep onset, sleep wakefulness and insomnia 8.
Stages of sleep
Stage 1 - Non-REM (rapid eye movement) sleep lasting only few minutes, light sleep, brain waves are slowing down so is breathing, eye movement, muscles relax.
Stage 2 - non-REM sleep, further relaxation and slowing down of heartbeat and breathing. Temperature drops and brain activity slows.
Stage 3 non REM sleep now reaching deep sleep with optimal requirements being 1-2 hours to feel refreshed up on waking. This is when the body starts to heal and rejuvenate and brainwaves slow further. Muscles are now fully relaxed you may be difficult to wake.
Stage 4 REM Sleep occurs around 90 minutes from sleep onset, eyes move rapidly and brain frequency increases similar to wakefulness. Most of your dreaming occurs in REM sleep. The consolidation of memory and learning occurs as well as processing emotions 8.
How Much Sleep Do We Need?
0-3 months - 14-17 hours
4-12 months - 12-16 hours
1-2 years - 11-14 hours
3-5 years - 10-13 hours
6-12 years - 9-12 hours
13-18 years - 8-10 hours
19-64 years - 7- 9 hours
65 + years - 7-8 hours
We can all agree how rejuvenating it is to have a good night sleep, for our physical and mental health. Hopefully you have gained a new found love and respect for your precious sleep. Stay tuned for Part 2. Optimise Your Sleep, covering diet, lifestyle, herbal and nutritional advice in how to gain good quality sleep for you and your family.
Sleep well and take care of you and each other, love and light, Jaunita ~ Your Family Naturopath xx
1. The Extraordinary Importance of Sleep, PubMed Central, Worley. SL, 2018
2.Functions and Mechanisms of Sleep, AIMS Neuroscience, Zielinski.MR, McKenna.JT, McCarley. RW, 2016.
3. Impact of sleep duration on executive function and brain structure, Communications in Biology, Tai.XY, Chen.C, Manohar.S, Husain. M, 2022
4. Neuroanatomy, Grey Matter, Stat Pearls, NCBI, Mecandante. AA, Tadi. P, 2021
5. Sleep and immune function, Pflugers Archive, Besedovsky. L, Lange. T, Born. J, 2011
6. American College of Sports Medicine, Sleep deprivation and its contribution to mood and performance deterioration in college athletes, Delmas. J MD, 2019
7.Alzheimer’s Research and Therapy, Association between insomnia and cognitive performance, gray matter volume, and white matter microstructure in cognitively unimpaired adults, Grau-Rivera. O et al. 2020.
8. Sleep Foundation Organisation, www.sleepfoundation.org
9. Cleveland Clinic, Health Essentials, 2021