Introduction :

Sleep is a universal behaviour occupying a significant fraction of the 24-hour day, but its regulation and function(s) are far from being understood 1. The foundation of sleep and wake promotion is laid by the neurotransmitters: γ-aminobutyric acid (GABA) for sleep and glutamate for the wake 2. Adults require 7 or more hours of sleep each night to stimulate optimal health. Regular, inadequate sleep - less than 7 hours, may give rise to weight gain & obesity, diabetes, hypertension, heart disease and stroke and depression. Sleep deprivation is also associated with increased pain and errors, impaired immune function and performance, and a greater risk of accidents and death. Sleeping more than 9 hours each night may be required for individuals with illnesses, young adults and individuals recovering from sleep debt 3.

Circadian Rhythms:

Circa=About

Dies=Day

Circadian rhythms are biological processes that display 24-hour endogenous oscillations, allowing organisms to adapt and respond to constantly changing environments. Circadian clocks (or most commonly known as biological clocks) exist in virtually all cells and organs. Autonomous circadian clocks interact with daily light-dark and feeding–fasting cycles to generate daily fluctuations in the expression rhythms of most genes4.

Circadian Locomotor Output Cycles Kaput (CLOCK) genes are responsible for generating circadian rhythm 4.

Disruptors of Circadian Rhythm:

• Caffeine consumption: Caffeine is responsible for prolonging sleep latency, reducing total sleep duration and sleep efficiency, and worsening the quality of sleep 6.
• Alcohol consumption: Even a small dose of alcohol can alter GABA and glutamate levels in the suprachiasmatic nuclei which is the location of the central circadian pacemaker 7.
• Light-emitting devices (White Lights, CFL bulbs, Tubelights, Electronic Gadgets) : Blue light emitted by light-emitting devices functions similar to natural light by inhibiting melatonin secretion, thereby causing trouble sleeping. Chronic exposure to low-intensity blue light directly before bedtime may have serious implications on sleep quality, circadian phase and cycle durations 5,7.     

• Electro Magnetic Fields (EMFs): Electromagnetic fields (EMF) from Mobile phone use can cause headaches, concentration difficulties, fatigue and sleep disturbances 8.

Regulating Circadian Rhythms With Better Sleep Hygiene:

• Nutritional effects on sleep: High-protein diets are associated with significantly fewer wake episodes and high-carbohydrate diets are associated with significantly shorter sleep latencies 9. Tryptophan causes an immediate reduction in sleep latency and induction of sleepiness 10.

• Dark pre-sleep environment: Complete darkness is optimal for sleep and blue light should be avoided during the sleep opportunity 11. If reading before bedtime, choose a printed book over a light-emitting electronic book (e-Book) 4.

• Warm pre-sleep thermal environment: Warm environment before sleep is associated with ease in falling asleep, increased sleep satisfaction, ease in awakening, lower sleep onset latency and increased duration of deep sleep. Whereas, a cool environment is associated with reduced sleep quality 12.

• Listen to relaxing music,  Sleep meditations or Sleep podcasts: Listening to relaxing music before sleeping can improve sleep parameters in some individuals 13. Deep breathing and body scan meditation combined with music has yielded a positive effect on improving sleep quality and quality of life 14.

• Exercise: Exercise especially resistance training may improve sleep through the following mechanisms7: 

           -  Improved symptoms of depression or anxiety

            - Alterations in energy expenditure

            - Increase in body temperature

           -  Relief of musculoskeletal pain

• Cut down on Electromagnetic field before bedtime Decreasing the numbers of calls and messages, decreasing the duration of calls, using earphones, keeping the phone away from the head and body and similar precautions might decrease the frequencies or prevalence of sleep disturbances 8.

How To Minimise Exposure To Electro-Magnetic Field (EMF)?

• Replace white bulbs with yellow lights
• Use f.lux app for electronic gadgets to filter & regulate blue light exposure.
• Place electronic gadgets 6-8 feet away from food & while sleeping
• Switch off Wi-Fi- when not in use.

• Exogenous Melatonin through food & supplements

The pineal gland synthesises a hormone called melatonin which plays a crucial role in circadian rhythm entrainment 5. 

• Light therapy: A specialized device, known as a light therapy box emits bright light similar to natural sunlight. Light therapy has a beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance. Its effect depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion 5,16.

Conclusion:

Sleep is regulated by CLOCK genes whose expression changes with response to light-dark and feeding-fasting cycles. Various factors influence both sleep quality and sleep duration. Unhealthy sleep patterns thereby give rise to many health conditions. Maintaining optimal sleep duration along with good quality uninterrupted sleep each day is the key to yielding all the benefits that sleep has to offer for our body and mind.

References:

•  Vyazovskiy, V. V. Sleep, Recovery, and Metaregulation: Explaining the Benefits of Sleep. Nat. Sci. Sleep 2015, 7, 171–184. https://doi.org/10.2147/NSS.S54036.
• Schneider, L. Neurobiology and Neuroprotective Benefits of Sleep. Contin. Lifelong Learn. Neurol. 2020, 26 (4), 848–870. https://doi.org/10.1212/CON.0000000000000878.
• Consensus Conference Panel; Watson, N. F.; Badr, M. S.; Belenky, G.; Bliwise, D. L.; Buxton, O. M.; Buysse, D.; Dinges, D. F.; Gangwisch, J.; Grandner, M. A.; Kushida, C.; Malhotra, R. K.; Martin, J. L.; Patel, S. R.; Quan, S. F.; Tasali, E. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. J. Clin. Sleep Med. 2015, 11 (06), 591–592. https://doi.org/10.5664/jcsm.4758.
• Burgess, H. J.; Emens, J. S. Circadian-Based Therapies for Circadian Rhythm Sleep-Wake Disorders. Curr. Sleep Med. Rep. 2016, 2 (3), 158–165. https://doi.org/10.1007/s40675-016-0052-1.
• Wahl, S.; Engelhardt, M.; Schaupp, P.; Lappe, C.; Ivanov, I. V. The Inner Clock—Blue Light Sets the Human Rhythm. J. Biophotonics 2019, 12 (12). https://doi.org/10.1002/jbio.201900102.
• Clark, I.; Landolt, H. P. Coffee, Caffeine, and Sleep: A Systematic Review of Epidemiological Studies and Randomized Controlled Trials. Sleep Med. Rev. 2017, 31, 70–78. https://doi.org/10.1016/j.smrv.2016.01.006.
• Burgess, H. J.; Emens, J. S. Circadian-Based Therapies for Circadian Rhythm Sleep-Wake Disorders. Curr. Sleep Med. Rep. 2016, 2 (3), 158–165. https://doi.org/10.1007/s40675-016-0052-1.
• Durusoy, R.; Hassoy, H.; Özkurt, A.; Karababa, A. O. Mobile Phone Use, School Electromagnetic Field Levels and Related Symptoms: A Cross-Sectional Survey among 2150 High School Students in Izmir. Environ. Health 2017, 16 (1), 51. https://doi.org/10.1186/s12940-017-0257-x.
• Lindseth, G.; Lindseth, P.; Thompson, M. Nutritional Effects on Sleep. West. J. Nurs. Res. 2013, 35 (4), 497–513. https://doi.org/10.1177/0193945911416379.
• Tryptophan and Human Sleep: An Analysis of 43 Studies. In Progress in Tryptophan and Serotonin Research; Schlossberger, H. G., Steinhart, H., Kochen, W., Linzen, B., International Study Group for Tryptophan Research, Eds.; De Gruyter, 1984; pp 297–304. https://doi.org/10.1515/9783111641546-039.
• Caddick, Z. A.; Gregory, K.; Arsintescu, L.; Flynn-Evans, E. E. A Review of the Environmental Parameters Necessary for an Optimal Sleep Environment. Build. Environ. 2018, 132, 11–20. https://doi.org/10.1016/j.buildenv.2018.01.020.
• Zhang, N.; Cao, B.; Zhu, Y. Effects of Pre-Sleep Thermal Environment on Human Thermal State and Sleep Quality. Build. Environ. 2019, 148, 600–608. https://doi.org/10.1016/j.buildenv.2018.11.035.
• Cordi, M. J.; Ackermann, S.; Rasch, B. Effects of Relaxing Music on Healthy Sleep. Sci. Rep. 2019, 9 (1), 9079. https://doi.org/10.1038/s41598-019-45608-y.
• Nanthakwang, N.; Siviroj, P.; Matanasarawoot, A.; Sapbamrer, R.; Lerttrakarnnon, P.; Awiphan, R. Effectiveness of Deep Breathing and Body Scan Meditation Combined with Music to Improve Sleep Quality and Quality of Life in Older Adults. Open Public Health J. 2020, 13 (1), 232–239. https://doi.org/10.2174/1874944502013010232.
• Riha, R. L. The Use and Misuse of Exogenous Melatonin in the Treatment of Sleep Disorders. Curr. Opin. Pulm. Med. 2018, 24 (6), 543–548. https://doi.org/10.1097/MCP.0000000000000522.
• Light Therapy: Can Light Combat Insomnia? https://www.sleepfoundation.org/light-therapy (accessed 2021 -10 -17).

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