By Ashley Han
Sleep is one of the most vital functions for not only humans but many organisms on the planet. However, the reason why we need to sleep is still not entirely understood by scientists, and only hypotheses are made (Pomeroy, 2021).
Despite sleep’s importance, many people choose to take it for granted. Whether it’s by pulling all-nighters caught up with binge-watching shows or getting little to no sleep due to schoolwork, many people are unaware of the consequences that lack of sleep may have on any internal functions—such as the circadian rhythm. The circadian rhythm is a natural process that repeats every 24 hours inside the body. This process regulates the sleep-wake cycle, which determines when we feel drowsy or active. By sleeping late, we are significantly delaying our circadian cycle. Our internal clock is put off-balance due to our inconsistent sleeping patterns, which may lead to health problems in the long run. (Suni, 2022)
Process of the secretion of melatonin and serotonin (Landgraf, 2022)
The naturally-secreted hormone that controls our drowsiness is melatonin, known as the “sleep hormone.” This hormone is located in the pineal gland in our brain and is released in the brain. Since melatonin is responsive to darkness, its levels vary depending on the time of day. If it’s daytime, there would be significantly less melatonin production compared to the nighttime, where melatonin would continue to be secreted until the next day (Cleveland Clinic, 2022). This is the reason why people who have struggles sleeping take synthetically-produced melatonin capsules to aid in sleep.
The circadian clock, responsible for the circadian rhythm, is located in the suprachiasmatic nucleus (SCN) in the hypothalamus—a structure in the brain responsible for maintaining the body’s homeostasis. The SCN, which delivers information for melatonin production to the brain, is located above the optic nerves and controls the production of melatonin depending on the intensity of light. (Jones, 2013)
Circadian rhythm sleep disorders (CRSDs) throw the sleep-wake cycle off balance by causing significant decreases in melatonin levels during the night and increases in melatonin production during the daytime, resulting in excessive daytime sleepiness and poor sleep quality. CRSDs can also lead to decreased alertness and struggles with decision-making and eventually lead to chronic obesity and depression.
Fortunately, not all CRSDs are severe, and most of us have experienced one form of a circadian rhythm disorder at some point in our lives. One of the most common types of CRSDs is jet lag. When people travel from one time zone to another by air, the circadian rhythm is knocked off balance and needs to adjust to the new time zone. Another type of CRSD is the delayed sleep phase disorder, which means that someone goes to sleep later and wakes up later. These kinds of people are more productive during the night and experience drowsiness if forcefully woken up (Cleveland Clinic, 2020).
A possible treatment for CRSDs is bright light therapy (BLT). BLT is conducted by exposing the patient to a certain amount of light for a period of time (U.S. Department of Health and Human Services, 2022). This treatment resets the unbalanced internal clock by using the light to mimic sunlight. The results of this are shown in one of the types of BLT—the dawn simulator. The patient sits in a dark room where lights gradually turn on to mimic sunrise. Some treatments also mimic a sunset by slowly dimming the lights. This has been shown to have helped patients wake up in the morning and fall asleep at night (Hershner, 2021).
With more insight into the concept of sleep than before, scientists have created many treatments to aid people in sleeping comfortably at night. Recently, there have been studies exploring the relationship between Parkinson’s and sleep disorders and potential treatment methods. With this new discovery, it is promising that scientists will discover more about sleep in the near future.
References
Cleveland Clinic. (2020). Circadian rhythm sleep disorders: Types, symptoms and management. Cleveland Clinic. Retrieved November 7, 2022, from https://my.clevelandclinic.org/health/diseases/12115-circadian-rhythm-disorders
Cleveland Clinic. (2022). Melatonin: What it is & function. Cleveland Clinic. Retrieved November 7, 2022, from https://my.clevelandclinic.org/health/articles/23411-melatonin#:~:text=Melatonin%20is%20a%20natural%20hormone,effects%20on%20the%20human%20body
Hershner, S. (2021, May 6). Bright Light Therapy. Sleep Education. Retrieved November 7, 2022, from https://sleepeducation.org/patients/bright-light-therapy/
Landgraf, B. (2022, March 14). Circadian rhythm: What it is, why it's important, and how to fix/maintain yours. Carex. Retrieved November 8, 2022, from https://carex.com/blogs/resources/circadian-rhythm
Jones, C. R., Huang, A. L., Ptáček, L. J., & Fu, Y. H. (2013). Genetic basis of human circadian rhythm disorders. Experimental neurology, 243, 28–33. https://doi.org/10.1016/j.expneurol.2012.07.012
Pomeroy, R. (2021, November 1). Why do we sleep? Scientists still don't know. Big Think. Retrieved November 7, 2022, from https://bigthink.com/health/why-we-sleep/
Suni, E. (2022, November 4). Circadian rhythm. Sleep Foundation. Retrieved November 7, 2022, from https://www.sleepfoundation.org/circadian-rhythm#:~:text=Without%20the%20proper%20signaling%20from,%2C%20and%20lower%2Dquality%20sleep
U.S. Department of Health and Human Services. (2022). Circadian Rhythm Disorders Treatment. National Heart Lung and Blood Institute. Retrieved November 7, 2022, from https://www.nhlbi.nih.gov/health/circadian-rhythm-disorders/treatment#:~:text=The%20most%20common%20treatments%20are,eligible%20for%20a%20clinical%20trial
Comments