Have you ever wondered why you feel sleepy at night and awake during the day? Or why you experience jet lag after a long flight? The answers to these questions lie in our body’s internal biological clock, regulated by a fascinating gene known as the CLOCK gene. This gene and its associated proteins play a crucial role in maintaining our circadian rhythms, the natural cycles that regulate our sleep-wake patterns, eating habits, and other physiological processes.
The CLOCK Gene: A Brief Overview
The CLOCK gene, an acronym for “Circadian Locomotor Output Cycles Kaput,” is a critical component of our body’s internal timekeeping system. It encodes a protein that interacts with other proteins to regulate our body’s circadian rhythms.1 This gene is expressed in various tissues throughout the body, including the brain, liver, and muscle tissues.2
The CLOCK protein, along with another protein called BMAL1, binds to specific regions in our DNA. This binding triggers the expression of other genes, such as Period and Cryptochrome, which are essential for maintaining our body’s circadian rhythms.1
The Role of the CLOCK Gene in Circadian Rhythms
Circadian rhythms are physical, mental, and behavioral changes that follow a daily cycle. They respond primarily to light and darkness in an organism’s environment. Sleeping at night and being awake during the day is an example of a light-related circadian rhythm.3 The CLOCK gene and its associated proteins help maintain these rhythms by regulating the expression of other genes.4
Disruptions in the CLOCK gene and circadian rhythms have been associated with certain health conditions.5 Researchers, for instance, were particularly interested in exploring the potential impact of CLOCK gene changes on sleep patterns, especially in individuals with mood disorders. To investigate this, a study was conducted involving over a thousand participants, including individuals with major depressive disorder, bipolar disorder, and healthy volunteers.6
The study yielded intriguing results. Two new variants or alterations in the CLOCK gene were identified, but only in two individuals with mood disorders, not in any of the healthy volunteers. Interestingly, these two participants also exhibited atypical sleep patterns, characterized by alternating periods of restful sleep and complete insomnia.6
The researchers proposed that these small genetic variants might disrupt the normal functioning of the CLOCK protein, thus influencing sleep patterns. However, further research is necessary to validate these findings and gain a comprehensive understanding of the role these variations play in sleep regulation.6
Protecting and Adjusting Your Circadian Rhythms While Traveling
Traveling across different time zones can disrupt our circadian rhythms, leading to a condition known as jet lag. Symptoms of jet lag include fatigue, insomnia, and gastrointestinal problems.
Six Tips for Minimizing Jet Lag
To minimize jet lag, it is essential to adjust your circadian rhythms to the new time zone by trying the following:
- Manipulating Light Exposure: Strategic light exposure may help to speed up acclimation. Light, particularly its level and timing, has a powerful influence on our circadian rhythms. Properly timed exposure can help your body quickly sync to local time zones.7 If you do not have access to natural light, certain light therapy lamps can be subbed in.
- Taking Melatonin: Melatonin is a hormone your body produces when exposed to darkness. It helps to time your circadian rhythms. Light exposure at night can disrupt melatonin production. Before taking melatonin it is best to consult a doctor.
- Planning in Advance: In the days leading up to your departure, start modifying your bedtime so that when you arrive at your destination there is less of a shock to your system.
- Hydrating Regularly: Dehydration is a common side effect of flying as the air inside the plane is typically extremely dry. Those suffering from extreme dehydration report increased feelings of fatigue and lethargy. Drink plenty of water while on the plane to reduce sleep disruption.
- Limiting Caffeine: During your flight, reduce caffeine intake, or better yet, eliminate it entirely. Caffeine is extremely disruptive and should not be ingested less than five hours before your bedtime.
- Maintaining a Healthy Routine: Keeping a healthy diet and exercise routine can also help adjust your circadian rhythms. Some studies suggest that timed meals and physical activity can help reset your biological clock.8
The CLOCK gene is a vital cog in the intricate machinery of our circadian rhythms, and understanding its workings can shed light on health conditions and help us adjust our internal clocks when we jet across time zones. As we continue to unravel the mysteries of the CLOCK gene, we can anticipate a wealth of exciting discoveries that will shape our understanding of health and daily living.
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- GeneCards. (n.d.). CLOCK Gene (Protein Coding). Retrieved July 5, 2023, from https://www.genecards.org/cgi-bin/carddisp.pl?gene=CLOCK#:~:text=CLOCK%20(Clock%20Circadian%20Regulator)%20is,Circadian%20Clock%20and%20Chromatin%20organization.
- National Center for Biotechnology Information. (n.d.). CLOCK clock circadian regulator [Homo sapiens (human)]. Retrieved July 5, 2023, from https://www.ncbi.nlm.nih.gov/gene/9575.
- Rijo-Ferreira, F., Takahashi, J.S. Genomics of circadian rhythms in health and disease. Genome Med 11, 82 (2019). https://doi.org/10.1186/s13073-019-0704-0.
- Youri G. Bolsius, Matias D. Zurbriggen, Jae Kyoung Kim, Martien J. Kas, Peter Meerlo, Sara J. Aton, Robbert Havekes,The role of clock genes in sleep, stress and memory, Biochemical Pharmacolo, Volume 191, 2021,114493, ISSN 0006-2952, https://doi.org/10.1016/j.bcp.2021.114493.
- Hastings M. (1998). The brain, circadian rhythms, and clock genes. BMJ (Clinical research ed.), 317(7174), 1704–1707. https://doi.org/10.1136/bmj.317.7174.1704.
- Pirovano, A., Lorenzi, C., Serretti, A. et al. Two new rare variants in the circadian “clock” gene may influence sleep pattern. Genet Med 7, 455–457 (2005). https://doi.org/10.1097/01.GIM.0000170996.58079.6D.
- Sandipan Ray et al.,Circadian rhythms in the absence of the clock gene Bmal1. Science 367,800-806(2020).DOI:10.1126/science.aaw7365.
- Howard Hughes Medical Institute. (2023, July 5). Clock gene may connect mood and sleep. https://www.hhmi.org/news/clock-gene-may-connect-mood-and-sleep.