Every physiological function and bio-molecular process in the human body is strictly regulated by an intricate loop of molecular feedback mechanisms. Although every cell in the human body has the presence of a molecular clock, an autonomous master clock in the brain is responsible for regulated gene expression and physiological rhythms. This master clock in the brain is called Suprachiasmatic Nucleus (SCN) and is autonomously influenced by the environmental light/dark cycle.
SCN is an incredibly vital component of the circadian system. Depending on the availability of light, it regulates the timing of various cellular and molecular processes. Hence, SCN ensures the appropriate alignment of functions between cells and tissues. SCN consequently synchronizes the communication between the heart, lungs, liver, muscles, stomach, and brain, which significantly affects human behavior. Enhanced attention/activity during the day, feeding habits, mood stabilization, and regenerative sleep are among some of the most predominant behaviors that SCN controls. Disruption in the circadian rhythm not only results in a dysfunction of components necessary for optimum functionality daily but also leads to detrimental long-term consequences like cancer, CVD, or diabetes.
There are several ways to reprogram the circadian rhythm.
First on the list is light therapy. Light therapy has already shown tremendous benefits in advanced sleep phase syndrome, depression, jet lags, and seasonal affective disorder. Moreover, unobstructed exposure to natural sunlight for at least 2 hours a day improves natural melatonin rhythm by 2 hours among young adults. Additionally, avoiding blue light at least 3-4 hours before bedtime substantially increases natural melatonin production in the body. Hence, just avoiding screen time before sleeping, performing prolonged physical/sporting activities in natural sunlight, or administration of artificial light therapy by a medical professional can potentially fix the broken circadian biological clock.
Next on the list is scheduled meals. Metabolic homeostasis is strictly regulated by SCN, which ultimately modulates physiological processes like appetite, GI function, insulin secretion, liver enzyme activity, and nutrient absorption. Disruption in the circadian rhythm causes SCN to negate the transcriptional process of crucial genes Bmal1 and Clock. It also reduces the availability of nuclear hormone receptors Rev-erb and Rora, which are not only essential for the proper functioning of the circadian rhythmic clock but also for metabolic homeostasis. Adherence to a proper and timely feeding schedule and refraining from consuming untimely meals can highly influence the reversal of a broken circadian biological clock.
Scheduled exercise also plays an integral role in fixing the circadian clock. In rodents, scheduled exercise causes effective phase shifts and plays a crucial role in maintaining the circadian rhythm. Scheduled daily exercise routines during the afternoon or early evening could substantially improve sleep schedule and quality. In consequence, this could certainly result in the reversal of a faulty circadian system.
Scheduled sleeping patterns and the usage of occasional exogenous melatonin or SSRIs can also fix sleep abnormalities and the circadian rhythm. However, the administration of exogenous melatonin and SSRIs must be under the advisement of a physician or a licensed therapist. In addition, since serotonin plays a crucial role in resynchronizing and strengthening the circadian rhythm, food items and activities that enhance serotonin production can be administered regularly. There are also several drugs (agonists, activators, and inhibitors) that pharmacologically target the circadian system. However, they are strictly controlled by the authorities and required to be prescribed and supervised by medical professionals.
If you or anyone you know has trouble sleeping or is affected by an irregular circadian rhythm, please contact The Functional Medicine Center for Personalized Care, LLC (www.FxMedCenters.com) at 201-880-8247 or Specialized Therapy Associates at 201-488-6678.
Ishtiak Ahmed Chowdhury
Acosta-Galvan, G., Yi, C. X., van der Vliet, J., Jhamandas, J. H., Panula, P., Angeles-Castellanos, M., et al. (2011). Interaction between hypothalamic dorsomedial nucleus and the suprachiasmatic nucleus determines intensity of food anticipatory behavior. Proc. Natl. Acad. Sci. U.S.A. 108, 5813–5818. doi: 10.1073/pnas.1015551108
Adamovich, Y., Ladeuix, B., Golik, M., Koeners, M. P., and Asher, G. (2017). Rhythmic oxygen levels reset circadian clocks through HIF1alpha. Cell Metab. 25, 93–101. doi: 10.1016/j.cmet.2016.09.014
Antle, M. C., and Mistlberger, R. E. (2000). Circadian clock resetting by sleep deprivation without exercise in the Syrian hamster. J. Neurosci. 20, 9326–9332. doi: 10.1523/jneurosci.20-24-09326.2000
Astiz, M., Heyde, I., and Oster, H. (2019). Mechanisms of communication in the mammalian circadian timing system. Int. J. Mol. Sci. 20:E343. doi: 10.3390/ijms20020343
Daan, S. (1977). Tonic and phasic effects of light in the entrainment of circadian rhythms. Ann. N. Y. Acad. Sci. 290, 51–59. doi: 10.1111/j.1749-6632.1977.tb39716.x
Dibner, C., Sage, D., Unser, M., Bauer, C., d’Eysmond, T., Naef, F., et al. (2009). Circadian gene expression is resilient to large fluctuations in overall transcription rates. EMBO J. 28, 123–134. doi: 10.1038/emboj.2008.262
Schroeder AM, Colwell CS. How to fix a broken clock. Trends Pharmacol Sci. 2013;34(11):605-619. doi:10.1016/j.tips.2013.09.002
Xie Y, Tang Q, Chen G, et al. New Insights Into the Circadian Rhythm and Its Related Diseases. Front Physiol. 2019;10:682. Published 2019 Jun 25. doi:10.3389/fphys.2019.00682