The circadian rhythm, also known as the circadian rhythm, is the body’s internal timing mechanism that regulates many biological processes on a 24-hour cycle. It is controlled by so-called biological clocks, which coordinate the work of organs and metabolic processes, adapting them to changing environmental conditions. The most important element regulating the circadian rhythm is the master clock in the brain, located in the suprachiasmatic nucleus (SCN) in the hypothalamus. This clock synchronizes peripheral clocks throughout the body, which affects the functioning of organs such as the liver, intestines, muscles, and the heart.
Aging is a complex and multifactorial process, and dysregulation of the circadian rhythm plays a key role in its acceleration. A regular circadian rhythm promotes the synchronization of biological processes such as metabolism, autophagy, DNA repair and hormonal balance. Disturbances in these processes, which are often the result of shift work, exposure to artificial light and irregular sleep, increase the risk of age-related diseases such as cardiovascular disease, type 2 diabetes and neurodegenerative disorders.
Biological Basis of Circadian Rhythm
The circadian rhythm is regulated by a network of clock genes, including PER, CRY, CLOCK and BMAL1, which create feedback loops at the level of gene expression and protein activity. This process is called the "transcriptional-translational feedback loop" (TTFL).
The PER (period) and CRY (cryptochrome) genes are active during the day, whereas their expression is repressed by the protein products of the same genes at night, creating a cyclical pattern of activity.
The SCN, the master biological clock, receives light signals through the retina and sends signals to other clocks throughout the body, which ensures circadian rhythms are synchronized in different tissues and organs. At the cellular level, almost every cell in the body has its own clock mechanism that controls the expression of 5% to 20% of all genes, depending on the tissue.
Circadian Rhythm Disruptions and Aging
Disruptions to circadian rhythms have serious health consequences. Studies show that people who work shifts or suffer from sleep disorders are more likely to develop age-related diseases. For example, women who work night shifts have an increased risk of breast cancer and other cancers.
Circadian dysregulation also affects metabolic health through changes in gene expression and activity of proteins related to metabolism. Studies in mice have shown that disruptions in circadian rhythms cause changes in protein synthesis, which affects liver function and ultimately leads to glycemia disorders and insulin resistance.
At the cellular level, disruption of the autophagy rhythm, the process of removing damaged cellular organelles, leads to the accumulation of harmful metabolic products, which accelerates cell aging.
Circadian rhythm and aging processes at the cellular level
One of the key mechanisms of aging is autophagy, the process of removing damaged organelles and excess proteins. Studies show that the circadian rhythm regulates the activity of autophagic enzymes, and their dysregulation leads to the accumulation of damage, which accelerates cell aging.
Similarly, circadian rhythm influences DNA repair, and disruption of this rhythm can lead to the accumulation of genetic damage and genome stability disorders.
Telomeres, structures at the ends of chromosomes, also play an important role in the aging process.Telomere shortening is associated with aging, and research shows that disruptions to circadian rhythms can accelerate this process. Shift workers and people with chronic sleep disorders have shorter telomeres and a higher risk of age-related diseases.
Circadian Rhythm Interventions to Extend Life
Maintaining a regular circadian rhythm is key to healthy aging. Here are some strategies:
- Sleep optimization: Practicing sleep hygiene, such as maintaining regular sleep hours, avoiding exposure to blue light, and reducing stress before bed, can improve sleep quality and reduce the risk of age-related diseases.
- Intermittent fasting: Scheduling meals in a time window that aligns with your circadian rhythm supports metabolic health and reduces oxidative stress. Studies show that intermittent fasting can extend life by improving mitochondrial function and autophagy.
- Phototherapy: Light therapy can help regulate circadian rhythms, especially in older adults and shift workers. Exposure to the right light spectrum at the right times of day improves the synchronization of internal clocks..
Future Research Directions
New technologies, such as devices monitoring circadian rhythm, can help to precisely assess the rhythm and intervene at the genetic and pharmacological level. Manipulation of clock gene expression may become an effective therapeutic strategy in the future in the prevention of aging.
Conclusions
Circadian rhythms are a key regulator of healthy aging. Disruptions to circadian rhythms accelerate aging and increase the risk of age-related diseases. Regular sleep patterns, intermittent fasting, and adequate light exposure can support healthy aging and extend life. A better understanding of circadian rhythms could lead to new therapeutic strategies for longevity.