The diurnal rhythm, also known as the circadian rhythm, is the body's internal timing mechanism that regulates many biological processes in a 24-hour cycle. It is controlled by so-called biological clocks, which coordinate the work of organs and metabolic processes, adjusting them to changing environmental conditions. The most important element regulating the diurnal rhythm is the main 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 heart.
Aging is a complex and multifactorial process, and dysregulation of the circadian rhythm plays a key role in accelerating it. A regular diurnal rhythm promotes synchronization of biological processes, such as metabolism, autophagy, DNA repair and hormonal balance. Disturbances of these processes, which often result from 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 form feedback loops at the level of gene expression and protein activity. This process is called a “transcriptional-translational feedback loop” (TTFL).
PER (period) and CRY (cryptochrome) genes are active during the day, while their expression is inhibited by the protein products of the same genes at night, creating a cyclic pattern of activity.
The SCN, a master biological clock, receives light signals through the retina and sends signals to other clocks throughout the body, ensuring synchronization of diurnal rhythms in various tissues and organs. At the cellular level, almost every cell in the body has its own clock mechanism, which controls the expression of 5% to 20% of all genes depending on the tissue.
Disruption of the diurnal rhythm and aging
Disruptions of the diurnal rhythm 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 show an increased risk of breast cancer and other cancers.
Dysregulation of the diurnal rhythm also affects metabolic health through changes in gene expression and the activity of proteins related to metabolism. In mouse studies, disruption of circadian rhythms has been shown to cause changes in protein synthesis, which affects liver function, resulting in glycemic disturbances and insulin resistance.
At the cellular level, disruption of the rhythm of autophagy, the process of removing damaged cellular organelles, leads to the accumulation of harmful metabolic products, which accelerates cellular aging.
Diurnal rhythm and aging processes at the cellular level
One of the key mechanisms of aging is autophagy, which is the process of removing damaged organelles and excess proteins. Studies show that the diurnal rhythm regulates the activity of autophagic enzymes, and their dysregulation leads to the accumulation of damage, which accelerates cellular aging.
Similarly, the diurnal rhythm affects DNA repair, and disruption of this rhythm can lead to the accumulation of genetic damage and disruption of genome stability.
Telomeres, structures at the ends of chromosomes, also play an important role in the aging process. Telomere length shortening is associated with the aging process, and studies show that disruptions to the diurnal rhythm can accelerate this process. Shift workers and people with chronic sleep disorders show shorter telomeres and a higher risk of age-related diseases.
Interventions to support the diurnal rhythm to extend life span
Maintaining a regular diurnal rhythm is key to healthy aging. Here are some strategies:
- Optimizing sleep: Observing sleep hygiene, such as regular bedtimes, avoiding exposure to blue light, and reducing stress before bedtime, can improve sleep quality and reduce the risk of age-related diseases.
- Intermittent fasting: Scheduling meals within a time window consistent with your diurnal rhythm supports metabolic health and reduces oxidative stress. Studies show that intermittent fasting can extend life by improving mitochondrial function and autophagy.
- Phototherapy: Light therapies can help regulate diurnal rhythms, especially in the elderly and shift workers. Exposure to the right spectrum of light at the right times of day improves the synchronization of internal clocks.
Future research directions
New technologies, such as devices that monitor the diurnal rhythm, can help accurately assess the rhythm and intervene at the genetic and pharmacological levels. Manipulation of clock gene expression may become an effective therapeutic strategy for the prevention of aging in the future.
Conclusions
Diurnal rhythm is a key regulator of healthy aging. Its disruption accelerates aging and increases the risk of age-related diseases. Regular sleep patterns, intermittent fasting and adequate light exposure can promote healthy aging and life extension. A better understanding of the circadian rhythm may lead to new therapeutic strategies in the pursuit of longevity.