Circadian Rhythms And Health Research Trends

A circadian rhythm is a roughly-24-hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria. The term 'circadian', comes from the Latin circa, 'around', and dies, 'day', meaning literally 'about a day'. The formal study of biological temporal rhythms such as daily, weekly, seasonal, and annual rhythms, is called chronobiology. In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature. Most of a person's body systems demonstrate circadian variations. The body systems with the most prominent circadian variations are the sleep-wake cycle, the temperature regulation system, and the endocrine system. The malfunctioning of a person's circadian system, or biological clock, causes circadian rhythm disorders. Circadian rhythms and their relation to health outcomes in the globalised hyper world of the 21st century are now understood to be extremely important.

"Circadian rhythm is the mechanism for measuring time by organisms in units of around 24 hours. Almost every organism has the ability to predict daily events such as sunrise and sunset, which is essential for their optimal survival strategies. Circadian rhythms persist even in the absence of time cues and ensure that behavioral, physiological and metabolic processes align with changing environmental conditions. Most organisms, irrespective of whether they are prokaryotic or eukaryotic, have evolved certain mechanisms to sense their external environment in order to prepare a biological response. Often, these biological responses result in changes in physiology and biochemistry of organisms for the optimization of their survival. There is no unified mechanism among organisms by which sensory environment can be applied to control their lifespan. In humans, disruptions of the circadian rhythm may have an increased risk of age-related neurodegenerative diseases such as cancer, diabetes, etc. This book encompasses the most recent knowledge and modern trends in the field of circadian rhythms research. It is also expected to provide a must-read guide for beginners as well as advanced researchers in this field of study. Undergraduate, post-graduate and research scholars of several disciplines such as chemistry, botany, microbiology, biochemistry, biotechnology, bioinformatics, life sciences and bionanotechnology will benefit from this book"--

This book sheds new light on the molecular mechanisms that generate circadian rhythms. It examines how biological rhythms influence physiological processes such as sleep, hormone synthesis and secretion, immunity, kidney function, the cardiovascular system, blood pressure, and the digestive system. Clinical implications are considered while exploring the impact of rhythms on neuropsychiatric disorders and chronotherapy’s potential for reducing cardiovascular risk. Offering a cross-section of expertise in both basic and translational (bench-to-bedside) research, this book serves as a guide for physicians and scientists who wish to learn more about the impact of circadian rhythms on physiological processes in health and disease.

Circadian rhythms are biological processes displaying endogenous and entrainable oscillations of about 24 hours. They are driven by a group of genes called clock genes that have been widely observed in plants, animals and even in bacteria. In mammals, the core clock genes are rhythmically expressed in both the suprachiasmatic nucleus (SCN), the master clock residing in the hypothalamus, and almost all peripheral tissues where they control numerous target genes in a circadian manner, and thus affect many physiological and biochemical processes. Evidence suggests that disruption of the circadian rhythms (or desynchronization) is a significant risk factor for the development of metabolic diseases, cardiovascular diseases, cancer and sleep disorders. Evidence also suggests that the disruption suppresses immune function and increases vulnerability to infectious diseases. Restoring or strengthening the circadian rhythm may be therapeutic for these conditions. This becomes exceptionally important in modern societies because many people are suffering from frequent desynchronization due to shift working, exposure to artificial light, travel by transmeridian air flight, and involvement in social activities. Besides, the temporal variations in the incidence and severity of many diseases, such as the onset of cardiovascular events, chronic obstructive pulmonary disease (COPD), inflammatory diseases and mental disorders have also drawn increasing attention to the circadian clock. The circadian rhythms affect not only the health status, but also the drug efficiency. The effects (and side effects) of many drugs vary with biological timing. The tolerance of many medications displays circadian variation as well. The timing of medical treatment in coordination with the body clock may significantly increase the desired effects of drugs, and lower the dose and toxicity. In addition, circadian rhythms can also be modulated by some therapeutic drugs, for example, melatonin and modafinil, which are used to treat circadian rhythm sleep disorders. In this Research Topic, we assemble a series of critical review and research articles that focus on the therapeutic implications of circadian rhythms. Topics include, but are not limited to: • Circadian disruption caused diseases or disorders and related intervention • Temporal manifestation of diseases or disorders and therapeutic implications • The effects of circadian rhythms on drugs • The effects of drugs on circadian rhythms

Circadian clocks are endogenous and temperature-compensating timekeepers that provide temporal organization of biological processes in living organisms. Circadian rhythms allow living organisms to adapt to the daily light cycles associated with Earth's rotation and to anticipate and prepare for precise and regular environmental changes. This book discusses the fundamental advances of how the circadian clock regulates critical biological functions as well as the cellular and molecular mechanisms controlling circadian rhythm in living organisms. It also provides new insights into and sheds new light on the current research trends and future research directions related to circadian rhythm. This book provokes interest in many readers, researchers and scientists, who can find this information useful for the advancement of their research works towards a better understanding of circadian rhythm regulatory mechanisms.

This book covers topics from a wide variety of disciplines including cell biology, developmental biology, ecology, endocrinology, genetics, molecular biology, neurobiology, and pharmacology. There is a focus on circadian (daily), tidal, seasonal, and annual rhythms, as well as other biological rhythms. Rhythms are placed within the context of the functional significance of these rhythms for the health and well-being of relevant organisms and include genetic and molecular mechanisms of biological timekeeping, melatonin and pineal gland rhythms, as well as on the chronobiology and chronotherapy of cardiovascular, pulmonary, ulcer, and other diseases.