Circadian rhythms in health and disease

Circadian rhythms, serving as a crucial temporal bridge linking neural activity and pathological biology, are regulated by central pacemaker neurons to maintain cellular homeostasis and coordinate diverse biological processes. Circadian rhythm disruption is closely associated with various diseases, including neurodegenerative disorders, metabolic disorders, and cancer. Circadian rhythms are controlled by core clock genes, such as BMAL1 and CLOCK, modulating numerous physiological processes, encompassing metabolism, immune responses, neural activity, and hormone regulation. Circadian rhythms disruptions arising from shift work, jet lag, or inconsistent sleep schedules are implicated in both the onset and progression of numerous diseases, notably Alzheimer's disease, Parkinson's disease, diabetes, and cardiovascular disease. The article highlights how circadian dysregulation alters cellular processes to potentially accelerate disease progression. Circadian disruption results in impaired immune function, further promoting disease development and resistance to treatment. Potential therapeutic applications based on circadian biology, such as chronotherapy and personalized medicine, are also discussed. Recent technological advances, embodied in wearable devices and omics approaches, are increasingly providing deeper insights into circadian biology. Further unveiling the role of circadian in health and disease opens new avenues for tailoring treatment timing to patients' biological rhythms, thereby enhancing therapeutic outcomes across various diseases. By bridging fundamental circadian mechanisms with clinical pathology, this review provides a roadmap for future chronotherapeutic interventions in precision medicine.