Circadian system and human health: From molecular mechanisms to clinical integration

The circadian system, an evolutionarily conserved endogenous oscillator coordinating physiological adaptation to geophysical cycles, coordinates hierarchical gene regulatory networks, metabolic pathways, and physiological functions to maintain organismal homeostasis. Circadian disturbances caused by modern lifestyle are recognized as key etiological factors in complex multisystem disorders, including neurodegenerative, cardiovascular, metabolic, and oncogenic pathologies. The review synthesizes current evidence to delineate that organ-specific physiological programs across the human body are under circadian clock, and chronic desynchronization of system drives a broad spectrum of clinical disorders. Moreover, the review critically assesses state-of-the-art therapeutic modalities, and identifies promising technological innovations. It advances precision chronomedicine by proposing public health interventions, such as environmental modification combined with behavioral education, offering a roadmap for clinical implementation of circadian restoration therapies.