Editorial: Circadian rhythms and aging

In most living organisms, circadian rhythms are physiological and behavioral fluctuations with a periodicity of approximately 24 hours, thought to have been ancestrally induced by the light-dark cycle of the day-night succession. These rhythms provide significant biological advantages by preparing organisms for day-night cycles and associated activities.Human society has rigid schedules for work, school, and social activities. These schedules frequently require people to work and be active when their endogenous circadian clock signals that it is time to sleep. Synchronized circadian rhythmicity is necessary for overall health, and circadian disruption leads to premature death and notable changes in the brain, metabolism, and behavior.Advances in healthcare and living conditions have significantly increased life expectancy; consequently, the global aging population is placing unprecedented demands on healthcare services and medical research. Aging alters circadian rhythms, both behaviorally (sleep disturbances) and physiologically, by decreasing their strength (lower amplitude) and duration (reduced period), weakening their synchronization with environmental light cues, and almost certainly impacting the health of the elderly (Farajnia et al., 2014).The eight manuscripts in this collection explore the interrelated domains of aging, sleep, circadian rhythms, and neurological or physiological function. The four review articles synthesize current knowledge on circadian biology, sleep regulation, and therapeutic strategies. This collection also includes four original research papers that provide experimental and observational evidence that deepens understanding of these processes. Together, they form a coherent body of work centered on aging-related changes in sleep and circadian systems, as well as potential interventions. Original research was reported by Zhao and colleagues (hyperlink) that circadian rhythm disruption is associated with increased postural sway and a higher risk of falls, particularly when visual input is limited. These findings suggest that circadian misalignment may contribute to fall risk in aging populations, highlighting the importance of maintaining circadian integrity for physical stability. In turn, Feeney et al. (hyperlink) found that overexpression of calcium/calmodulin-dependent protein kinase IV (CaMKIV), a protein closely linked to memory consolidation, enhanced both the non-rapid eye movement (NREM) and rapid eye movement (REM) sleep in aged male mice, but not in (hyperlink) used computational and experimental methods to investigate the mechanisms of the Bushen Anzhi recipe (Chinese herbal medicine) in the treatment of aging-related insomnia. Their findings reveal that treated animals exhibited increased total sleep time and slow-wave sleep, as well as improved memory and exploratory behavior. These effects were associated with the regulation of key target genes, including H1F1A, PTGS2, and GSK3B, suggesting a potential role for the Wnt signaling pathway.Collectively, the studies included in this Research Topic highlight the central role of circadian rhythms in the aging process and their broad impact on sleep, cognition, metabolism, and overall health. Importantly, they disclose that age-related circadian disruption is not irreversible but rather adjustable. Future research should prioritize integrative and personalized approaches that combine chronobiology, lifestyle interventions, and targeted therapies to preserve circadian integrity and promote healthy aging.