Emotion–sleep–cognition interactions during aging: mechanisms, evidence, and prospects

Emotional problems, sleep disorders, and cognitive decline are common and interrelated problems in older adults. Aging causes gradual declines in brain functional reserve, homeostatic regulatory capacity, and cognitive reserve, creating a background of vulnerability to interactions among the three; neural circuit dysregulation, chronic inflammation and metabolic disturbances, cerebrovascular injury, and neurodegenerative pathology constitute their shared mechanisms. When emotional and sleep abnormalities persistently coexist, they may compound the burden through bidirectional feedback, exceed compensatory thresholds, and synergistically amplify the risk of cognitive impairment. On this basis, this paper proposes a "compensatory imbalance–synergistic amplification" model and reviews the relevant evidence along the framework of "aging background–shared mechanisms–interactions–clinical interventions," recommending a shift from single-symptom management to combined emotion–sleep–cognition screening, risk stratification, etiological assessment, and integrated interventions. Existing interventions can improve sleep, emotion, and daytime functioning with reasonable certainty, but whether these improvements translate into long-term cognitive benefits or slow the progression of dementia still requires verification through longitudinal studies and randomized controlled trials.