Sleep and Subjective Age: A Narrative Review of Epidemiological Evidence, Underlying Mechanisms, and Population Differences.

Subjective age-how old an individual feels-is a robust predictor of health outcomes and mortality independent of chronological age. Sleep, as a fundamental and modifiable health behavior, has been increasingly implicated as a determinant of subjective aging, yet the evidence remains fragmented across disciplines. This narrative review synthesizes current knowledge on the association between sleep problems and subjective age by critically appraising epidemiological evidence, delineating potential mechanistic pathways, and examining population-level moderators. Converging evidence from cross-sectional surveys, longitudinal cohorts, and one randomized crossover trial consistently demonstrates that poor sleep quality and insufficient sleep are associated with older subjective age. Daytime sleepiness is the only mediator with preliminary empirical support; additional candidate pathways-including accelerated brain aging, cortisol rhythm dysregulation, impaired emotional regulation, and appearance-related social feedback-remain theoretically plausible but empirically untested. The association appears stronger in women, middle-aged and older adults, and morning chronotypes, although moderator evidence is limited. Critical gaps persist, including the absence of chronic sleep intervention trials in older populations, near-exclusive reliance on self-reported sleep measures, and insufficient mechanistic research. Future priorities include prospective studies integrating objective sleep assessment, randomized trials of evidence-based sleep interventions targeting subjective age in midlife and older populations, and direct testing of the proposed multi-level mechanistic framework. These findings position sleep health as a promising yet underexplored leverage point for promoting psychological healthy aging.