Abstract
Sleep is a fundamental biological process associated with diverse physiological and psychological functions, yet systematic, population-level, objective descriptions of its variation across demographic and psychological factors are still emerging. Here, we characterize age- and sex-related differences in sleep and their associations with mood using week-long actigraphy data from UK Biobank participants aged 44-82. Robust age- and sex-related differences in sleep were identified (n = 38 546) and replicated (n = 38 547), reflecting reliable nonlinear interactions between age and sex. Younger women slept about 17 min more than their male counterparts, though this difference diminished with age, with both sexes reducing total sleep duration in later life. Middle-aged individuals exhibited shorter sleep durations during the week, with weekend sleep increasing by as much as 50 min. Participants in their seventh and eighth decades showed more consistent sleep patterns throughout the week. Sleep patterns also suggest maintenance of total sleep duration: individuals reporting waking too early maintain sleep duration by going to sleep earlier, while individuals reporting sleeping too much fall asleep later but also wake later, again maintaining sleep duration. Self-reported depression and anhedonia were associated with reduced total sleep duration across multiple age groups and both sexes. By systematically mapping actigraphy-derived sleep features across demographic strata and linking them to subjective reports of sleep and mood, this study provides an integrated framework that complements and extends prior findings, offering a valuable reference point for future investigations of sleep-mood associations in large cohorts.