Sleep longer, think sharper: extra sleep offsets poor sleep quality in young-old adults

OBJECTIVES: Sleep and cognitive functioning are linked. Yet, how sleep hours and sleep quality shape day-to-day subjective cognition, including cognitive interference and memory lapses, remains unclear. This study examined the unique and joint associations of sleep hours and quality with daily cognitive interference and memory lapses, investigating age-related variations. METHODS: Participants were 915 adults (aged 43-83) from the Midlife in the United States Study who completed 8 days' diaries. Multilevel models evaluated the unique and joint associations of sleep hours and sleep quality with cognitive interference and memory lapses focusing at the within-person level, beyond between-person associations. Age-stratified models explored potential differences across age groups. RESULTS: Poorer sleep quality was associated with increased next-day cognitive interference, controlling for sleep hours. Individuals with poorer sleep quality across the study period also experienced greater cognitive interference and more frequent memory lapses. The association between poorer sleep quality and heightened cognitive interference was mitigated both on days when sleep hours were longer than usual and among individuals with longer sleep hours than others in the sample. Age-stratified analyses demonstrated that longer daily and habitual sleep hours mitigated the adverse effects of poorer sleep quality on cognitive interference only in adults aged 60-67. DISCUSSION: Poor sleep hours and quality may impair daily cognition, yet extra sleep hours can mitigate the negative association of poor sleep quality on daily cognitive interference, especially among young-old adults. These findings highlight the nuanced interplay of sleep hours, sleep quality, and age in shaping daily cognition.