Day-to-day associations between nightly sleep and next-day well-being amid the COVID-19 pandemic in North America

OBJECTIVE: Sleep may be especially important for maintaining health and well-being in daily life amid the stress of the coronavirus disease 2019 (COVID-19) pandemic. This preregistered study examined the associations of sleep quality, duration, and efficiency with next-day physical symptoms, affect, and stressors during the COVID-19 pandemic in North America, in addition to evaluating individual differences in COVID-19 threat as a moderator. METHOD: From mid-March to early August 2020, 1025 adults from Canada and the United States aged 18-91 reported COVID-19 threat at baseline and subsequently completed twice-daily diaries for one week about their sleep, negative affect, stressors, and physical symptoms. RESULTS: Within-persons, nights with better-than-usual sleep quality predicted lower next-day negative affect, physical symptoms, and stressor occurrence. Better-than-usual sleep efficiency and longer-than-usual sleep duration also predicted lower next-day physical symptoms. COVID-19 threat ratings moderated several of these associations, such that individuals with higher COVID-19 threat showed weaker within-person associations of sleep duration and efficiency with next-day well-being, compared to individuals with lower-to-moderate levels of COVID-19 threat. For the reversed direction of association, stressor occurrence predicted shorter-than-usual sleep that night, but no other links between daily well-being and subsequent sleep were observed. DISCUSSION: Sleep quality, efficiency, and duration were important predictors of daily health and well-being during the COVID-19 pandemic, but the protective associations between sleep and next-day well-being were attenuated among people with higher COVID-19 threat. These findings highlight the role of heightened stress contexts when considering the benefits of sleep on daily health and well-being.