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Sleep and circadian indices for planning post-pandemic university timetables

The aims of the present study were to obtain sleep quality and sleep timing information in a group of university students, and to evaluate the effects of a circadian hygiene education initiative. All students of the University of Padova (approximately 64,000) were contacted by e-mail (major campaigns in October 2019 and October 2020) and directed to an ad hoc website for collection of demographics and sleep quality/timing information. Participants (n=5740) received one of two sets of circadian hygiene advice ('A regular life' or 'Bright days and dark nights'). Every month, they were then asked how easy it had been to comply, and provided with the advice again. At any even month from joining, they completed the sleep quality/timing questionnaires again. Information on academic performance was obtained post hoc, together with representative samples of lecture (n=5972) and exam (n=1800) timings, plus lecture attendances (n=25,302). 52% of students had poor sleep quality and 82% showed signs of sleep deprivation. Those who joined in October 2020, after several months of lockdown and distance learning, had better sleep quality, less sleep deprivation and later sleep habits. The 'Bright days and dark nights' advice resulted in earlier get-up time/midsleep compared to the 'A regular life' advice. Significant changes in most sleep quality and sleep timing variables were observed in both advice groups over time, also in relation to pandemic-related events characterising 2020. Early-chronotype students had better academic performances compared to their later chronotype counterparts. In a multivariate model, sleep quality, chronotype and study subject were independent predictors of academic performance. Taken together, these results underlie the importance of designing circadian-friendly university timetables.