Going to bed later than intended is associated with shorter sleep and poorer next-day mood and sleepiness in residential college students

STUDY OBJECTIVES: The tendency to procrastinate bedtime is associated with poorer sleep and wellbeing. However, day-specific effects of bedtime procrastination are rarely studied and may differ depending on whether an individual has school/work the next day versus the flexibility to wake up later. We tested the hypothesis that going to bed later than intended would be associated with shorter sleep and worse next-day mood on school nights, but not nonschool nights, in residential college students. METHODS: Actigraphy-estimated sleep timing and duration were measured for 2 weeks in 104 university students. Daily diaries recorded instances of going to bed later than intended, morning mood, and daytime sleepiness. Mixed-effects models tested associations of delaying bedtime with same-night sleep duration and next-day mood and sleepiness, adjusting for demographics, chronotype, and school start time. RESULTS: Students went to bed later than intended on 54% of all nights. Individuals who delayed their bedtime more frequently had poorer self-rated sleep, higher presleep arousal, and higher depression scores. Going to bed later than intended was associated with shorter sleep by 0.91 h on school nights and 0.86 h on nonschool nights because there was no compensatory delay in wake-up time. Next-morning mood and daytime sleepiness were worse compared with nights with no bedtime delay. CONCLUSIONS: Residential college students who went to bed later than intended showed deficits in sleep duration and wellbeing irrespective of whether they needed to wake up for classes. Interventions to prevent bedtime procrastination may help students to achieve better sleep and mental health.