Subjective sleep may mediate the associations between tomorrow anticipations and next-day affect.

This study investigated whether stress and positive anticipations about tomorrow are associated with emotional experiences the following day, mediated by the preceding night's sleep. Data were from 141 full-time nurses, utilizing a 14-day ecological momentary assessment combined with actigraphy sleep monitoring. Each evening, participants rated the anticipated pleasantness or stressfulness of the following day. Each morning, participants reported on their previous night's sleep. Additionally, participants reported their momentary positive affect (PA) and negative affect (NA) three times per day, with daily averages computed. Multilevel mediation models, adjusted for sociodemographics, work shift, workday, and previous day's affect, revealed that days following more stress anticipations were associated with reduced PA and increased NA. Conversely, days following more pleasantness anticipations were associated with increased PA and decreased NA. These within-person associations were mediated by self-reported time-in-bed, sufficiency, and quality, such that less stressful and more pleasant anticipations were associated with better sleep, and better sleep was subsequently associated with increased PA and decreased NA. No mediation was found by the actigraphy sleep parameters. Findings suggest that emotional states may covary not only with present stimuli but also with anticipation of future events and subjective sleep recovery in the context of those anticipations.