0193 Sleep Value Is Not Stable: Hourly Fluctuations and Their Association with Insomnia Symptoms

Abstract Introduction Sleep value is the relative worth individuals place on sleep and may be a critical component in understanding decisions made around sleep and the daily experience of sleep disorders. Previous studies have linked sleep value to individual traits and broader personal value systems, yet it remains unclear how sleep value fluctuates across the day or shifts in relation to momentary sleep–wake intentions. The current study presented a novel method of measuring monetary sleep value across the 24-hour day and aimed to characterize how monetary sleep value relates to daily activities and insomnia symptoms. Methods Undergraduates (N=45) completed a baseline survey of demographics and sleep-related information including the Insomnia Severity Index (ISI) grouping participants as insomnia vs no insomnia (ISI < 10). They then completed the Sleep Value State Questionnaire (SVSQ) once each hour for twenty-four consecutive hours reporting their intended activity for the next hour (sleep or stay awake). If intending to sleep, they reported how much they would need to be paid to stay awake; if intending to stay awake, how much to attempt to sleep. They also reported sleepiness and how much they would pay for a quality hour of sleep. Mixed-design repeated-measures ANOVAs assessed within-person differences by planned activity and between-person differences by insomnia severity. Results Significant time effects emerged for sleepiness and the monetary value of a quality hour of sleep, peaking at $20 at 4 a.m., F(5.62, 236.08) = 13.95, p < .001. Participants placed higher monetary value on sleep when it conflicted with their planned state, requiring $25 to do the opposite, F(1,42) = 54.85, p < .001, partial η² = .57. They were willing to pay more for quality sleep when planning to sleep (M = $20) versus stay awake (M = $3). Insomnia did not significantly affect monetary sleep value. Conclusion These findings show that perceived sleep value is dynamic, rising sharply during the biological night and further when aligned with immediate intentions. Planned state strongly influences sleep valuation, whereas insomnia status does not. Circadian timing and momentary goals both shape how people prioritize and value sleep. Support (if any)