Comprehensive Assessment of Sleep, Well-being, and Work Factors

A few days before the start of the pre-intervention period, participants filled out an entry questionnaire (T1), where demographic data and information about individual sleep problems using the PSQI were assessed. The PSQI reliably measures the self-reported sleep quality over the past 4 weeks by means of 19 items and covers seven areas, namely, subjective sleep quality, sleep latency, sleep duration, habitual SE, sleep disturbances, use of sleep medication, and daytime dysfunction. The global PSQI score ranges from 0 to 21, while a value of >5 suggests “bad sleep,” and a value of >10 is considered a sleep disorder with clinical relevance. Furthermore, work-related demands and resources [COPSOQ; (39 (link))], work-related distress and eustress (40 ), as well as subjective general well-being [HSWBS; (41 )] were collected in this questionnaire. The COPSOQ, work-related distress and eustress, and the HSWBS were collected again at T2 and T3¹. In addition to this, participants completed daily morning and evening protocols, which were available using the “PsyDiary” mobile-phone app (Eating Behavior Laboratory, University Salzburg–SmartHealthCheck Project). The morning diary (refer to Supplementary Table 1) collected (based on one item each) the subjective evaluation of the previous night's sleep quality (“How did you sleep tonight?”, from “very bad” to “very good”), self-reported vitality (“How do you feel at the moment?”, from “faint” to “alive”), and current mood (“How is your mood at the moment?”, from “very bad” to “very good”) via a slider bar from 0 to 100. Furthermore, subjective psychological well-being was assessed as part of the morning diary by the use of an adapted version of the WHO-Five Well-Being Index (42 ), which is answered on a 5-point Likert scale and consists of five statements like, for example, “I feel cheerful and in good spirits.” In the evening, the evaluation of daily job demands and resources, self-reported tension, psychological detachment, and daily sleepiness was assessed using 15 questions (refer to Supplementary Table 2). Participants were instructed to fill out the daily protocol in the morning 30–60 min after turning on the lights and in the evening at least 2 h before going to bed. Questionnaire data (i.e., T2 and T3) were obtained before the personal meetings with the study team.