Sleep and work functioning in nurses undertaking inpatient shifts in a blue-depleted light environment.

BACKGROUND: Blue-depleted light environments (BDLEs) may result in beneficial health outcomes for hospital inpatients in some cases. However, less is known about the effects on hospital staff working shifts. This study aimed to explore the effects of a BDLE compared with a standard hospital light environment (STLE) in a naturalistic setting on nurses' functioning during shifts and sleep patterns between shifts. METHODS: Twenty-five nurses recruited from St. Olavs Hospital in Trondheim, Norway, completed 14 days of actigraphy recordings and self-reported assessments of sleep (e.g., total sleep time/sleep efficiency) and functioning while working shifts (e.g., mood, stress levels/caffeine use) in two different light environments. Additionally, participants were asked to complete several scales and questionnaires to assess the symptoms of medical conditions and mental health conditions and the side effects associated with each light environment. RESULTS: A multilevel fixed-effects regression model showed a within-subject increase in subjective sleepiness (by 17%) during evening shifts in the BDLE compared with the STLE (p = .034; Cohen's d = 0.49) and an 0.2 increase in number of caffeinated beverages during nightshifts in the STLE compared with the BDLE (p = .027; Cohen's d = 0.37). There were no significant differences on any sleep measures (either based on sleep diary data or actigraphy recordings) nor on self-reported levels of stress or mood across the two conditions. Exploratory between-group analyses of questionnaire data showed that there were no significant differences except that nurses working in the BDLE reported perceiving the lighting as warmer (p = .009) and more relaxing (p = .023) than nurses working in the STLE. CONCLUSIONS: Overall, there was little evidence that the change in the light environment had any negative impact on nurses' sleep and function, despite some indication of increased evening sleepiness in the BDLE. We recommend further investigations on this topic before BDLEs are implemented as standard solutions in healthcare institutions and propose specific suggestions for designing future large-scale trials and cohort studies. TRIAL REGISTRATION: The study was registered before data collection was completed on the ISRCTN website ( ISRCTN21603406 ).

The effects of digital CBT-I on work productivity and activity levels and the mediational role of insomnia symptoms: Data from a randomized controlled trial with 6-month follow-up.

STUDY OBJECTIVES: Cognitive behavioral therapy for insomnia (CBT-I) is a well-established treatment for insomnia, but few studies have explored its impact on work and activity impairment. METHODS: Data stem from 1721 participants enrolled in a randomized controlled trial comparing the efficacy of digital CBT-I compared with Patient Education. Baseline and 6-month follow-up assessments included self-reported ratings of presenteeism and general impairment (Work Productivity and Activity Impairment Questionnaire), and absenteeism (hours of missed work) and employment status. Insomnia was measured using the Insomnia Severity Index (ISI). Mediation analyses were conducted for each outcome with ISI scores at baseline and 9-week follow-up as the mediator. The analyses were adjusted for potential confounders (e.g., sex, age, comorbidities). RESULTS: dCBT-I was found to be associated with reduced activity impairment compared with PE (by 5.6%) but not presenteeism, absenteeism, or changes in employment status. Mediation analysis showed that changes in insomnia severity largely mediated improvements in presenteeism (by 5.4%) and activity impairment (by 5.5%). There were no significant mediational effects on absenteeism or employment status. CONCLUSIONS: This study shows that dCBT-I is not only effective in improving insomnia. But also demonstrates positive effects on work and daily activities in general, supporting the need for increased access to dCBT-I.

The evening light environment in hospitals can be designed to produce less disruptive effects on the circadian system and improve sleep.

STUDY OBJECTIVES: Blue-depleted lighting reduces the disruptive effects of evening artificial light on the circadian system in laboratory experiments, but this has not yet been shown in naturalistic settings. The aim of the current study was to test the effects of residing in an evening blue-depleted light environment on melatonin levels, sleep, neurocognitive arousal, sleepiness, and potential side effects. METHODS: The study was undertaken in a new psychiatric hospital unit where dynamic light sources were installed. All light sources in all rooms were blue-depleted in one half of the unit between 06:30 pm and 07:00 am (melanopic lux range: 7-21, melanopic equivalent daylight illuminance [M-EDI] range: 6-19, photopic lux range: 55-124), whereas the other had standard lighting (melanopic lux range: 30-70, M-EDI range: 27-63, photopic lux range: 64-136), but was otherwise identical. A total of 12 healthy adults resided for 5 days in each light environment (LE) in a randomized cross-over trial. RESULTS: Melatonin levels were less suppressed in the blue-depleted LE (15%) compared with the normal LE (45%; p = 0.011). Dim light melatonin onset was phase-advanced more (1:20 h) after residing in the blue-depleted LE than after the normal LE (0:46 h; p = 0.008). Total sleep time was 8.1 min longer (p = 0.032), rapid eye movement sleep 13.9 min longer (p < 0.001), and neurocognitive arousal was lower (p = 0.042) in the blue-depleted LE. There were no significant differences in subjective sleepiness (p = 0.16) or side effects (p = 0.09). CONCLUSIONS: It is possible to create an evening LE that has an impact on the circadian system and sleep without serious side effects. This demonstrates the feasibility and potential benefits of designing buildings or hospital units according to chronobiological principles and provide a basis for studies in both nonclinical and clinical populations.

The Effect of Reducing Insomnia Severity on Work- and Activity-Related Impairment.

OBJECTIVE/BACKGROUND: The effectiveness of Cognitive Behavioral Therapy for Insomnia (CBT-I) for alleviating sleep problems is well established. However, few studies have explored its impact on work productivity and activity. PARTICIPANTS: Seventy-seven currently employed adults with insomnia disorder (59 females) recruited to a randomized trial of digital versus face-to-face CBT-I. METHODS AND MATERIALS: The general health version of the Work Productivity and Activity Impairment questionnaire was used to measure absenteeism, presenteeism, total work impairment, and activity impairment. We assessed changes in work productivity and activity pre-to-post-therapy for the total sample and then for subgroups categorized according to response or remission of insomnia disorder (evaluated using the Insomnia Severity Index). RESULTS: Study participants showed significant improvements in presenteeism (p = .001; Cohen's d= 0.46), total work impairment (p < .001; d= 0.48), and activity (p < .001; d= 0.66), but not absenteeism (p = .51; d= 0.084) between baseline and follow-up assessment. Individuals meeting criteria for remission showed significantly greater improvement in presenteeism (p = .002), total work impairment (p < .001), and activity (p = .006), but not absenteeism (p = .064). CONCLUSION: This study suggests that the benefits of CBT-I extend beyond improvement in sleep to encompass moderate-to-large improvements in work productivity and activity levels particularly for individuals who achieve remission from insomnia. Given the importance of these behaviors, there is a need for future large-scale randomized trials and cohort studies which should strive to include objective measurement of daytime activity and work performance more frequently.