Interventions to improve the sleep of nurses: A systematic review.

Nurses are at a high risk for short sleep duration and poor sleep quality due to irregular work schedules and high occupational stress. Considering the effect of nurses' sleep on the safety and health of themselves and their patients, it is important to promote healthy sleep for nurses. We sought to synthesize the published experimental and quasi-experimental studies that address interventions to improve sleep in nurses. A systematic search was conducted for studies published in English up until May 15, 2023, using the databases PubMed, CINAHL, Academic Search Ultimate, and PsycINFO. In total, 38 articles were included, covering 22 experimental and 16 quasi-experimental studies with sample sizes ranging from 9 to 207. Studies were assessed using the Cochrane Risk of Bias tool and considered as low to medium quality. Thirty-six of the 38 studies reported positive findings for at least one sleep outcome. Intervention types included aroma therapy, dietary supplements, cognitive behavioral therapy, light therapy, mind-body therapy, sleep education, exercise, napping, shift schedule modification, and multicomponent intervention, all of which showed moderate effectiveness in promoting sleep outcomes of nurses. Comparing and contrasting studies on specific interventions for improving sleep in nurses is sparse and often equivocal. With the variations of research methodology and outcome measures, it is difficult to make a conclusion about each intervention's effectiveness on specific sleep outcomes. Additional high-quality research, including randomized controlled trials, is needed to evaluate strategies for improving sleep in this unique, safety-sensitive occupational group.

Understanding the association between sleep, shift work and COVID-19 vaccine immune response efficacy: Protocol of the S-CORE study.

This protocol describes an innovative study to investigate the relationship between sleep, shift work and the immune response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2; coronavirus disease 2019 [COVID-19]) vaccination. As the COVID-19 pandemic is a global crisis with devastating health, social and economic impacts, there is a pressing need for effective vaccination programmes. Previous influenza and hepatitis vaccination studies suggest that lack of sleep can negatively alter immune responsiveness, while circadian misalignment most likely may also play an important role in the immune response to vaccination. Our present study will be the first to address this question in actual shift workers and in relation to COVID-19 vaccination. We hypothesise that the occurrence of recent night shifts and diminished sleep will negatively alter the immune response to vaccination in shift workers compared to dayworkers. We aim to recruit 50 shift workers and 50 dayworkers. Participants will receive an mRNA-based vaccination, through the Dutch vaccination programme. To assess immune responsiveness, blood will be drawn at baseline (before first vaccination), 10 days after first vaccination, the day prior to the second vaccination; and 28 days, 6 and 12 months after the second vaccination. Actigraphy and daily sleep e-diaries will be implemented for 7 days around each vaccination to assess sleep. The Pittsburgh Sleep Quality Index will be used to monitor sleep in the long term. Optimising the efficacy of the COVID-19 vaccines is of outmost importance and results of this study could provide insights to develop sleep and circadian-based interventions to enhance vaccination immunity, and thereby improve global health.

Evaluation of sleep strategies between night shifts in actual shift workers.

OBJECTIVES: The aim of this observational study was to examine sleep obtained between consecutive night shifts from shift workers in their natural environment. The goal was to identify the various sleep strategies and the timing, duration, regularity, and quality of sleep associated with the strategies. METHODS: Participants (N = 33, 23 women, aged 40 ± 15years) reported their sleep information in daily diaries over 2weeks while working at least one series of consecutive night shifts. Sleep timing, duration, quality, and regularity were calculated for each sleep episode between consecutive night shifts. RESULTS: Based on the reported sleep behavior, shift workers were categorized as either morning, delayed, split- or mixed sleepers. We found significant differences between the groups in timing of sleep, feeling refreshed, and regularity of sleep between consecutive night shifts, whereas duration and subjective soundness of sleep did not show significant differences. CONCLUSIONS: In this sample, four sleep strategies were observed between consecutive night shifts in actual shift workers. These observations may help design future interventions to improve sleep that are individualized to the worker.

Feasibility, effectiveness, and acceptability of an afternoon-evening sleep schedule in older nightshift workers.

Study Objectives: To explore the feasibility, effectiveness, and acceptability of an afternoon-evening sleep schedule in older (age 50-65 years) nightshift workers. Methods: We used a three-part strategy: a screening survey to identify individuals who said they could adopt an 8-hour afternoon-evening sleep schedule; a field study where daily diary and actigraphy data were collected during a baseline week and intervention week, with randomization to self-selected sleep, 8-hour afternoon-evening time in bed (TIB), or 8-hour self-selected TIB; and follow-up focus groups to understand the acceptability of the intervention. Results: Gender (p < 0.001), Hispanic ethnicity (p = 0.023), the care of children (p = 0.014), and chronotype (p = 0.012), predicted the reported ability to spend 8 hours in bed in the afternoon-evening. Participants assigned to the 8-hour self-selected and 8-hour afternoon-evening groups significantly increased their TIB and sleep duration compared to baseline (p < 0.05), while the control group did not. Although spending 8 hours in bed was feasible for the participants during the study, focus group discussions indicated participants would not continue an 8-hour TIB schedule after the study due to family responsibilities and other activities of daily living. Conclusions: Spending 8 hours in bed between successive night shifts, initiated at both a self-selected time and in the afternoon-evening, increased the sleep duration of older shiftworkers, but most would not continue such a schedule on their own. Additional research is needed to find countermeasures for the reduced sleep duration experienced by most shiftworkers that are not only effective, but also compatible with shiftworkers' lifestyles.

The Importance of Sleep and Circadian Rhythms for Vaccination Success and Susceptibility to Viral Infections.

Sleep and circadian rhythms are closely involved in the immune system and its regulation. Here, we describe this relationship and provide recommendations regarding the influence of sleep and circadian rhythms on vaccination success. We review studies investigating how viral susceptibility is influenced by changes in immunological parameters as a consequence of sleep deprivation. Short sleep duration and poor sleep efficiency both appear to be strong factors leading to greater vulnerability. In addition, both sleep duration and the time of day of the vaccination seem to be associated with the magnitude of the antibody response after vaccination. Based on these findings, a recommendation would consist of a sleep duration of 7 h or more every night to both reduce the risk of infection and to optimize the efficacy of vaccination with respect to circadian timing. Improving sleep quality and its circadian timing can potentially play a role in preventing infection and in vaccination benefits. In conclusion, sufficient (or longer) sleep duration is important in both reducing susceptibility to infection and increasing antibody response after vaccination.

Google Trends reveals increases in internet searches for insomnia during the 2019 coronavirus disease (COVID-19) global pandemic.

STUDY OBJECTIVES: The 2019 coronavirus disease (COVID-19) has become a global health and economic crisis. Recent evidence from small samples suggest that it has increased mood and sleep disturbances, including insomnia, around the world. This study aimed to estimate the effect of COVID-19 on insomnia levels worldwide and in the United States during the acute phase of the pandemic. METHODS: We analyzed search query data recorded between January 2004 and May 2020 from Google Trends and Google Keyword Planner for the search term "insomnia". RESULTS: The number of search queries for insomnia has increased over the past decade and is greater than the number of search queries for other major sleep disorders. The COVID-19 pandemic increased search queries for insomnia both worldwide and in the United States, with the number in the United States increasing by 58% during the first 5 months of 2020 compared with the same months from the previous 3 years. There is a robust diurnal pattern in insomnia search queries in the United States, with the number of queries peaking around 3 am and the overall pattern remaining stable during the pandemic. CONCLUSIONS: These results highlight the impact the COVID-19 pandemic has had on sleep health and the urgent need for making effective interventions accessible. Future studies will be needed to determine whether the increase in insomnia symptoms will persist and lead to higher rates of chronic insomnia in the population.

Efficacy of intermittent exposure to bright light for treating maladaptation to night work on a counterclockwise shift work rotation.

OBJECTIVES: Rotating shift work is associated with adverse outcomes due to circadian misalignment, sleep curtailment, work-family conflicts, and other factors. We tested a bright light countermeasure to enhance circadian adaptation on a counterclockwise rotation schedule. METHODS: Twenty-nine adults (aged 20-40 years; 15 women) participated in a 4-week laboratory simulation with weekly counterclockwise transitions from day, to night, to evening, to day shifts. Each week consisted of five 8-hour workdays including psychomotor vigilance tests, two days off, designated 8-hour sleep episodes every day, and an assessment of circadian melatonin secretion. Participants were randomized to a treatment group (N=14), receiving intermittent bright light during work designed to facilitate circadian adaptation, or a control group (N=15) working in indoor light. Adaptation was measured by how much of the melatonin secretion episode overlapped with scheduled sleep timing. RESULTS: On the last night shift, there was a greater overlap between melatonin secretion and scheduled sleep time in the treatment group [mean 4.90, standard deviation (SD) 2.8 hours] compared to the control group (2.62, SD 2.8 hours; P=0.002), with night shift adaptation strongly influenced by baseline melatonin timing (r2=-0.71, P=0.01). While the control group exhibited cognitive deficits on the last night shift, the treatment group's cognitive deficits on the last night and evening shifts were minimized. CONCLUSIONS: In this laboratory setting, intermittent bright light during work hours enhanced adaptation to night work and subsequent readaptation to evening and day work. Light regimens scheduled to shift circadian timing should be tested in actual shift workers on counterclockwise schedules as a workplace intervention.

Prediction of individual differences in circadian adaptation to night work among older adults: application of a mathematical model using individual sleep-wake and light exposure data.

Circadian misalignment remains a distinct challenge for night shift workers. Variability in individual sleep-wake/light-dark patterns might contribute to individual differences in circadian alignment in night shift workers. In this simulation study, we compared the predicted phase shift from a mathematical model of the effect of light on the human circadian pacemaker to the observed melatonin phase shift among individuals who completed one of four interventions during simulated night shift work. Two inputs to the model were used to simulate circadian phase: sleep-wake/light-dark patterns measured from a wrist monitor (Simulation 1) and sleep-wake/light-dark patterns measured from a wrist monitor enhanced by known light levels measured at the level of the eye during simulated night shifts (Simulation 2). The estimated phase shift from the model was within 2 hours of the observed phase shift in ~80% of night shift workers for both simulations; none of the model-predicted phase shifts was more than ~3 hours from the observed phase shift. Overall, the root-mean-square error between observed and predicted phase shifts was better for Simulation 1. The light input from the wrist monitor informed by actual light level measured at the eye performed better in the sub-group exposed to bright light during their night shifts. The findings from this simulation study suggest that using a mathematical model combined with sleep-wake and light exposure data from a wrist monitor can facilitate the design of shift work schedules to enhance circadian alignment, which is expected to improve sleep, alertness, and performance.

Are individuals' nighttime sleep characteristics prior to shift-work exposure predictive for parameters of daytime sleep after commencing shift work?

This study aimed to examine prospectively whether individual nighttime sleep characteristics at baseline (prior to shift-work exposure) are related to parameters of daytime sleep after commencing shift work. A longitudinal field study was carried out with novice police officers of the Dutch Police Force. A total of 26 subjects were examined at baseline before they entered shift work and re-examined during follow-up sessions after four and twelve months of shift-work exposure. Wrist actigraphy and sleep diaries were used to study nocturnal sleep at baseline and daytime sleep after night shifts during follow-up sessions. As outcome variables, estimated total sleep time, sleep efficiency, and subjective sleep quality were analyzed. Daytime total sleep time showed a 66 min decline during the first year of shift-work exposure. Systematic inter-individual differences were observed for daytime total sleep time and subjective sleep quality (explaining 53% and 38% of the variance, respectively), suggesting potential predictability of these sleep parameters. Although no predictors were found for daytime total sleep time, the subjective quality of nighttime sleep before the onset of shift work predicted 40% of the variance in the subjective quality of daytime sleep after commencing shift work. Follow-up studies may reveal whether the subjective quality of baseline nighttime sleep also predicts long-term overall tolerance for shift work.

Inter-individual differences in sleep response to shift work in novice police officers - A prospective study.

The aim of this longitudinal study on novice police officers was to investigate inter-individual differences in sleep response to shift work, and to identify potential baseline predictors thereof. A total of 42 subjects were assessed at baseline, prior to commencing shift work. They were re-assessed during three follow-up sessions within the first 2 years of shift work exposure after approximately 4, 12, and 20 months of rotating shift work. Wrist actigraphy and sleep logs were used to investigate nocturnal sleep at baseline and daytime sleep after night shifts during the follow-up sessions. Actigraphically estimated total sleep time and subjective sleep quality were analyzed as outcome variables, using mixed-effects analysis of variance. Systematic inter-individual differences were observed in the overall response of these outcome variables to shift work. In this sample, flexibility of sleeping habits and gender were found to be predictors of daytime total sleep time in the first 2 years of shift work exposure. Flexibility of sleeping habits and subjective quality of nighttime sleep prior to shift work were found to be predictors of subjective quality of daytime sleep. These results suggest that it may be possible to detect and even predict sleep deficiencies in response to shift work early on, which could be a basis for the development of individualized interventions to improve shift work tolerance.

Individual differences in the cortisol-awakening response during the first two years of shift work: A longitudinal study in novice police officers.

Cortisol acts as a critical biological intermediary through which chronic stressors like shift work impact upon multiple physiological, neuro-endocrine and hormonal functions. Therefore, the cortisol awakening response (CAR) is suggested as a prime index of shift work tolerance. Repeated assessments of the CAR (calculated as MnInc) in a group of 25 young novice police officers showed that in the interval between about 4 and 14 months after transitioning from regular day work to rotating shift work, mean values began to rise from baseline to significantly higher levels at about 14 months after they commenced shift work. Visual inspection of the individual trends revealed that a subgroup of 10 subjects followed a monotonically rising trend, whereas another 14 subjects, after an initial rise from about 4-14 months, reverted to a smaller, baseline level cortisol response at about 20 months after the start of shift work. If the initial increase in the cortisol response marks the development of a chronic stress response, the subsequent reversal to baseline levels in the subgroup of 14 participants might be indicative of a process of recovery, possibly the development of shift work tolerance.