Night Shift Work Research Articles

Compassion fatigue prevalence and risk factors among Saudi psychiatric nurses: A cross-sectional study.

In recent times, compassion fatigue is increasingly being recognized as a damaging outcome associated with the stress experienced by psychiatric nurses. In addition to affecting their job performance work-related stress undermines nurses' physical and emotional well-being. However, there is a lack of research on compassion fatigue that specifically focuses on psychiatric nurses working in Saudi Arabia. This cross-sectional study investigated the prevalence and factors associated with compassion fatigue among Saudi psychiatric nurses. The study participants were asked to complete a demographic questionnaire and the Arabic form of the Professional Quality of Life Scale. Statistical analyses, including one-way ANOVA, t-tests, the Levene test, and multiple linear regression, were employed to assess variables related to compassion fatigue. The survey spanned 158 psychiatric nurses from the Mental Health Complex located in Riyadh City. The mean scores for compassion satisfaction, burnout, and secondary traumatic stress were 39.72 ± 6.881, 24.29 ± 5.386, and 26.94 ± 6.973, respectively. The analysis revealed that variables such as age range (36-55 years) and an associated degree or lower explained 5.2% of the variance in compassion satisfaction. Age range (18-25 years), exercise frequency, and years of nursing experience collectively accounted for 8.4% of the variables contributing to burnout. The age range (25 to 35 years) and working night shifts also explained 5% of the variance in secondary traumatic stress. The findings indicated that compassion satisfaction, burnout, and secondary traumatic stress among the population of psychiatric nurses working in Saudi Arabia were at a moderate level. A higher frequency of healthy lifestyle practices, such as regular exercise, and being in an older age range, were positively associated with compassion satisfaction and negatively associated with burnout and secondary traumatic stress.

The Effect of Night Shifts on Nurses' Health and Well-Being in Itanagar, Arunachal Pradesh

Objective: The objective of this study was to analyze the effect of night shift work on nurses’ health and well-being. Methods: 100 nurses in all were chosen at random from various hospital located in Itanagar. Data was collected from night shift working nurses by self-administered questionnaire through personal interview method. Data was used to gather information on socio- demographic, anthropometric measurements, professional, physical activity, food habits and intakes were collected. To study the detrimental impact of night shift employment on the health and wellbeing descriptive frequency and correlation were used. Results: One hundred nurses in all, the majority of them had one or more health issues, digestive problems includes- disturbed appetite (60%), heartburn or stomach-ache (71%), feeling nausea/ dizziness (75%), difficulty in digestion (72%) and suffer from constipation (52%). Cardiovascular problems of the respondents it was found that out of 100 respondents (16%) workers reported that they are on their high blood pressure or cardiac problems and chronic chest disorder (6%) followed by (45%) workers were low blood pressure. About 23% of nurses regularly skip meals, followed by 52% of nurses who did so once or twice, and the majority of nurses did not eat at set times. The results showed that 72% of nurses often ate fast food; only 8% of nurses took home-cooked meals with them for dinner. During night shifts, chips, cookies, sweets, and were the most popular munchies. Conclusion: This study demonstrated that nurses working nights have bad eating habits that cause their diets to be unbalanced. They eat less nutrient-dense foods but a greater number of meals that are rich in calories. They also rarely engage in any sort of exercise outdoors from what they do for a living and frequently prefer to eat snacks rather than full meals. The hospital's nurses need to get nutritional hygiene counseling, and night shift food service needs to be enhanced.

Development and validation of a questionnaire for assessment of happiness with reference to behavioral determinants of health. The Indian happiness rating scale III

Background: Recent surveys indicate that the prevalence of happiness is more common in developed countries compared to developing countries, which is considered due to better availability of affordable medical care, more satisfaction in life and economic development. It is possible that chronic anxiety, aggression and depression may be associated with lack of happiness which may predispose poor social, and physical health, leading to unhappiness. This study aims to develop and validate questionnaire for assessment of happiness with greater accuracy, in the behavioral risk factors, so that the same can be used as a tool in the population studies. Subjects and methods: This cross-sectional survey was conducted at Halberg Hospital and Research Institute, Moradabad, India. All subjects; 980 urban (495 men and 485 women), 900 rural (510 men and 390 women) above 25 years of age were randomly selected and recruited from urban and rural populations. Clinical data as well as risk factors were recorded with the help of case record form using the validated questionnaires. Assessment of happiness was made by a new more detailed modified questionnaire involving happiness of mind by including questions related to social, emotional and psychological health behaviours with reference to behavioural risk factors. Results: The prevalence of happiness was 62.2% (n=612) among urban and 63.2% (n=569) among rural subjects. The prevalence of very happy and satisfied (20.2 vs 22.2 %), moderately happy and satisfied (23.7 vs 22.9 %) and the modestly happy and satisfied (18.4 vs 17.9 %) were not significantly different among urban and rural subjects. It seems that the accuracy of the Indian Happiness Rating Scale III is good enough to assess happiness in other populations. The prevalence of behavioral risk factors; alcoholism, alcohol intake in moderation, sedentary behavior, western type diet intake, sleep disorders, emotional stress disorders, breakfast missing, late night dinner, night shift work, were significantly greater among urban subjects compared with rural subjects. However, among subjects with happiness, the frequency of moderate alcohol intake was significantly greater compared to subjects with no happiness among urbans. There were no gender differences in happiness. Conclusions: It is possible that this modified questionnaire with 16 attributes, may accurately assess the status of happiness and successfully used for assessment of happiness rates in urban and rural populations. The questionnaire allowed us to identify approximately two third subjects with happiness, among both urban and rural populations. Similar prevalence of happiness among urban and rural subjects, despite more behavioral risk factors among urbans, indicate that economic development may not be necessary for happiness. Further studies are necessary to find out the role of happiness in relations to health and behavioral risk factors.

Macronutrient intake and alertness during night shifts - the time interval matters.

Working night shifts is associated with higher safety risks due to shift work-related fatigue. Nutrition, especially certain (macro) nutrient compositions, has been suggested to reduce fatigue, however, results of studies are contradictory. This could be explained by differences in the time interval investigated between the consumption of a meal and measurement of cognitive performance. Therefore, this observational study investigated the association between macronutrient intake and objective alertness at different time intervals during the night shift in nurses. 128 nurses, aged 20-61 years, completed an alertness test (Psychomotor Vigilance Task) during the night shift and a 24-h dietary recall after the night shift. This was repeated three times, always on the first night shift in a night shift series. The associations between macronutrient intake 0 to 1, 1 to 2, and 2 to 3 h before the PVT with alertness during the night shift were analyzed through Linear Mixed Models. The basic model was adjusted for age and gender and the adjusted model additionally for BMI, start time of PVT and energy and caffeine intake during the relevant time interval. Protein intake was not associated with objective alertness levels, while fat and carbohydrates intake had opposite associations with objective alertness levels over similar time intervals. Fat intake up to 1 h prior to the PVT was borderline associated with a longer median reaction time (RT) (ß = 9.00 ms/10 g fat, 95% CI: -0.21, 18.20), while a higher carbohydrate intake up to 1 h prior to the PVT was borderline associated with shorter median RTs (ß = -3.89, 95% CI: -7.85, 0.06). A higher fat intake 2 to 3 h prior to the PVT was associated with less lapses (log transformed ß = -0.16; 95% CI: -0.31, -0.02), while a higher carbohydrate intake 2 to 3 h prior to the PVT was associated with more lapses (ß = 0.06, 95% CI: 0.01, 0.12). Our results contribute to understanding the association between macronutrient intake, as part of a mixed meal, and alertness levels. Conflicting results from previous studies may probably be due to time differences between macronutrient intake and alertness testing.

Association between physical activity and health in healthcare professionals : Results from the nationwide AMADEUS survey

ObjectiveThe objective of this study was to assess the prevalence of healthcare professionals engaging in insufficient levels of physical activity (PA) and to identify sociodemographic, professional and health characteristics associated with insufficient PA levels. MethodsWe conducted a nationwide online cross-sectional study targeting healthcare professionals in France from May 2021 to June 2021. Participant recruitment involved outreach through social networks, professional networks, and email invitations. PA levels were assessed using the International Physical Activity Questionnaire (IPAQ), with insufficient PA defined as weekly PA totaling less than 600 mets/week. ResultsThe study included a total of 10,325 participants, of whom 3939 (38.1%, 95% confidence interval 37.1–39.0%) exhibited insufficient levels of PA. In the multivariable analysis, we identified factors associated with insufficient PA: ages between 35–44 (aOR=1.58, 95%CI [1.21–2.06], p=.001) and 45–54 years (aOR=1.40, 95%CI [1.07–1.83], p =.015), gender (female aOR=1.47, 95%CI [1.12–1.44], p<.001), and professions including health executive (aOR=1.27, 95%CI [1.32–1.64], p<.001), nurse assistant (aOR=1.25, 95%CI [1.07–1.47], p=.006), and physician (aOR=1.18, 95%CI [1.03–1.34], p=.015). Additionally, burnout (aOR=1.32, 95%CI [1.21–1.44], p<.001), tobacco use (aOR=1.33, 95%CI [1.20–1.58], p<.001), being overweight (aOR=1.39, 95%CI [1.28–1.52], p<.001), major depression (aOR=1.44, 95%CI [1.20–1.47], p<.001), and sleep disorders (aOR=1.14, 95%CI [1.05–1.25], p=.002) were associated with insufficient PA. Work night shifts was associated with sufficient PA. ConclusionOur study has revealed a substantial prevalence of healthcare professionals with insufficient PA levels. This prevalence, coupled with various associated health-damaging behaviors and mental health issues, underscores the importance of acknowledging the barriers they encounter in adopting a physically active lifestyle.

Poor sleep and shift work associate with increased blood pressure and inflammation in UK Biobank participants

Disrupted circadian rhythms have been linked to an increased risk of hypertension and cardiovascular disease. However, many studies show inconsistent findings and are not sufficiently powered for targeted subgroup analyses. Using the UK Biobank cohort, we evaluate the association between circadian rhythm-disrupting behaviours, blood pressure (SBP, DBP) and inflammatory markers in >350,000 adults with European white British ancestry. The independent U-shaped relationship between sleep length and SBP/DBP is most prominent with a low inflammatory status. Poor sleep quality and permanent night shift work are also positively associated with SBP/DBP. Although fully adjusting for BMI in the linear regression model attenuated effect sizes, these associations remain significant. Two-sample Mendelian Randomisation (MR) analyses support a potential causal effect of long sleep, short sleep, chronotype, daytime napping and sleep duration on SBP/DBP. Thus, in the current study, we present a positive association between circadian rhythm-disrupting behaviours and SBP/DBP regulation in males and females that is largely independent of age.

Evaluation of the Diurnal Cycle of Blood Pressure and Sleep in Shift Workers.

Circadian misalignment of physiological factors in shift workers is poorly studied in the Indian population. In the present study, 24-hour blood pressuremeasurements were taken on the same subject twice, once during his morning and night shifts. Sleep was also monitored by a self-reported sleep diary, which was confirmed with an activity monitor, and the sleep quality was assessed using sleep questionnaires. This study aimed to discover the pattern of blood pressure variation, the dipping and non-dipping status, and its correlation with sleep. This observational study was conducted in the Department of Physiology, All India Institute of Medical Sciences (AIIMS), Rishikesh, from April 2019to September 2019, among security guards working rotating shifts in theRishikesh hospital premises. Participants were given an activity sheet with instructions to document their daily activities for a complete 24-hour period on the designated measurement day, including recording the time of waking up and going to sleep. A wrist-worn activity monitor was utilised to assess the self-reported sleep duration provided by each participant on the activity sheet. The present study showed the mean age of the participants as 27.03 ± 2.71 years, along with a mean body mass index (BMI) of 22.10 ± 1.64.Sleep duration was significantly higher during the morning shift (5.81 ± 1.08 hours) compared to the night shift (4.02 ± 1.70 hours) on the day of ambulatory blood pressure monitoring (ABPM) recording.The mean difference in systolic blood pressure between night shift workers between their awake and sleep periods was 15.91 ± 8.44 mmHg.However, no statistically significant disparity was seen when comparing the systolic blood pressure at the 24-hour mark during wakefulness and sleep between those working morning and night shifts(p >0.05). The current study's findings indicate that participation in shift work, particularly night shift work, could potentially play a role in the emergence of irregular circadian blood pressure patterns and potentially lead to a lack of nocturnal blood pressure decline.

Analysis of the Stress of Health Workers of Psychiatry Clinic and Dermatovenerology Clinic

Abstract Stress at a workplace represents stress caused by the job of a person, which occurs when the demands of the workplace are not in accordance with the needs of health workers. Two basic types of pathological stress at workplace are: burnout syndrome at work and technostress. The set goals were to assess the level of stress among health workers employed by the Psychiatric Clinic and the Dermatovenerology Clinic, and compare the results obtained, and identify a group of health workers exposed to the highest level of stress within the studied healthcare institutions. A total of 93 respondents were included in the study, of which 43 were from the Dermatovenerology Clinic and 50 from the Psychiatric Clinic. In the process of collecting data from respondents, the questionnaire used is modified version of “The Workplace Stress Scale”. The most important is to note that there is no correlation between night-shift work and stress level, as well as gender, or level of education, even though many studies in the world indicate a connection between these factors - which is marked as an increased risk of stress. Starting from the goals of the work, it is concluded that employees at the Dermatovenerology Clinic are more exposed to stress than employees in the Psychiatric Clinic. The level of education, gender, age, shift work does not affect the level of stress. The factor that most affects the level of stress is personal income and a short deadline for executing the given actions.

Circadian adaptation to night shift work is associated with higher REM sleep duration

ObjectiveTo investigate the influence of the degree of circadian adaptation to night work on sleep architecture following night shift. MethodsThirty four night workers (11 females; 33.8 ± 10.1years) completed a simulated night shift following 2-7 typical night shifts. Participants completed a laboratory-based simulated night shift (21:00-07:00 hours), followed by a recovery sleep opportunity (∼09:00-17:00 hours), recorded using polysomnography. Urinary 6-sulphatoxymelatonin (aMT6s) rhythm acrophase was used as a marker of circadian phase. Sleep duration and architecture were compared between individuals with aMT6s acrophase before (unadapted group, n = 22) or after (partially adapted group, n = 12) bedtime. ResultsBedtime occurred on average 2.16 hours before aMT6s acrophase in the partially adapted group and 3.91 hours after acrophase in the unadapted group. The partially adapted group had more sleep during the week before the simulated night than the unadapted group (6.47 ± 1.02 vs. 5.26 ± 1.48 hours, p = .02). After the simulated night shift, both groups had similar total sleep time (partially adapted: 6.68 ± 0.80 hours, unadapted: 6.63 ± 0.88 hours, p > .05). The partially adapted group had longer total rapid eye movement sleep duration than the unadapted group (106.79 ± 32.05 minutes vs. 77.90 ± 28.86 minutes, p = .01). After 5-hours, rapid eye movement sleep accumulation was higher in the partially adapted compared to the unadapted group (p = .02). Sleep latency and other stages were not affected by circadian adaptation. DiscussionPartial circadian adaptation to night shift was associated with longer rapid eye movement sleep duration during daytime sleep, highlighting the influence of entrainment between the sleep-wake cycle and the circadian pacemaker in night workers. The findings have important implications for sleep and subsequent alertness associated with shift work.

Interindividual variability in coherence between self-reported alertness and performance in shift workers

ObjectivesEvidence indicates that self-reported measures of alertness do not always reflect performance impairments. The present study aims to explore whether subjective and objective measures of vigilance vary in the same direction in individuals working nights. MethodsA total of 76 police officers participated to a month-long observational study. They worked either a 2 or 3-shift system during which they self-reported alertness and completed a psychomotor vigilance task several times a day. ResultsA reduction in alertness and reaction speed was observed with time awake. At the group level, changes in alertness and reaction speed with time awake were positively correlated during night shifts only. In 63.6% of the officers, changes were coherent between both variables. The other officers reported that their alertness dropped (25.5%) or improved (10.9%) whereas their performance changed in the opposite direction. ConclusionSignificant interindividual variability exists in self-appraisal vigilance impairment due to night shift work.

Daily trend of blood pressure in staff under conditions of shift work of railway transport

Introduction. The results of the study of features of the daily rhythm of blood pressure in people who constantly work in a rotational shift schedule, arising under the influence of night shift work, are discussed.&#x0D; The purpose of the study was to determine the modifying effect of working night wakefulness on the parameters of the daily rhythm of blood pressure in persons employed in work with a night shift schedule.&#x0D; Materials and methods. The analysis was carried out, in two cohorts of 19 years – 62 years employees of locomotive crews of Russian Railways. The study included drivers, assistant locomotive drivers, for at least 1 year, with night shifts n = 30,566, the number of measurements = 4,497,122, but borderline (high normal) blood pressure.&#x0D; Results. The lowest levels of systolic blood pressure (SBP) were found to be recorded in a cohort of subjects per day with a night shift, the highest – in the general group of workers and in a cohort of subjects per day with a day shift.&#x0D; The daily trend of SBP was characterized by a regular change of phases in all observation groups. In the general group, a subgroup of persons with normotonia, in a cohort of subjects, when working on a day shift, a DECLINE curve of the same type in configuration was formed.&#x0D; Limitations. The representativeness of the sample size was ensured by the participation in the study of employees of locomotive crews with a range of ages &#x0D; of 19-62 years. The limitations of the study are related to the distribution of respondents by gender: there are no female respondents in the sample.&#x0D; Conclusions. Parameters of the daily rhythm of blood pressure sensitively react to changes in working hours. To the greatest extent, changes in the daily rhythm during the hours of night working wakefulness are typical for the indicators of the daily rhythm of diastolic blood pressure.

Psychological Symptoms Among Iranian Healthcare Workers During COVID-19 Pandemic

Background: The coronavirus disease 2019 (COVID-19) pandemic affected working conditions in healthcare systems and caused occupational stress and challenges for the majority of healthcare workers (HCWs). Objectives: This study aimed to examine the prevalence of anxiety, depression, burnout, and career resilience and assess the personal and occupational risk factors contributing to psychological symptoms in Iranian HCWs during the COVID-19 pandemic. Methods: Through a cross-sectional study, HCWs were surveyed within January to February 2022 to evaluate the prevalence of anxiety and depression (using the Hospital Anxiety and Depression Scale [HADS]), burnout (using the Maslach burnout inventory health services survey for medical personnel [MBI-HSS-MP]), and career resilience (using the Career Resilience Questionnaire [CRQ]). The correlation between demographic-occupational factors and psychological symptoms was analyzed. A total of 610 complete responses were received from Iranian HCWs. Results: Approximately 87.9% of HCWs had symptoms of both anxiety and depression (HADS score ≥ 11). The results indicated that most HCWs experienced various signs of burnout (i.e., emotional exhaustion, decreased sense of personal accomplishment, and depersonalization, respectively). The mean score for career resilience reported by the participants was appropriate; however, a fifth of the HCWs had poor career resilience. The highest scores of burnout, anxiety, and depression, in addition to the lowest scores of career resilience, were reported by intensive care unit (ICU) professionals. Conclusions: Marital status, long daily working hours, night shift work, access to personal protective equipment (PPE), and direct exposure to patients with COVID-19 had a significant impact on the anxiety, depression, burnout, and resilience of the HCWs.

Occupational and Psychological Factors Associated With Burnout in Night Shift Nurses.

Providing inpatient nursing care inevitably involves night shift work. However, night shift work nurses often face psychiatric health problems such as burnout. If night shift work is an essential work type for nurses, it is necessary to select personnel suitable for night shift work or establish improvement measures such as psychiatric intervention through psychiatric evaluation. The objective of this study was to identify factors that could be interventional among factors affecting burnout in shift-working nurses. A total of 231 night shift female nurses participated in this study. A questionnaire survey was given to assess their general characteristics. To assess burnout, the Maslach Burnout Inventory-General Survey Korean version was adopted. In addition, several mental health scales were used to identify individual psychological characteristics. To identify variables associated with the presence of burnout, odds ratios were calculated using a logistic regression model taking three dimensions of burnout as a dependent variable after adjusting for psychological and occupational factors. High resilience was a significant preventive factor in the three dimensions of burnout. Regarding occupational factor, the longer the duration of employment, the higher depersonalization, but the professional efficacy was good. Our results indicate that resilience and social support could be prevention factors for burnout. This study is meaningful in examining items that require active intervention and support for burnout targeting night shift nurses who are indispensable for patient care.

Night shift work and sickness absence – many for the few or few for the many?

Abstract Background Night shift work is related to adverse health outcomes. Yet, some choose working permanent night and it is speculated that they tolerate night work better. However, research on permanent night work is sparse. The aim was to study the association between organisation of night work and sickness absence. Should we allow many night shifts for the few or should we enforce few night shifts for the many? Methods Information on working hours, age (19-70 years), gender (women, men) and sickness absence (annual number of days) was obtained from 94 815 nurses and nurse assistants (88% women) from the Danish Working Hour Database (DAD). DAD contains daily information on working hours based on payroll data for all employees in Danish public hospitals (2017-2020). For each year with &amp;gt;50% work participation, individual schedules were classified into “no night shifts”, “1-50 night shifts”, “51-100 night shifts”, “101-150 night shifts” and “more than 150 night shifts”. We applied linear regression (with individual as random intercept) for risk of sickness absence the following year adjusted for age, gender and calendar year. Results Preliminary results showed night shift workers with more than 150 night shifts per year had 5.0 more sick days (95% CI: 3.5-6.4, p = &amp;lt;0.001) than employees with no night shifts. No statistically significant differences were observed between the four night shift groups. Conclusions Employees had more sickness absence the year after working during the night compared to employees without night shift work. However, no differences were seen when yearly comparing employees with many night shifts to those with few night shifts. The study adds to scientific support to guidelines on scheduling of shift work in governmental policies with the aim of securing healthy and safe workplaces. Key messages • Night shift workers have higher number of sick days compared to daytime workers; however, number of night shifts during a year did not affect the results. • The study adds value for the use of the scientific recommendations for minimizing health risk for night shift workers in governmental policies with the aim of securing healthy and safe workplaces.

Artificial light at night and breast cancer risk: The findings from CECILE study (France)

Abstract Background Environmental exposure to artificial light at night (LAN) has become ubiquitous in modern societies. Experimental and epidemiological studies suggested that LAN exposure disrupts circadian rhythm, inhibits melatonin production, and increases the risk of breast cancer. Objectives We aimed to assess the association of exposure to outdoor LAN with breast cancer risk, along with possible effect modifications of this association. Methods We used data from a population-based case-control study, including 1185 incident breast cancer cases and 1282 healthy controls enrolled in 2005-2007 from two French departments- Côte d’Or and Ille-et-Vilaine. Data for outdoor LAN exposure was obtained using radiance-calibrated images from Defense Meteorological Satellite Program (DMSP) for 1995-2006. Exposure was assessed for 10 years before inclusion in the study by cross-referencing the DMSP images and the geocoded locations of residences in ArcGIS. Logistic regression was used to obtain odds ratios (OR) and 95% confidence intervals (CI) for the association, adjusting for sociodemographic factors, urbanization, reproductive factors, lifestyle-related factors, night shift work, and air pollution. Results The overall OR for breast cancer per 1 interquartile range (IQR) increase in LAN exposure (159.9 nW/cm2/sr) was 0.98 (95% CI: 0.81-1.17). Subgroup analyses showed slightly higher ORs in post-menopausal women (OR: 1.15; 95% CI: 0.97-1.37) and a stronger association for HER2-positive breast tumors (OR: 1.55; 95% CI: 1.03-2.31). Conclusions We did not find any overall association between outdoor LAN and breast cancer; however, possible associations in certain subgroups were indicated. The strength of this study was the use of calibrated satellite images for exposure assessment and the consideration of a large set of potential confounders. Further large-scale studies using improved exposure assessment methods, including blue light and indoor exposure measurement, are required. Key messages • Light pollution is growing as the newest form of environmental pollution in modern society, potentially affecting health. • More studies are required to explore and ascertain its public health impact.

Relationship between night shift and sleep problems, risk of metabolic abnormalities of nurses: a 2 years follow-up retrospective analysis in the National Nurse Health Study (NNHS)

Background and purposeEfforts to improve nurses’ physical and mental health are critical to ensuring the safety and quality of the healthcare system. Long-term studies targeting the relevancy of nurses’ occupation characteristics with health conditions remain insufficient. This study aimed to examine the relationship between nurses’ night shift and sleep problems and metabolic abnormalities risk.MethodsThis study was a part of the National Nurse Health Study, an ambispective cohort study in China, in 2021. Based on an integration physical examination data system, this study carried out a retrospective analysis of 730 nurses from 2018 to 2020 and combined with a questionnaire survey in 2021. The STROBE guidelines were adopted for reporting.ResultsIn the 23 (23.0, 24.0) months follow-up, higher night shift load was associated with more sleep problems such as shortened sleep duration, sleep disorders, poor sleep quality, and sleep deprivation. Moreover, night shift load was associated with chronic diseases risk factors, increasing body mass index and body fat, with more night shift density, increasing the occurrence of low levels of high-density lipoprotein cholesterol, high triglyceride, triglyceride/high-density lipoprotein cholesterol ratio, and serum uric acid.ConclusionThe night shift load has become an occupational health concern, contributing to chronic diseases relevant metabolic risk factors and negative influence on sleep health. Focus on the strategies to improve the sleep quality of nurses undergoing night shift work, optimize work scheduling and ongoing monitor the relevant risk factors are essential to enhance the stability and well-being of the nursing workforce.Clinical Trials registration information: NCT04572347, on October 1, 2020. https://www.clinicaltrials.gov/ct2/show/NCT04572347

O061 Maternal Circadian Disruption from Shift Work and the Impact on the timing of Melatonin in their Breast Milk

Abstract Introduction Infants are not born with a circadian rhythm. Research shows that breast milk clearly exhibits a 24-hour pattern, with melatonin concentrations high during the evening and night but barely detectable in daytime milk. The presence and timing of melatonin in breast milk suggests that this hormone may help provide sleep timing information to infants, thereby supporting the development of their own circadian cycle. Currently, it is not known if disturbances of maternal circadian rhythm, such as shift work, impact the circadian rhythmicity of breastmilk. The aim of this study was to investigate whether maternal circadian disruption, from working night shift has an impact on melatonin timing in breastmilk. Methods A prospective repeated measures study design was undertaken to compare melatonin levels in breastmilk across shift types (day shift/non-workdays and night shifts). Four 10ml breastmilk samples were collected by participants the same time of the day, across five consecutive days. Results. A total of 11 mothers completed the study. Analysis is still ongoing but preliminary results show a potential difference in breastmilk melatonin between pre-night shift, night shift and post night shift, indicating a change in the circadian timing of the breastmilk. Discussion The findings from this study suggest that there is a potential effect from maternal circadian disruption from shift work on breast milk melatonin. This is an important first step in exploring the impact of maternal circadian misalignment disorders on breastmilk hormones and provides preliminary evidence that future research is needed in this area.

O003 Investigating the relationship between core body temperature and changes in cognitive performance during simulated night shifts

Abstract Introduction The timing of circadian and sleep-wake behaviours is disrupted by night shift-work. Interventions involving light may prove beneficial in adjusting the circadian rhythm to shift work, although the changes in vigilance remain uncertain. This study examined the temporal relationship between core body temperature (CBT) rhythm and vigilance during a work-shift through lighting. Methods 19 healthy individuals (12 males, mean±SD age of 28.7±10.4 years) participated in two 8-day experimental conditions with 4 days of circadian-informed lighting vs standard lighting. On Day 2, participants transitioned from a typical day-night wake-sleep schedule to night shift-work from 00:00 to 08:00 on Days 3 to 7. Psychomotor vigilance tasks (PVTs) were administered six times on shift. CBT was monitored via ingestible capsules. Daily CBT minimum (CBTmin) time was compared to the timing of the worst PVT performance on-shift (task with most lapses). Results In the parent study, circadian lighting improved on-shift performance and sleep quality. These effects were accompanied by a significant day-by-condition interaction effect on the degree of temporal offset between CBTmin time and worst PVT performance time during the work shift, F(3,74.660)= 4.09, p=0.01; the disparity increased over successive days under the influence of circadian-informed lighting compared to standard lighting., p&amp;lt;0.01. Conclusions The modest adjustment in the timing of the worst on-shift performance provides support that circadian lighting improves on-shift performance. These results emphasise the importance of considering the combined impact of circadian rhythms, sleep patterns, and time-on-task effects on performance outcomes when assessing fatigue and implementing countermeasures to phase-shift biological rhythms.

O077 The Impact of Breaking up sitting during Simulated Nightshifts on Driving Performance during the Commute Home

Abstract Introduction The commute home from a nightshift is associated with increased accident risk. Driving performance strategies typically occur immediately before or during the commute, such as napping and caffeine. It is unknown whether strategies that target alertness throughout the nightshift could impact the commute home. Breaking up sitting with walking is an effective strategy to improve alertness during dayshifts. This study investigated the impact of breaking up sitting during the nightshift on driving performance post-shift. Method 41 adults (age M±SD: 24.4±4.6 years; 21 females) participated in a 7-day laboratory study, with 5 nightshifts (2200-0630). Participants were randomly allocated to: Breaking up sitting (BUS; n=21) or Sedentary (SED; n=20). Every 30-min during the nightshift BUS participants completed 3-min bouts of light-intensity walking, while SED participants remained sitting. At 2130 (pre-shift) and 0700 (post-shift) participants completed a 20-min simulated drive and the Karolinska Sleepiness Scale. Results Linear mixed models revealed a significant interaction between time (pre- or post-shift) and nightshift on driving performance and sleepiness, such that there was increased lane variability (p=0.03), speed variability (p&amp;lt;0.05), and sleepiness (p&amp;lt;0.05) post-shift compared to pre-shift, with performance worse on the first nightshift. There were no significant 2-way or 3-way interactions between condition (BUS or SED), time, or nightshift. Discussion Breaking up sitting with light-intensity walking did not improve performance for the commute home. However, given that breaking up sitting did not increase risk on the commute home, and it has benefits for cardiovascular health, it is an important strategy to promote to nightshift workers.

O073 The Relationship between Circadian type and Physical Activity on Cognitive Performance during Simulated Nightshifts: A Randomised Controlled Trial.

Abstract Introduction Physical activity might be a nonphotic strategy which could improve cognitive performance for nightshift workers. Innate characteristics like circadian type may also influence individual performance. Thus, this study explores the relationship between circadian type and physical activity on cognition over consecutive nightshifts. Methods Thirty-two healthy adults (age M±SD: 24.3±4.6 years; 19 females) participated in a 7-day laboratory study, with 5 nightshifts (2200-0600). Participants were randomised into the Breaking up sitting (BUS; n=19) or Sedentary (SED; n=13) condition. Overnight, BUS participants completed 3-min bouts of light-intensity walking every 30-min, while SED participants remained seated. At 2200, 0000, 0200, 0400 and 0600, participants completed the 10-min Psychomotor Vigilance Task (mean RRT). Participants completed the 11-item revised Circadian Type Inventory (factor 1: rigid/flexible; factor 2: languid/vigorous), resulting in four-subgroups (rigid; n= 12, flexible; n= 11, and languid; n= 11, vigorous; n= 13). Participants may only be one type from either factor (i.e. rigid and vigorous). Results Linear mixed models showed a significant 3-way interaction between nightshift (1-5), condition (BUS, SED), and circadian type (rigid/flexible) for mean RRT (p=0.03), such that flexible types in the Breaking up sitting condition outperformed Sedentary flexible types and Breaking up sitting rigid types, with performance worse on the first nightshift. There were no significant interactions between nightshift, condition and circadian type (languid/vigorous). Discussion Breaking up sitting improved performance for flexible types over rigid types. These findings have significant implications for nightshift rostering, suggesting that incorporating breaking up sitting may optimise cognitive performance, and therefore work efficiency.