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Introduction Night shift-work results in misalignment between circadian timing and the sleep/wake schedule, negatively impacting sleep and performance. In encapsulated environments (e.g., submarines), the lack of strong daily solar lighting cues may impair circadian entrainment to the night shift-work schedule. This study designed and tested a circadian-informed lighting strategy to promote faster circadian phase delays to adjust to night shift-work compared to standard lighting. Methods Nineteen healthy sleepers (12 males/7 females, mean±SD aged 28.7±10.4 years) underwent two separate 8-day experimental conditions (circadian-informed lighting versus standard lighting). After a baseline sleep from 22:00 – 07:00 (day 1) and salivary dim light melatonin onset assessment ([DLMO], day 2), participants undertook simulated night shift-work (00:00 - 08:00) and slept during the day (10:00 - 19:00) for days 3-7 followed by a post-DLMO assessment on day 8. Ingestible capsules collected core body temperature (CBT) continuously throughout days 2-8, and cosine curve fitting was applied to estimate the timing of each daily temperature minima. The standard lighting condition mimicked current lighting on submarines (largely dim, blue-depleted light), while the circadian-informed lighting administered bright, blue-enriched and dim, blue-depleted lighting at times estimated to facilitate rapid circadian delay. The magnitude of daily CBT minima changes and the delay in pre- vs. post-DLMO were compared across conditions. Results There were significant day-by-condition interactions on CBT minima timing and DLMO timing (both p< 0.001). After 4 days of simulated night-shift work there was a mean [95%CI] 4.5 [3.4 to 5.7] hour greater delay in CBT minima and a 4.6 [3.6 to 5.6] hour greater delay in DLMO timing compared to standard lighting, equating to 3.6 and 2.4-fold faster delays in DLMO and CBT minima timing shifts, respectively. Conclusion Circadian-informed lighting substantially accelerates circadian re-adjustment to night shift-work. Lighting interventions could usefully improve sleep, performance, and safety in shift-workers. Support (if any) This research is supported by the Commonwealth of Australia as represented by the Defence Science and Technology Group of the Department of Defence through the Research Network for Undersea Decision Superiority (research agreement number: 9334), with additional financial support from Flinders University and lighting provision support from REDARC.

Rationale: Sleep-disordered breathing (SDB) is associated with increased vascular resistance in children and adults. Persistent increased vascular resistance damages vascular endothelial cells-a marker of which is increased platelet activation.Objectives: This study compared whole-blood impedance platelet aggregation in children with clinically diagnosed SDB warranting adenotonsillectomy and healthy control subjects.Methods: Thirty children who had SDB warranting intervention clinically diagnosed by experienced pediatric otolaryngologists were recruited from adenotonsillectomy waitlists, and 20 healthy children from the community underwent overnight polysomnography to determine SDB severity (obstructive apnea-hypopnea index). Snoring frequency was collected from parents. In the morning, a fasting blood sample was taken, and whole-blood platelet aggregation was measured.Measurements and Main Results: Children with SDB exhibited increased platelet aggregation to TRAP (thrombin receptor-activating peptide) (children with SDB = 114.8 aggregation units [AU] vs. control subjects = 98.0 AU; P < 0.05) and COL antibody (96.7 vs. 82.2 AU; P < 0.05) and an increased trend in ADP antibody (82.3 vs. 69.2 AU; P < 0.07) but not aspirin dialuminate (82.1 vs. 79.5 AU; P > 0.05). No significant association was observed between either the obstructive apnea-hypopnea index and any aggregation parameter, but parental report of snoring was positively associated with TRAP aggregation (Kendall's τ-c = 0.23; P < 0.05).Conclusions: The finding of increased platelet aggregation is consistent with endothelial damage. This suggests that the profile of cardiovascular changes noted in adults with SDB may also occur in children with SDB. Refereed/Peer-reviewed

BACKGROUND: Residential support workers (RSWs) provide 24-hour care to clients and many work overnight sleepover nightshifts. Although RSWs perform safety-critical tasks and are at high-risk of work stress and exhaustion, the health and safety of RSWs has not been investigated. OBJECTIVE: This explorative workplace case study explored the impact of support work on the eating and driving behaviours of RSWs. METHODS: Thirteen RSWs who had worked a dayshift (n = 6) or a sleepover nightshift (n = 7) completed questions on the timing of food intake during their shift, motivations for eating during the shift, subjective work performance, alertness and sleepiness post-shift, and driving performance post-shift. RESULTS: RSWs reported snacking during the night on a sleepover nightshift. Time available was the biggest determinant for when RSWs ate during a day and sleepover nightshift. Ratings of subjective alertness and sleepiness after eating were not different between shift types, however participants reported an increase in work performance after eating during a dayshift. Driving events were more frequently reported post-sleepover nightshift, compared to post-dayshift. CONCLUSIONS: Findings demonstrate an impact of shift type on eating and driving behaviours of RSWs and highlight the importance of further investigation of this under-researched group to identify appropriate strategies for improving health and safety. Refereed/Peer-reviewed

Shiftworkers are more likely to suffer from gastrointestinal disease and Type 2 Diabetes than the general population, likely due to their altered dietary intakes. Previous research has suggested that coping strategies and health behaviours may be linked, however, questions remain regarding these relationships in shiftworking populations. The Standard Shiftwork Index and Food Frequency Questionnaire were completed by nurses/midwives working forward rotating shifts (N=27, female=24, age=38.4 ± 13.1 y). Greater engaged coping strategy usage was associated with lower total energy, fat, carbohydrate and sugar intake (ρs>−0.1). Greater disengaged coping strategy usage was associated with greater intake of these nutrients (ρs>0.1). Results suggest that engaged coping strategies may contribute to healthier dietary choices. A greater focus on coping styles, particularly during nursing education, may improve shiftworkers’ health. Refereed/Peer-reviewed

Attending to the visuospatial field is paramount for safety. The inability to sufficiently allocate attention in the environment could lead to unfavourable consequences. One's ability to attend quickly to left- and right-sided stimuli can vary depending on the person's level of alertness. A dominant model of this relationship proposes that low alertness is associated with a rightward bias in attention, with increases in alertness shifting attention leftward. The current study sought to synthesise the literature on spatial attention and alertness and identify modulators of this relationship in healthy adults. Nineteen articles meeting inclusion criteria were identified for meta-analysis. A small effect of alertness on spatial bias (d =.302)with no evidence for a systematic publication bias was found. Of the five investigated modulators, namely, the experimental design relative to alertness, direction of alertness manipulation, measurement of alertness, the nature of the spatial task, and handedness, only the latter was identified as a significant modulator of the relationship between alertness and spatial attention. The review's findings tie in with the influential framework by Corbetta and Shulman (2011)and support the idea to increase alertness as a rehabilitation approach to reduce inattention to the left side in neglect patients. Findings also suggest a need for future research to investigate neurological processes that underlie the alertness and spatial attention relationship, and a need to examine the transfer effects of laboratory-based experiments for real-world implications. Refereed/Peer-reviewed

Self-assessment is the most common method for monitoring performance and safety in the workplace. However, discrepancies between subjective and objective measures have increased interest in physiological assessment of performance. In a double-blind placebo-controlled study, 23 healthy adults were randomly assigned to either a placebo (n = 11; 5 F, 6 M) or caffeine condition (n = 12; 4 F, 8 M) while undergoing 50 h (i.e. two days) of total sleep deprivation. In previous work, higher salivary alpha-amylase (sAA) levels were associated with improved psychomotor vigilance and simulated driving performance in the placebo condition. In this follow-up article, the effects of strategic caffeine administration on the previously reported diurnal profiles of sAA and performance, and the association between sAA and neurobehavioural performance were investigated. Participants were given a 10 h baseline sleep opportunity (monitored via standard polysomnography techniques) prior to undergoing sleep deprivation (total sleep time: placebo = 8.83 ± 0.48 h; caffeine = 9.01 ± 0.48 h). During sleep deprivation, caffeine gum (200 mg) was administered at 01:00 h, 03:00 h, 05:00 h, and 07:00 h to participants in the caffeine condition (n = 12). This strategic administration of caffeine gum (200 mg) has been shown to be effective at maintaining cognitive performance during extended wakefulness. Saliva samples were collected, and psychomotor vigilance and simulated driving performance assessed at three-hour intervals throughout wakefulness. Caffeine effects on diurnal variability were compared with previously reported findings in the placebo condition (n = 11). The impact of caffeine on the circadian profile of sAA coincided with changes in neurobehavioural performance. Higher sAA levels were associated with improved performance on the psychomotor vigilance test during the first 24 h of wakefulness in the caffeine condition. However, only the association between sAA and response speed (i.e. reciprocal-transform of mean reaction time) was consistent across both days of sleep deprivation. The association between sAA and driving performance was not consistent across both days of sleep deprivation. Results show that the relationship between sAA and reciprocal-transform of mean reaction time on the psychomotor vigilance test persisted in the presence of caffeine, however the association was relatively weaker as compared with the placebo condition. Refereed/Peer-reviewed

Introduction Children commonly have access to mobile devices that allow them to send and receive texts at night when they should be sleeping. This may contribute to an increase in cyber-bullying and sleep problems, with negative effects on mental wellbeing. Methods Young children (7-11y, n = 22,597), early adolescents (12-14y, n = 19,470) and late adolescents (15-19y, n = 14,156) completed a survey examining mental wellbeing and the frequency of obtaining 8h sleep, texting at night and cyber-bullying.. Generalised structural equation modelling was used to investigate the effects of texting at night on mental wellbeing, directly, and indirectly via effects on sleep. Cyber-bullying was also specified as a moderator of the effect of texting at night on sleep. Results Text messaging at night in the last week was reported by 51% and cyber-bullied in the last school term by 15% of children. For all children, obtaining at least 8h of sleep increased the odds of better mental wellbeing, Conversely, texting messaging and cyber-bullied reduced the odds of obtaining 8h sleep in both male and female young children and female early and late adolescents. In all cohorts except late adolescent males, obtaining less than 8h sleep and cyber-bullied accounted for a large proportion of the effects of text messaging on mental wellbeing. Conclusion Mobile phone use at night impairs sleep which contributes to poor mental wellbeing. The effect on sleep is exacerbated by cyber-bullying. Strategies to discourage small screen use at night, promote adequate sleep and reduce cyber-bullying are needed.

Nightwork is associated with fatigue, decreased sleep quality, and impairments in cognitive function. While attentional tasks have been widely investigated, there are limited data on more complex tasks, such as executive functioning during nightwork. Workers often need to rapidly shift between tasks, adapting to new and complex situations. The aim of this study was to investigate the impact of nightwork on executive functioning. Healthy, non-shift working individuals (N=8; 5F, 24.8±5.0y) participated in a 7-day live-in laboratory study. Participants underwent an 8h TIB baseline sleep, followed by 4 consecutive simulated nightshifts with 7h TIB sleep during the day and an 8h TIB recovery sleep. Participants were assessed for executive function at 2000h, 2200h, 0100h and 0400h. Executive functioning was assessed with a mental flexibility switching task where a 3D rotation and math task were displayed simultaneously with an arrow indicating which task to complete in a random order. Resulting throughput data were analysed using linear mixed models. There was a main effect of time of night (F(3,77)=4.81,p=.004) on throughput such that there was a speed accuracy trade off over the night shift with slower switching ability later in the shift. There was also a main effect of nightshift (F(2,77)=54.33,p This study suggests executive functioning is impaired on nightshift with worse performance at 0400h. Task improvements over consecutive nightshifts may have been due to learning or acclimation to nightwork. Understanding complex task performance on nightshift is important for tailoring countermeasures.

Nightwork disrupts circadian rhythms and impairs glucose metabolism, increasing the risk for type 2 diabetes. We investigated eliminating or reducing the amount of food consumed during simulated nightwork as a countermeasure to reduce the impact of circadian disruption on glucose metabolism. N=52 healthy, non-shiftworking participants (24.4±4.9 years; 26 Females; BMI 23.8±2.5kg/m2) underwent a 7-day laboratory protocol with an 8h TIB baseline sleep, followed by 4 simulated nightshifts with 7h TIB daytime sleep and an 8h TIB recovery sleep in groups of 4 participants. Each group was randomly assigned to a meal-at-midnight (n=17, 30% energy requirements), snack-at-midnight (n=16, 10% energy requirements) or no-eating-at-midnight (n=19) condition. Total 24h energy and macronutrient intake were constant across conditions. Standard oral glucose tolerance tests (OGTT) were conducted on day2 (baseline), and day7 (recovery). Plasma was sampled at -15, 0, 15, 30, 60, 90, 120, 150 mins, assayed for glucose and insulin. Area under the curve (AUC) was the calculated. Mixed model analyses of glucose AUC found a condition-by-day interaction (p

Background: Mental health disorders are prevalent and costly to workplaces and individuals in Australia. Work-life interference is thought to contribute negatively. The interplay between work-life interference, depressive symptoms and sleep has not been explored to date in population data. The aims of this study were to establish whether sleep duration moderates the relationship between work-life interference and depressive symptoms, and whether this is expressed differentially in male and female respondents. Methods: Data were drawn from the North West Adelaide Health Study (NWAHS) longitudinal, representative population-based cohort study. Working members of the cohort were invited to participate in a telephone survey about their work conditions, with an 86.7% response rate achieved. Data from 823 respondents were analysed after employing purposeful selection of covariates, using multivariable regression analysis. Results: Sleep duration was found to moderate the relationship between work-life interference and depressive symptoms (F7,815 = 26.60, p

OBJECTIVE The sleep of individuals who provide unpaid care for children with medical needs is likely to be significantly impacted by this role. Sleep may be affected by the practical tasks undertaken during the night (e.g., administering medication), in addition to the emotional impact (e.g., worry, rumination). The aim of this systematic review was to examine the available literature on the impact of caregiving for children with medical needs on caregivers' sleep. METHOD Electronic databases, including PubMed, Medline, and Web of Science, were searched using predetermined criteria. Studies were included if they used validated subjective or objective measures of caregiver sleep, in contexts where caregivers were providing care for one or more children with medical needs. Data on study population, research design, and outcome measures were extracted, and study quality was reviewed by two authors. RESULTS Search criteria produced 2,172 studies for screening. Based on inclusion criteria, 40 studies were included in the final review. Sleep of caregivers of children with medical needs was poorer than that for noncaregivers. Poor sleep included reduced sleep duration, impaired sleep efficiency, increased wake after sleep onset, and perceived poorer sleep quality. CONCLUSIONS Providing unpaid care for children with medical needs is associated with sleep disturbances, including less total sleep, and poorer sleep quality. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Mental health disorders are prevalent and costly to workplaces and individuals in Australia. Work-life interference is thought to contribute negatively. The interplay between work-life interference, depressive symptoms and sleep has not been explored to date in population data. The aims of this study were to establish whether sleep duration moderates the relationship between work-life interference and depressive symptoms, and whether this is expressed differentially in male and female respondents.Data were drawn from the North West Adelaide Health Study (NWAHS) longitudinal, representative population-based cohort study. Working members of the cohort were invited to participate in a telephone survey about their work conditions, with an 86.7% response rate achieved. Data from 823 respondents were analysed after employing purposeful selection of covariates, using multivariable regression analysis.Sleep duration was found to moderate the relationship between work-life interference and depressive symptoms (FSupporting and educating workers about the benefits of sleep for managing the relationship between work-life interference and depressive symptoms may offer a novel strategy for improving worker well-being, particularly when negative facets of work-life interference are not easily remedied or 'reduced'. There is a need for education and support strategies around sleep in Australian workplaces.

We examined whether sunlight affects hot flushes in working menopausal women and explored effect modification by shift work and season. In this prospective cohort study, daily hot flush score (outcome) was measured by the 7-day North Central Cancer Treatment Group Daily Vasomotor Symptoms Diary. Daily duration of sunlight (≥2000 lux) was recorded by the HOBO MX2202 pendant. Both variables were measured in two 7-day data collection phases. T0 data were collected during the Australian Summer (December 2017, January and February 2018); and T1 data were collected in the Australian winter (June, July and August 2018). Linear mixed effects model was used. Shift work and season were both confounders and effect modifiers. To detect a median effect size of R2 = 0.2, 34 women were required to achieve an effective sample size of 41. A total of 49 menopausal women were recruited, 11 shift and 38 day workers. Some 13 women had various missing observations. For shift workers, an hour increase in sunlight exposure was associated with a 1.4-point reduction in hot flush score (p = .016). This relationship was not significant for day workers (p = .185). The finding of this study suggests increased sunlight exposure might improve hot flushes in menopausal shift workers who are moderately bothered by hot flushes, but probably not in day workers. The possible role of shift-work associated circadian disruption on estrogen level in regard to elevated intensity and frequency of hot flush in menopausal women is discussed.

Shiftworkers have impaired performance when driving at night and they also alter their eating patterns during nightshifts. However, it is unknown whether driving at night is influenced by the timing of eating. This study aims to explore the effects of timing of eating on simulated driving performance across four simulated nightshifts. Healthy, non-shiftworking males aged 18–35 years (n = 10) were allocated to either an eating at night (n = 5) or no eating at night (n = 5) condition. During the simulated nightshifts at 1730, 2030 and 0300 h, participants performed a 40-min driving simulation, 3-min Psychomotor Vigilance Task (PVT-B), and recorded their ratings of sleepiness on a subjective scale. Participants had a 6-h sleep opportunity during the day (1000–1600 h). Total 24-h food intake was consistent across groups; however, those in the eating at night condition ate a large meal (30% of 24-h intake) during the nightshift at 0130 h. It was found that participants in both conditions experienced increased sleepiness and PVT-B impairments at 0300 h compared to 1730 and 2030 h (p < 0.001). Further, at 0300 h, those in the eating condition displayed a significant decrease in time spent in the safe zone (p < 0.05; percentage of time within 10 km/h of the speed limit and 0.8 m of the centre of the lane) and significant increases in speed variability (p < 0.001), subjective sleepiness (p < 0.01) and number of crashes (p < 0.01) compared to those in the no eating condition. Results suggest that, for optimal performance, shiftworkers should consider restricting food intake during the night. Refereed/Peer-reviewed

Shiftwork leads to altered eating patterns, with workers often eating foods at all times across the 24h period. Strategies to reduce the burden of shiftwork on the workers should be prioritised and altering these eating patterns is an important area for change. This narrative review examines the current evidence on the individual and environmental factors influencing the eating behaviours of shiftworkers. A systematic search was conducted and yielded 62 articles. These were split into four themes that influence eating patterns; When shiftworkers eat, What type of foods shiftworkers eat, Where the food is sourced from, and Why shiftworkers choose to eat on shift. Irregular working hours was the biggest influence on when workers ate on shift, shift-type was the biggest influence on what workers ate, the majority of food was sourced from canteens and cafeterias, and socialising with colleagues was the biggest reason why workers chose to eat. While more research is needed to explore multiple industries and shift-types, and to investigate the ideal size, type and timing of food on shift, this review has highlighted that future research into shiftworker eating needs to adopt an integrative approach and consider the different individual and social contexts that influence eating patterns. Refereed/Peer-reviewed

More than seven billion mobile phones are estimated to be in service globally, with more than a billion older phones likely to be retired. A major barrier to a sustainable circular economy for mobile phones is people’s hoarding of their retired phones. Old mobile phones may be refurbished for re-use or ultimately dismantled for possible extraction of elements, including ‘conflict’ metals such as coltan (containing elements tantalum and niobium), mined in eastern Democratic Republic of Congo and threatening wild populations of eastern Grauer’s gorillas (Gorilla beringei graueri). Zoos Victoria cares for western gorillas (Gorilla gorilla gorilla) who served as ambassadors for their Grauer’s gorilla counterparts in this community-based social marketing initiative. Through tracking of barcodes on satchels of recycled mobile phones, efficiency of ten different points of influence could be calculated for the ‘They’re Calling on You’ mobile phone recycling community campaign at Zoos Victoria in Australia. Over a six-year period (2009–2014), a total of 115,369 mobile phones were donated. The Courier Collect initiative resulted in 50,883 mobile phone donations (44% of total), followed by the Static Display at Melbourne Zoo, resulting in 29,778 mobile phone donations (26% of total). The number of phones collected for Keeper Talks (at Melbourne Zoo and Werribee Open Range Zoo) was 12,684 (11% of total), and in terms of fostering close connections between visitors and the conservation campaign, keeper talks were effective as one phone was donated for every four people attending a keeper talk at Werribee Open Range Zoo and one phone was donated for every 28 people who attended a keeper talk at Melbourne Zoo. We provide suggestions for future campaigns, so that accurate data capture can allow cost-benefit analyses to be conducted. Our results demonstrate that a conservation-based organisation, in partnership with corporate sponsors and community groups can effectively influenced people’s mobile phone recycling behavior, paving the way for international collaborations to maximize scale and impact. Refereed/Peer-reviewed

During sleep deprivation, neurobehavioral functions requiring sustained levels of attention and alertness are significantly impaired. Discrepancies between subjective measures of sleepiness and objective performance during sustained operations have led to interest in physiological monitoring of operator performance. Alertness, vigilance, and arousal are modulated by the wake-promoting actions of the central noradrenergic system. Salivary alpha-amylase (sAA) has been proposed as a sensitive peripheral measure of noradrenergic activity, but limited research has investigated the relationship between sAA and performance. In a laboratory-controlled environment, we investigated the relationship between sAA levels, subjective sleepiness, and performance during two days (50 h) of total sleep deprivation. Beginning at 09:00, twelve healthy participants (5 females) aged 22.5 ± 2.5 years (mean ± SD) provided saliva samples, recorded ratings of subjective sleepiness, completed a brief 3-min psychomotor vigilance task (PVT-B) and performed a 40-min simulated driving task, at regular 3 h intervals during wakefulness. Ratings of subjective sleepiness exhibited a constant linear increase (p

Objective: Little is known about the personal factors that increase vulnerability to job-related stress and burnout among psychologists in training. This study was based on a large international sample and aimed to explore the role of early maladaptive schemas (EMS) in predicting vulnerability to burnout, as well as attendant effects on short-term physical health, in clinical and counseling postgraduate psychology trainees. Method: An online, quantitative, cross-sectional survey method design was used to collect self-report data that measured burnout, EMS, and physical health from 1,297 trainees. Results: Only the unrelenting standards (US) schema predicted high burnout among trainees. The most commonly endorsed physical health symptoms were back and neck pain and tiredness, and were more severe for those experiencing high burnout. Conclusion: The current study contributes to our understanding of the role of the US EMS in the evolution of burnout in trainees and has implications for the development of self-awareness training programs for this population. Refereed/Peer-reviewed

There are few studies examining changes in waking function in a laboratory environment with no sleep deprivation and mood has been largely overlooked in this context. The present study examined changes in mood, performance, sleep and sleepiness in the laboratory study with no sleep deprivation. Nineteen participants (10M, 9F; 22 ± 4.2 years) were given nine 9-h sleep opportunities (23.00–08.00 hours). Every 2 h during wake, participants completed the Mood Scale II, a 10-min Psychomotor Vigilance Task and measures of sleepiness and fatigue. Sleep was monitored using an electroencephalographic montage. Findings revealed significant negative mood change, performance impairment, reduced total sleep time and sleep efficiency (all P < 0.05). These findings suggest that the laboratory environment or procedural factors may impair mood, performance and sleep. These findings may have implications for interpreting impairments in mood, performance and sleep when observed in laboratory environments.

Behavioral markers are used in training and assessment of nontechnical skills (NTSs). This study tested the reliability of a unique set of markers designed to help assess heightened emotional activity (HEA) as a response to perceived threats. Using five markers that represent instances of negative emotional states, 27 commercial airline pilots recorded their observations of HEA in eight video vignettes of scripted flight deck situations. The raters’ scores were analyzed using Cronbach’s alpha for dichotomous data. The alpha statistics indicated high inter-rater reliability across all five HEAs. This study demonstrates that the chosen instances of HEA can be reliably identified by airline pilots.

Worker involvement in decision-making about the workplace can improve safety, health, productivity and the quality of organizational outputs. Australian work health and safety (WHS) legislation mandates worker involvement and gives elected Health and Safety Representatives (HSRs) specific powers, but there has been limited research about the impact of that regulatory framework on the nature, quality and outcomes of worker involvement. As part of a wider review of worker representation in WHS, we investigated the role and impact (positive and negative) of elected HSRs on WHS] in South Australia using a newly-constructed survey instrument. This paper reports on the development of the instrument and the initial findings of the research. The initial survey dimensions and items were developed from earlier research on consultation in South Australia and were refined and validated through this research. The survey has 9 constructs and 61 items and has both face validity and high internal consistency. This research is a step forward for researchers and policy makers seeking a means of determining the effectiveness of worker participation in WHS. It provides an instrument, pilot baseline data and a method that could be used internationally to enable this assessment. Refereed/Peer-reviewed

When a person is sleep deprived, someone who knows them and their usual voice may comment that they sound tired, often supporting their observation with comments, which may include, “you sound croaky” or “rough,” or “you don’t sound too bright,” (meaning the voice and not intellectual capacity) or “you sound down” or “flat.” To explore the concept that fatigue may produce such recognizable, consistent, and measurable voice changes, a study was designed in which 15 participants underwent 24 hours of sleep deprivation. They were recorded at specific intervals reading a standard passage and the results indicated that the voices deteriorated. The team of trained listener judges perceived the voices as sounding more tired, specifically rougher and less brilliant and the acoustic analysis revealed that the mean fundamental frequency fell, providing some validation for the comments “croaky,” “not so bright,” and “down,” respectively. To explore the possibility of prevention of such deterioration, the participants subsequently received a specific voice training, followed by a second, identical sleep deprivation study. The results of the second, posttraining sleep deprivation study indicated that the voices had become more resilient to the effects of sleep deprivation. The results are discussed in light of the fact that such deterioration as a consequence of sleep deprivation may compromise the quality of vocal performance, contributing to vocal disorder, proving costly should it result in absence from work. Furthermore, for those fatigued individuals for whom a robust voice is essential, there may be a way to “fatigue proof” the voice. Refereed/Peer-reviewed

The aim of the present study was to investigate the relationship between perceived and actual sleepiness and performance during a simulated night-shift that included a 30-min night-nap as an on-duty sleepiness countermeasure. Twenty-four healthy young adults (nine males, fifteen females) participated in a repeated measures design comprising two experimental conditions: no night-nap and 30-min night-nap. Both groups were given a 2-h prophylactic afternoon sleep opportunity (1500-1700 h). Measures of subjective sleepiness (Stanford Sleepiness Scale, Karolinska Sleepiness Scale and Visual Analogue Scale), objective sleepiness (sleep latency tests), objective performance (Symbol-Digit Substitution Task) and reaction time (Psychomotor Vigilance Task) were taken before the night-nap (0230 h) and at several intervals post-nap. Time-series correlation analyses indicated that subjective sleepiness was less correlated with objective sleepiness and objective performance when participants were given a 30-min night-nap. However subjective sleepiness and reaction time performance was strongly correlated in both conditions, and there was no significant difference between the nap and no-nap conditions. Consistent with previous research, results of the present study indicate that subjective and objective indicators of sleepiness and performance may not always correspond, and this relationship may be reduced by the inclusion of a night-nap. Refereed/Peer-reviewed

The aim of the study was to examine the adaptation of participants to a common night work schedule using urinary 6-sulphatoxymelatonin (aMT6s) concentration as the circadian phase marker. Fifteen adults (7 male, 8 female, age = 21.9 yr) spent nine consecutive nights in the laboratory, including: (i) adaptation sleep, (ii) baseline sleep, and (iii) seven simulated night shifts (23:00-07:00 h) followed by daytime sleep. During the baseline and daytime sleeps, participants collected urine samples which were subsequently assayed for aMT6s. The concentration of aMT6s in urine for the first three day sleeps was significantly lower than for the baseline sleep, but there was no difference in aMT6s concentrations between any of the last three day sleeps and the baseline sleep. The data indicate that people may adapt to a pattern of work that includes seven consecutive night shifts if they adhere to a fixed sleep schedule, if their exposure to morning sunlight is minimised, and if they are provided with an ideal sleep environment.

There are few studies examining changes in waking function in a laboratory environment with no sleep deprivation and mood has been largely overlooked in this context. The present study examined changes in mood, performance, sleep and sleepiness in the laboratory study with no sleep deprivation. Nineteen participants (10M, 9F; 22y ± 4.2y) were given nine 9h sleep opportunities (2300-0800). Every two hours during wake, participants completed the Mood Scale II, a 10-minute Psychomotor Vigilance Task and measures of sleepiness and fatigue. Sleep was monitored using an electroencephalographic montage. Findings revealed significant negative mood change, performance impairment, reduced total sleep time and sleep efficiency (all p < .05). These findings suggest that the laboratory environment or procedural factors may impair mood, performance and sleep. These findings may have implications for interpreting impairments in mood, performance and sleep when observed in laboratory environments.

Study Objectives: Obstructive sleep apnea (OSA) is associated with driving impairment and road crashes. However, daytime function varies widely between patients presenting a clinical challenge when assessing crash risk. This study aimed to determine the proportion of patients showing “normal” versus “abnormal” driving simulator performance and examine whether anthropometric, clinical, and neurobehavioral measures predict abnormal driving. Methods: Thirty-eight OSA patients performed a 90-min simulated driving task under 3 conditions: normal sleep, restricted sleep (4 h in bed), and normal sleep + alcohol (BAC~0.05 g/dL). Patients were classifi ed as “resilient” drivers if, under all 3 experimental conditions their mean steering deviation fell within 2 standard deviations of the mean steering deviation of 20 controls driving under baseline normal sleep conditions, or a “vulnerable” driver if mean steering deviation was outside this range in at least one experimental condition. Potentially predictive baseline anthropometric, clinical, neurocognitive, and cortical activation measures were examined. Results: Of the 38 OSA patients examined, 23 (61%) and 15 (39%) were classifi ed as resilient and vulnerable drivers, respectively. There were no differences in baseline measures between the groups, although the proportion of females was greater and self-reported weekly driving exposure was less among vulnerable drivers (p < 0.05). On univariate analysis gender, weekly driving hours, and auditory event related potential P2 amplitude were weakly associated with group status. Multivariate analysis showed weekly driving hours (OR 0.69, 95%CI, 0.51-0.94, p = 0.02) and P2 amplitude (OR 1.34, 95%CI 1.02-1.76, p = 0.035) independently predicted vulnerable drivers. Conclusions: Most OSA patients demonstrated normal simulated driving performance despite exposure to further sleep loss or alcohol. Most baseline measures did not differentiate between resilient and vulnerable drivers, although prior driving experience and cortical function were predictive. Novel measures to assist identifi cation of OSA patients at risk of driving impairment and possibly accidents are needed. Trial Registration: Data presented in this manuscript was collected as part of a clinical trial “Experimental Investigations of Driving Impairment in Obstructive Sleep Apnea.” Trial ID: ACTRN12610000009011, URL: http://www.anzctr.org.au/trial_

Train drivers rely on an expert knowledge of their route and highly sophisticated strategies to navigate the railway. A well-developed research base has conceptualised the processes required to apply route knowledge but has yet to explore how the track is internally represented. Fifty-six train drivers from 7 organisations across Australia participated in a novel qualitative research methodology. The data collected were analysed thematically, and preliminary results showed that route knowledge representation varies according operation type and as a function of expertise. Refereed/Peer-reviewed

'Safety culture' is identified in the literature as a critical element of healthy and safe workplaces. How can rail organizations ensure that consistently effective work health and safety cultures are maintained across the diversity of their operations? This paper reports on research that is currently underway in the Australian rail industry aimed at producing a Model of Best Practice in Safety Culture for the industry. Located in rail organizations dedicated to the mining industry as well as urban rail and national freight operations, the research examines the constructs of organizational culture that impact on the development and maintenance of healthy and safe workplaces. The research uses a multi-method approach incorporating quantitative (survey) and qualitative (focus groups, interviews and document analysis) methods along with a participative process to identify interventions to improve the organization and develop plans for their implementation. The research uses as its analytical framework the 10 Platinum Rules, from the findings of earlier research in the New South Wales (Australia) mining industry, Digging Deeper. Data collection is underway at the time of writing and preliminary findings are presented at this stage. The research method may be adapted for use as a form of organizational review of safety and health in organizational culture. Refereed/Peer-reviewed

There are many factors that may affect the sleep behaviour and subsequent fatigue risk of shift workers. In the Australian rail industry the emphasis is primarily on the impact of working time on sleep. The extent to which factors other than working time might affect the sleep behaviour of employees in the large and diverse Australian rail industry is largely unknown. The present study used sleep, work and fatigue diaries completed for two weeks, in conjunction with actigraphy, to understand the contribution of demographic and health factors to sleep behaviour in 40 rail safety workers. Both shift type and having dependents were significant predictors of sleep duration (P

This study aimed to provide a comparative index of the performance impairment associated with the fatigue levels frequently experienced in workplaces that require night work. To do this, we equated fatigue-related impairment with the impairment resulting from varying levels of alcohol intoxication. Fifteen young individuals participated in two counterbalanced conditions which required them to (1). 'work' seven consecutive 8-h night shifts, and (2). consume an alcoholic beverage at hourly intervals until their blood alcohol concentration (BAC) reached 0.10%. In each condition, performance was measured at hourly intervals using a 10-min psychomotor vigilance task (PVT). Analysis indicated that as BAC increased, performance impairment significantly increased. Similarly, response times significantly increased during the first six simulated night-shifts, and lapse frequency significantly increased during the first two shifts. Equating the two conditions indicated that the first simulated night shift was associated with the greatest degree of performance impairment. In general, the impairment at the end of this shift was greater than that observed at a BAC of 0.10%. During the second and third simulated night shifts, the performance impairment was less than on the first night, but greater than that observed at a BAC of 0.05%. For the final four nights, the performance decrements generally did not exceed those observed at a BAC of 0.05%. This suggests that during a week of consecutive night shifts, adaptation of performance occurs.

The 10-min psychomotor vigilance task (PVT) has often been used to assess the impact of sleep loss on performance. Due to time constraints, however, regular testing may not be practical in field studies. The aim of the present study was to examine the suitability of tests shorter than 10 min. in duration. Changes in performance across a night of sustained wakefulness were compared during a standard 10-min PVT, the first 5 min of the PVT, and the first 2 min of the PVT. Four performance metrics were assessed: (1) mean reaction time (RT), (2) fastest 10% of RT, (3) lapse percentage, and (4) slowest 10% of RT. Performance during the 10-min PVT significantly deteriorated with increasing wakefulness for all metrics. Performance during the first 5 min and the first 2 min of the PVT deteriorated in a manner similar to that observed for the whole 10-min task, with all metrics except lapse percentage displaying significant impairment across the night. However, the shorter the task sampling time, the less sensitive the test is to sleepiness. Nevertheless, the 5-min PVT may provide a viable alternative to the 10-min PVT for some performance metrics.