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Refereed/Peer-reviewed Objective: The commute home following a night shift is associated with an increased risk for accidents. This study investigated the relationship between food intake during the night shift and simulated driving performance post-shift. Methods: Healthy non-shift working males (N=23) and females (N=16), aged 18–39 years (mean 24.5, standard deviation 5.0, years) participated in a seven-day laboratory study and underwent four simulated night shifts. Participants were randomly allocated to one of three conditions: meal at night (N=12; 7 males), snack at night (N=13; 7 males) or no eating at night (N=14; 9 males). During the night shift at 00:30 hours, participants either ate a large meal (meal at night condition), a snack (snack at night condition), or did not eat during the night shift (no eating at night condition). During the second simulated night shift, participants performed a 40-minute York driving simulation at 20:00, 22:30, 01:30, 04:00, and 07:30 hours (similar time to a commute from work) Results: The effects of eating condition, drive time, and time-on-task, on driving performance were examined using mixed model analyses. Significant condition×time interactions were found, where at 07:30 hours, those in the meal at night condition displayed significant increases in time spent outside of the safe zone (percentage of time spent outside 10 km/hour of the speed limit and 0.8 meters of the lane center; P

Consuming coffee immediately prior to a nap, known as a caffeine-nap, has been shown to improve alertness during the day, but it is unknown whether a caffeine-nap is effective at reducing sleep inertia during the night. A simulated shiftwork cross-over laboratory study was conducted whereby participants (N = 6, 4 F, 21–36y) consumed 200 mg of caffeine, or decaffeinated coffee (placebo), immediately prior to a 30 min nap opportunity at 03:30 h. Compared to placebo, the caffeine-nap resulted in improved vigilant attention and subjective fatigue in the 45 min post-nap opportunity. The caffeine-nap may be useful in reducing sleep inertia in shift workers who nap on nightshift. Refereed/Peer-reviewed

As the number of older people increases, so too does the prevalence of neurodegenerative disease. Worldwide, health organisations have identified the need for practical, affordable interventions to slow or delay the onset of neurodegenerative diseases such as dementia, for which there are multiple modifiable risk factors. The effects of various interventions on brain health has been investigated, including achieving sufficient physical activity, getting appropriate amounts and quality of sleep, and limiting sedentary behaviours. Few of these studies, though, have taken into account more than one lifestyle behaviour within a single study. Epidemiologists have recently initiated a paradigm shift to move away from studying the independent effects of each physical activity, sleep and sedentary behaviour, and towards an integrated 24-h time-use paradigm. Time is finite, and thus to increase time in one activity (for example physical activity), equal time must be taken away from other activities (sleep and sedentary behaviour). This 24-h time-use paradigm has begun to be used when studying obesity, adiposity and quality of life; however, to the authors’ knowledge, it has not yet been adopted by cognitive neuroscientists for the study of cognition or brain function. This narrative review synthesises the evidence for the neurophysiological effects of physical activity, sleep and sedentary behaviour independently, with a particular focus on brain structure, function and neurodegenerative disease risk. Then, we conclude with a call to action, addressing the need for studies to move towards an integrated 24-h time-use paradigm Refereed/Peer-reviewed

Cardiovascular disease (CVD) risk in train drivers is associated with health conditions that can result in sudden incapacity. Drivers are at high risk on several CVD risk factors with research suggesting that sleep may predict CVD risk, however this relationship has not yet been explored. This study investigated the link between sleep and CVD risk, in relation to hours of work day and days off sleep. N=309 Australian drivers completed a cross-sectional survey. A CVD risk score was calculated by summing scores from behavioural and biomedical risk factors. Sleep was most frequently cited as the main reason for decline in perceived health status. Main analyses showed that shorter work day sleep (M=5.79 h) was a significant predictor of increased CVD risk (p=0.013). This relationship was moderated by days off sleep, such that when days off sleep (M=8.17 h) was higher, the effect of work day sleep on CVD risk was weaker (p=0.047). Findings indicate the amount of sleep a driver obtains on non-work days may compensate for adverse health outcomes. Successful management of fatigue in safety critical occupations appears essential not only for the prevention of safety hazards, but also for the long-term health of shift workers. Further investigation is warranted Refereed/Peer-reviewed

Introduction: Social media interactions via email and instant messaging (E/IM) are common in children and adolescents and may lead to insufficient sleep. This study investigated associations between high-frequency E/IM use to interact with peers, perceived insufficient sleep, and reduced time in bed (TIB) in female children and adolescents. Methods: The Children's Report of Sleep Patterns was completed by 189 female primary and secondary school students (8-16 years old). Responses were categorized as binary variables (high-frequency use vs not high-frequency use; right amount of sleep vs too little sleep), and TIB was calculated from bed and wake times for the previous 24 hours. Results: High-frequency social media interactions using E/IMduring the hour before bed were significantly associated with perceived insufficient sleep (odds ratio [confidence interval]: 2.68 [1.39-5.17]) but not with reduced TIB (−19.07 [−40.02 to 1.89]). Conclusions: High-frequency social media interactions using E/IM in the hour before bed are a potentially modifiable risk factor for insufficient sleep in female students. Strategies to reduce nighttime usage may improve sleep in children and adolescents. Refereed/Peer-reviewed

Background: There is a disconnect between what maternity care providers consider should be done and what they actually do with respect to talking with their pregnant clients about reducing their risk of stillbirth. This suggests that they would benefit from receiving up-to-date knowledge about stillbirth, alongside education that provides them with strategies for talking about stillbirth with pregnant women. Objectives: To gain an understanding of maternity care provider (obstetricians and midwives) knowledge of stillbirth and determine whether delivering a half day workshop improves knowledge and results in intention to change practice. Design: A pre-post intervention study. Setting: Maternity care providers (Obstetricians, Midwives) working in the northern areas of Tasmania, Australia were asked, via questionnaire, about their knowledge of stillbirth both before and after attending a half-day workshop. Participants: Maternity care providers (n = 51) attended the workshop and 30 (59%) completed both the pre-workshop and post-workshop surveys. Methods: A four hour interactive workshop grounded in understanding the stillbirth experience. Participants were given up-to-date information about stillbirth risks and current prevention research as well as provided with an actionable step wise approach to talking about stillbirth prevention in pregnancy. Results: Stillbirth knowledge scores (total of 8-points) significantly increased following the workshop (pre: mean = 2.9 ± 1.5; post: mean = 4.7 ± 1.4 points, t 29 = 7.9

Bullying is known to negatively impact the health of young people, but a less well appreciated sequelae is its impact on sleep. Disturbed sleep in-of-itself is known to also negatively impact health, raising the possibility that sleep disruption may explain some of the impact of bullying on health. Participants (n = 27,208, age = 9.7–17.7 years, 51% male) completed in the classroom the South Australian Wellbeing and Engagement Collection, which contained items assessing exposure to bullying, subjective sleep quality, timing of sleep, anxiety, sadness and physical health. Analyses revealed that bullying was related to later bedtimes, poorer subjective sleep quality, higher sadness, higher anxiety, and poorer physical health ratings. Poorer subjective sleep quality and later bedtimes were related to higher sadness and poorer physical health ratings. Poorer subjective sleep quality, but not bedtimes, was related to higher anxiety. The findings suggest that some of the relationship between bullying and health may be explained by the relationship between bullying and sleep. Including measures to promote better sleep is recommended in future anti-bullying strategies. Refereed/Peer-reviewed

There is a wealth of evidence to say that sleep impacts maternal health during pregnancy, however, little has been published on fetal health and maternal sleep. This scoping review summarises current literature on maternal sleep including sleep disordered breathing, sleep quality, sleep duration and supine sleep position, as these relate to fetal outcomes specifically birth weight, growth, preterm birth and stillbirth. An overall interpretation of the studies evaluated shows that events occurring during maternal sleep such as obstructive sleep apnea, sleep disruption and sleep position may have a negative effect on the fetus resulting in altered growth, gestational length and even death. These effects are biologically and physically plausible. In conclusion, there is limited and often conflicting information on maternal sleep and fetal outcomes. However, existing evidence suggests that this is an important area for future research. This area is ripe for investigation if there is to be reduction in the physical, emotional, and financial burden of poor fetal outcomes related to maternal sleep. Refereed/Peer-reviewed

Study Objectives: To test whether a customized positional therapy device, PrenaBelt, would reduce time spent sleeping supine and evaluate any change in maternal or fetal parameters, in a group of healthy pregnant women in the third trimester of pregnancy. Methods: Participants underwent an in-home, overnight sleep study during late pregnancy (32-38 weeks). Participants were observed over 2 nights: 1 night when the PrenaBelt was not worn (nonintervention or control) and 1 night when it was (intervention). The intervention night was randomly allocated, and the study nights were consecutive. On the control night, participants were filmed using a night-capable (infrared) video camera, maternal sleep was measured by the Watch-PAT200, and the fetus was continuously monitored using the Monica AN24. On the intervention night, video, maternal, and fetal monitoring were repeated with the addition of the mother wearing the PrenaBelt. Results: A total of 25 healthy pregnant women were studied. Four had missing data for the Watch-PAT or Monica, and eight had missing or disrupted video data. Video-determined time in bed was not significantly different during intervention and control nights (P = .196, r = −.23). Median time spent supine during the intervention night was reduced from 48.3 minutes, to 28.5 minutes during the control night (P = .064, r = −.33). The difference in the proportion of time spent supine was significant (P = .039). There was no significant difference in objectively estimated sleep time (P = .651, r = −.07). Improvement was observed in both maternal and fetal parameters during the intervention night with an increase in median minimum maternal oxygen saturations (control = 91.6%,intervention = 92.4%, P = .006, r = −.42), fewer maternal oxygen desaturations (control = 7.1, intervention = 5.9, P = .095, r = −.26), and fewer fetal heart rate decelerations (control = 14.0, intervention = 10.4, P = .045, r = −.31) compared to the control night. Conclusions: Results provide preliminary evidence that an intervention to reduce supine sleep in late pregnancy may provide maternal and fetal health benefits, with minimal effect on maternal perception of sleep quality and objectively estimated sleep time. Further research to explore relationships between objectively determined maternal sleep position, maternal respiratory indices, and fetal well-being is warranted. Refereed/Peer-reviewed

Objectives: Napping is a widely used countermeasure to sleepiness and impaired performance caused by sleep loss and circadian pressure. Sleep inertia, the period of grogginess and impaired performance experienced after waking, is a potential side effect of napping. Many industry publications recommend naps of 30 min or less to avoid this side effect. However, the evidence to support this advice is yet to be thoroughly reviewed. Methods: Electronic databases were searched, and defined criteria were applied to select articles for review. The review covers literature on naps of 30 min or less regarding (a) sleep inertia, (b) slow-wave sleep (SWS) and (c) the relationship between sleep inertia and SWS. Results: The review found that although the literature on short afternoon naps is relatively comprehensive, there are very few studies on naps of 30 min or less at night. Studies have mixed results regarding the onset of SWS and the duration and severity of sleep inertia following short naps, making guidelines regarding their use unclear. The varying results are likely due to differing sleep/wake profiles before the nap of interest and the time of the day at waking. Conclusions: The review highlights the need to have more detailed guidelines about the implementation of short naps according to the time of the day and prior sleep/wake history. Without this context, such a recommendation is potentially misleading. Further research is required to better understand the interactions between these factors, especially at night, and to provide more specific recommendations. Refereed/Peer-reviewed

This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p < 0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p < 0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort. Refereed/Peer-reviewed

There is evidence to indicate that the central biological clock (i.e., our endogenous circadian system) plays a role in physiological processes in the body that impact energy regulation and metabolism. Cross-sectional data suggest that energy consumption later in the day and during the night is associated with weight gain. These findings have led to speculation that when, as well as what, we eat may be important for maintaining energy balance. Emerging literature suggests that prioritising energy intake to earlier during the day may help with body weight maintenance. Evidence from tightly controlled acute experimental studies indicates a disparity in the body's ability to utilise (expend) energy equally across the day and night. Energy expenditure both at rest (resting metabolic rate) and after eating (thermic effect of food) is typically more efficient earlier during the day. In this review, we discuss the key evidence for a circadian pattern in energy utilisation and balance, which depends on meal timing. Whilst there is limited evidence that simply prioritising energy intake to earlier in the day is an effective strategy for weight loss, we highlight the potential benefits of considering the role of meal timing for improving metabolic health and energy balance. This review demonstrates that to advance our understanding of the contribution of the endogenous circadian system toward energy balance, targeted studies that utilise appropriate methodologies are required that focus on meal timing and frequency. Refereed/Peer-reviewed

Objectives: Unhealthy dietary profiles contribute to the elevated risk of chronic diseases for shift workers. There has been limited investigation into factors associated both with shift work and diet, such as sleep and mood, that may further influence food intake among shift workers. The aim of this study was to explore the relationship between shift work, sleep, mood, and diet. Methods: Shift working nurses [N=52; 46 female; age: mean 39.8 (SD 12.4) years] participated in a 14-day, repeated measures, within- and between-subjects design study. Analyses included data from 40 nurses over 181 shifts. Food diaries were completed for a minimum of three days per shift type (morning, afternoon, night). Foodworks nutrition software was used to determine energy intake in kilojoules and macronutrient intake (as a percentage of total energy intake). Mood (happiness, anxiety, depressive mood, stress, and tiredness) was measured using visual analog scales. Sleep was estimated using actigraphy. Demographic and work-related variables (covariates) were measured using a modified version of the Standard Shiftwork Index. A path analysis was conducted using generalized structural equation modelling with a random effect of participant ID. Predictors were selected using purposive selection of covariates (an alternative to stepwise modelling) and final models included important predictors only. Results: Compared to night and morning shifts, results showed that working an afternoon shift was associated with a lower energy intake (β= -1659.4, P

Flight attendants experience circadian misalignment and disrupted sleep and eating patterns. This survey study examined working time, sleep, and eating frequency in a sample (n=21, 4 males, 17 females) of Australian flight attendants (mean age=41.8 y, SD=12.0 y, mean BMI=23.8 kg/m2, SD=4.1 kg/m2). Respondents indicated frequencies of snack, meal, and caffeine consumption during their last shift. Reported sleep duration on workdays (mean=4.6 h, SD=1.9 h) was significantly lower than on days off (M=7.2 h, SD=1.2 h, p

Understanding shift workers dietary intake patterns may inform interventions targeted at lowering chronic disease risk. This study examined the temporal distribution of food intake as shift workers rotate between night shifts, day shift and/or days off to identify differences in energy intake, eating frequency, and adherence to dietary guidelines by shift type (night shift vs. day). Night shift (NS) workers completed a four-day food diary that included a minimum of two night shifts and one-day shift (DS)/day off (DO), recording all food, beverages and time of consumption. Comparisons were between shift types, using ANOVA for continuous data and generalized estimating equations for count data, data reported as mean (SE). When comparing NS and DSDO, there were no differences in energy intake (24 h) (8853 (702) vs. 9041 (605) kJ, n = 22) or adherence to dietary guidelines. There was no difference between the number of eating occasions on NS and DSDO (5.6(0.3) vs 5.1(0.6) occasions) but less energy per eating occasion at night (1661(125) vs 1933(159) kJ). When working NS compared with DSDO there was higher total sugar (%E, 19.1(2.0) vs 15.0(2.4)) and lower saturated fat (%E, 13.8(1.2) vs 15.7(1.3)). Further, DSDO were characterized by a pattern of three main meals and a prolonged fasting period. It is important to determine if reducing eating occasions and providing opportunities for fasting improves metabolic health. Refereed/Peer-reviewed

This laboratory study investigated the impact of restricted sleep during a simulated school week on circadian phase, sleep stages and daytime functioning. Changes were examined across and within days and during a simulated weekend recovery. Participants were 12 healthy secondary school students (six male) aged 15-17 years [mean = 16.1 years, standard deviation (SD) = 0.9]. After 2 nights with 10 h (21:30-07:30 hours), time in bed was restricted to 5 h for 5 nights (02:30-07:30 hours), then returned to 10 h time in bed for 2 nights (21:30-07:30 hours). Saliva was collected in dim light on the first and last sleep restriction nights to measure melatonin onset phase. Sleep was recorded polysomnographically, and the Psychomotor Vigilance Task (PVT) and Karolinska Sleepiness Scale were undertaken 3-hourly while awake. Average phase delay measured by melatonin was 3 h (SD = 50 min). Compared to baseline, sleep during the restriction period contained a smaller percentage of Stages 1 and 2 and rapid eye movement (REM) and a greater percentage of Stage 4. PVT lapses increased significantly during sleep restriction and did not return to baseline levels during recovery. Subjective sleepiness showed a similar pattern during restriction, but returned to baseline levels during recovery. Results suggest that sustained attention in adolescents is affected negatively by sleep restriction, particularly in the early morning, and that a weekend of recovery sleep is insufficient to restore performance. The discrepancy between sleepiness ratings and performance may indicate a lack of perception of this residual impairment. Refereed/Peer-reviewed

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

Shorter, more frequent rosters, such as 6h-on/6h-off split shifts, may offer promise to sleep, subjective sleepiness and performance by limiting shift length and by offering opportunities for all workers to obtain some sleep across the biological night. However, there exists a paucity of studies that have examined these shifts using objective measures of sleep and performance. The present study examined neurobehavioural performance, sleepiness and sleep during 6h-on/6h-off split sleep schedules. Sixteen healthy adults (males, 26.13y ± 4.46) participated in a 9-day laboratory study that included two baseline nights (BL, 10h time in bed (TIB), 2200h-0800h), 4 days on one of two types of 6h-on/6h-off split sleep schedules with 5h TIB during each 'off' period (6h early: TIB 0300h-0800h and 1500h-20000h, or 6-late: TIB 0900h-1400h and 2100h-0200h), and two recovery nights (10h TIB per night, 2200h-0800h). Participants received 10h TIB per 24h in total across both shift schedules. A neurobehavioural test bout was completed every 2 h during wake, which included the Psychomotor Vigilance Task (PVT) and the Karolinska Sleepiness Scale (KSS). Linear mixed effects models were used to assess the effect of day (BL, shift days 1-4), schedule (6h early, 6h late) and trial (numbers 1-6) on PVT lapses (operationalised as the number of reaction times >500 ms), PVT total lapse time, PVT fastest 10% of reaction times and KSS. Analyses were also conducted examining the effect of day and schedule on sleep variables. Overall, PVT lapses and total lapse time did not differ significantly between baseline and shift days, however, peak response speeds were significantly slower on the first shift day when compared to baseline, but only for those in the 6h-late condition. Circadian variations were apparent in performance outcomes, with individuals in the 6h-late condition demonstrated significantly more and longer lapses and slower peak reaction times at the end of their night shift (0730h) than at any other time during their shifts. In the 6h-early condition, only response speed significantly differed across trials, with slower response speeds occurring at trial 1 (0930h) than in trials 3 (1330h) or 4 (2130h). While subjective sleepiness was higher on shift days than at baseline, sleepiness did not accumulate across days. Total sleep was reduced across split sleep schedules compared to baseline. Overall, these results show that while there was not a cumulative cost to performance across days of splitting sleep, participants obtained less sleep and reported lowered alertness on shift days. Tests near the circadian nadir showed higher sleepiness and increased performance deficits. While this schedule did not produce cumulative impairment, the performance deficits witnessed during the biological night are still of operational concern for industry and workers alike. Refereed/Peer-reviewed

Short naps on night shift are recommended in some industries. There is a paucity of evidence to verify the sustained recovery benefits of short naps in the last few hours of the night shift. Therefore, the current study aimed to investigate the sustained recovery benefits of 30 and 10-min nap opportunities during a simulated night shift. Thirty-one healthy participants (18F, 21–35 y) completed a 3-day, between-groups laboratory study with one baseline night (22:00–07:00 h time in bed), followed by one night awake (time awake from 07:00 h on day two through 10:00 h day three) with random allocation to: a 10-min nap opportunity ending at 04:00 h, a 30-min nap opportunity ending at 04:00 h or no nap (control). A neurobehavioral test bout was administered approximately every 2 h during wake periods. There were no significant differences between nap conditions for post-nap psychomotor vigilance performance after controlling for pre-nap scores (p > 0.05). The 30-min nap significantly improved subjective sleepiness compared to the 10-min nap and no-nap control (p < 0.05). The 10-min nap significantly worsened negative mood compared to the 30-min nap and no-nap control (p < 0.01). Contrary to some evidence suggesting “power naps” can help to alleviate performance decrements, a 30-min nap opportunity at approximately 04:00 h was found to improve subjective, but not objective sleepiness. A 10-min nap may lead to increased negative mood in the hours following the nap due to a "short nap aversion" effect. Refereed/Peer-reviewed

Study Objectives: To assess sleep inertia following 10-min and 30-min naps during a simulated night shift. Methods: Thirty-one healthy adults (aged 21–35 y; 18 females) participated in a 3-day laboratory study that included one baseline (BL) sleep (22:00–07:00)and one experimental night involving randomization to either: total sleep deprivation (NO-NAP), a 10-min nap (10-NAP) or a 30-min nap (30-NAP). Nap opportunities ended at 04:00. A 3-min psychomotor vigilance task (PVT-B), digit-symbol substitution task (DSST), fatigue scale, sleepiness scale, and self rated performance scale were undertaken pre-nap (03:00) and at 2, 17, 32, and 47 min post-nap. Results: The 30-NAP (14.7 ± 5.7 min) had more slow wave sleep than the 10-NAP (0.8 ± 1.5 min; P < 0.001) condition. In the NO-NAP condition, PVT-B performance was worse than pre-nap (4.6 ± 0.3 1/sec) at 47 min post-nap (4.1 ± 0.4 1/sec; P < 0.001). There was no change across time in the 10-NAP condition. In the 30-NAP condition, performance immediately deteriorated from pre-nap (4.3 ± 0.3 1/sec) and was still worse at 47 min post-nap (4.0 ± 0.51/sec; P < 0.015). DSST performance deteriorated in the NO-NAP (worse than pre-nap from 17 to 47 min; P < 0.008), did not change in the 10-NAP, and was impaired 2 min post-nap in the 30-NAP condition (P = 0.028). All conditions self-rated performance as better than pre-nap for all post-nap test points(P < 0.001). Conclusions: This study is the first to show that a 10-min (but not a 30-min) nighttime nap had minimal sleep inertia and helped to mitigate short-term performance impairment during a simulated night shift. Self-rated performance did not reflect objective performance following a nap. Refereed/Peer-reviewed

The effects on dehydration and cognitive performance from heat and/or physical activity are well established in the laboratory, although have not yet been studied for personnel working in occupations such as wildland firefighting regularly exposed to these types of conditions. This study aimed to investigate the effects of temperature and dehydration on seventy-three volunteer firefighters (35.7 ± 13.7 years, mean ± standard deviation) during a simulation of wildfire suppression under either control or hot (18–20; or 33–35 °C) temperature conditions. Results showed cognitive performance on the psychomotor vigilance task declined when participants were dehydrated in the heat and Stroop task performance was impaired when dehydrated late in the afternoon.Firefighters may be at risk of deteriorations in simple cognitive functions in the heat whilst dehydrated, although may also experience impairments in complex cognitive functions if dehydrated late in the day, irrespective of the environmental temperature. Refereed/Peer-reviewed

Introduction: Two of the most ubiquitous fatigue countermeasures used by shift-working nurses are napping and caffeine. This mixed-methods case study investigated the ways nurses and midwives utilised napping and caffeine countermeasures to cope with shift work, and associated sleep, physical health and psychological health outcomes. Materials and Methods: N = 130 Australian shift-working nurses and midwives (mean age = 44 years, range = 21–67, 115F, 15M) completed the Standard Shiftwork Index. A sub-set of 22 nurses and midwives completed an in-depth interview. Results: Nearly 70% of participants reported napping. Those who napped during night shifts had significantly less total sleep time before (F 2,75 = 5.5, p < 0.01) and between days off (F 2,82 = 3.9, p < 0.05). By the end of the night shift, average hours of time awake were significantly less for prophylactic and on-shift nappers compared to non-nappers (F 2,85 = 97.2, p < 0.001). Since starting shift work, the percentage of high caffeine consumers ( > 400 mg/day) increased from 15% to 33% of the sample and an average of 4 (SD = 2) caffeinated beverages per day was reported. Increased caffeine consumption was associated with greater sleep disturbance (r = 0.26, p < 0.05), psychological distress (r = 0.37, p < 0.001), abdomen pain (r = 0.27, p < 0.05) and weight gain since starting shift work (r = 0.25, p < 0.05). Interviews confirmed these relationships and revealed that caffeine consumption on night shift was common, whereas napping on night shift was dependent on a number of factors including ability to sleep during the day. Conclusion: This study identified reasons shift workers chose to engage in or abstain from napping and consuming caffeine, and how these strategies related to poor sleep and health outcomes. Further research is required to help develop recommendations for shift workers regarding napping and caffeine consumption as fatigue countermeasures, whilst taking into account the associated hazards of each strategy. Refereed/Peer-reviewed

Studies suggest that there may be an association between sleep and growth; however, the relationship is not well understood. Changes in biology and external factors such as school schedule heavily impact the sleep of adolescents, during a critical phase for growth. This study assessed the changes in sleep across school days, weekends and school holidays, while also measuring height and weight changes, and self-reported alterations in food intake and physical activity. The impact of morningness–eveningness (M-E) on height change and weight gain was also investigated. In a sample of 63 adolescents (mean age = 13.13, SD = 0.33, 31 males) from two independent schools in South Australia, height and weight were measured weekly for 4 weeks prior to the school holidays and 4 weeks after the school holidays. Participants also completed a Morningness/Eveningness Scale and 7-day sleep, diet and physical activity diaries prior to, during and after the school holidays. Participants at one school had earlier wake times during the weekends than participants attending the other school, leading to a significantly shorter sleep duration on weekends for those participants. Regardless of school, sleep was significantly later and longer during the holidays (p < 0.001) and those with a stronger morning preference fell asleep (F 18,36 = 3.4, p = 0.001) and woke (F 18,44 = 2.0, p = 0.027) earlier than evening types. Growth rate was lower during the holiday weeks. For those attending the school with limited sleep in opportunities, growth after the holidays was lower for those with greater evening preference, whereas for those at the other school, growth was greater for those with greater evening preference. The increase in average weight from pre- to post-holidays was greater for those attending the school with limited opportunities to sleep longer. Participants reported greater food intake during the holidays compared to school days and greater physical activity levels on weekends compared to school days, and school days compared to holidays. Results suggest that time of day preference may impact growth, with evening types who cannot sleep in growing at a slower rate than evening types who can or morning types. This may be related to sleep restriction. Despite sleep being both later and longer during the school holidays, participants’ growth slowed during the holiday period. It is possible that this may be a reflection of other behavioural changes in the holidays (increased food intake and reduced physical activity), as sleep timing during the school period was related to growth. Refereed/Peer-reviewed

Objectives: The aim of this review was to identify which limited wake shift work schedules (LWSW) best promote sleep, alertness, and performance. LWSW are fixed work/rest cycles where the time-at-work does is ≤8 hours and there is >1 rest period per day, on average, for ≥2 consecutive days. These schedules are commonly used in safety-critical industries such as transport and maritime industries.Methods: Literature was sourced using PubMed, Embase, PsycInfo, Scopus, and Google Scholar databases. We identified 20 independent studies (plus a further 2 overlapping studies), including 5 laboratory and 17 field-based studies focused on maritime watch keepers, ship bridge officers, and long-haul train drivers. The measurement of outcome measures was varied, incorporating subjective and objective measures of sleep: sleep diaries (N=5), actigraphy (N=4), and polysomnography, (N=3); sleepiness: Karolinska Sleepiness Scale (N=5), visual analog scale (VAS) alertness (N=2) and author-derived measures (N=2); and performance: Psychomotor Vigilance Test (PVT) (N=5), Reaction Time or Vigilance tasks (N=4), Vector and Letter Cancellation Test (N=1), and subjective performance (N=2). Results: Of the three primary rosters examined (6 hours-on/6 hours-off, 8 hours-on/8 hours-off and 4 hours-on/8 hours-off), the 4 hours-on/8 hours-off roster was associated with better sleep and lower levels of sleepiness. Individuals working 4 hours-on/8 hours-off rosters averaged 1 hour more sleep per night than those working 6 hours-on/6 hours-off and 1.3 hours more sleep than those working 8 hours-on/8 hours-off (P

Technology-supported methods for sleep recording are becoming increasingly affordable. Sleep history feedback may help with fatigue-related decision making - Should I drive? Am I fit for work? This study examines a "sleep tank" model (SleepTank ™ ), which is analogous to the fuel tank in a car, refilled by sleep, and depleted during wake. Required inputs are sleep period time and sleep efficiency (provided by many consumer-grade actigraphs). Outputs include suggested hours remaining to "get sleep" and percentage remaining in tank (Tank%). Initial proof of co ncept analyses were conducted using data from a laboratory-based simulated nightshift study. Ten, healthy males (18-35y) undertook an 8h baseline sleep opportunity and daytime performance testing (BL), followed by four simulated nightshifts (2000 h-0600 h), with daytime sleep opportunities (1000 h-1600 h), then an 8 h night-time sleep opportunity to return to daytime schedule (RTDS), followed by daytime performance testing. Psychomotor Vigilance Task (PVT) and Karolinska Sleepiness Scale were performed at 1200 h on BL and RTDS, and at 1830 h, 2130 h 0000 h and 0400 h each nightshift. A 40-minute York Driving Simulation was performed at 1730 h, 2030 h and 0300 h on each nightshift. Model outputs were calculated using sleep period timing and sleep efficiency (from polysomnography) for each participant. Tank% was a significant predictor of PVT lapses (p < 0.001), and KSS (p < 0.001), such that every 5% reduction resulted in an increase of two lapses, or one point on the KSS. Tank% was also a significant predictor of %time in the Safe Zone from the driving simulator (p = 0.001), such that every 1% increase in the tank resulted in a 0.75% increase in time spent in the Safe Zone. Initial examination of the correspondence between model predictions and performance and sleepiness measures indicated relatively good predictive value. Results provide tentative evidence that this "sleep tank" model may be an informative tool to aid in individual decision-making based on sleep history. Refereed/Peer-reviewed

Shift work is a risk factor for chronic diseases such as Type 2 diabetes. Food choice may play a role, however simply eating at night when the body is primed for sleep may have implications for health. This study examined the impact of consuming a big versus small snack at night on glucose metabolism. N = 31 healthy subjects (21–35 y; 18 F) participated in a simulated nightshift laboratory study that included one baseline night of sleep (22:00 h-07:00 h) and one night awake with allocation to either a big snack (2100 kJ) or small snack (840 kJ) group. The snack was consumed between 00:00–00:30 h and consisted of low fat milk, a sandwich, chips and fruit (big snack) or half sandwich and fruit (small snack). Subjects ate an identical mixed meal breakfast (2100 kJ) at 08:30 h after one full night of sleep and a simulated nightshift. Interstitial glucose was measured continuously during the entire study using Medtronic Continual Glucose Monitors. Only subjects with identical breakfast consumption and complete datasets were analysed (N = 20). Glucose data were averaged into 5-minute bins and area under the curve (AUC) was calculated for 90 min post-breakfast. Pre-breakfast, glucose levels were not significantly different between Day1 and Day2, nor were they different between snack groups (p > 0.05). A snack group by day interaction effect was found (F1,16 = 5.36, p = 0.034) and post-hocs revealed that in the big snack group, AUC response to breakfast was significantly higher following nightshift (Day2) compared to Day1 (p = 0.001). This translated to a 20.8% (SEM 5.6) increase. AUC was not significantly different between days in the small snack group. Consuming a big snack at 00:00 h impaired the glucose response to breakfast at 08:30 h, compared to a smaller snack. Further research in this area will inform dietary advice for shift workers, which could include recommendations on how much to eat as well as content., Highlights • Eating at night when the body is primed for sleep may have implications for health of shift workers. • This study examined the impact of consuming a big versus small snack at night on glucose metabolism. • Consuming a big snack at midnight impaired the glucose response to breakfast at 08:30 h, compared to consuming a smaller snack at midnight.

Eating during the night may increase the risk for obesity and type 2 diabetes in shift workers. This study examined the impact of either eating or not eating a meal at night on glucose metabolism. Participants underwent four nights of simulated night work (SW1–4, 16:00–10:00 h

Short, nighttime naps are used as a fatigue countermeasure in night shift work, and may offer protective benefits on the morning commute. However, there is a concern that nighttime napping may impact upon the quality of daytime sleep. The aim of the current project was to investigate the influence of short nighttime naps ( 0.05). Short nighttime naps did not significantly affect daytime recovery total sleep time (p > 0.05). Slow wave sleep (SWS) obtained during the 30-min nighttime nap resulted in a significant reduction in SWS during subsequent daytime recovery sleep (p

There is evidence that a decrease in alertness is associated with a rightward shift of attention. Alertness fluctuates throughout the day and peak times differ between individuals. Some individuals feel most alert in the morning; others in the evening. Our aim was to investigate the influence of morningness/eveningness and time of testing on spatial attention. It was predicted that attention would shift rightwards when individuals were tested at their non-optimal time as compared to tests at peak times. A crowdsourcing internet marketplace, Amazon Mechanical Turk (AMT) was used to collect data. Given questions surrounding the quality of data drawn from such virtual environments, this study also investigated the sensitivity of data to demonstrate known effects from the literature. Five-hundred and thirty right-handed participants took part between 6 am and 11 pm. Participants answered demographic questions, completed a question from the Horne and Östberg Morningness/Eveningness Scale, and performed a spatial attentional task (landmark task). For the landmark task, participants indicated whether the left or right segment of each of 72 pre-bisected lines was longer (longer side counterbalanced). Response bias was calculated by subtracting the ‘number of left responses’ from the ‘number of right responses’, and dividing by the number of trials. Negative values indicate a leftward attentional bias, and positive values a rightward bias. Well-supported relationships between variables were reflected in the dataset. Controlling for age, there was a significant interaction between morningness/eveningness and time of testing (morning = 6 am–2.30 pm, evening = 2.30 pm–11 pm) (p

Shiftworkers report eating during the night when the body is primed to sleep. This study investigated the impact of altering food timing on subjective responses. Healthy participants (n = 44, 26 male, age Mean &plusmn, SD = 25.0 &plusmn, 2.9 years, BMI = 23.82 &plusmn, 2.59kg/m2) participated in a 7-day simulated shiftwork protocol. Participants were randomly allocated to one of three eating conditions. At 00:30, participants consumed a meal comprising 30% of 24 h energy intake (Meal condition, n = 14, 8 males), a snack comprising 10% of 24 h energy intake (Snack condition, n = 14, 8 males) or did not eat during the night (No Eating condition, n = 16, 10 males). Total 24 h individual energy intake and macronutrient content was constant across conditions. During the night, participants reported hunger, gut reaction, and sleepiness levels at 21:00, 23:30, 2:30, and 5:00. Mixed model analyses revealed that the snack condition reported significantly more hunger than the meal group (p &lt, 0.001) with the no eating at night group reporting the greatest hunger (p &lt, 0.001). There was no difference in desire to eat between meal and snack groups. Participants reported less sleepiness after the snack compared to after the meal (p &lt, 0.001) or when not eating during the night (p &lt, 0.001). Gastric upset did not differ between conditions. A snack during the nightshift could alleviate hunger during the nightshift without causing fullness or increased sleepiness.

Adequate sleep is fundamental to workplace performance. For volunteer firefighters who work in safety critical roles, poor performance at work can be life threatening. Extended shifts and sleeping conditions negatively impact sleep during multi-day fire suppression campaigns. Having sleep disordered breathing (SDB) could contribute further to sleep deficits. Our aim was to investigate whether those with suspected SDB slept and performed more poorly during a fire ground simulation involving sleep restriction. Participants, n = 20 participated in a 3-day-4-night fire ground simulation. Based on oximetry desaturation index data collected during their participation, participants were retrospectively allocated to either a SDB (n = 8) or a non-SDB group (n = 12). The simulation began with an 8 h Baseline sleep (BL) followed by two nights of restricted (4 h) sleep and an 8 h recovery sleep (R). All sleeps were recorded using a standard electroencephalography (EEG) montage as well as oxygen saturation. During the day, participants completed neurobehavioral (response time, lapses and subjective fatigue) tasks. Mixed effects ANOVA were used to compare differences in sleep and wake variables. Analyses revealed a main effect of group for Total sleep (TST), REM, wake after sleep onset (WASO) and Arousals/h with the SDB group obtaining less TST and REM and greater WASO and Arousals/h. The group × night interaction was significant for N3 with the SDB group obtaining 42 min less during BL. There was a significant main effect of day for RRT, lapses and subjective fatigue and a significant day × group interaction for RRT. Overall, the SDB group slept less, experienced more disturbed sleep and had poorer response time performance, which was exacerbated by the second night of sleep restriction. This could present a safety concern, particularly during longer campaigns and is worthy of further investigation. In addition, we would recommend promotion of awareness of SDB, its symptoms and potential impact among volunteers and relevant agencies. Refereed/Peer-reviewed

Sleep deprivation is known to have serious deleterious effects on executive functioning and job performance. Augmented reality has an ability to place pertinent information at the fore, guiding visual focus and reducing instructional complexity. This paper presents a study to explore how spatial augmented reality instructions impact procedural task performance on sleep deprived users. The user study was conducted to examine performance on a procedural task at six time points over the course of a night of total sleep deprivation. Tasks were provided either by spatial augmented reality-based projections or on an adjacent monitor. The results indicate that participant errors significantly increased with the monitor condition when sleep deprived. The augmented reality condition exhibited a positive influence with participant errors and completion time having no significant increase when sleep deprived. The results of our study show that spatial augmented reality is an effective sleep deprivation countermeasure under laboratory conditions. Refereed/Peer-reviewed

Sleep inertia is a safety concern for shift workers returning to work soon after waking up. Split duty schedules offer an alternative to longer shift periods, but introduce additional wake-ups and may therefore increase risk of sleep inertia. This study investigated sleep inertia across a split duty schedule. Sixteen participants (age range 21–36 years; 10 females) participated in a 9-day laboratory study with two baseline nights (10 h time in bed, [TIB]), four 24-h periods of a 6-h on/6-h off split duty schedule (5-h TIB in off period; 10-h TIB per 24 h) and two recovery nights. Two complementary rosters were evaluated, with the timing of sleep and wake alternating between the two rosters (2 am/2 pm wake-up roster versus 8 am/8 pm wake-up roster). At 2, 17, 32 and 47 min after scheduled awakening, participants completed an 8-min inertia test bout, which included a 3-min psychomotor vigilance test (PVT-B), a 3-min Digit-Symbol Substitution Task (DSST), the Karolinska Sleepiness Scale (KSS), and the Samn–Perelli Fatigue Scale (SP-Fatigue). Further testing occurred every 2 h during scheduled wakefulness. Performance was consistently degraded and subjective sleepiness/fatigue was consistently increased during the inertia testing period as compared to other testing times. Morning wake-ups (2 am and 8 am) were associated with higher levels of sleep inertia than later wake-ups (2 pm and 8 pm). These results suggest that split duty workers should recognise the potential for sleep inertia after waking, especially during the morning hours. Refereed/Peer-reviewed

Sleep-Disordered Breathing (SDB) has been associated with possible negative outcomes, such as preeclampsiaand foetal growth restriction. SDB screening tools have been developed for use within general populations.These included the use of self-reports and objective measurements. Seventeen pregnant women withintheir 34th to 37th week of pregnancy were recruited. Participants undertook an overnight study withintheir home and SDB symptoms were monitored using the Watch-PAT 200 and an infra-red video camera. Thewomen were administered an online questionnaire comprised of the Multivariable Apnea Risk Index (MAPIndex) and the Basic Nordic Sleep Questionnaire (BNSQ). More than half of our participants (n = 10) wereidentified as snorers while much fewer (n = 4) met the current cut off for diagnosis of mild SDB. Investigationof concordance and predictive value of self-report measures compared to standard video-scoring and Watch-PAT 200 determined SDB indicators suggests that self-reports may not provide an accurate assessment ofSBD symptoms in late pregnancy. Self-report in this study, resulted in an underestimation of the number ofparticipants who experienced SDB symptoms. This was a pilot study, with a small sample size. However, ourstudy lends weight to others that found poor predictive value of common scales to detect SDB in pregnancy.Future study is therefore needed to validate screening tools, which may need to be a combination of measures. Refereed/Peer-reviewed

The detrimental effects of excessive alcohol consumption are well documented. There is some evidence that shiftworkers consume more alcohol than dayworkers as a sleep aid to compensate for sleep difficulties associated with work schedules. This study investigated drinking patterns between shiftworkers and dayworkers using the 2006 and 2007 waves from the Household Income and Labour Dynamics Survey. A subset of workers who were not in full-time study and had a single job were selected; participants who did not drink alcohol (n = 2090) were excluded. Using the 2001 Australian Government alcohol guidelines, alcohol consumption for risk of short-term harm (7+ standard drinks for men, 5+ for women) was investigated. The number of workers who drank alcohol "nearly every day" or "every day" was also examined. Some 13% of shiftworkers and 10% of those on standard schedules reported consuming alcohol at levels risky for short-term harm. Having a child less than 17 yrs (odds ratio [OR] = .39, 95% confidence interval [CI] = .22-.69), higher job demands (OR = .71, 95% CI = .58-.86), being female (OR = .45, 95% CI=. 26-.79), and being older (OR = .89, 95% CI = .87-.92) significantly reduced, whereas being a shiftworker (OR = 2.10, 95% CI = 1.08-4.12) significantly increased, the odds of drinking alcohol in short-term risky levels. Nearly 10% of shiftworkers and 8% of those on standard schedules reported consuming alcohol in short-term risky levels at least weekly. Having a child less than 17 yrs (OR = .40, 95% CI = .22-.74), higher job demands (OR = .69, 95% CI = .56-.86), being female (OR = .28, 95% CI = .15-.53), and being older (OR = .92, 95% CI = .89-.94) were associated with a significant reduction in the odds of consuming alcohol at risky levels at least weekly. Being a shiftworker was not associated with a significant increase in the odds of consuming alcohol at such risky levels at least weekly, but a trend was evident (OR = 1.47, 95% CI = .73-3.00). Some 13.5% of shiftworkers and 21% of those on standard schedules reported consuming alcohol in any amount "near daily" or "daily." Working more hours than preferred (OR = 1.80, 95% CI = 1.12-2.89) and being older (OR = 1.10, 95% CI = 1.07-1.13) were associated with a significant increase, and being female (OR = .18, 95% CI = .10-.33), and being a shiftworker (OR = .20, 95% CI = .09-.45) were associated with a significant decrease in the odds of consuming alcohol "daily" or "near daily." Overall, the results suggest that shiftworkers may be more likely to consume alcohol at levels considered to be risky for health in the short term. In contrast, they appear less likely to drink alcohol daily. This pattern is suggestive of "binge drinking" behavior. Refereed/Peer-reviewed

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

Midwives often work night and rotating shift schedules, which can lead to sleep disturbances, increased fatigue, and greater likelihood of accidents or errors. This study investigated the sleep of midwives ( n = 17) in an Australian metropolitan hospital. Midwives completed work and sleep logbooks and wore wrist actigraphs for 28 days. Midwives worked combinations of morning, afternoon, and/or night shifts on constant ( n = 6) or rotating schedules ( n = 11). They obtained less than recommended amounts of sleep, getting only 6–7 hr per 24-hr period. Morning shifts were associated with the lowest sleep durations, lowest subjective sleep quality, and highest postsleep fatigue ratings. Despite the significantly higher amount of wake after sleep onset (51 min), the sleep before afternoon shifts had significantly lower postsleep fatigue ratings and was rated as significantly higher quality than sleep before other shifts or days off. Those who were married or living with a partner reported significantly more sleep and lower postsleep fatigue than those who were separated or divorced ( p < .05). Seventy-one percent of midwives took naps, primarily before night shifts, with nearly 40% of nightshifts preceded by a nap. Average nap durations were nearly 1.5 hr. Midwives reported feeling moderately to very physically or mentally exhausted on 22–50% of all shifts and days off. Exhaustion was most common on night shift. This study suggests that midwives may be suffering from chronic sleep loss and as a consequence may be at risk of impairments in functioning that accompany fatigue.

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

This study examined the associations between self-reported sleep timing and quality, and the frequency of breakfast and junk food consumption in 28,010 Australian school students (mean ± SD age = 13.3 ± 1.2 years, 51% male). After controlling for age, sex and socioeconomic status, regression analyses revealed that the odds of missing breakfast were significantly higher in children who reported poor sleep or later bedtimes, while the odds of junk food consumption were significantly higher in children reporting later weeknight bedtimes (p < 0.001). These findings suggest that sleep timing and quality influence the dietary choices of adolescents. Refereed/Peer-reviewed

This Australian national study was undertaken to profile the unsuitable counselling student, and to achieve greater operational specificity to guide counselling educators who must make critical decisions that impact admittance to the counselling profession. Findings suggest that in every 25 students as many as three will have questionable suitability for counselling, evidenced primarily by problems associated with self awareness and interpersonal issues, areas of functioning that are rarely systematically or objectively assessed. Such students are likely to be identified via skills-based classes and, of concern, at least half of these students “slip through the gate” and go on to graduate. Discussion addresses implications for educators.

Vigilance technologies are used in the Australian rail industry to address the risks associated with driver sleepiness and fatigue. The aim of this study was to investigate whether a new device, designed to detect lowered statesof arousal using electrodermal activity (EDA), would be sensitive to experimentally induced sleepiness and fatigue. Fifteen individuals (7 of them female, 9 male; 18-32 years of age) spent 3 consecutive days in the laboratory, which included 1 night of sustained wakefulness (28 h). The participants completed a 10-min psychomotor vigilance task (PVT) and fatigue and sleepiness ratings every 2 h, and a 30-min driving simulator every 4 h. As was expected,simulated driving, PVT, and subjective ratings indicated increasing levels of sleepiness and fatigue during sustained wakefulness. The EDA device output did not coincide with these findings. The results indicated that the EDA indicatorwas not sensitive to increased sleepiness and fatigue at the levels produced in the present study. Refereed/Peer-reviewed

Objective As feelings of alertness are reported to be highly correlated with performance perception, the objective of this study was to determine whether caffeine, a common countermeasure to driver sleepiness, affected a sleepy driver's ability to monitor his or her simulated driving performance. Methods Twelve healthy young adults (six males, six females) participated in three counterbalanced, blinded, daytime conditions: control [9 h time in bed (TIB)], 100 mg caffeine (4 h TIB), and placebo (4 h TIB). Driving performance was measured through lane drift on a series of 30-min simulated driving sessions. Subjective sleepiness and perception of driving performance were measured at 5-min intervals during driving sessions via the Karolinska Sleepiness Scale and a corresponding perception scale. Results Sleep restriction had a significant detrimental effect on driving performance and subjective measures. Caffeine resulted in significant improvements across all measures. Subjective measures were found to be significantly correlated after sleep restriction and prior to caffeine. Correlations between actual and perceived performance were nonsignificant across all conditions. Conclusions The strong correlation between subjective measures supports the postulation that sleepiness is used as a cue for performance prediction when sleep restricted. The relationship between perceived and actual performance after fatigue countermeasures remains inconclusive. Further research, addressing limitations, is needed.

Wildland firefighting exposes personnel to combinations of occupational and environmental stressors that include physical activity, heat and sleep restriction. However, the effects of these stressors on sleep have rarely been studied in the laboratory, and direct comparisons to field scenarios remain problematic. The aim of this study was to examine firefighters’ sleep during a three-day, four-night simulated wildfire suppression that included sleep restriction and physical activity circuits representative of firefighting wildfire suppression tasks in varied temperatures. Sixty-one volunteer firefighters (37.5 ± 14.5 years of age, mean ± SD) were assigned to one of three conditions: control (n = 25; 8 h sleep opportunities and 18–20 °C), awake (n = 25; 4 h sleep opportunities and 18–20 °C) or awake/hot (n = 11; 4 h sleep opportunities and 33–35 °C during the day and 23–25 °C during the night). Results demonstrated that amounts of N1, N2 and R sleep, TST, SOL and WASO declined, whilst sleep efficiency increased significantly in the awake and awake/hot conditions compared to the control condition. Results also demonstrated that SWS sleep remained relatively stable in the awake and awake/hot conditions compared to control values. Most importantly, no significant differences were found for any of the sleep measures between the awake and awake/hot conditions. Thus, working in hot daytime temperatures in combination with sleep restriction during the night did not affect patterns of sleep compared to working in temperate conditions in combination with sleep restriction during the night. However, the effects on sleep of high (>25 °C) night-time temperatures with sleep restriction in addition to physical activity remains to be studied. Refereed/Peer-reviewed

It has been suggested that shiftworkers may consume alcohol to help them sleep, resulting in greater consumption. A large study in Australian workers suggested that those on non-standard schedules (outside 8 am–6 pm, Monday–Friday) do not drink more, but are at increased odds of binge drinking (heavy periods of drinking followed by abstinence) than workers on standard schedules. However, differences in types of non-standard schedules were not examined in the study. The current study examined the alcohol intake of Australian shiftworkers on fixed and rotating shifts. Shiftworkers (n = 118, age = 43.4 ± 9.9 y, 68% male) on 12 h-rotating (n = 29), 8 h-rotating (n = 29), morning (n = 33) and night (n = 27) schedules from printing, postal, nursing and oil industries participated. They completed a Cancer Council Dietary Questionnaire, recording frequency and amount of alcohol consumed on average per day over the preceding year. They also completed a shortened Standard Shiftwork Index, including questions on shift schedule, sleep duration, tiredness, gender and age. Average alcohol consumption was 9.6 ± 13.1 standard drinks/week. One in six reported using alcohol as a sleep aid between shifts at least sometimes and nearly one third reported consuming 12 or more drinks in 24 h. Alcohol consumption was higher for males and decreased with age. Controlling for gender and age, there were no significant differences between shift types in standard drinks/week (p = 0.50). However, those on 12-h rotating shifts consumed more drinks per 24 h (p = 0.04) and had less sleep (p

Shiftworkers work while biologically primed for sleep and sleep while primed for wake. This leads to reduced sleep and, in turn, elevated sleepiness and impaired performance, health, and safety. Shiftworkers may use alcohol to promote sleep. Although alcohol has sedative properties, reducing the time taken to fall asleep, it disrupts sleep architecture. The negative effects of alcohol, particularly at high doses, are wide-ranging. Alcohol use among shiftworkers is likely to put extra pressure on already vulnerable physiological systems. This perceived compensatory mechanism for facilitating sleep may actually be exacerbating sleep loss, as well as further increasing health and safety risk. This chapter describes the way that the body processes alcohol, the negative impact on health, and the specific effects of alcohol on sleep. We then examine the evidence surrounding patterns of alcohol use in shiftworkers, before turning to consideration of the potential impact of these patterns.

Fatigue is an increasingly noted factor in road accidents. The ability to predict and be aware of impairment in terms of driving capability is important for potential legal liability and road safety. However, to date, there have been few studies that have investigated the accuracy of individuals in predicting how safely they could drive during conditions of sleep loss. Research has demonstrated that individuals rate themselves as better than the population average in a number of domains, including driving-related skills. Therefore, this study also aimed to investigate self-ratings of predicted driving ability during extended wakefulness and compare them to ratings made of a hypothetical other person under the same conditions. Thirty-two participants remained awake for a period of 40 h. Every 2 h, they completed the Psychomotor Vigilance Task (PVT) and rated on a seven-point scale how well they thought they could drive safely, react quickly in an emergency, and stay in their own lane. They were also asked to assess how they thought someone else in their own position could drive. The participants rated their driving ability as becoming significantly poorer at the same time that their PVT performance became significantly slower. Self-ratings indicating a qualitative assessment of poorer than neutral driving occurred at 03:00 h for both the "drive safely" and "react quickly" questions, after 19 h of continuous wakefulness (starting at 08:00 h). This occurred at 05:00 h for the "keep in my lane" question. Previous studies with a similar protocol demonstrated that under these conditions, individuals exhibit a performance decrements equivalent to someone with a blood alcohol concentration of 0.05% (the legal driving limit in Australia). Participants consistently rated the ability of others to drive as poorer than their own. The main implication from this study for road safety and legal liability is that it is reasonable to focus on a person's perception of the situation, as it does align with objective reality to a certain extent. A concern in terms of road safety is potential overconfidence, indicated by rating others consistently poorer than themselves.

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.

Waking neurobehavioural or cognitive functioning is largely dependent on two mechanisms both in synchrony and in opposition to each other: the sleep homeostatic and circadian systems. The influences of these systems are particularly evident during periods of sustained wakefulness or sleep deprivation. Although the effects of these two systems on neurobehavioural functioning during periods of extended wakefulness have been demonstrated experimentally, there does not exist an adequate theory to describe the underlying brain mechanisms responsible for these neurobehavioural deficits. Much research has in fact concentrated not on understanding the nature of these deficits, but rather in counteracting them, via the use of countermeasures, such as naps and wake promoting compounds.

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_

Although shift and break timing is known to affect the sleep of shiftworkers, this has not been demonstrated in Fly-in, Fly-out (FIFO) settings which, compared to residential based settings, may be favourable for sleep. This study investigated the sleep quantity and quality of shiftworkers working a FIFO operation comprising of shifts, and therefore breaks, across the 24-h day. The sleep of 24 males (50.43 ± 8.57 yr) was measured using actigraphy and sleep diaries. Morning breaks were associated with less sleep (09:00-12:00 h; 4.4 ± 1.3 h) and a poorer sleep quality (06:00-09:00 h; 3.1 ± 1.0, "average") compared to breaks beginning between 00:00 h and 03:00 h (6.8 ± 1.7 h; 2.2 ± 0.9, "good"). Sleep efficiency remained constant regardless of break timing (85.9 ± 5.0% to 89.9 ± 3.5%). Results indicate that even in operations such as FIFO where sleeping conditions are near-optimal and the break duration is held constant, the influence of the endogenous circadian pacemaker on sleep duration is evident. Refereed/Peer-reviewed