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Research has indicated that individuals with certain traits may be better suited to shiftwork and non-standard working arrangements. However, no research has investigated how individual differences impact on-call outcomes. As such, this study investigated the impact of trait anxiety on sleep and performance outcomes on-call. Seventy male participants (20–35 years) completed an adaptation night, a control night, and two on-call nights in a laboratory. Trait anxiety was determined using the State Trait Anxiety Inventory (STAI) X-2, and participants completed the STAI X-1 prior to bed each night to assess state anxiety. Sleep was measured using polysomnography and quantitative electroencephalographic analysis. Performance was assessed using a 10-min psychomotor vigilance task (PVT) performed each day at 0930, 1200, 1430 and 1700 h. Data pooled from three separate but inter-related studies was used for these analyses. Results indicated that the effects of trait anxiety on state anxiety, sleep and performance outcomes on-call were generally limited. These findings suggest that on-call outcomes are not negatively affected by higher levels of trait anxiety. Refereed/Peer-reviewed

On-call working arrangements have been shown to negatively impact sleep. However, workers may perceive their sleep to be worse than it actually is. The aim of this study was to compare participants' pre- and post-sleep estimates of sleep duration and sleep quality with objectively measured sleep when on-call under laboratory conditions.72 healthy, adult males.Analyses were performed on three interrelated studies, all of which consisted of four nights in a sleep laboratory. Following adaptation and baseline nights were two on-call nights (sleep opportunity 23:00 h - 07:00 h). Before and after each sleep opportunity, participants provided subjective estimates of sleep. Sleep was objectively measured using polysomnography.Estimated sleep duration (6.74 ± 1.13 h) and sleep onset latency (20.55 ± 14.85 min) were significantly poorer than objectively measured sleep outcomes (sleep duration 7.21 ± 1.25 h; sleep latency 13.20 ± 10.06 min). Of the variance in post-sleep estimated sleep duration, 14% was associated with objectively measured minutes of N3 (RSome objective measures of sleep were associated with subjective estimates of sleep duration and sleep quality. However, individuals may overestimate sleep onset latency and underestimate sleep duration during on-call periods. It may be beneficial for on-call workers to actively reflect on feelings of fatigue/alertness for workplace fatigue management, rather than relying solely on estimates of sleep.

University employees experience high levels of workplace stress, with the perception that it is increasing, due to less autonomy, increased student numbers, excessive administrative work and role a...

The on-call schedule is a common work arrangement that allows for the continuance of services during periods of low demand or emergencies. Even though 17%–25% of the world’s population participate in on-call work, the human impacts of on-call are generally poorly described in the literature. Of the studies available on the effects of on-call work on workers, disturbances to sleep duration and sleep quality are the most commonly reported, along with negative sleep-related consequences on sleepiness, fatigue, stress and mood. Research has shown that for couples sharing a bed, disturbances to sleep can impair relationship conflict resolution and reduce relationship quality. In the ‘off-site’ on-call scenario where workers are sleeping at home, their co-sleeping partner may be at risk of sleep disturbances and the subsequent detrimental consequences of this disturbed sleep for themselves and their relationship. To date, few studies have investigated the impact of on-call work for partners’ sleep and the potential sleep-related consequences. Therefore, further studies are needed to specifically address whether on-call work impacts the sleep of partners and whether these sleep disturbances also impact the partner’s daily performance and relationship quality. Our aim was to provide a narrative around the existing, relevant literature that both investigate and inform the potential impact of on-call for workers’ partners’ sleep and related consequences.

Working time arrangements that require shift work or other non-standard working hours have significant potential to encroach on time that is highly valued for family, social and leisure activity. This can often result in workers experiencing poorer work-family or work-life balance. Based on an extensive literature search and expert knowledge, primary risk factors were identified including shift work; long, irregular and unpredictable working hours; and work on evenings and weekends (in combination and independent of shift work). On the other hand, flexibility, in the form of adequate worker control over work schedules, may be a protective factor. In addition, workers experiencing excessive work-life conflict are likely to reduce their working hours, reflecting a reciprocal relationship between working hours and work-life balance. Workers’ families are also affected by shift work and non-standard working hours. Parents’ shift work is associated with poorer emotional and developmental outcomes for their children, and to a greater likelihood of risky behavior in adolescence. Additionally, the risk of separation or divorce is increased, especially for parents working night shifts. Due to relationships such as those above, the consequences of shiftwork and non-standard working hours on family and social life are largely dependent on a complex interaction between specific work schedules, other aspects of work organization, and family and individual worker characteristics. This article provides an overview of current evidence regarding the relationships between working time arrangements and various social and family variables, and concludes with shift scheduling and intervention recommendations to improve work-life balance and social well-being.

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).

Objectives: This study examines the impacts of peak summer demand on operator workload and fatigue in a maritime environment. Methods: Participants (n = 12) were senior shipboard personnel who were working during the summer “double sailing” period for a roll-on roll-off ferry service. Wrist actigraphy was used to determine sleep opportunity and sleep duration, as well as prior sleep, total wake time, performance and alertness at the beginning and end of work periods. Results: Contrary to expectations, sleep was significantly greater, and both subjective estimates of fatigue and objective neurobehavioral performance were not impacted negatively by periods of increased work intensity. Conclusions: This study highlights a number of features of a fatigue-risk management system that appear to have been instrumental in ensuring adequate sleep and performance was maintained throughout periods of increased operational intensity. As a simple colloquial description of the fatigue-risk management system at play in this operation, it was fine to “work hard” if you were able to “sleep hard” as well. Refereed/Peer-reviewed

The unpredictable, "on-call" component of the emergency services (ES) may be difficult to navigate in the context of domestic and work responsibilities, and especially difficult for women, given they tend to take on a greater household burden than do men. Our aim was to understand women's experiences in the ES, particularly the impact of being on-call and related coping strategies.Twenty-four women were recruited from two ES agencies in Australia. Participation involved a brief questionnaire and a 45-60-min interview. Interviews were recorded, and audio files were transcribed before analysis using nVIVO software.Interview data identified two major themes: impact and management. Women talked about the impact of on-call for themselves (e.g. disturbed? sleep, fatigue and the relentlessness of the role) but also discussed the, largely negative, impact for their family/household. In terms of management, support (family, social and work) and planning and preparation were identified as important in helping women manage their multiple roles in the context of on-call unpredictability.The negative impacts of on-call work on women's sleep supports existing quantitative and qualitative data in the broader on-call area. For those women with children, managing their care presents one of the biggest challenges to being able to manage the on-call component of their work. Future research should to focus on quantifying the impact of on-call for both men and women, particularly the "relentlessness" of the work identified in this study and whether this toll changes based on other factors such as experience, role or gender.

The nature of on-call work is such that workers can be called and required to respond immediately after being woken. However, due to sleep inertia, impaired performance immediately upon waking is t...

Objectives: To investigate the acute benefits of breaking up prolonged sitting with light-intensity physical activity on (i) glucose metabolism under conditions of sleep restriction, and (ii) cognitive deficits associated with sleep restriction. Methods: This counterbalanced, crossover trial consisted of two five-day (5 night) experimental conditions separated by a two-week washout period. On the first night, participants were given a 9-h sleep opportunity to allow the collection of steady-state baseline measures the following day. This was followed by three consecutive nights of sleep restriction (5-h sleep opportunity). In the sitting condition (SIT), participants remained seated between 1000 and 1800 h. In the physical activity condition (ACT), participants completed 3-min bouts of light-intensity walking every 30 min on a motorised treadmill between 1000 and 1800 h. At all other times, in both conditions, participants remained seated, except when walking to the dining room or to use the bathroom (max distance = 32 m). Six physically inactive, healthy males were randomised to one of two trial orders, 1) SIT then ACT, or 2) ACT then SIT. Continuous measures of interstitial glucose were measured at 5-min intervals. A cognitive and subjective test battery was administered every two hours during wake periods. Analyses were conducted using a series of linear mixed-effect ANOVAs. Results: No differences in interstitial glucose concentration or cognitive performance were observed between the SIT condition and the ACT condition. Participants reported higher levels of sleepiness, and felt less alert in the SIT condition compared with the ACT condition. Conclusions: There were no observable benefits of breaking up prolonged sitting on glucose metabolism under conditions of sleep restriction. These findings have implications for behaviour change interventions. Future studies will need to include larger, less homogenous study populations and appropriate control conditions (i.e., 8–9 h sleep opportunities). Keywords: Physical activity, Exercise, Sitting breaks, Sedentary behaviour, Fatigue, Sleepiness

On-call work is prevalent worldwide and is associated with adverse outcomes, including disrupted sleep, impaired leisure time, and difficulties in mentally detaching from work. Limited studies specifically explored whether men and women experience on-call differently, therefore, our aim was to investigate whether sex differences exist in terms of both the impacts of and coping strategies to deal with on-call work. On-call workers (n = 228) participated in an online survey to investigate how on-call work impacts domestic, non-domestic, and leisure activities, and coping strategies. Pearson chi-squared analyses were used to determine sex differences for each construct of interest. Results indicated that female respondents were more likely to be responsible for running their household, and reported that being on call disturbed leisure, domestic, and non-domestic activities &ldquo, a lot/very much&rdquo, While both males and females adopted engaged coping styles, a greater proportion of males used &ldquo, problem solving&rdquo, and a greater proportion of females &ldquo, talked about their feelings&rdquo, when managing on-call work. These findings provide valuable insight into how males and females are differentially impacted and cope with on-call work. Further research is required to better understand these impacts, particularly over time, and should include measures such as of quality of life, relationship satisfaction, and physical and mental health outcomes.

Introduction On-call schedules are associated with stress and disrupted sleep. In a recent study, under non-sleep deprived conditions, low and high-stress on-call conditions did not significantly impact sleep quality but did impact next day performance. Our aim was to determine whether quantitative electroencephalography (qEEG) would reflect changes in cortical activity in on-call conditions, predicting that the high-stress condition would display faster qEEG frequencies compared with the control and low-stress condition. Methods Twenty-four healthy male participants (age: 26.5 ± 4.0 yrs) spent four nights in a time-isolated sleep laboratory. The within-subjects, repeated measures experimental design assessed waking EEG, via the Karolinska Drowsiness Test (KDT) during four time-points across a control day and two experimental (on-call) days. Experimental days comprised a low-stress (LS – reading task) and high-stress (HS – speech task) condition and were counterbalanced. Mixed-models analysis was used to assess condition and time by EEG biomarkers: Alpha Attenuation Coefficient (AAC), Slowing Ratio (SR) and Scaling Exponent (SE). Results Main effects were found for all three biomarkers by condition, with pairwise analysis reported. There was a significant difference in AAC between the LS condition (M = 1.26 ± =1.24) and HS condition (M = 1.01 ± 0.76 p = .02) indicating decreased alertness between LS and HS. A significant increase in SR between control (M = 7.1 ± 4.3) and LS (M = 10.1 ± 8.5 p = .0001), and a significant increase between the LS and HS (M = 7.8 ± 6.8 p = .018) showing greatest EEG slowing in the LS condition, reflecting of a passive, sleepier brain state. The SE was significantly higher in the LS (M = 1.09, ±0.17) condition compared with control (M = 1.0, ±0.11 p = .001) indicating decreased alertness in the LS task. Discussion Using qEEG biomarkers, in contrast with our initial hypothesis, the current study found that compared with control, the LS condition resulted in greater EEG slowing. These findings have implications for on-call workers who engage in periods of passive attention and highlight a protective role task stress may play in maintaining alertness levels during on-call conditions.

Anecdotally, people report disturbed sleep when ‘on-call’ and field data suggest that being on-call, even if ‘undisturbed’, may result in sleep disturbance. We investigated changes to sleep when expecting a loud, on-call alarm as compared to sleep when not expecting an alarm. Healthy males (n = 16) aged 24.6 ± 4.0 years took part in a simulated on-call scenario involving two conditions; Control and on-call. Prior to the Control sleep, participants were told that they would not be woken during the night, prior to the on-call sleep, participants were told to expect a loud alarm during the night, following which they were to complete 2 h of testing. Sleep was measured using a standard 5-channel polysomnograhic (PSG) montage. Sleep diaries were used to compare subjective variables; pre- and post-sleep sleepiness and sleep quality. There was no significant difference between the two nights for any of the PSG variables, except for REM where there was a non-significant trend (p = .051) with 8 min more REM on the on-call night. Participants were significantly sleepier following the on-call night, likely due to the earlier wake time (p

In response to demand for the '24/7' service availability, shift work has become increasingly common. Given their non-traditional working hours, shift workers sleep at non-traditional times, with significant research undertaken to understand shift worker sleep. However, sleep hygiene in shift workers has been paid little research attention. To investigate shift worker engagement with sleep hygiene, a systematic review using the databases Sage, ScienceDirect, and Scopus was undertaken. The search terms utilised were: shift work, shiftwork, shift-work, sleep hygiene, sleep routine, and sleep habit. Sixteen studies were included for review. Findings show that shift workers frequently report caffeine consumption and daytime napping, in line with best-practice fatigue-management strategies, but contrary to existing sleep hygiene recommendations. Shift workers also altered their bedroom environment to optimise sleep. Diet, exercise, alcohol and nicotine consumption were investigated minimally from a sleep hygiene perspective. Given that shift workers are engaging in practices in-line with current fatigue-management strategies, but contrary to sleep hygiene recommendations, further research is required. Specifically, assessment of the applicability of current sleep hygiene guidelines to shift workers (particularly caffeine and napping recommendations) is required, in addition to the development of shift work-specific sleep hygiene guidelines and interventions for this sleep-vulnerable population.

Sleep inertia, the state of reduced alertness upon waking, can negatively impact on-call workers. Anticipation of a stressful task on sleep inertia, while on-call was investigated. Young, healthy males (n = 23) spent an adaptation, control and two counterbalanced on-call nights in the laboratory. When on-call, participants were told they would be woken to a high or low stress task. Participants were not woken during the night, instead were given a 2300-0700 sleep opportunity. Participants slept ∼7.5-h in all conditions. Upon waking, sleep inertia was quantified using the Karolinska Sleepiness Scale and Psychomotor Vigilance and Spatial Configuration Tasks, administered at 15-min intervals. Compared to control, participants felt sleepier post waking when on-call and sleepiest in the low stress compared to the high stress condition (p .001). Spatial performance was faster when on-call compared to control (p .001). Findings suggest that anticipating a high-stress task when on-call, does not impact sleep inertia severity.

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

This pilot study investigated the impact of breaking up prolonged sitting with light-intensity walking on postprandial glucose responses and sleep architecture. In a randomized, counterbalanced, crossover design, six healthy males completed a sitting condition and an active condition (sitting interrupted with light-intensity walking) for three consecutive days, following 5-h sleep opportunities at night. Postprandial glucose response and sleep (time spent in all stages) was assessed. Breaking up prolonged sitting with light-intensity walking did not affect postprandial glucose responses in sleep-restricted participants; however a small increase (similar to 9min) in slow-wave sleep was observed. Refereed/Peer-reviewed

On-call working arrangements are employed in a number of industries to manage unpredictable events, and often involve tasks that are safety- or time-critical. This study investigated the effects of call likelihood during an overnight on-call shift on self-reported pre-bed anxiety, sleep and next-day cognitive performance. A four-night laboratory-based protocol was employed, with an adaptation, a control and two counterbalanced on-call nights. On one on-call night, participants were instructed that they would definitely be called during the night, while on the other on-call night they were told they may be called. The State-Trait Anxiety Inventory form x-1 was used to investigate pre-bed anxiety, and sleep was assessed using polysomnography and power spectral analysis of the sleep electroencephalographic analysis. Cognitive performance was assessed four times daily using a 10-min psychomotor vigilance task. Participants felt more anxious before bed when they were definitely going to be called, compared with the control and maybe conditions. Conversely, participants experienced significantly less non-rapid eye movement and stage two sleep and poorer cognitive performance when told they may be called. Further, participants had significantly more rapid eye movement sleep in the maybe condition, which may be an adaptive response to the stress associated with this on-call condition. It appears that self-reported anxiety may not be linked with sleep outcomes while on-call. However, this research indicates that it is important to take call likelihood into consideration when constructing rosters and risk-management systems for on-call workers.

This study investigated how the chance of missing an alarm affects pre-bed anxiety, sleep and next day cognitive performance during on-call shifts. Participants (n = 24) completed one adaptation night, one control night and two on-call nights in a time-isolated sleep laboratory. On one of the on-call nights, participants were informed that they would be woken by a loud alarm that they would definitely not be able to sleep through (low chance of missing the alarm). On the other on-call night, participants were informed that they would be woken by a quiet alarm that they may sleep through (high chance of missing the alarm). The two on-call nights were counterbalanced. Pre-bed anxiety was measured using the State Trait Anxiety Inventory x-1, while sleep macro- and micro-architecture was examined via routine polysomnography and power spectral analyses respectively. Following each sleep, cognitive performance was assessed four times (0930, 1200, 1430, 1700) using the 10-min psychomotor vigilance task (PVT). Results indicated that while pre-bed anxiety was similarly increased during both high and low chance of missing the on-call alarm conditions compared with control, only in the high chance condition was total sleep time shorter and sleep efficiency lower compared with the control condition. However, more wake after sleep onset was found in the low chance condition compared with control. PVT data indicate that response times (mean reciprocal and mean fastest 10% of reaction time) were fastest in the low chance condition, indicating better performance when compared with both other conditions. However, there were significantly more lapses in the low chance condition compared with control. No significant EEG power spectral differences were observed. As such, it appears that there are detrimental effects of both on-call conditions on anxiety, sleep and performance, with sleep poorest when the chance of missing the alarm is high. The adverse impacts on sleep and performance outcomes while on-call may be mitigated by the implementation of workplace systems to reduce the chance of missing alarms (e.g., having two available options for contacting on-call workers).

Wildland firefighters perform physical work while being subjected to multiple stressors and adverse, volatile working environments for extended periods. Recent research has highlighted sleep as a significant and potentially modifiable factor impacting operational performance. The aim of this review was to (1) examine the existing literature on firefighters' sleep quantity and quality during wildland firefighting operations; (2) synthesise the operational and environmental factors that impact on sleep during wildland firefighting; and (3) assess how sleep impacts aspects of firefighters' health and safety, including mental and physical health, physical task performance, physical activity and cognitive performance. Firefighters' sleep is restricted during wildfire deployments, particularly when shifts have early start times, are of long duration and when sleeping in temporary accommodation. Shortened sleep impairs cognitive but not physical performance under simulated wildfire conditions. The longer-term impacts of sleep restriction on physiological and mental health require further research. Work shifts should be structured, wherever possible, to provide regular and sufficient recovery opportunities (rest during and sleep between shifts), especially in dangerous working environments where fatigue-related errors have severe consequences. Fire agencies should implement strategies to improve and manage firefighters' sleep and reduce any adverse impacts on firefighters' work. Refereed/Peer-reviewed

Introduction:Emergency service workers perform physical work while being subjected to multiple stressors and adverse, volatile working environments for extended periods. Recent research has highlighted sleep as a significant and potentially modifiable factor impacting operational performance.Aim:This presentation would (a) examine the existing literature on emergency service workers’ sleep quantity and quality during operations, (b) synthesize the operational and environmental factors that impact sleep (e.g., shift start times, shift length, sleeping location, smoke, noise, heat), and (c) assess how sleep impacts aspects of emergency service workers’ health and safety, including mental and physical health and performance.Methods:This presentation would be based on a narrative review conducted by the authors which used a systematic search strategy of health-related databases. Articles that were not relevant, duplicate or from non-peer-reviewed sources were excluded.Results:Sleep is restricted during emergency service deployments, particularly when shifts have early start times, are long duration, and/or when sleeping in temporary accommodation (e.g., tents, vehicles). Shortened sleep impairs cognitive but not physical performance under simulated emergency services conditions.Discussion:Depending on the organization and jurisdiction, these findings warrant re-evaluation of existing policies, formalization of beneficial but currently ad-hoc practice, or provide support for current procedures. Work shifts should be structured, wherever possible, to provide regular and sufficient recovery opportunities (rest during and sleep between shifts), especially in dangerous working environments where fatigue-related errors have more severe consequences. For agencies to continue to defend local communities against natural hazards, strategies should be implemented to improve and manage emergency service workers sleep and reduce any adverse impacts on work.

Working arrangements in industries that use non-standard hours sometimes necessitate an 'onsite' workforce where workers sleep in accommodation within or adjacent to the workplace. Of particular relevance to these workers is the widely held (and largely anecdotal) assumption that sleep at home is better than sleep away, particularly when away for work. This narrative review explores the idea that sleep outcomes in these unique work situations are the product of an interaction between numerous factors including timing and duration of breaks, commute length, sleeping environment (noise, movement, vibration, light), circadian phase, demographic factors and familiarity with the sleep location. Based on the data presented in this review, it is our contention that the location of sleep, whilst important, is secondary to other factors such as the timing and duration of sleep periods. We suggest that future research should include measures that allow conceptualisation of other critical factors such as familiarity with the sleeping environment.

Cardiometabolic disease poses a serious health and economic burden worldwide and its prevalence is predicted to increase. Prolonged sitting, lack of physical activity, poor diet, and short sleep duration are ubiquitous behaviors in modern society, and all are independent risk factors in the development of cardiometabolic disease. Existing evidence demonstrates that breaking up prolonged periods of sitting is beneficial for cardiometabolic health, however, studies have not controlled for prior sleep duration. This article examines how prolonged sitting and short sleep duration independently contribute to cardiometabolic risk, and how breaking up sitting and obtaining adequate sleep may reduce this risk. We suggest that as prolonged sitting and short sleep duration influence the same cardiometabolic parameters, there is potential for short sleep to attenuate the positive impact of breaking up prolonged sitting with physical activity. Likewise, breaking up prolonged sitting and obtaining adequate sleep together could improve predictors of cardiometabolic disease, i.e., the combined effect may be stronger than either alone. To explore these perspectives, we propose a research agenda to investigate the relationship between breaking up prolonged sitting with physical activity and short sleep duration. This will provide an evidence-base for informing the design of interventions to reduce the burden of cardiometabolic disease on communities worldwide. Refereed/Peer-reviewed

On-call work is used to manage around the clock working requirements in a variety of industries. Often, tasks that must be performed while on-call are highly important, difficult and/or stressful by nature and, as such, may impact the level of anxiety that is experienced by on-call workers. Heightened anxiety is associated with poor sleep, which affects next-day cognitive performance. Twenty-four male participants (20-35 years old) spent an adaptation, a control and two counterbalanced on-call nights in a time-isolated sleep laboratory. On one of the on-call nights they were told that they would be required to do a speech upon waking (high-stress condition), whereas on the other night they were instructed that they would be required to read to themselves (low-stress condition). Pre-bed anxiety was measured by the State Trait Anxiety Inventory form x-1, and polysomnography and quantitative electroencephalogram analyses were used to investigate sleep. Performance was assessed across each day using the 10-min psychomotor vigilance task (09:30 hours, 12:00 hours, 14:30 hours, 17:00 hours). The results indicated that participants experienced no significant changes in pre-bed anxiety or sleep between conditions. However, performance on the psychomotor vigilance task was best in the high-stress condition, possibly as a result of heightened physiological arousal caused by performing the stressful task that morning. This suggests that performing a high-stress task may be protective of cognitive performance to some degree when sleep is not disrupted.

Prolonged sitting, restricted sleep, and circadian disruption are all independent risk factors for non-communicable diseases. Previous research has demonstrated that breaking up sitting with light-intensity physical activity has clear benefits for the health of day workers, but these findings may not apply in the presence of sleep restriction and/or circadian disruption—both of which are commonly experienced by shift-workers. Specifically, sleep restriction, and circadian disruption result in acute physiological changes that may offset the benefits of breaking up sitting. This commentary will explore the potential benefits of breaking up sitting for health, work performance, and subsequent sleep in shift-workers. Future areas of research designed to understand the mechanisms by which prolonged sitting and shift work impact worker health and safety and to support the design of effective occupational health and safety interventions are proposed.

Exposure to workplace hazards, such as dust, solvents, and fumes, has the potential to adversely affect the health of people. However, the effects of workplace hazards on health may differ when exposure occurs at different times in the circadian cycle, and among people who work longer hours or who do not obtain adequate sleep. The aim of the present study was to document exposures to workplace hazards across a national sample of New Zealanders, comparing people who work a standard 08:00 -17:00 h Monday-to-Friday working week (Std hours) and those who do not (N-Std hours). New Zealanders (n = 10 000) aged 20-64 yrs were randomly selected from the Electoral Roll to take part in a nationwide survey of workplace exposures. Telephone interviews were conducted between 2004 and 2006, using a six-part questionnaire addressing demographics, detailed information on the current or most recent job (including exposures to a range of workplace hazards), sleep, sleepiness, and health status. N-Std hours were categorised on the basis of: being required to start work prior to 07:00 h or finish work after 21:00 h and/or; having a regular on-call commitment (at least once per week) and/or; working rotating shifts and/or; working night shift(s) in the last month. The response rate was 37% (n = 3003), with 22.2% of participants (n = 656) categorised as working N-Std hours. Industry sectors with the highest numbers of participants working N-Std hours were manufacturing, health and community services, and agriculture, fishing, and forestry. Response rate was 37% (n = 3003) with 22.2% (n = 656) categorised as working N-Std hours. Participants working N-Std hours were more likely to be exposed to all identified hazards, including multiple hazards (OR = 2.45, 95% CI = 2.01-3.0) compared to those working Std hours. Participants working N-Std hours were also more likely to report 'never/rarely' getting enough sleep (OR = 1.38, 95% CI = 1.15-1.65), 'never/rarely' waking refreshed (OR = 1.23, 95% CI = 1.04-1.47), and excessive sleepiness (OR = 1.77, 95% CI = 1.29-2.42). New Zealanders working N-Std hours are more likely to be exposed to hazards in the workplace, to be exposed to multiple hazards, and to report inadequate sleep and excessive sleepiness than their colleagues working a standard 08:00-17:00 h Monday-to-Friday working week. More research is needed on the effects of exposure to hazardous substances outside the usual waking day, on the effects of exposure to multiple hazards, and on the combination of hazard exposure and sleep restriction as a result of shift work.

Objective This study had two specific objectives, 1) to investigate the impact of being on-call on overnight heart rate variability during sleep and; 2) to examine whether being on-call overnight impacted next-day salivary cortisol concentrations. Methods Data are reported from three within-subject laboratory studies (n = 24 in each study) that assessed varying on-call conditions. Healthy male participants (n = 72 total) completed a four-night laboratory protocol, comprising an adaptation night, a control night, and two counterbalanced on-call nights with varying on-call conditions. These on-call conditions were designed to determine the impact of, Study 1: the likelihood of receiving a call (definitely, maybe), Study 2: task stress (high-stress, low-stress), and Study 3: chance of missing the alarm (high-chance, low-chance), on measures of physiological stress. Overnight heart rate variability (HRV) (during sleep) was measured using two-lead electrocardiography, and time- and frequency-domain variables were analysed. Saliva samples were collected at 15-min time intervals from 0700-0800 h to determine cortisol awakening response outcomes and at four daily time points (0930 h, 1230 h, 1430 h, and 1730 h) to assess diurnal cortisol profiles. Results There were few differences in HRV measures during sleep across all three studies. The only exception was in Study 1 where the standard deviation of the time interval between consecutive heartbeats and the root mean square of consecutive differences between heartbeats were lower across all sleep stages in the definitely condition, when compared to control. Across all three studies, being on-call overnight also had little impact on next-day cortisol awakening response (CAR), with the exception of Study 2 where the 1) CAR area under the curve with respect to increase was blunted in the high-stress condition, compared to the control and low-stress conditions and, 2) CAR reactivity was higher in low-stress condition, compared with the high-stress condition. In Study 1, diurnal cortisol area under the curve with respect to ground was lower in the on-call conditions (definitely and maybe) when compared to control. There were no differences in diurnal cortisol measures in Study 3. Conclusion This is the first study to investigate how different aspects of being on-call affect physiological stress responses. Overall, relatively little differences in measures of overnight heart rate variability and next-day cortisol response were recorded in all three studies. Further research utilising real on-call work tasks, not just on-call expectations (as in the current study) will help determine the impact of on-call work on the physiological stress response.

Introduction:All Fire and Emergency Services (FES) personnel must balance FES work with their other responsibilities. Given that women tend to take on a greater responsibility for management of household/domestic activities than men, the on-call component of their FES work may be associated with very different challenges. Despite this, women have rarely been the focus of on-call research.Aim:To explore women’s on-call experiences in the FES by examining coping styles and strategies, with the goal of helping to innovate the way women are supported in FES roles.Methods:Relevant findings from two studies are included. The first study involved FES personnel from two agencies in Australia (n=24) who participated in a semi-structured interview. The second study was an anonymous online survey to determine work characteristics, sleep, stress, and coping in on-call workers more broadly, with workers from all industries across Australia (n=228) invited to participate.Results:Interview data identified two major themes in terms of coping with on-call work. Support (from family, social, and work), planning, and preparation were identified as important in helping women cope in the context of on-call unpredictability. Results from the survey (43% women) showed that on-call workers were an engaged group in terms of their coping, with 67% classified as having a positive coping style and 58% of women indicating that they agreed/strongly agreed with the statement, “I cope well with on-call work.”Discussion:Taken together, these data highlight engagement with positive coping by women who do on-call work, including in the FES. Importantly, positive coping strategies, such as talking about emotions, problem-solving, and seeking support have been linked to increased shift work tolerance in other populations. Coping style and strategies represent modifiable variables which could be specifically applied to assist women to manage the unique challenges associated with on-call work in the FES.

Summary This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn–Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations.

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.

On-call working time arrangements are increasingly common, involve work only in the event of an unpredictable incident and exist primarily outside of standard hours. Like other non-standard working time arrangements, on-call work disrupts sleep and can therefore have negative effects on health, safety and performance. Unlike other non-standard working time arrangements, on-call work often allows sleep opportunities between calls. Any sleep obtained during on-call periods will be beneficial for waking performance. However, there is evidence that sleep while on call may be of substantially reduced restorative value because of the expectation of receiving the call and apprehension about missing the call. In turn, waking from sleep to respond to a call may be associated with temporary increases in performance impairment. This is dependent on characteristics of both the preceding sleep, the tasks required upon waking and the availability and utility of any countermeasures to support the transition from sleep to wake. In this paper, we critically evaluate the evidence both for and against sleeping during on-call periods and conclude that some sleep, even if it is of reduced quality and broken by repeated calls, is a good strategy. We also note, however, that organisations utilising on-call working time arrangements need to systematically manage the likelihood that on-call sleep can be associated with temporary performance impairments upon waking. Given that the majority of work in this area has been laboratory-based, there is a significant need for field-based investigations of the magnitude of sleep inertia, in addition to the utility of sleep inertia countermeasures. Field studies should include working with subject matter experts to identify the real-world impacts of changes in performance associated with sleeping, or not sleeping, whilst on call.

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

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. On-call or stand-by is becoming an increasingly prevalent form of work scheduling. However, on-call arrangements are typically utilised when workloads are low, for example at night, which can result in inadequate sleep. It is a matter of concern that on-call work is associated with an increased risk of workplace injury. This study sought to determine the economic cost of injury due to inadequate sleep in Australian on-call workers. The prevalence of inadequate sleep among on-call workers was determined using an online survey, and economic costs were estimated using a previously validated costing methodology. Two-thirds of the sample (66%) reported obtaining inadequate sleep on weekdays (work days) and over 80% reported inadequate sleep while on-call. The resulting cost of injury is estimated at $2.25 billion per year ($1.71–2.73 billion). This equates to $1222 per person per incident involving a short-term absence from work; $2.53 million per incident classified as full incapacity, and $1.78 million for each fatality. To the best of our knowledge this is the first study to quantify the economic cost of workplace injury due to inadequate sleep in on-call workers. Well-rested employees are critical to safe and productive workplace operations. Therefore, it is in the interest of both employers and governments to prioritise and invest far more into the management of inadequate sleep in industries which utilise on-call work arrangements.

Objectives Relay is an effective mode of freight transportation within Australia. Relay requires two crews to drive the train continuously from one specified destination to another and return with crews working in alternating shifts. The aim of the current investigation was to assess fatigue levels during extended relay operations. Methods Nine drivers participated and data were collected from 16 four-day trips. Fatigue was assessed objectively and subjectively prior to and following each trip and before and after each 8 h shift. Results Analyses revealed a trend for elevated fatigue at the end of each shift. Designated 8 h rest periods appeared sufficient to reduce fatigue to levels recorded prior to departure and prevent accumulation of fatigue across the trip. Conclusions Drivers seemed to cope well with the 8 h rotating sleep/wake regime. While fatigue did not observably accumulate, it is possible that operational measures may better reflect fatigue experienced over the course of each trip.

The aim of this study was to examine the impact of brief, unscheduled naps during work periods on alertness and vigilance in coastal pilots along the Great Barrier Reef. On certain routes, the duration of the work period can extend well beyond 24 h. Seventeen coastal pilots volunteered for the study, representing almost one-third of the population. Participants collected sleep/wake and performance data for 28 days using a sleep and work diary and the palm PVT task. The average length of sleep on board was 1.4+/-1.0 h. Naps were taken regularly such that the average length of time awake between sleep periods on board a ship was 5.3+/-4.3 h. There was no change in mean reaction time across either the length of a pilotage or across the 24 h day. The results indicate that even though the naps were taken opportunistically, they tended to cluster at the high sleep propensity times. Further, frequent, opportunistic naps appeared to provide adequate recovery such that PVT performance remained stable. Pilots did report increases in subjective fatigue ratings at certain times of the 24 h day and at the end of a work period; however, these did not reach the high range. The fatigue-risk minimization strategies employed by the Australian Maritime Safety Authority and the coastal pilots appear to be effective in maintaining alertness and vigilance while at work aboard ships.

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

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.

Fatigue associated with shiftwork is a key contributor to human error in the workplace. One way to prevent fatigue-related errors from occurring is to identify fatigue in employees using fitness-for-duty measures. The Occupational Safety Performance Assessment Test (OSPAT), an unpredictable tracking task that measures hand-eye coordination, is currently being used as a fitness-for-duty measure in a variety of industries, but has not yet been validated as a test sensitive to the effects of fatigue. Consequently, the aim of this study was to systematically examine the impact of sustained wakefulness and time-of-day on OSPAT performance. Twenty individuals (10 male, 10 female), aged between 18-25 yr (M=20.90, SD=2.29) participated in the study, which was conducted in Australia. The study had a repeated measures design, whereby participants completed the OSPAT and measures of sustained attention (i.e., the psychomotor vigilance task: PVT), and subjective alertness (i.e., the Visual Analog Scale: VAS) every 2 h during 24 h of sustained wakefulness, beginning at 07:00 h. Results revealed that VAS ratings of alertness, PVT performance, and OSPAT performance declined significantly as hours of wakefulness increased during the night-time (all p

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.

The objective of the study was to describe the work and sleep patterns of doctors working in Australian hospitals. Specifically, the aim was to examine the influence of work-related factors, such as hospital type, seniority, and specialty on work hours and their impact on sleep. A total of 635 work periods from 78 doctors were analyzed together with associated sleep history. Work and sleep diary information was validated against an objective measure of sleep/wake activity to provide the first comprehensive database linking work and sleep for individual hospital doctors in Australia. Doctors in large and small facilities had fewer days without work than those doctors working in medium-sized facilities. There were no significant differences in the total hours worked across these three categories of seniority; however, mid-career and senior doctors worked more overnight and weekend on-call periods than junior doctors. With respect to sleep, although higher work hours were related to less sleep, short sleeps (< 5 h in the 24 h prior to starting work) were observed at all levels of prior work history (including no work). In this population of Australian hospital doctors, total hours worked do impact sleep, but the pattern of work, together with other nonwork factors are also important mediators. Refereed/Peer-reviewed

A number of studies have described mood change during sleep loss in the laboratory, however, an understanding of fluctuations in structural aspects of mood under such conditions is lacking. Sixty-two healthy young adults completed one of three possible conditions: one (n= 20) or two (n= 23) nights of sleep loss or the control condition which consisted of one (n= 9) or two (n= 10) nights of 9 h time in bed. The Mood Scale II was completed every two waking hours and data were analysed in terms of the frequency and intensity of mood reports. Overall, sleep loss conditions were associated with significantly less frequent happiness and activation and more frequent fatigue reports (p< 0.001). Intensity was also significantly reduced for activation and happiness, and increased for depression, anger and fatigue (p< 0.05). Interestingly, there were no significant differences in anger following two nights in the laboratory with or without sleep. Further, two nights in the lab with normal sleep was associated with significant increases in depression intensity (p< 0.05). Findings support the hypothesis of a mood regulatory function of sleep and highlight the relative independence of frequency and intensity and of positive and negative mood dimensions. Findings also suggest that the laboratory environment, in the absence of sleep loss, may have a significant negative impact on mood. Refereed/Peer-reviewed

Shiftwork involving early morning starts and night work can affect both sleep and fatigue. This study aimed to assess the impact of different rostering schedules at an Australian mine site on sleep and subjective sleep quality. Participants worked one of four rosters; 4 × 4 (n = 14) 4D4O4N4O7 × 4 (n = 10) 7D4O7N4010 × 5 (n = 17) 5D5N5014 × 7 (n = 12) 7D7N70Sleep (wrist actigraphy and sleep diaries) was monitored for a full roster cycle including days off. Total sleep time (TST) was longer on days off (7.0 ± 1.9) compared to sleep when on day (6.0 ± 1.0) and nightshifts (6.2 ± 1.6). Despite an increase in TST on days off, this may be insufficient to recover from the severe sleep restriction occurring during work times. Restricted sleep and quick shift-change periods may lead to long-term sleep loss and associated fatigue Refereed/Peer-reviewed

In this study, we evaluated the sensitivity of a 5-min personal digital assistant—psychomotor vigilance test (PDA-PVT) to severe sleep loss. Twenty-one participants completed a 10-min PVT-192 and a 5-min PDA—PVT at two hourly intervals during 62 h of sustained wakefulness. For both tasks, response speed and number of lapses (RTs > 500) per minute significantly increased with increasing hours of wakefulness. Overall, standardized response speed scores on the 5-min PDA—PVT closely tracked those of the PVT-192; however, the PDA—PVT was generally associated with more lapses/minute. Closer inspection of the data indicated that when the level of sleep loss and fatigue became more severe (i.e., Day 3), the 5-min PDA—PVT was not quite as sensitive as the 10-min PVT-192 when 2- to 10-sec foreperiods were used for both. It is likely, however, that the observed differences between the two devices was due to differences in task length. Thus, the findings provide further evidence of the validity of the 5-min PDA—PVT as a substitute for the 10-min PVT-192, particularly in circumstances in which a shorter test is required and/or the PVT-192 is not as practical.

Study Objectives: The aim of this study was to investigate the recovery of sleep and waking functions following one night of total sleep deprivation, when recovery opportunity was either augmented or restricted. Design: The 9-day laboratory study involved a baseline night, a night of sleep loss (approximately 40 h) followed by 5 nighttime recovery sleep periods. Recovery consisted of either five 9-h sleep opportunities or five 6-h sleep opportunities. Setting: All data collection took place in a controlled laboratory environment at the Centre for Sleep Research. Participants: A total of n=20 healthy adults (18-35 yrs) participated in the study. Results: Each sleep period was recorded using a standard polysomnographic EEG montage. Waking functions were assessed every 2 hours during all wake periods, using a 10 minute psychomotor vigilance task (PVT) and a subjective alertness visual analogue scale (VAS). Sleep analyses indicated that across the week TST, SOL, REM, and sleep efficiency varied significantly between the 2 conditions, but amounts of SWS did not. Waking functions in the 9-h condition recovered after one sleep period. In the 6-h condition however, mean response time on the PVT was 10% below baseline and subjective alertness 20% below baseline for the entire recovery period. Conclusions: The results suggest that TST is a key factor in determining recovery. When recovery opportunity is restricted, both sleep variables and measures of waking functions do not recover.

Rate of recovery of daytime performance and sleepiness following moderate and severe sleep deprivation (SD) was examined when recovery opportunity was either augmented or restricted. Thirty healthy non-smokers, aged 18-33 years, participated in one of three conditions: moderate SD with augmented (9-h) recovery opportunities, moderate SD with restricted (6-h) recovery opportunities, or severe SD with augmented recovery opportunities. Each participant attended the laboratory for 8-9 consecutive nights: an adaptation and baseline night (23:00-08:00 hours), one or two night(s) of wakefulness, and five consecutive recovery sleep opportunities (23:00-08:00 hours or 02:00-08:00 hours). On each experimental day, psychomotor vigilance performance (PVT) and subjective sleepiness (SSS) were assessed at two-hourly intervals, and MSLTs were performed at 1000 h. PSG data was collected for each sleep period. For all groups, PVT performance significantly deteriorated during the period of wakefulness, and sleepiness significantly increased. Significant differences were observed between the groups during the recovery phase. Following moderate SD, response speed, lapses and SSS returned to baseline after one 9-h sleep opportunity, while sleep latencies required two 9-h opportunities. When the recovery opportunity was restricted to six hours, neither PVT performance nor sleepiness recovered, but stabilised at below-baseline levels. Following severe SD, sleepiness recovered after one (SSS) or two (physiological) 9-h sleep opportunities, however PVT performance remained significantly below baseline for the entire recovery period. These results suggest that the mechanisms underlying the recovery process may be more complicated than previously thought, and that we may have underestimated the impact of sleep loss and/or the restorative value of subsequent sleep.

Relay operations are an important mode of freight transportation within Australia. Relay work requires multiple crews to drive the train continuously from one specified destination to another and return. Importantly, the nature of relay work requires train drivers to sleep on-board during designated resting shifts. The main aim of the present study was to investigate the quality and quantity of sleep obtained in on-board rest facilities (relay vans) during extended (four-day) relay operations. Drivers (n = 9) working the Port Augusta to Darwin relay operation volunteered to participate. The first leg of the trip typically took 40 h followed by an overnight stay in Darwin (between 8-12 h) prior to return. Two crews, each consisting of two drivers, changed every 8 h, giving the crew an 8 h rest in the relay van prior to each 8 h working shift. Using polysomnography, home sleep data were collected prior to and following each trip using a standard five-channel EEG montage. All sleep periods during the relay trip (including Darwin) were also recorded. Additionally, subjective sleep quality ratings were recorded following each sleep period. Analyses revealed that the quantity of sleep obtained in the relay vans (3.3 h) was significantly reduced compared to home (6.8 h). In general, the total sleep time was increased at night and reduced during the day. In terms of quality, sleep onset latency, sleep efficiency, and amount of slow wave and rapid eye movement sleep did not differ significantly between home and the relay vans. The results of the study highlight sleep quantity as the main concern during extended relay operations. Future research should focus on investigating the subjective and objective impact of this sleep reduction on waking functions.

Past research has indicated that caffeinated 'functional energy drinks' (FEDs) are effective in counteracting sleepiness. It is not known however, what impact FEDs have on sleep itself. FEDs contain several active ingredients, including caffeine. They may therefore impact negatively on sleep and hence subsequent performance, deeming their use counterproductive. In a randomised cross-over design, 15 young adults participated in a simulated first night-shift protocol with 2 conditions, Functional Energy Drink (FED) and Non Functional Energy Drink (NonFED). Both involved a period of extended wakefulness (0700-0730 h-24.5 h) followed by an 8-h daytime 'recovery' sleep (0730-1530 h). During the FED condition, a commercially available FED was administered twice during the night. Sleepiness was assessed during the period of extended wakefulness and for a further 6h after waking. Sleep periods were recorded using a standard 5 channel polysomnogram. Comparison of the sleep periods showed that sleep onset latency remained unchanged as did stage 2 and slow wave sleep. Total sleep time however, was 29.1 min shorter (p