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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 hourson/ 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<0.01). More broadly, findings indicate that LWSW schedules were associated with better sleep and lower sleepines in the case of (i) shorter time-at-work, (ii) more frequent rest breaks, (iii) shifts that start and end at the same clock time every 24 hours, and (iv) work shifts commencing in the daytime (as opposed to night). The findings for performance remain incomplete due to the small number of studies containing a performance measure and the heterogeneity of performance measures within those that did. Conclusion The literature supports the utility of LWSW in industries where individuals sleep at or near the workplace as they facilitate at least some sleep during the biological night and minimize deficits associated with time-on-shift with shorter shifts. Overall, the 4 hour-on/8 hour-off roster best promoted sleep and minimized sleepiness compared to other LWSW schedules. Nevertheless, and considering the safety-critical nature of industries which employ LWSW, the limited literature needs to be greatly expanded with specific focus on the consequences for performance and comparison to mainstream rosters. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) poses a serious health and economic burden worldwide. Modifiable lifestyle factors are a focus of research into reducing the burden of CVD, with diet as one of the most investigated factors. Specifically, the timing and regularity of food intake is an emerging research area, with approaches such as time-restricted eating (TRE) receiving much attention. TRE involves shortening the time available to eat across the day and is associated with improved CVD outcomes compared with longer eating windows. However, studies that have examined TRE have not considered the impact of sleep on CVD outcomes despite recent evidence showing that sleep duration can influence the timing and amount of food eaten. In this article, we argue that as TRE and sleep influence each other, and influence the same cardiometabolic parameters, experiencing inadequate sleep may attenuate any positive impact TRE has on CVD. We examine the relationship between TRE and CVD, with sleep as a potential mediator in this relationship, and propose a research agenda to investigate this relationship. This will provide necessary evidence to inform future interventions aimed at reducing the burden of CVD. [ABSTRACT FROM AUTHOR]

Abstract: Biomathematical models are used in industry to estimate how much sleep people are likely to get on different work patterns, and how efficient and safe people are likely to be at work. Since there is evidence to suggest that individuals respond differently to sleep loss, there has been a recent focus on trying to account for individual differences. One possible approach could use past behaviour to predict future responses to similar working conditions. This study investigated the predictive value of sleep timing and duration data for a particular individual on a break between shifts relative to data from their colleagues. Sleep diaries and wrist actigraphy were collected from 306 international long-haul pilots for at least 2-weeks. Fifty layovers, equivalent in origin and destination, length and timing, were completed twice by individual pilots. Matched layovers done by other pilots (n =2311) were also identified. Layover periods were analysed for minute-by-minute correspondence of sleep or wake (yes/no), and total sleep time (TST). Using an individual''s own data improved concordance by approximately 5% relative to using a large sample of different pilots, and by 10% relative to using a random sample of 50 different pilots. Using an individual''s own TST to predict their TST on an equivalent layover yielded an r value of 0.83, compared to r =0.78 when data from a colleague was used, and r =0.73 using different pilots in a random sample of equivalent size. The mean difference in TST using pilots’ own data was <20min, compared to <40min using data from colleagues. However, the confidence limits on these differences were large (up to 8h). Results suggest that for international pilots on specific layover patterns, knowing the past behaviour of an individual may only represent a modest improvement over knowing the length and timing of a colleague''s sleep, when it comes to predicting their sleep behaviour. [Copyright &y& Elsevier]

The article discusses the role of deterrence as a regulatory method in the enforcement of occupational health and safety (OHS) legislation. The authors evaluate quantitative and qualitative studies that sought to determine the deterrent effect of OHS enforcement on the behaviour of employers. The authors conclude that there are many gaps in the understanding of the role played by enforcement in promoting compliance with OHS obligations and reducing work-related injury.

Abstract: Research suggests that less than 5h sleep in the 24h prior to work and/or more than 16h of wakefulness can significantly increase the likelihood of fatigue-related impairment and error at work. Studies have also shown exponential safety declines with time on shift, with roughly double the likelihood of accident or injury after 10h relative to the first 8h. While it is acknowledged that reduced sleep, increased wakefulness and longer work hours produce work-related fatigue, few studies have examined the impact of workload on this relationship. Studies in the rail industry have focused on drivers. This study investigated fatigue in a large sample of Australian Rail Industry Employees. Participants were from four companies (n =90: 85m, 5f; mean age 40.2±8.6y). Data was analysed for a total of 713 shifts. Subjects wore wrist actigraphs and completed sleep and work diaries for 14-days. They also completed the Samn–Perelli Fatigue Scale at the beginning and end of shifts, and the NASA-TLX workload scale at least twice during each shift. Average (±SD) sleep length (7.2±2.6h), prior wake at shift end (12.0±4.7h), shift duration (8.0±1.3) and fatigue (4.1±1.3, “a little tired, less than fresh”) were within limits generally considered acceptable from a fatigue perspective. However, participants received 5h or less sleep in the prior 24h on 13%, were awake for at least 16h at the end of 16% and worked at least 10h on 7% of shifts. Subjects reported that they felt “extremely tired, very difficult to concentrate,” or “completely exhausted, unable to function effectively” on 13% of shifts. Sleep length (OR=0.88, p <0.01), shift duration (OR=1.18, p <0.05), night shift (REF=morning shift, OR=2.12, p <0.05) and workload ratings (OR=1.2, p <0.05) were significant predictors of ratings of extreme tiredness/exhaustion (yes/no). While on average, sleep loss, extended wakefulness, longer work hours and work-related fatigue do not appear problematic in this sample, there is still a notable percentage of shifts that are likely to be associated with high levels of work-related fatigue. Given the size of the Australian Rail Industry, with thousands of shifts occurring each day, this is potentially of operational concern. Further, results indicate that, in addition to sleep length, wakefulness and work hours, workload significantly influences fatigue. This has possible implications for bio-mathematical predictions of fatigue and for fatigue management more generally. [Copyright &y& Elsevier]

The article discusses a study that examines the relationship between mood change and workload of midwives in Australia. The researchers investigate 20 midwives in a metropolitan hospital regarding their daily fluctuations in subjective mood and workload. Study reveals that mood change influenced the safety, performance and psychological wellbeing of the midwives.

Unusual meal timing has been associated with a higher prevalence of chronic disease. Those at greater risk include shift workers and evening chronotypes. This study aimed to validate the content of a Chrononutrition Questionnaire for shift and non-shift workers to identify temporal patterns of eating in relation to chronotype. Content validity was determined using a Delphi study of three rounds. Experts rated the relevance of, and provided feedback on, 46 items across seven outcomes: meal regularity, times of first eating occasion, last eating occasion, largest meal, main meals/snacks, wake, and sleep, which were edited in response. Items with greater than 70% consensus of relevance were accepted. Rounds one, two, and three had 28, 26, and 24 experts, respectively. Across three rounds, no outcomes were irrelevant, but seven were merged into three for ease of usage, and two sections were added for experts to rate and comment on. In the final round, all but one of 29 items achieved greater than 70% consensus of relevance with no further changes. The Chrononutrition Questionnaire was deemed relevant to experts in circadian biology and chrononutrition, and could represent a convenient tool to assess temporal patterns of eating in relation to chronotype in future studies. [ABSTRACT FROM AUTHOR]

Summary: Chronic sleep restriction, common in today's 24/7 society, causes cumulative neurobehavioural impairment, but the dynamics of the build‐up and dissipation of this impairment have not been fully elucidated. We addressed this knowledge gap in a laboratory study involving two, 5‐day periods of sleep restriction to 4 hr per day, separated by a 1‐day dose–response intervention sleep opportunity. We measured sleep physiological and waking neurobehavioural responses in 70 healthy adults, each randomized to one of seven dose–response intervention sleep doses ranging from 0 to 12 hr, or a non‐sleep‐restricted control group. As anticipated, sleep physiological markers showed homeostatic dynamics throughout the study, and waking neurobehavioural impairment accumulated across the two sleep restriction periods. Unexpectedly, there was only a slight and short‐lived effect of the 1‐day dose–response intervention sleep opportunity. Whether the dose–response intervention sleep opportunity involved extension, further restriction or total deprivation of sleep, neurobehavioural functioning during the subsequent second sleep restriction period was dominated by prior sleep–wake history. Our findings revealed a profound and enduring influence of long‐term sleep–wake history as a fundamental aspect of the dynamic regulation of the neurobehavioural response to sleep loss. [ABSTRACT FROM AUTHOR]

The Australian mass media frequently discusses sharks and shark-human interactions. There is initial evidence to suggest that this coverage could impact people's perceptions of risk of sharks and in-turn people's support for shark conservation initiatives. This current study utilises a mixed-method experimental design to investigate if perception of risk, acceptance of sharks, who/what participant's blamed for shark bites, and support for lethal mitigation policies is impacted by various kinds of media headlines that discuss sharks. Participants (N = 257) were randomly allocated into one of four headline conditions and exposed to headlines that fell into the categories of; non-shark attack, non-intent, statistics, or sensationalism. No differences were found between the conditions on risk perception, acceptance of sharks, blame towards sharks, or mitigation preferences. An unexpected positive correlation between risk perception and acceptance of sharks was found and both these measures increased after exposure to media headlines discussing sharks. A low preference for lethal mitigation techniques was found both pre and post exposure to the media headlines. A more in depth understanding of the relationship between risk perception and shark conservation, particularly in relation to media coverage of sharks is required. • Sharks are commonly discussed by Australian media outlets. • Participants were randomly assigned to view four different categories of media headlines that discuss sharks. • Participant's risk perception of sharks and acceptance of sharks increased after exposure to the media headlines. • Participant's had very low support for lethal shark mitigation policies. [ABSTRACT FROM AUTHOR]

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. 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. A pre-post intervention study. 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. Maternity care providers (n = 51) attended the workshop and 30 (59%) completed both the pre-workshop and post-workshop surveys. 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. 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, <0.001). Before the workshop, only 20% of participants responded that they "always" or usually" discussed the possibility stillbirth occurring with pregnant women in their care whereas, after the workshop, nearly all (88%) indicated that they planned to "always" discuss stillbirth with their pregnant clients. Attending a stillbirth awareness for prevention education workshop resulted in significant knowledge improvement and self-reported intention to change practice in a group of Australian maternity care providers. While these results are promising, further study is needed to determine the presence and extent of actual practice change following such education. [ABSTRACT FROM AUTHOR]

In 24/7 operations, fatigue from extended work hours and shift work is ubiquitous. Fatigue is a significant threat to performance, productivity, safety, and well-being, and strategies for managing fatigue are an important area of research. At the level of individuals, the effects of fatigue on performance are relatively well understood, and countermeasures are widely available. At the level of organizations, the effects of fatigue are also relatively well understood, and organizational approaches to fatigue risk management are increasingly well documented. However, in most organizational settings, individuals work in teams, and teams are the building blocks of the organizational enterprise. Yet, little is known about the effects of fatigue on team functioning. Here we discuss the effects of fatigue at the levels of individuals, teams, and organizations, and how the consequences of fatigue cross these levels to impact overall productivity and safety. Furthermore, we describe the pivotal role of teams in understanding the adverse organizational effects of fatigue in 24/7 operations and argue that teams may be leveraged to mitigate these effects. Systematic investigation of the effects of fatigue on teams is a promising avenue toward advances in fatigue risk management and provide some ideas for how this may be approached. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Flight crew experience fatigue due to sleep loss, circadian desynchrony, early duty start times, long duty periods, high and low workloads, and unscheduled duties. As fatigue is considered a significant safety risk in the air transport industry, the primary approaches to managing fatigue are mandating prescriptive limits for work and rest periods or adopting performance-based fatigue risk management systems (FRMS). However, recent aviation incidents indicate that current regulations may not be adequate to manage the fatigue risk experienced by the flight crew. This study evaluates Australian flight crew fatigue management regulations using a new fatigue regulation evaluation framework (FREF) adapted from Jones et al. (2005). Results show that Australian regulations for flight crew include limits on flight duty period (FDP), off duty period, FDP start time, sleep requirements for flight crew before starting an FDP, high and low workloads, circadian rhythm disruptions, and fatigue awareness. However, there are regulation variations in addressing lengths of sectors and methods to report fatigue, which may need to be reviewed to manage fatigue better. Recommendations are made to consider incorporating these factors into fatigue regulations to ensure a safe air transport system. • Fatigue is considered a significant safety risk in air transport. • Factors related to fatigue require to be adequately addressed in the regulations. • There are variations in addressing these flight crew fatigue related factors. • Adequately addressing the flight crew fatigue related factors in the regulations can assist to manage fatigue [ABSTRACT FROM AUTHOR]

The irregular eating patterns of both shift workers and evening chronotypes adversely affect cardiometabolic health. A tool that conveniently captures temporal patterns of eating alongside an indicator of circadian rhythm such as chronotype will enable researchers to explore relationships with diverse health outcome measures. We aimed to investigate the test-retest reliability and convergent validity of a Chrononutrition Questionnaire (CNQ) that captures temporal patterns of eating and chronotype in the general population (non-shift workers, university students, retirees, unemployed individuals) and shift work population. Participants attended two face-to-face/virtual sessions and completed the CNQ and food/sleep/work diaries. Outcomes included subjective chronotype, wake/sleep/mid-sleep time, sleep duration, meal/snack regularity, meal/snack/total frequency, times of first/last/largest eating occasions (EO), main meal (MM) 1/2/3, and duration of eating window (DEW). 116 participants enrolled (44.5 ± 16.5 years, BMI: 27.3 ± 5.8 kg/m2, 73% female, 52% general population); 105 completed the study. Reliability was acceptable for chronotype, sleep, and all temporal eating patterns except on night shifts. Convergent validity was good for chronotype and sleep except for certain shift/shift-free days. Generally, meal/snack regularity and frequency, and times of first/last EO showed good validity for the general population but not shift workers. Validity was good for DEW (except work-free days and afternoon shifts) and times of MM 1/2/3 (except afternoon and night shifts), while time of largest EO had poor validity. The CNQ has good test-retest reliability and acceptable convergent validity for the general and shift work population, although it will benefit from further validation, especially regarding regularity, frequency, and times of first and last eating occasions across more days amongst a larger sample size of shift workers. Use of the CNQ by researchers will expand our current understanding of chrononutrition as relationships between timing of food intake and the multitude of health outcomes are examined. [ABSTRACT FROM AUTHOR]

Background: Increasing physical activity (PA) is an effective strategy to slow reductions in cortical volume and maintain cognitive function in older adulthood. However, PA does not exist in isolation, but coexists with sleep and sedentary behaviour to make up the 24-hour day. We investigated how the balance of all three behaviours (24-hour time-use composition) is associated with grey matter volume in healthy older adults, and whether grey matter volume influences the relationship between 24-hour time-use composition and cognitive function. Methods: This cross-sectional study included 378 older adults (65.6 ± 3.0 years old, 123 male) from the ACTIVate study across two Australian sites (Adelaide and Newcastle). Time-use composition was captured using 7-day accelerometry, and T1-weighted magnetic resonance imaging was used to measure grey matter volume both globally and across regions of interest (ROI: frontal lobe, temporal lobe, hippocampi, and lateral ventricles). Pairwise correlations were used to explore univariate associations between time-use variables, grey matter volumes and cognitive outcomes. Compositional data analysis linear regression models were used to quantify associations between ROI volumes and time-use composition, and explore potential associations between the interaction between ROI volumes and time-use composition with cognitive outcomes. Results: After adjusting for covariates (age, sex, education), there were no significant associations between time-use composition and any volumetric outcomes. There were significant interactions between time-use composition and frontal lobe volume for long-term memory (p = 0.018) and executive function (p = 0.018), and between time-use composition and total grey matter volume for executive function (p = 0.028). Spending more time in moderate-vigorous PA was associated with better long-term memory scores, but only for those with smaller frontal lobe volume (below the sample mean). Conversely, spending more time in sleep and less time in sedentary behaviour was associated with better executive function in those with smaller total grey matter volume. Conclusions: Although 24-hour time use was not associated with total or regional grey matter independently, total grey matter and frontal lobe grey matter volume moderated the relationship between time-use composition and several cognitive outcomes. Future studies should investigate these relationships longitudinally to assess whether changes in time-use composition correspond to changes in grey matter volume and cognition. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

While many countries have dual-driver ("two-up") modes in freight rail, driver shortage creates increasing pressure to move to single-driver operations. While this change has implications for workload and safety, the roles of the primary and second drivers have not been systematically mapped. This mapping is the focus of this paper, which presents a hierarchical task analysis (HTA) from a multi-methods study (n = 40). Results indicated that transitioning from two-up to single driver operations will result in substantial changes in physical and cognitive workload for the remaining driver. These changes go much further than the simple loss of a crew-mate to double-check or verify actions and cues. This HTA can form the basis of an evidence-based safety case for the change from two-up to single-driver operations, as well as a platform for considering mechanisms to maintain safety and productivity for the now solo train driver. [ABSTRACT FROM AUTHOR]

Situation awareness (SA) is an important component of an individual's ability to function in a complex environment. As such, it is essential to have effective measures of an individual's SA. The most widely used subjective measure of SA is the Situation Awareness Rating Technique [SART]. However, SART has been criticised for not predicting performance or objective SA, and being highly correlated with workload. This paper describes the development and testing of a new subjective measure of SA, the Low-Event Task Subjective Situation Awareness (LETSSA) measure. To evaluate LETSSA a train simulator study was conducted with 23 novice and 26 expert freight train drivers. LETSSA was able to detect differences in manipulated SA and was comparable to an established objective SA measure (SAGAT). LETSSA was significantly associated with performance but not significantly associated with workload. While further validation is required, LETSSA shows promise as an effective subjective measure of SA. [ABSTRACT FROM AUTHOR]

Background: There is now robust evidence that when women settle to sleep on their back in late pregnancy (>28 weeks) they are at increased risk of stillbirth. Therefore, there are several stillbirth prevention programs worldwide that have begun advising pregnant women to adopt a side position when settling to sleep in late pregnancy. However, some hold concerns that giving women information about sleep position and stillbirth risk may make them anxious. Aim: This study aimed to determine what influences how 'safe sleep' messages are perceived by pregnant women and if there is anxiety associated with receiving this message. Materials and Methods: An online survey of 537 Australian women (n = 97 were 'currently pregnant'). The survey examined participant's views regarding sleep position messages, type of information source as well as participant characteristics such as general anxiety and their fetal health locus of control (FHLC). Results: Our findings suggest that the FHLC may influence how health messaging regarding sleep in pregnancy is perceived and acted upon. We have also shown a subset of pregnant women may feel anxiety associated with the sleep position in pregnancy message. This may not be related to history of anxiety, but rather to their higher 'internal' FHLC, ie those who reflect a greater sense of personal agency over fetal health. Conclusions: Our findings suggest most women will perceive information about settling into sleep position as informative rather than anxiety provoking. Therefore, maternity care providers should not be overly concerned about provoking anxiety when providing this information. [ABSTRACT FROM AUTHOR]

Circadian rhythms, metabolic processes and dietary intake are inextricably linked. Timing of food intake is a modifiable temporal cue for the circadian system and may be influenced by numerous factors, including individual chronotype – an indicator of an individual's circadian rhythm in relation to the light–dark cycle. This scoping review examines temporal patterns of eating across chronotypes and assesses tools that have been used to collect data on temporal patterns of eating and chronotype. A systematic search identified thirty-six studies in which aspects of temporal patterns of eating, including meal timings; meal skipping; energy distribution across the day; meal frequency; time interval between meals, or meals and wake/sleep times; midpoint of food/energy intake; meal regularity; and duration of eating window, were presented in relation to chronotype. Findings indicate that, compared with morning chronotypes, evening chronotypes tend to skip meals more frequently, have later mealtimes, and distribute greater energy intake towards later times of the day. More studies should explore the difference in meal regularity and duration of eating window amongst chronotypes. Currently, tools used in collecting data on chronotype and temporal patterns of eating are varied, limiting the direct comparison of findings between studies. Development of a standardised assessment tool will allow future studies to confidently compare findings to inform the development and assessment of guidelines that provide recommendations on temporal patterns of eating for optimal health. [ABSTRACT FROM AUTHOR]

Sleep and fatigue were investigated in aviation search and rescue, firefighting, emergency medical services and offshore transfer operations in 210 participants, for 21 days each, across 17 datasets in seven countries. Sleep data were collected using wrist-worn actigraphs and sleep diaries. Sustained attention was assessed using a 5-min Psychomotor Vigilance Task (PVT). Duty information was provided from corporate IT systems. Despite the number of 24 h operations, most work occurred during daytime hours, and most sleep occurred at night. There were seasonal changes in work and sleep patterns, with naps used to augment total sleep time. The proportion of sleep occurring during duty varied from zero to 30%. Differences in PVT response times were trivial to small. Legislation that defines flight, duty time and minimum rest limits assume that sleep is not obtained during duty periods, apart from some napping under Fatigue Risk Management Systems (FRMS). However, especially in cases where the aviation service requires waiting for tasks (e.g. search and rescue, emergency medical response), this assumption may not always hold. FRMS should accommodate different modes of working that safely facilitate sleep during duty time where appropriate. [ABSTRACT FROM AUTHOR]

Abstract: Due to irregular working hours shiftworkers experience circadian disruption and sleep restriction. There is some evidence to indicate that these factors adversely affect health through changes in snacking behaviour. The aim of this study was to investigate the impact of sleep restriction, prior wake and circadian phase on snacking behaviour during a week of simulated shiftwork. Twenty-four healthy males (age: 22.0±3.6 years, mean±SD) lived in a sleep laboratory for 12 consecutive days. Participants were assigned to one of two schedules: a moderate sleep restriction condition (n =10) equivalent to a 6-h sleep opportunity per 24h or a severe sleep restriction condition (n =14) equivalent to a 4-h sleep opportunity per 24h. In both conditions, sleep/wake episodes occurred 4h later each day to simulate a rotating shiftwork pattern. While living in the laboratory, participants were served three meals and were provided with either five (moderate sleep restriction condition) or six (severe sleep restriction condition) snack opportunities daily. Snack choice was recorded at each opportunity and assigned to a category (sweet, savoury or healthy) based on the content of the snack. Data were analysed using a Generalised Estimating Equations approach. Analyses show a significant effect of sleep restriction condition on overall and sweet snack consumption. The odds of consuming a snack were significantly greater in the severe sleep restriction condition (P <0.05) compared to the moderate sleep restriction condition. In particular, the odds of choosing a sweet snack were significantly increased in the severe sleep restriction condition (P <0.05). Shiftworkers who are severely sleep restricted may be at risk of obesity and related health disorders due to elevated snack consumption and unhealthy snack choice. To further understand the impact of sleep restriction on snacking behaviour, future studies should examine physiological, psychological and environmental motivators. [Copyright &y& Elsevier]

Abstract: The purpose of the current study was to investigate the impact of work- and sleep-related factors on an objective measure of response time in a field setting. Thirty-five mining operators working 12-h shift patterns completed daily sleep and work diaries, wore activity monitors continuously and completed palm-based psychomotor vigilance tests (palmPVT) at the start and end of each shift. Linear mixed models were used to test the main effects on response time of roster, timing of test, sleep history and prior wake. The time at which the test occurred was a significant predictor of response time (F 3,403.4 =6.72, p <.01) with the end of night shifts being associated with significantly slower response times than the start of night shifts, and the start or end of day shifts. Further, the amount of sleep obtained in the 24h prior to the test was also a significant predictor of response time (F 3,407.0 =3.05, p <.01). The results suggest that, as expected, the end of night shift is associated with changes in response time indicative of performance impairments. Of more interest however is that immediate sleep history was also predictive of changes in response time with lower amounts of prior sleep related to slower response times. The current data provides further evidence that sleep is a primary mediator of performance, independent of roster pattern. [ABSTRACT FROM AUTHOR]