The effects of anticipating a high-stress task on sleep and performance during simulated on-call work.

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.

In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

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.

Sleep disturbances in caregivers of children with medical needs: A systematic review and meta-analysis.

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).

Sleep hygiene in shift workers: A systematic literature review.

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.

Are Individuals with Low Trait Anxiety Better Suited to On-Call Work?

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.

The impact of anticipating a stressful task on sleep inertia when on-call.

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 Impact of on-Call Work for Partners' Sleep, Relationship Quality and Daytime Functioning.

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.

Understanding the Differing Impacts of On-Call Work for Males and Females: Results from an Online Survey.

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 "a lot/very much". While both males and females adopted engaged coping styles, a greater proportion of males used "problem solving" and a greater proportion of females "talked about their feelings" 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.

More than hours of work: fatigue management during high-intensity maritime operations.

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.

Overnight heart rate variability and next day cortisol response during simulated on-call conditions.

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.

The effects of hydration on cognitive performance during a simulated wildfire suppression shift in temperate and hot conditions.

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 ±â€¯13.7 years, mean ±â€¯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.

Driver fatigue during extended rail operations.

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 8h shift. RESULTS: Analyses revealed a trend for elevated fatigue at the end of each shift. Designated 8h 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 8h 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 Cost of Inadequate Sleep among On-Call Workers in Australia: A Workplace Perspective.

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.

No rest for the women: Understanding the impact of on-call work for women in the emergency services.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

How the chance of missing the alarm during an on-call shift affects pre-bed anxiety, sleep and next day cognitive performance.

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).

Uncertain call likelihood negatively affects sleep and next-day cognitive performance while on-call in a laboratory environment.

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.

The impact of breaking up prolonged sitting on glucose metabolism and cognitive function when sleep is restricted.

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).

Does breaking up prolonged sitting when sleep restricted affect postprandial glucose responses and subsequent sleep architecture? - a pilot study.

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 (~9 min) in slow-wave sleep was observed.

The characteristics of recovery sleep when recovery opportunity is restricted.

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.

Breaking Up Sitting with Light-Intensity Physical Activity: Implications for Shift-Workers.

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.