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Sprajcer M, Dawson D, Kosmadopoulos A, Sach EJ, Crowther ME, Sargent C, Roach GD. How Tired is Too Tired to Drive? A Systematic Review Assessing the Use of Prior Sleep Duration to Detect Driving Impairment. Nat Sci Sleep 2023; 15:175-206. [PMID: 37038440 PMCID: PMC10082604 DOI: 10.2147/nss.s392441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/03/2023] [Indexed: 04/12/2023] Open
Abstract
Driver fatigue is a contributory factor in approximately 20% of vehicle crashes. While other causal factors (eg, drink-driving) have decreased in recent decades due to increased public education strategies and punitive measures, similar decreases have not been seen in fatigue-related crashes. Fatigued driving could be managed in a similar way to drink-driving, with an established point (ie, amount of prior sleep) after which drivers are "deemed impaired". This systematic review aimed to provide an evidence-base for the concept of deemed impairment and to identify how much prior sleep may be required to drive safely. Four online databases were searched (PubMed, Web of Science, Scopus, Embase). Eligibility requirements included a) measurement of prior sleep duration and b) driving performance indicators (eg, lane deviation) and/or outcomes (eg, crash likelihood). After screening 1940 unique records, a total of 61 studies were included. Included studies were categorised as having experimental/quasi-experimental (n = 21), naturalistic (n = 3), longitudinal (n = 1), case-control (n = 11), or cross-sectional (n = 25) designs. Findings suggest that after either 6 or 7 hours of prior sleep, a modest level of impairment is generally seen compared with after ≥ 8 hours of prior sleep (ie, well rested), depending on the test used. Crash likelihood appears to be ~30% greater after 6 or 7 hours of prior sleep, as compared to individuals who are well rested. After one night of either 4 or 5 hours of sleep, there are large decrements to driving performance and approximately double the likelihood of a crash when compared with well-rested individuals. When considering the scientific evidence, it appears that there is a notable decrease in driving performance (and associated increase in crash likelihood) when less than 5h prior sleep is obtained. This is a critical first step in establishing community standards regarding the amount of sleep required to drive safely.
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Affiliation(s)
- Madeline Sprajcer
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
- Correspondence: Madeline Sprajcer, Central Queensland University, Appleton Institute, 44 Greenhill Road, Wayville, SA, 5034, Australia, Email
| | - Drew Dawson
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
| | - Anastasi Kosmadopoulos
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
| | - Edward J Sach
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
| | - Meagan E Crowther
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
| | - Charli Sargent
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
| | - Gregory D Roach
- Appleton Institute for Behavioural Sciences, Central Queensland University, Wayville, SA, Australia
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2
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Jones A, Jha R. Exploring the associative learning capabilities of the segmented attractor network for lifelong learning. Front Artif Intell 2022; 5:910407. [PMID: 35978653 PMCID: PMC9376266 DOI: 10.3389/frai.2022.910407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/11/2022] [Indexed: 12/02/2022] Open
Abstract
This work explores the process of adapting the segmented attractor network to a lifelong learning setting. Taking inspirations from Hopfield networks and content-addressable memory, the segmented attractor network is a powerful tool for associative memory applications. The network's performance as an associative memory is analyzed using multiple metrics. In addition to the network's general hit rate, its capability to recall unique memories and their frequency is also evaluated with respect to time. Finally, additional learning techniques are implemented to enhance the network's recall capacity in the application of lifelong learning. These learning techniques are based on human cognitive functions such as memory consolidation, prediction, and forgetting.
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Affiliation(s)
- Alexander Jones
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
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3
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Lok R, Woelders T, van Koningsveld MJ, Oberman K, Fuhler SG, Beersma DGM, Hut RA. Bright Light Increases Alertness and Not Cortisol in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light (I). J Biol Rhythms 2022; 37:403-416. [PMID: 35686534 PMCID: PMC9326799 DOI: 10.1177/07487304221096945] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Light-induced improvements in alertness are more prominent during nighttime than during the day, suggesting that alerting effects of light may depend on internal clock time or wake duration. Relative contributions of both factors can be quantified using a forced desynchrony (FD) designs. FD designs have only been conducted under dim light conditions (<10 lux) since light above this amount can induce non-uniform phase progression of the circadian pacemaker (also called relative coordination). This complicates the mathematical separation of circadian clock phase from homeostatic sleep pressure effects. Here we investigate alerting effects of light in a novel 4 × 18 h FD protocol (5 h sleep, 13 h wake) under dim (6 lux) and bright light (1300 lux) conditions. Hourly saliva samples (melatonin and cortisol assessment) and 2-hourly test sessions were used to assess effects of bright light on subjective and objective alertness (electroencephalography and performance). Results reveal (1) stable free-running cortisol rhythms with uniform phase progression under both light conditions, suggesting that FD designs can be conducted under bright light conditions (1300 lux), (2) subjective alerting effects of light depend on elapsed time awake but not circadian clock phase, while (3) light consistently improves objective alertness independent of time awake or circadian clock phase. Reconstructing the daily time course by combining circadian clock phase and wake duration effects indicates that performance is improved during daytime, while subjective alertness remains unchanged. This suggests that high-intensity indoor lighting during the regular day might be beneficial for mental performance, even though this may not be perceived as such.
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Affiliation(s)
- R Lok
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands.,Current address: Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, California, USA.,University of Groningen, Leeuwarden, the Netherlands
| | - T Woelders
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - M J van Koningsveld
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - K Oberman
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - S G Fuhler
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - D G M Beersma
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - R A Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
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4
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Sargent C, Kosmadopoulos A, Zhou X, Roach GD. Timing of Sleep in the Break Between Two Consecutive Night-Shifts: The Effect of Different Strategies on Daytime Sleep and Night-Time Neurobehavioural Function. Nat Sci Sleep 2022; 14:231-242. [PMID: 35210890 PMCID: PMC8860456 DOI: 10.2147/nss.s336795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE The aim of this study was to examine whether the timing of sleep in the break between consecutive night-shifts affects the quantity and quality of sleep obtained during the daytime and/or neurobehavioural function and self-perceived capacity during the night-time. METHODS Participants (n = 12, all male, aged 22.9±5.2 y) completed three randomised, counterbalanced conditions in a sleep laboratory, consisting of two consecutive 12-hour night-shifts (18:00-06:00) with 7 hours in bed in the break between shifts. The three conditions differed only in the timing of the sleep opportunities - immediate (07:00-14:00), delayed (10:00-17:00), split (07:00-10:30 and 13:30-17:00). Neurobehavioural function (attention, memory, throughput) and self-perceived capacity (sleepiness, alertness, fatigue, mood) were assessed at 2-hour intervals during the night-shifts. RESULTS Condition did not affect total sleep time (p = 0.465), but it did affect sleep onset latency (p < 0.001; W = 0.780; large effect), wake after sleep onset (p = 0.018; W = 0.333; moderate effect) and the amount of Stage N3 sleep (p < 0.001; η2=0.510; small effect). Compared to the immediate and delayed sleep conditions, the split sleep condition had less wake after sleep onset and more Stage N3 sleep; and compared to the delayed condition, the split sleep condition had longer latency to sleep onset. There was no effect of condition on measures of neurobehavioural function or self-perceived capacity during the second night-shift. CONCLUSION None of the three sleep strategies examined here - immediate, delayed or split - are clearly superior or inferior to the others in terms of the capacity to sleep during the daytime or to work at night. Therefore, those who work consecutive night-shifts should employ the strategy that best suits their personal preferences and/or circumstances.
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Affiliation(s)
- Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, Wayville, SA, Australia
| | - Anastasi Kosmadopoulos
- Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Xuan Zhou
- Centre for Quantitative Genetics and Genomics, Aarhus University, Aarhus, Denmark
| | - Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, Wayville, SA, Australia
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Caffeine may disrupt the impact of real-time drowsiness on cognitive performance: a double-blind, placebo-controlled small-sample study. Sci Rep 2021; 11:4027. [PMID: 33597580 PMCID: PMC7889923 DOI: 10.1038/s41598-021-83504-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 01/29/2021] [Indexed: 01/20/2023] Open
Abstract
Caffeine is widely used to promote alertness and cognitive performance under challenging conditions, such as sleep loss. Non-digestive modes of delivery typically reduce variability of its effect. In a placebo-controlled, 50-h total sleep deprivation (TSD) protocol we administered four 200 mg doses of caffeine-infused chewing-gum during night-time circadian trough and monitored participants' drowsiness during task performance with infra-red oculography. In addition to the expected reduction of sleepiness, caffeine was found to disrupt its degrading impact on performance errors in tasks ranging from standard cognitive tests to simulated driving. Real-time drowsiness data showed that caffeine produced only a modest reduction in sleepiness (compared to our placebo group) but substantial performance gains in vigilance and procedural decisions, that were largely independent of the actual alertness dynamics achieved. The magnitude of this disrupting effect was greater for more complex cognitive tasks.
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Huber R, Ghosh A. Large cognitive fluctuations surrounding sleep in daily living. iScience 2021; 24:102159. [PMID: 33681725 PMCID: PMC7918275 DOI: 10.1016/j.isci.2021.102159] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/07/2020] [Accepted: 02/02/2021] [Indexed: 01/06/2023] Open
Abstract
Cognitive output and physical activity levels fluctuate surrounding sleep. The ubiquitous digitization of behavior via smartphones is a promising avenue for addressing how these fluctuations occur in daily living. Here, we logged smartphone touchscreen interactions to proxy cognitive fluctuations and contrasted these to physical activity patterns logged on wrist-worn actigraphy. We found that both cognitive and physical activities were dominated by diurnal (∼24 h) and infra-radian (∼7 days) rhythms. The proxy measures of cognitive performance—tapping speed, unlocking speed, and app locating speed—contained lower-powered diurnal rhythm than physical activity. The difference between cognitive and physical activity was vivid during bedtime as people continued to interact with their smartphones at physical rest. The cognitive performance measures in this period were worse than those in the hour before or after bedtime. We suggest that the rhythms underlying cognitive activity in the real world are distinct from those underlying physical activity, and this discord may be a hallmark of modern human behavior. Daily and weekly rhythms shape our day-to-day behavior The speed of smartphone interactions fluctuates according to the time of the day These fluctuations do not strictly follow the physical activity cycles The worst performing time on the smartphone is around bedtime
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Affiliation(s)
- Reto Huber
- Child Development Center, University Children's Hospital Zurich, Switzerland & Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital University of Zurich, Switzerland
| | - Arko Ghosh
- Institute of Psychology, Cognitive Psychology Unit, Leiden University, Wassenaarseweg 52, Leiden 2333 AK, the Netherlands
- Corresponding author
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7
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Hao C, Li M, Luo W, Ma N. Dissociation of Subjective and Objective Alertness During Prolonged Wakefulness. Nat Sci Sleep 2021; 13:923-932. [PMID: 34234597 PMCID: PMC8254410 DOI: 10.2147/nss.s312808] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/16/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Although the deterioration of subjective and objective alertness during prolonged wakefulness has been investigated rigorously, whether perceived sleepiness and fatigue are consistent with actual decrements in behavioral performance in the time course is still disputed. The present study examined the dissociation between decrements of subjective alertness and performance deficits during prolonged wakefulness of one night and explored the relationship between body temperature and the impairments of subjective and objective alertness. PARTICIPANTS AND METHODS Thirty-eight participants (27 females; age: 21.76 ± 2.37 years old) underwent prolonged wakefulness for one night at habitual bedtime (0:00-6:00 am). Participants completed a 10-min PVT to assess objective alertness, fatigue, and sleepiness ratings to assess subjective alertness every 2 hours, and body temperature was measured every hour during scheduled wakefulness. RESULTS Subjective alertness reflected a linear decline with time, but the magnitudes of objective performance deterioration increased significantly between 4:00 and 6:00 am. The increasing magnitudes of performance deficits were associated with the change of body temperature between 4:00 and 6:00 am. CONCLUSION These results indicate that the perceived degree of decline in alertness is temporally dissociated with the actual decline in objective vigilance with increased duration of wakefulness. The dissociation of magnitudes of subjective and objective alertness decrements mainly occurs between 4:00 and 6:00 am, and the changes of performance deficits have a relationship with body temperature.
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Affiliation(s)
- Chao Hao
- Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; Center for Sleep Research, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - Mingzhu Li
- Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; Center for Sleep Research, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - Wei Luo
- School of Architecture and Urban Planning, Shenzhen University, Shenzhen, 518060, People's Republic of China
| | - Ning Ma
- Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; Center for Sleep Research, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, South China Normal University, Guangzhou, 510631, People's Republic of China
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8
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Gupta CC, Centofanti S, Dorrian J, Coates AM, Stepien JM, Kennaway D, Wittert G, Heilbronn L, Catcheside P, Tuckwell GA, Coro D, Chandrakumar D, Banks S. The impact of a meal, snack, or not eating during the night shift on simulated driving performance post-shift. Scand J Work Environ Health 2021; 47:78-84. [PMID: 33190160 PMCID: PMC7801136 DOI: 10.5271/sjweh.3934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective: The commute home following a night shift is associated with an increased risk for accidents. This study investigated the relationship between food intake during the night shift and simulated driving performance post-shift. Methods: Healthy non-shift working males (N=23) and females (N=16), aged 18–39 years (mean 24.5, standard deviation 5.0, years) participated in a seven-day laboratory study and underwent four simulated night shifts Participants were randomly allocated to one of three conditions: meal at night (N=12; 7 males), snack at night (N=13; 7 males) or no eating at night (N=14; 9 males). During the night shift at 00:30 hours, participants either ate a large meal (meal at night condition), a snack (snack at night condition), or did not eat during the night shift (no eating at night condition). During the second simulated night shift, participants performed a 40-minute York driving simulation at 20:00, 22:30, 01:30, 04:00, and 07:30 hours (similar time to a commute from work). Results: The effects of eating condition, drive time, and time-on-task, on driving performance were examined using mixed model analyses. Significant condition×time interactions were found, where at 07:30 hours, those in the meal at night condition displayed significant increases in time spent outside of the safe zone (percentage of time spent outside 10 km/hour of the speed limit and 0.8 meters of the lane center; P<0.05), and greater lane and speed variability (both P<0.01) compared to the snack and no eating conditions. There were no differences between the snack and no eating conditions. Conclusion: Driver safety during the simulated commute home is greater following the night shift if a snack, rather than a meal, is consumed during the shift.
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Affiliation(s)
- Charlotte C Gupta
- Appleton Institute, Central Queensland University, 44 Greenhill Road, Wayville 5034, Adelaide, Australia.
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Vincent GE, Gupta CC, Sprajcer M, Vandelanotte C, Duncan MJ, Tucker P, Lastella M, Tuckwell GA, Ferguson SA. Are prolonged sitting and sleep restriction a dual curse for the modern workforce? a randomised controlled trial protocol. BMJ Open 2020; 10:e040613. [PMID: 32718927 PMCID: PMC7389768 DOI: 10.1136/bmjopen-2020-040613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Prolonged sitting and inadequate sleep are a growing concern in society and are associated with impairments to cardiometabolic health and cognitive performance. However, the combined effect of prolonged sitting and inadequate sleep on measures of health and cognitive performance are unknown. In addition, the circadian disruption caused by shiftwork may further impact workers' cardiometabolic health and cognitive performance. This protocol paper outlines the methodology for exploring the impact of simultaneous exposure to prolonged sitting, sleep restriction and circadian disruption on cardiometabolic and cognitive performance outcomes. METHODS AND ANALYSIS This between-subjects study will recruit 208 males and females to complete a 7-day in-laboratory experimental protocol (1 Adaptation Day, 5 Experimental Days and 1 Recovery Day). Participants will be allocated to one of eight conditions that include all possible combinations of the following: dayshift or nightshift, sitting or breaking up sitting and 5 hour or 9 hour sleep opportunity. On arrival to the laboratory, participants will be provided with a 9 hour baseline sleep opportunity (22:00 to 07:00) and complete five simulated work shifts (09:00 to 17:30 in the dayshift condition and 22:00 to 06:30 in the nightshift condition) followed by a 9 hour recovery sleep opportunity (22:00 to 07:00). During the work shifts participants in the sitting condition will remain seated, while participants in the breaking up sitting condition will complete 3-min bouts of light-intensity walking every 30 mins on a motorised treadmill. Sleep opportunities will be 9 hour or 5 hour. Primary outcome measures include continuously measured interstitial blood glucose, heart rate and blood pressure, and a cognitive performance and self-perceived capacity testing battery completed five times per shift. Analyses will be conducted using linear mixed models. ETHICS AND DISSEMINATION The CQUniversity Human Ethics Committee has approved this study (0000021914). All participants who have already completed the protocol have provided informed consent. Study findings will be disseminated via scientific publications and conference presentations. TRIAL REGISTRATION DETAILS This study has been registered on Australian New Zealand Clinical Trials Registry (12619001516178) and is currently in the pre-results stage.
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Affiliation(s)
- Grace E Vincent
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
| | - Charlotte C Gupta
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
| | - Madeline Sprajcer
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
| | - Corneel Vandelanotte
- School of Health Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia
| | - Mitch J Duncan
- School of Medicine & Public Health, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia
- Priority Research Centre for Physical Activity and Nutrition, The University of Newcastle, Callaghan, NSW, Australia
| | - Phil Tucker
- Psychology Department, Swansea University, Swansea, United Kingdom
- Stress Research Institute, Department of Psychology, Stocklholm University, Stockholm, Sweden
| | - Michele Lastella
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
| | - Georgia A Tuckwell
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
| | - Sally A Ferguson
- Appleton Institute, Central Queensland University - Adelaide Campus, Wayville, South Australia, Australia
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10
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Roach GD, Sargent C. Interventions to Minimize Jet Lag After Westward and Eastward Flight. Front Physiol 2019; 10:927. [PMID: 31417411 PMCID: PMC6684967 DOI: 10.3389/fphys.2019.00927] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/09/2019] [Indexed: 01/09/2023] Open
Affiliation(s)
- Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, SA, Australia
| | - Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, SA, Australia
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Boudreau P, Lafrance S, Boivin DB. Alertness and psychomotor performance levels of marine pilots on an irregular work roster. Chronobiol Int 2018; 35:773-784. [DOI: 10.1080/07420528.2018.1466796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Philippe Boudreau
- Centre for Study and Treatment of Circadian Rhythms, Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Canada
| | | | - Diane B. Boivin
- Centre for Study and Treatment of Circadian Rhythms, Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Canada
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Paech GM, Crowley SJ, Fogg LF, Eastman CI. Advancing the sleep/wake schedule impacts the sleep of African-Americans more than European-Americans. PLoS One 2017; 12:e0186887. [PMID: 29059251 PMCID: PMC5653363 DOI: 10.1371/journal.pone.0186887] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 10/09/2017] [Indexed: 12/16/2022] Open
Abstract
There are differences in sleep duration between Blacks/African-Americans and Whites/European-Americans. Recently, we found differences between these ancestry groups in the circadian system, such as circadian period and the magnitude of phase shifts. Here we document the role of ancestry on sleep and cognitive performance before and after a 9-h advance in the sleep/wake schedule similar to flying east or having a large advance in sleep times due to shiftwork, both of which produce extreme circadian misalignment. Non-Hispanic African and European-Americans (N = 20 and 17 respectively, aged 21-43 years) were scheduled to four baseline days each with 8 h time in bed based on their habitual sleep schedule. This sleep/wake schedule was then advanced 9 h earlier for three days. Sleep was monitored using actigraphy. During the last two baseline/aligned days and the first two advanced/misaligned days, beginning 2 h after waking, cognitive performance was measured every 3 h using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Mixed model ANOVAs assessed the effects of ancestry (African-American or European-American) and condition (baseline/aligned or advanced/misaligned) on sleep and cognitive performance. There was decreased sleep and impaired performance in both ancestry groups during the advanced/misaligned days compared to the baseline/aligned days. In addition, African-Americans obtained less sleep than European-Americans, especially on the first two days of circadian misalignment. Cognitive performance did not differ between African-Americans and European-Americans during baseline days. During the two advanced/misaligned days, however, African-Americans tended to perform slightly worse compared to European-Americans, particularly at times corresponding to the end of the baseline sleep episodes. Advancing the sleep/wake schedule, creating extreme circadian misalignment, had a greater impact on the sleep of African-Americans than European-Americans. Ancestry differences in sleep appear to be exacerbated when the sleep/wake schedule is advanced, which may have implications for individuals undertaking shiftwork and transmeridian travel.
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Affiliation(s)
- Gemma M. Paech
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Stephanie J. Crowley
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Louis F. Fogg
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Charmane I. Eastman
- Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America
- * E-mail:
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GRANT CL, DORRIAN J, COATES AM, PAJCIN M, KENNAWAY DJ, WITTERT GA, HEILBRONN LK, DELLA VEDOVA C, GUPTA CC, BANKS S. The impact of meal timing on performance, sleepiness, gastric upset, and hunger during simulated night shift. INDUSTRIAL HEALTH 2017; 55:423-436. [PMID: 28740034 PMCID: PMC5633358 DOI: 10.2486/indhealth.2017-0047] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/18/2017] [Indexed: 06/01/2023]
Abstract
This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p<0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p<0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort.
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Affiliation(s)
| | - Jillian DORRIAN
- Centre for Sleep Research, University of South Australia, Australia
| | - Alison Maree COATES
- Alliance for Research in Exercise, Nutrition and Activity, University of South Australia, Australia
| | - Maja PAJCIN
- School of Pharmacy and Medical Sciences, University of South Australia, Australia
| | - David John KENNAWAY
- Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Australia
| | - Gary Allen WITTERT
- Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Australia
- South Australian Health and Medical Research Institute, Australia
| | - Leonie Kaye HEILBRONN
- Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Australia
- South Australian Health and Medical Research Institute, Australia
| | - Chris DELLA VEDOVA
- School of Pharmacy and Medical Sciences, University of South Australia, Australia
| | | | - Siobhan BANKS
- Centre for Sleep Research, University of South Australia, Australia
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14
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Abstract
Previous work from our laboratory has shown that a measure of attention to emotionally-charged stimuli, the late positive potential (LPP) event related potential (ERP), distinguished neutral from emotional pictures on a baseline day, but not after sleep deprivation. Here we sought to extend these findings and address the uncertainty about the effect of time-of-day on emotion processing by testing a morning group (8:00–10:00 a.m., n = 30) and an evening group (8:00–10:00 p.m., n = 30). We also examined the extent of diurnal changes in cortisol related to the emotion processing task. Results from this study mirrored those found after one night of sleep deprivation. Compared to the morning group, the LPP generated by the evening group (who had a greater homeostatic sleep drive) did not distinguish neutral from emotionally-charged stimuli. New to this study, we also found that there was a time-of-day effect on positive, but not negative pictures. While, as expected, cortisol levels were higher in the morning relative to the evening group, there was no relationship between cortisol and the LPP ERP emotion measure. In addition, neither time-of-day preference nor sleep quality was related to the LPP measure. These findings show that, similar to what occurs after sleep deprivation, increased sleep pressure throughout the day interferes with attention processing to emotional stimuli.
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15
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Fang Z, Rao H. Imaging homeostatic sleep pressure and circadian rhythm in the human brain. J Thorac Dis 2017; 9:E495-E498. [PMID: 28616320 PMCID: PMC5465131 DOI: 10.21037/jtd.2017.03.168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 03/17/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Zhuo Fang
- Laboratory of Applied Brain and Cognitive Sciences, Shanghai International Studies University, Shanghai 200000, China
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hengyi Rao
- Laboratory of Applied Brain and Cognitive Sciences, Shanghai International Studies University, Shanghai 200000, China
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
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16
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Barclay NL, Myachykov A. Sustained wakefulness and visual attention: moderation by chronotype. Exp Brain Res 2016; 235:57-68. [PMID: 27624836 PMCID: PMC5225193 DOI: 10.1007/s00221-016-4772-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/06/2016] [Indexed: 11/15/2022]
Abstract
Introduction Attentional networks are sensitive to sleep deprivation and increased time awake. However, existing evidence is inconsistent and may be accounted for by differences in chronotype or time-of-day. We examined the effects of sustained wakefulness over a normal “socially constrained” day (following 18 h of sustained wakefulness), following a night of normal sleep, on visual attention as a function of chronotype. Methods Twenty-six good sleepers (mean age 25.58; SD 4.26; 54 % male) completed the Attention Network Test (ANT) at two time points (baseline at 8 am; following 18-h sustained wakefulness at 2 am). The ANT provided mean reaction times (RTs), error rates, and the efficiency of three attentional networks—alerting, orienting, and executive control/conflict. The Morningness–Eveningness Questionnaire measured chronotype. Results Mean RTs were longer at time 2 compared to time 1 for those with increasing eveningness; the opposite was true for morningness. However, those with increasing morningness exhibited longer RT and made more errors, on incongruent trials at time 2 relative to those with increasing eveningness. There were no significant main effects of time or chronotype (or interactions) on attentional network scores. Conclusion Sustained wakefulness produced differential effects on visual attention as a function of chronotype. Whilst overall our results point to an asynchrony effect, this effect was moderated by flanker type. Participants with increasing eveningness outperformed those with increasing morningness on incongruent trials at time 2. The preservation of executive control in evening-types following sustained wakefulness is likely driven by differences in circadian phase between chronotypes across the day.
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Affiliation(s)
- Nicola L Barclay
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
| | - Andriy Myachykov
- Department of Psychology, Faculty of Health and Life Sciences, Northumbria University, Newcastle, UK.,Center for Cognition and Decision Making, Higher School of Economics, Moscow, Russia
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17
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Postnova S, Lockley SW, Robinson PA. Sleep Propensity under Forced Desynchrony in a Model of Arousal State Dynamics. J Biol Rhythms 2016; 31:498-508. [DOI: 10.1177/0748730416658806] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An improvement to our current quantitative model of arousal state dynamics is presented that more accurately predicts sleep propensity as measured with sleep dynamics depending on circadian phase and prior wakefulness. A nonlinear relationship between the circadian variables within the dynamic circadian oscillator model is introduced to account for the skewed shape of the circadian rhythm of alertness that peaks just prior to the onset of the biological night (the “wake maintenance zone”) and has a minimum toward the end of the biological night. The revised circadian drive thus provides a strong inhibitory input to the sleep-active neuronal population in the evening, counteracting the excitatory effects of the increased homeostatic sleep drive as originally proposed in the opponent process model of sleep-wake regulation. The revised model successfully predicts the sleep propensity profile as reflected in the dynamics of the total sleep time, sleep onset latency, wake/sleep ratio, and sleep efficiency during a wide range of experimental protocols. Specifically, all of these sleep measures are predicted for forced desynchrony schedules with day lengths ranging from 1.5 to 42.85 h and scheduled time in bed from 0.5 to 14.27 h. The revised model is expected to facilitate more accurate predictions of sleep under normal conditions as well as during circadian misalignment, for example, during shiftwork and jetlag.
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Affiliation(s)
- Svetlana Postnova
- School of Physics, University of Sydney, New South Wales, Australia
- Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia
- Centre of Excellence for Integrative Brain Function, University of Sydney, New South Wales, Australia
| | - Steven W. Lockley
- Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Centre for Translational Sleep and Circadian Neurobiology, Monash University, Victoria, Australia
| | - Peter A. Robinson
- School of Physics, University of Sydney, New South Wales, Australia
- Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia
- Centre of Excellence for Integrative Brain Function, University of Sydney, New South Wales, Australia
- Centre for Translational Sleep and Circadian Neurobiology, University of Sydney, New South Wales, Australia
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18
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Gander P, Mulrine HM, van den Berg MJ, Wu L, Smith A, Signal L, Mangie J. Does the circadian clock drift when pilots fly multiple transpacific flights with 1- to 2-day layovers? Chronobiol Int 2016; 33:982-94. [DOI: 10.1080/07420528.2016.1189430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Philippa Gander
- Massey University, Sleep/Wake Research Centre, Wellington, New Zealand
| | - Hannah M. Mulrine
- Massey University, Sleep/Wake Research Centre, Wellington, New Zealand
| | | | - Lora Wu
- Massey University, Sleep/Wake Research Centre, Wellington, New Zealand
| | - Alexander Smith
- Massey University, Sleep/Wake Research Centre, Wellington, New Zealand
| | - Leigh Signal
- Massey University, Sleep/Wake Research Centre, Wellington, New Zealand
| | - Jim Mangie
- Delta Air Lines, Flight Operations, Atlanta, Georgia, USA
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19
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Rabat A, Gomez-Merino D, Roca-Paixao L, Bougard C, Van Beers P, Dispersyn G, Guillard M, Bourrilhon C, Drogou C, Arnal PJ, Sauvet F, Leger D, Chennaoui M. Differential Kinetics in Alteration and Recovery of Cognitive Processes from a Chronic Sleep Restriction in Young Healthy Men. Front Behav Neurosci 2016; 10:95. [PMID: 27242464 PMCID: PMC4876616 DOI: 10.3389/fnbeh.2016.00095] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/02/2016] [Indexed: 01/01/2023] Open
Abstract
Chronic sleep restriction (CSR) induces neurobehavioral deficits in young and healthy people with a morning failure of sustained attention process. Testing both the kinetic of failure and recovery of different cognitive processes (i.e., attention, executive) under CSR and their potential links with subject's capacities (stay awake, baseline performance, age) and with some biological markers of stress and anabolism would be useful in order to understand the role of sleep debt on human behavior. Twelve healthy subjects spent 14 days in laboratory with 2 baseline days (B1 and B2, 8 h TIB) followed by 7 days of sleep restriction (SR1-SR7, 4 h TIB), 3 sleep recovery days (R1-R3, 8 h TIB) and two more ones 8 days later (R12-R13). Subjective sleepiness (KSS), maintenance of wakefulness latencies (MWT) were evaluated four times a day (10:00, 12:00 a.m. and 2:00, 4:00 p.m.) and cognitive tests were realized at morning (8:30 a.m.) and evening (6:30 p.m.) sessions during B2, SR1, SR4, SR7, R2, R3 and R13. Saliva (B2, SR7, R2, R13) and blood (B1, SR6, R1, R12) samples were collected in the morning. Cognitive processes were differently impaired and recovered with a more rapid kinetic for sustained attention process. Besides, a significant time of day effect was only evidenced for sustained attention failures that seemed to be related to subject's age and their morning capacity to stay awake. Executive processes were equally disturbed/recovered during the day and this failure/recovery process seemed to be mainly related to baseline subject's performance and to their capacity to stay awake. Morning concentrations of testosterone, cortisol and α-amylase were significantly decreased at SR6-SR7, but were either and respectively early (R1), tardily (after R2) and not at all (R13) recovered. All these results suggest a differential deleterious and restorative effect of CSR on cognition through biological changes of the stress pathway and subject's capacity (ClinicalTrials-NCT01989741).
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Affiliation(s)
- Arnaud Rabat
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Danielle Gomez-Merino
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Laura Roca-Paixao
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; University of Paris 11Orsay, France
| | - Clément Bougard
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Pascal Van Beers
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Garance Dispersyn
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Mathias Guillard
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Cyprien Bourrilhon
- Department of Operational Environments, Armed Forces Biomedical Research Institute (IRBA) Brétigny-sur-Orge, France
| | - Catherine Drogou
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Pierrick J Arnal
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Fabien Sauvet
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
| | - Damien Leger
- VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France; Alertness and Sleep Center, Hôtel Dieu de Paris, Public Assistance of Paris Hospitals, University of Paris 5 DescartesParis, France
| | - Mounir Chennaoui
- Fatigue and Vigilance Unit, Department of Neurosciences and Operational Constraints, Armed Forces Biomedical Research Institute (IRBA)Brétigny-sur-Orge, France; VIFASOM team (EA 7330), University of Paris 5 DescartesParis, France
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20
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Nota JA, Schubert JR, Coles ME. Sleep disruption is related to poor response inhibition in individuals with obsessive-compulsive and repetitive negative thought symptoms. J Behav Ther Exp Psychiatry 2016; 50:23-32. [PMID: 25989071 DOI: 10.1016/j.jbtep.2015.04.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/22/2015] [Accepted: 04/25/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Obsessive-compulsive (OC) symptoms and repetitive negative thinking (RNT) are associated with poor inhibitory control. Sleep disruptions may partially mediate these relations and/or act as a "second hit" to individuals with OC symptoms and RNT. Models including habitual (past month) hours slept and bedtimes were tested. METHODS We employed a go/no-go task that allowed us to examine the relation between sleep and inhibition with various task contingencies. Sixty-seven unselected individuals were recruited from the participant pool at a public university. RESULTS Bias-corrected bootstrap estimates did not show that sleep disruption mediated the relation between OC symptoms and response inhibition nor the relation between RNT and response inhibition. Multiple linear regression analyses found significant interactions between hours slept and OC symptom severity and between RNT and hours slept to predict poor response inhibition. Hours slept significantly negatively predicted commission errors when OC symptoms and RNT levels were relatively heightened but not when OC symptoms and RNT levels were relatively low. These effects were present in blocks where task contingencies were designed to shape a no-go bias. No significant relations were found with habitual bedtimes. LIMITATIONS The cross-sectional study design precludes testing the temporal precedence of symptoms in the "second hit" model. The unselected sample also limits generalization to clinical samples. CONCLUSIONS These findings support a "second hit" model of interaction between sleep disruption and perseverative thoughts and behaviors. Further research on the mechanisms of the relation between sleep disruption and perseverative thought symptoms (OC and RNT) is warranted.
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Affiliation(s)
- Jacob A Nota
- Binghamton University, Department of Psychology, USA.
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21
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Sargent C, Zhou X, Matthews RW, Darwent D, Roach GD. Daily Rhythms of Hunger and Satiety in Healthy Men during One Week of Sleep Restriction and Circadian Misalignment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:170. [PMID: 26840322 PMCID: PMC4772190 DOI: 10.3390/ijerph13020170] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/14/2015] [Accepted: 09/29/2015] [Indexed: 01/09/2023]
Abstract
The impact of sleep restriction on the endogenous circadian rhythms of hunger and satiety were examined in 28 healthy young men. Participants were scheduled to 2 × 24-h days of baseline followed by 8 × 28-h days of forced desynchrony during which sleep was either moderately restricted (equivalent to 6 h in bed/24 h; n = 14) or severely restricted (equivalent to 4 h in bed/24 h; n = 14). Self-reported hunger and satisfaction were assessed every 2.5 h during wake periods using visual analogue scales. Participants were served standardised meals and snacks at regular intervals and were not permitted to eat ad libitum. Core body temperature was continuously recorded with rectal thermistors to determine circadian phase. Both hunger and satiety exhibited a marked endogenous circadian rhythm. Hunger was highest, and satiety was lowest, in the biological evening (i.e., ~17:00–21:00 h) whereas hunger was lowest, and satiety was highest in the biological night (i.e., 01:00–05:00 h). The results are consistent with expectations based on previous reports and may explain in some part the decrease in appetite that is commonly reported by individuals who are required to work at night. Interestingly, the endogenous rhythms of hunger and satiety do not appear to be altered by severe—as compared to moderate—sleep restriction.
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Affiliation(s)
- Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, P.O. Box 42, Goodwood 5034, Australia.
| | - Xuan Zhou
- Appleton Institute for Behavioural Science, Central Queensland University, P.O. Box 42, Goodwood 5034, Australia.
| | - Raymond W Matthews
- Appleton Institute for Behavioural Science, Central Queensland University, P.O. Box 42, Goodwood 5034, Australia.
| | - David Darwent
- Appleton Institute for Behavioural Science, Central Queensland University, P.O. Box 42, Goodwood 5034, Australia.
| | - Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, P.O. Box 42, Goodwood 5034, Australia.
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22
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Roach GD, Lamond N, Dawson D. Feedback has a positive effect on cognitive function during total sleep deprivation if there is sufficient time for it to be effectively processed. APPLIED ERGONOMICS 2016; 52:285-290. [PMID: 26360220 DOI: 10.1016/j.apergo.2015.07.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 06/05/2023]
Abstract
This study examined whether the provision of feedback and the interval between successive stimuli interact to affect performance on a serial simple reaction time test during sleep deprivation. Sixteen participants (9 female, 7 male, aged 18-27 yr) completed four versions of the 5-min psychomotor vigilance task for a handheld personal digital assistant (PalmPVT) every 2 h during 28 h of sustained wakefulness. The four versions differed in terms of whether or not they provided feedback immediately after each response, and whether the inter-stimulus intervals (ISIs) were long (2-10 s) or short (1-5 s). Cognitive function was assessed using reciprocal response time and percentage of responses that were lapses (i.e., had a response time ≥ 500 ms). Data were analysed using repeated measures ANOVA with three within-subjects factors: test session, feedback, and ISI. For both measures, the only significant interaction was between feedback and ISI. Cognitive function was enhanced by feedback when the ISIs were long because it provided motivation. Cognitive function was not affected by feedback when the ISIs were short because there was insufficient time to both attend to the feedback and prepare for the subsequent stimulus.
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Affiliation(s)
- Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, PO Box 42, Goodwood, SA 5034, Australia.
| | - Nicole Lamond
- Emergency Department, Flinders Medical Centre, Flinders Drive, Bedford Park, SA 5042, Australia.
| | - Drew Dawson
- Appleton Institute for Behavioural Science, Central Queensland University, PO Box 42, Goodwood, SA 5034, Australia.
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23
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Loh DH, Jami SA, Flores RE, Truong D, Ghiani CA, O'Dell TJ, Colwell CS. Misaligned feeding impairs memories. eLife 2015; 4. [PMID: 26652002 PMCID: PMC4729691 DOI: 10.7554/elife.09460] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/19/2015] [Indexed: 01/23/2023] Open
Abstract
Robust sleep/wake rhythms are important for health and cognitive function. Unfortunately, many people are living in an environment where their circadian system is challenged by inappropriate meal- or work-times. Here we scheduled food access to the sleep time and examined the impact on learning and memory in mice. Under these conditions, we demonstrate that the molecular clock in the master pacemaker, the suprachiasmatic nucleus (SCN), is unaltered while the molecular clock in the hippocampus is synchronized by the timing of food availability. This chronic circadian misalignment causes reduced hippocampal long term potentiation and total CREB expression. Importantly this mis-timed feeding resulted in dramatic deficits in hippocampal-dependent learning and memory. Our findings suggest that the timing of meals have far-reaching effects on hippocampal physiology and learned behaviour. DOI:http://dx.doi.org/10.7554/eLife.09460.001 Many processes within the body follow an approximately 24-hour cycle. In addition to patterns of sleep and wakefulness, such circadian rhythms help to regulate body temperature, blood pressure and hormone levels. They also affect when we feel hungry, when our muscles work most efficiently, and when we are mentally at our sharpest. A region of the brain called the suprachiasmatic nucleus (SCN) generates and maintains circadian rhythms, and thus acts as the body’s master clock. Daily exposure to light keeps the SCN synchronized with the 24-hour day/night cycle. However, most organs, from the heart to the pancreas, also possess their own clocks, which help to regulate organ-specific processes. These secondary clocks normally operate in synchrony with the SCN. Exposure to light has long been known to influence circadian rhythms. However, more recent evidence suggests that the timing of meals may also affect circadian clocks, particularly those within the digestive system. Loh et al. therefore decided to investigate whether eating outside normal waking hours would also affect other key physiological processes, specifically the cognitive processes of learning and memory. Mice normally consume most of their food after sunset. Loh et al. showed that rodents that were instead fed during the day performed less well on cognitive tests than other mice who received the same food at night. The daytime-fed mice showed changes in a region of the brain called the hippocampus, which supports learning and memory. In particular, daytime feeding changed the timing of the secondary circadian clock within the hippocampus, although it had no effect on the master clock in the SCN. Loh et al. therefore suggest that the misalignment of these circadian clocks impairs cognition. Further experiments are needed to determine whether a similar relationship exists between the timing of meals and cognitive performance in humans. If so, these findings will have implications for the many individuals whose mealtimes, for work or social reasons, are out of synchrony with their body clocks. DOI:http://dx.doi.org/10.7554/eLife.09460.002
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Affiliation(s)
- Dawn H Loh
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States
| | - Shekib A Jami
- UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States.,Molecular, Cellular, and Integrative Physiology PhD Program, University of California, Los Angeles, Los Angeles, United States
| | - Richard E Flores
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Danny Truong
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Cristina A Ghiani
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Thomas J O'Dell
- UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States
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24
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Wu LJ, Acebo C, Seifer R, Carskadon MA. Sleepiness and Cognitive Performance among Younger and Older Adolescents across a 28-Hour Forced Desynchrony Protocol. Sleep 2015; 38:1965-72. [PMID: 26194564 DOI: 10.5665/sleep.5250] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/28/2015] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Quantify the homeostatic and circadian effects on sleepiness and performance of adolescents. Examine age-related changes in homeostatic and circadian regulation of sleepiness and performance by comparing younger and older adolescent groups. DESIGN Three-week laboratory study including 12 cycles of a 28-h forced desynchrony protocol. SETTING Controlled laboratory environment with individual sleep and performance testing rooms and shared common areas. PARTICIPANTS Twenty-seven healthy adolescents including 16 females. Ages ranged from 9.6-15.2 years and participants were split into younger (n = 14 ages 9-12) and older (n = 13 ages 13-15) groups based on median age split of 13.0 years. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Testing occurred every 2 h during scheduled wake periods. Measures included sleep latency during repeated nap opportunities and scores from a computerized neurobehavioral assessment battery including a 10-min psychomotor vigilance task, a digit symbol substitution task, and the Karolinska Sleepiness Scale. Significant main effects of circadian and homeostatic factors were observed, as well as several circadian and homeostatic interaction effects. Age group did not have a significant main effect on sleep and performance data. A significant interaction of circadian phase and age group was found for sleep latency, with younger adolescents showing greater circadian modulation than older teens during the circadian night. CONCLUSIONS Adolescents demonstrated a similar pattern of response to forced desynchrony as reported for adults. Sleepiness and performance were affected by homeostatic and circadian factors, and age group did not interact with homoeostatic and circadian factors for subjective sleepiness and most performance metrics. Younger adolescents had a shorter latency to sleep onset than older during the circadian bin spanning 4 to 8 h after the onset of melatonin secretion.
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Affiliation(s)
- Lora J Wu
- Sleep/Wake Research Centre, Massey University, Wellington, New Zealand.,E.P. Bradley Hospital Sleep and Chronobiology Research Laboratory, Providence, RI
| | - Christine Acebo
- E.P. Bradley Hospital Sleep and Chronobiology Research Laboratory, Providence, RI.,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI
| | - Ronald Seifer
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI
| | - Mary A Carskadon
- E.P. Bradley Hospital Sleep and Chronobiology Research Laboratory, Providence, RI.,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI.,Centre for Sleep Research, School of Psychology, Social Work, and Social Policy, University of South Australia, Adelaide, Australia
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25
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Kim Y, Elmenhorst D, Weisshaupt A, Wedekind F, Kroll T, McCarley RW, Strecker RE, Bauer A. Chronic sleep restriction induces long-lasting changes in adenosine and noradrenaline receptor density in the rat brain. J Sleep Res 2015; 24:549-558. [PMID: 25900125 PMCID: PMC4583343 DOI: 10.1111/jsr.12300] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/15/2015] [Indexed: 01/10/2023]
Abstract
Although chronic sleep restriction frequently produces long-lasting behavioural and physiological impairments in humans, the underlying neural mechanisms are unknown. Here we used a rat model of chronic sleep restriction to investigate the role of brain adenosine and noradrenaline systems, known to regulate sleep and wakefulness, respectively. The density of adenosine A1 and A2a receptors and β-adrenergic receptors before, during and following 5 days of sleep restriction was assessed with autoradiography. Rats (n = 48) were sleep-deprived for 18 h day(-1) for 5 consecutive days (SR1-SR5), followed by 3 unrestricted recovery sleep days (R1-R3). Brains were collected at the beginning of the light period, which was immediately after the end of sleep deprivation on sleep restriction days. Chronic sleep restriction increased adenosine A1 receptor density significantly in nine of the 13 brain areas analysed with elevations also observed on R3 (+18 to +32%). In contrast, chronic sleep restriction reduced adenosine A2a receptor density significantly in one of the three brain areas analysed (olfactory tubercle which declined 26-31% from SR1 to R1). A decrease in β-adrenergic receptors density was seen in substantia innominata and ventral pallidum which remained reduced on R3, but no changes were found in the anterior cingulate cortex. These data suggest that chronic sleep restriction can induce long-term changes in the brain adenosine and noradrenaline receptors, which may underlie the long-lasting neurocognitive impairments observed in chronic sleep restriction.
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Affiliation(s)
- Youngsoo Kim
- Department of Psychiatry, VA Boston Healthcare System, Research Service and Harvard Medical School, Brockton, MA, USA
| | - David Elmenhorst
- Department of Psychiatry, VA Boston Healthcare System, Research Service and Harvard Medical School, Brockton, MA, USA
- Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Angela Weisshaupt
- Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Franziska Wedekind
- Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Tina Kroll
- Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Robert W McCarley
- Department of Psychiatry, VA Boston Healthcare System, Research Service and Harvard Medical School, Brockton, MA, USA
| | - Robert E Strecker
- Department of Psychiatry, VA Boston Healthcare System, Research Service and Harvard Medical School, Brockton, MA, USA
| | - Andreas Bauer
- Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
- Neurological Department, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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26
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Burke TM, Scheer FAJL, Ronda JM, Czeisler CA, Wright KP. Sleep inertia, sleep homeostatic and circadian influences on higher-order cognitive functions. J Sleep Res 2015; 24:364-371. [PMID: 25773686 PMCID: PMC5124508 DOI: 10.1111/jsr.12291] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 02/01/2015] [Indexed: 11/28/2022]
Abstract
Sleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-day-long study that included two 14-day-long 28-h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2-4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep.
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Affiliation(s)
- Tina M. Burke
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, USA
| | - Frank A. J. L. Scheer
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Joseph M. Ronda
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Charles A. Czeisler
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Kenneth P. Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, USA
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital and Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
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27
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Gander PH. Evolving Regulatory Approaches for Managing Fatigue Risk in Transport Operations. ACTA ACUST UNITED AC 2015. [DOI: 10.1177/1557234x15576510] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fatigue is a physiological state of reduced performance capability resulting from sleep loss or extended wakefulness, circadian phase, or workload (mental and/or physical activity) that can impair a transport worker’s alertness and ability to work safely. Fatigue is affected by all waking activities, not only those that are work related. Consequently, fatigue management must be a shared responsibility of regulators, employers, and employees. Prescriptive hours-of-service limits, the traditional regulatory approach for managing fatigue, are increasingly being challenged with regard to their effectiveness in delivering safety and their cost to industry. Fatigue risk management systems (FRMSs) are a new regulatory approach that combines advances in the understanding of worker fatigue and accident causation with advances in safety management. FRMSs are data driven, are based on combined scientific and operational expertise, and include processes for monitoring their safety performance and for continuous improvement. Prescriptive hours-of-work limits are familiar and are arguably adequate in circumstances where fatigue-related safety risk is low. On the other hand, economic pressures are expected to continue to push transport companies to maximize use of vehicles/locomotives/vessels/aircraft with minimum safe manning levels. These pressures will drive the need for more tailored and flexible approaches to fatigue management, such as FRMSs.
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28
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Goel N, Basner M, Dinges DF. Phenotyping of Neurobehavioral Vulnerability to Circadian Phase During Sleep Loss. Methods Enzymol 2015; 552:285-308. [DOI: 10.1016/bs.mie.2014.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Affiliation(s)
- Masaya Takahashi
- National Institute of Occupational Safety and Health; Kawasaki Japan
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30
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Hughes ATL, Piggins HD. Disruption of daily rhythms in gene expression: the importance of being synchronised. Bioessays 2014; 36:644-8. [PMID: 24832865 PMCID: PMC4314670 DOI: 10.1002/bies.201400043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extending a normal 24 hours day by four hours is unexpectedly highly disruptive to daily rhythms in gene expression in the blood. Using a paradigm in which human subjects were exposed to a 28 hours day, Archer and colleagues show how this sleep-altering forced desynchrony protocol caused complex disruption to daily rhythms in distinct groups of genes. Such perturbations in the temporal organisation of the blood transcriptome arise quickly, and point to the fragile nature of coordinated genomic activity. Chronic disruption of the daily and circadian rhythms in sleep compromise health and well-being and this study reveals potential new molecular targets to combat the disruptive effects of shift work and jetlag.
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Affiliation(s)
- Alun T L Hughes
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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31
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Abstract
There is increasing awareness of the role of sleep disturbance as an important factor in health and disease. Although sub-clinical sleep disturbances (insufficient sleep duration or inadequate sleep quality) may be difficult to assess with conceptual and/or methodological clarity, this review attempts to summarize and synthesize these findings. First, the concept of sleep disturbance in a public health context is introduced, to provide context and rationale. Second, operational definitions of 'cardiometabolic disease' and 'sleep disturbance' are offered, to address many unclear operationalizations. Third, the extant literature is summarized regarding short or long sleep duration and/or insufficient sleep, insomnia and insomnia symptoms, general (non-specific sleep disturbances), circadian rhythm abnormalities that result in sleep disturbances, and, briefly, sleep-disordered breathing. Fourth, the review highlights the social/behavioural context of sleep, including discussions of sleep and race/ethnicity, socio-economic position, and other social/environmental factors, in order to place these findings in a social-environmental context relevant to public health. Fifth, the review highlights the issue of sleep as a domain of health behaviour and addresses issues regarding development of healthy sleep interventions. Finally, a research agenda of future directions is proposed.
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Affiliation(s)
- Michael A Grandner
- Behavioral Sleep Medicine Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania , USA
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32
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McCauley P, Kalachev LV, Mollicone DJ, Banks S, Dinges DF, Van Dongen HPA. Dynamic circadian modulation in a biomathematical model for the effects of sleep and sleep loss on waking neurobehavioral performance. Sleep 2013; 36:1987-97. [PMID: 24293775 DOI: 10.5665/sleep.3246] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Recent experimental observations and theoretical advances have indicated that the homeostatic equilibrium for sleep/wake regulation--and thereby sensitivity to neurobehavioral impairment from sleep loss--is modulated by prior sleep/wake history. This phenomenon was predicted by a biomathematical model developed to explain changes in neurobehavioral performance across days in laboratory studies of total sleep deprivation and sustained sleep restriction. The present paper focuses on the dynamics of neurobehavioral performance within days in this biomathematical model of fatigue. Without increasing the number of model parameters, the model was updated by incorporating time-dependence in the amplitude of the circadian modulation of performance. The updated model was calibrated using a large dataset from three laboratory experiments on psychomotor vigilance test (PVT) performance, under conditions of sleep loss and circadian misalignment; and validated using another large dataset from three different laboratory experiments. The time-dependence of circadian amplitude resulted in improved goodness-of-fit in night shift schedules, nap sleep scenarios, and recovery from prior sleep loss. The updated model predicts that the homeostatic equilibrium for sleep/wake regulation--and thus sensitivity to sleep loss--depends not only on the duration but also on the circadian timing of prior sleep. This novel theoretical insight has important implications for predicting operator alertness during work schedules involving circadian misalignment such as night shift work.
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Affiliation(s)
- Peter McCauley
- Sleep and Performance Research Center, Washington State University, Spokane, WA ; Department of Mathematical Sciences, University of Montana, Missoula, MT
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33
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Basner M, Rao H, Goel N, Dinges DF. Sleep deprivation and neurobehavioral dynamics. Curr Opin Neurobiol 2013; 23:854-63. [PMID: 23523374 PMCID: PMC3700596 DOI: 10.1016/j.conb.2013.02.008] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 11/18/2022]
Abstract
Lifestyles involving sleep deprivation are common, despite mounting evidence that both acute total sleep deprivation and chronically restricted sleep degrade neurobehavioral functions associated with arousal, attention, memory and state stability. Current research suggests dynamic differences in the way the central nervous system responds to acute versus chronic sleep restriction, which is reflected in new models of sleep-wake regulation. Chronic sleep restriction likely induces long-term neuromodulatory changes in brain physiology that could explain why recovery from it may require more time than from acute sleep loss. High intraclass correlations in neurobehavioral responses to sleep loss suggest that these trait-like differences are phenotypic and may include genetic components. Sleep deprivation induces changes in brain metabolism and neural activation that involve distributed networks and connectivity.
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Affiliation(s)
- Mathias Basner
- Unit of Experimental Psychiatry, Division of Sleep and Chronobiology, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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34
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Goel N, Basner M, Rao H, Dinges DF. Circadian rhythms, sleep deprivation, and human performance. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 119:155-90. [PMID: 23899598 DOI: 10.1016/b978-0-12-396971-2.00007-5] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Much of the current science on, and mathematical modeling of, dynamic changes in human performance within and between days is dominated by the two-process model of sleep-wake regulation, which posits a neurobiological drive for sleep that varies homeostatically (increasing as a saturating exponential during wakefulness and decreasing in a like manner during sleep), and a circadian process that neurobiologically modulates both the homeostatic drive for sleep and waking alertness and performance. Endogenous circadian rhythms in neurobehavioral functions, including physiological alertness and cognitive performance, have been demonstrated using special laboratory protocols that reveal the interaction of the biological clock with the sleep homeostatic drive. Individual differences in circadian rhythms and genetic and other components underlying such differences also influence waking neurobehavioral functions. Both acute total sleep deprivation and chronic sleep restriction increase homeostatic sleep drive and degrade waking neurobehavioral functions as reflected in sleepiness, attention, cognitive speed, and memory. Recent evidence indicating a high degree of stability in neurobehavioral responses to sleep loss suggests that these trait-like individual differences are phenotypic and likely involve genetic components, including circadian genes. Recent experiments have revealed both sleep homeostatic and circadian effects on brain metabolism and neural activation. Investigation of the neural and genetic mechanisms underlying the dynamically complex interaction between sleep homeostasis and circadian systems is beginning. A key goal of this work is to identify biomarkers that accurately predict human performance in situations in which the circadian and sleep homeostatic systems are perturbed.
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Affiliation(s)
- Namni Goel
- Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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35
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Matthews RW, Ferguson SA, Zhou X, Sargent C, Darwent D, Kennaway DJ, Roach GD. Time-of-day mediates the influences of extended wake and sleep restriction on simulated driving. Chronobiol Int 2012; 29:572-9. [PMID: 22621353 DOI: 10.3109/07420528.2012.675845] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Although a nonlinear time-of-day and prior wake interaction on performance has been well documented, two recent studies have aimed to incorporate the influences of sleep restriction into this paradigm. Through the use of sleep-restricted forced desynchrony protocols, both studies reported a time-of-day × sleep restriction interaction, as well as a time-of-day × prior wake × sleep dose three-way interaction. The current study aimed to investigate these interactions on simulated driving performance, a more complex task with ecological validity for the problem of fatigued driving. The driving performance of 41 male participants (mean ± SD: 22.8 ±2.2 yrs) was assessed on a 10-min simulated driving task with the standard deviation of lateral position (SDLAT) measured. Using a between-group design, participants were subjected to either a control condition of 9.33 h of sleep/18.66 h of wake, a moderate sleep-restriction (SR) condition of 7 h of sleep/21 h of wake, or a severe SR condition of 4.66 h of sleep/23.33 h of wake. In each condition, participants were tested at 2.5-h intervals after waking across 7 × 28-h d of forced desynchrony. Driving sessions occurred at nine doses of prior wake, within six divisions of the circadian cycle based on core body temperature (CBT). Mixed-models analyses of variance (ANOVAs) revealed significant main effects of time-of-day, prior wake, sleep debt, and sleep dose on SDLAT. Additionally, significant two-way interactions of time-of-day × prior wake and time-of-day × sleep debt, as well as significant three-way interactions of time-of-day × prior wake × sleep debt and time-of-day × sleep debt × sleep dose were observed. Although limitations such as the presence of practice effects and large standard errors are noted, the study concludes with three findings. The main effects demonstrate that extending wake, reducing sleep, and driving at poor times of day all significantly impair driving performance at an individual level. In addition to this, combining either extended wake or a sleep debt with the early morning hours greatly decreases driving performance. Finally, operating under the influence of a reduced sleep dose can greatly decrease performance at all times of the day.
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Affiliation(s)
- Raymond W Matthews
- Centre for Sleep Research, University of South Australia, Adelaide, Australia.
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36
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Lo JC, Groeger JA, Santhi N, Arbon EL, Lazar AS, Hasan S, von Schantz M, Archer SN, Dijk DJ. Effects of partial and acute total sleep deprivation on performance across cognitive domains, individuals and circadian phase. PLoS One 2012; 7:e45987. [PMID: 23029352 PMCID: PMC3454374 DOI: 10.1371/journal.pone.0045987] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 08/23/2012] [Indexed: 01/21/2023] Open
Abstract
Background Cognitive performance deteriorates during extended wakefulness and circadian phase misalignment, and some individuals are more affected than others. Whether performance is affected similarly across cognitive domains, or whether cognitive processes involving Executive Functions are more sensitive to sleep and circadian misalignment than Alertness and Sustained Attention, is a matter of debate. Methodology/Principal Findings We conducted a 2 × 12-day laboratory protocol to characterize the interaction of repeated partial and acute total sleep deprivation and circadian phase on performance across seven cognitive domains in 36 individuals (18 males; mean ± SD of age = 27.6±4.0 years). The sample was stratified for the rs57875989 polymorphism in PER3, which confers cognitive susceptibility to total sleep deprivation. We observed a deterioration of performance during both repeated partial and acute total sleep deprivation. Furthermore, prior partial sleep deprivation led to poorer cognitive performance in a subsequent total sleep deprivation period, but its effect was modulated by circadian phase such that it was virtually absent in the evening wake maintenance zone, and most prominent during early morning hours. A significant effect of PER3 genotype was observed for Subjective Alertness during partial sleep deprivation and on n-back tasks with a high executive load when assessed in the morning hours during total sleep deprivation after partial sleep loss. Overall, however, Subjective Alertness and Sustained Attention were more affected by both partial and total sleep deprivation than other cognitive domains and tasks including n-back tasks of Working Memory, even when implemented with a high executive load. Conclusions/Significance Sleep loss has a primary effect on Sleepiness and Sustained Attention with much smaller effects on challenging Working Memory tasks. These findings have implications for understanding how sleep debt and circadian rhythmicity interact to determine waking performance across cognitive domains and individuals.
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Affiliation(s)
- June C. Lo
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - John A. Groeger
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Psychology, University of Hull, Hull, United Kingdom
| | - Nayantara Santhi
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Emma L. Arbon
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Alpar S. Lazar
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Sibah Hasan
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Malcolm von Schantz
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Simon N. Archer
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- * E-mail:
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37
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Paech GM, Ferguson SA, Sargent C, Kennaway DJ, Roach GD. The relative contributions of the homeostatic and circadian processes to sleep regulation under conditions of severe sleep restriction. Sleep 2012; 35:941-8. [PMID: 22754040 PMCID: PMC3369229 DOI: 10.5665/sleep.1956] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To investigate the relative contributions of the homeostatic and circadian processes on sleep regulation under conditions of severe sleep restriction. DESIGN The 13-day laboratory based study consisted of 3 × 24-h baseline days (8 h sleep opportunity, 16 h wake) followed by 7 × 28-h forced desynchrony days (4.7 h sleep opportunity, 23.3 h wake). SETTING The study was conducted in a time isolation unit at the Centre for Sleep Research, University of South Australia. PARTICIPANTS Fourteen healthy, nonsmoking males, aged 21.8 ± 3.8 (mean ± SD) years participated in the study. INTERVENTIONS N/A. MEASUREMENTS Sleep was measured using standard polysomnography. Core body temperature (CBT) was recorded continuously using a rectal thermistor. Each epoch of sleep was assigned a circadian phase based on the CBT data (6 × 60-degree bins) and an elapsed time into sleep episode (2 × 140-min intervals). RESULTS The percentage of SWS decreased with elapsed time into the sleep episode. However, no change in the percentage of REM sleep was observed with sleep progression. Whilst there was a circadian modulation of REM sleep, the amplitude of the circadian variation was smaller than expected. Sleep efficiency remained high throughout the sleep episode and across all circadian phases. CONCLUSIONS Previous forced desynchrony studies have demonstrated a strong circadian influence on sleep, in the absence of sleep restriction. The current study suggests that in the presence of high homeostatic pressure, the circadian modulation of sleep, in particular sleep efficiency and to a lesser extent, REM sleep, are reduced.
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Affiliation(s)
- Gemma M Paech
- Centre for Sleep Research, University of South Australia, Adelaide, South Australia, Australia.
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38
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Sargent C, Darwent D, Ferguson SA, Kennaway DJ, Roach GD. Sleep Restriction Masks the Influence of the Circadian Process on Sleep Propensity. Chronobiol Int 2012; 29:565-71. [DOI: 10.3109/07420528.2012.675256] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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39
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Wright KP, Lowry CA, LeBourgeois MK. Circadian and wakefulness-sleep modulation of cognition in humans. Front Mol Neurosci 2012; 5:50. [PMID: 22529774 PMCID: PMC3328852 DOI: 10.3389/fnmol.2012.00050] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 03/27/2012] [Indexed: 11/13/2022] Open
Abstract
Cognitive and affective processes vary over the course of the 24 h day. Time of day dependent changes in human cognition are modulated by an internal circadian timekeeping system with a near-24 h period. The human circadian timekeeping system interacts with sleep-wakefulness regulatory processes to modulate brain arousal, neurocognitive and affective function. Brain arousal is regulated by ascending brain stem, basal forebrain (BF) and hypothalamic arousal systems and inhibition or disruption of these systems reduces brain arousal, impairs cognition, and promotes sleep. The internal circadian timekeeping system modulates cognition and affective function by projections from the master circadian clock, located in the hypothalamic suprachiasmatic nuclei (SCN), to arousal and sleep systems and via clock gene oscillations in brain tissues. Understanding the basic principles of circadian and wakefulness-sleep physiology can help to recognize how the circadian system modulates human cognition and influences learning, memory and emotion. Developmental changes in sleep and circadian processes and circadian misalignment in circadian rhythm sleep disorders have important implications for learning, memory and emotion. Overall, when wakefulness occurs at appropriate internal biological times, circadian clockwork benefits human cognitive and emotion function throughout the lifespan. Yet, when wakefulness occurs at inappropriate biological times because of environmental pressures (e.g., early school start times, long work hours that include work at night, shift work, jet lag) or because of circadian rhythm sleep disorders, the resulting misalignment between circadian and wakefulness-sleep physiology leads to impaired cognitive performance, learning, emotion, and safety.
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Affiliation(s)
- Kenneth P. Wright
- Department of Integrative Physiology, Sleep and Chronobiology Laboratory, University of Colorado, BoulderCO, USA
| | - Christopher A. Lowry
- Department of Integrative Physiology, Behavioral Neuroendocrinology Laboratory, University of Colorado, BoulderCO, USA
| | - Monique K. LeBourgeois
- Department of Integrative Physiology, Sleep and Development Laboratory, University of Colorado, BoulderCO, USA
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40
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Sargent C, Darwent D, Ferguson SA, Roach GD. Can a simple balance task be used to assess fitness for duty? ACCIDENT; ANALYSIS AND PREVENTION 2012; 45 Suppl:74-79. [PMID: 22239936 DOI: 10.1016/j.aap.2011.09.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/05/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
Abstract
Human fatigue, caused by sleep loss, extended wakefulness, and/or circadian misalignment, is a major cause of workplace errors, incidents and accidents. In some industries, employees are required to undertake fitness for duty testing at the start of a shift to identify instances where their fatigue risk is elevated, so that minimisation and/or mitigation strategies can be implemented. Postural balance has been proposed as a fitness for duty test for fatigue, but it is largely untested. Therefore, the purpose of this study was to examine the impact of sleep loss, extended wakefulness and circadian phase on postural balance. Fourteen male participants spent 10 consecutive days in a sleep laboratory, including three adaptation days and eight simulated shiftwork days. To simulate a quickly rotating roster, shiftwork days were scheduled to begin 4h later each day, and consisted of a 23.3-h wake episode and a 4.7-h sleep opportunity. Every 2.5h during wake, balance was measured while standing as still as possible on a force platform with eyes open for one minute, and eyes closed for one minute. Subjective sleepiness was assessed using the Karolinska Sleepiness Scale. Core body temperature, continuously recorded with rectal thermistors, was used to determine circadian phase. For measures of postural balance and subjective sleepiness, data were analysed using three separate repeated measures ANOVA with two within-subjects factors: circadian phase (six phases) and prior wake (nine levels). For subjective sleepiness, there was a significant effect of prior wake and circadian phase. In particular, sleepiness increased as prior wake increased, and was higher during biological night-time than biological daytime. For the eyes open balance task, there was no effect of prior wake or circadian phase. For the eyes closed balance task, there was a significant effect of circadian phase such that balance was poorer during the biological night-time than biological daytime, but there was no effect of prior wake. These results indicate that postural balance may be a viable tool for assessing fatigue associated with time of day, but may not be useful for assessing fatigue associated with extended hours of wake.
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Affiliation(s)
- Charli Sargent
- Centre for Sleep Research, University of South Australia, GPO Box 2471, Adelaide, South Australia 5001, Australia.
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41
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Ferguson SA, Paech GM, Sargent C, Darwent D, Kennaway DJ, Roach GD. The influence of circadian time and sleep dose on subjective fatigue ratings. ACCIDENT; ANALYSIS AND PREVENTION 2012; 45 Suppl:50-54. [PMID: 22239932 DOI: 10.1016/j.aap.2011.09.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 07/28/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
Abstract
Subjective ratings of fatigue are increasingly being used as part of a suite of tools to assess fatigue-related risk on the road and in the workplace. There is some debate however, as to whether individuals can accurately gauge their own fatigue states, particularly under conditions of sleep restriction. It is also unclear which references are used by individuals to assess fatigue - for example prior sleep, time of day, workload, or previous ratings. The current study used a sophisticated laboratory protocol to examine the independent contributions of sleep, circadian phase and sleep debt to fatigue ratings. Importantly, participants had no knowledge of time of day, how much sleep they were getting, or how long they were awake. Twenty-eight healthy, young males participated in one of two conditions of a 28 h forced desynchrony protocol - severe sleep restriction (4.7h sleep and 23.3h wake) or moderate sleep restriction (7h sleep and 21 h wake). Fatigue ratings were provided prior to and following each sleep period using the Samn-Perelli fatigue scale. Repeated measures ANOVAs were used to analyse the effects of circadian phase, sleep dose and study day. Results demonstrated an effect of circadian phase on both pre-sleep and post-sleep fatigue ratings. The significant effect of study day is interpreted as an effect of circadian time, as opposed to accumulating sleep debt. An effect of sleep dose was only seen in post-sleep fatigue ratings. The findings suggest that post-sleep fatigue ratings may be sensitive to prior sleep and may be useful as an indicator of fatigue-related risk, particularly when triangulated with information about recent total sleep time.
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Affiliation(s)
- Sally A Ferguson
- Centre for Sleep Research, University of South Australia, GPO Box 2471, Adelaide, South Australia 5001, Australia.
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42
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Heath G, Roach GD, Dorrian J, Ferguson SA, Darwent D, Sargent C. The effect of sleep restriction on snacking behaviour during a week of simulated shiftwork. ACCIDENT; ANALYSIS AND PREVENTION 2012; 45 Suppl:62-67. [PMID: 22239934 DOI: 10.1016/j.aap.2011.09.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 08/04/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
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.
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Affiliation(s)
- Georgina Heath
- Centre for Sleep Research, University of South Australia GPO Box 2471 Adelaide, South Australia 5001, Australia.
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Spaeth AM, Goel N, Dinges DF. Managing neurobehavioral capability when social expediency trumps biological imperatives. PROGRESS IN BRAIN RESEARCH 2012; 199:377-398. [PMID: 22877676 PMCID: PMC3600847 DOI: 10.1016/b978-0-444-59427-3.00021-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sleep, which is evolutionarily conserved across species, is a biological imperative that cannot be ignored or replaced. However, the percentage of habitually sleep-restricted adults has increased in recent decades. Extended work hours and commutes, shift work schedules, and television viewing are particularly potent social factors that influence sleep duration. Chronic partial sleep restriction, a product of these social expediencies, leads to the accumulation of sleep debt over time and consequently increases sleep propensity, decreases alertness, and impairs critical aspects of cognitive functioning. Significant interindividual variability in the neurobehavioral responses to sleep restriction exists-this variability is stable and phenotypic-suggesting a genetic basis. Identifying vulnerability to sleep loss is essential as many adults cannot accurately judge their level of impairment in response to sleep restriction. Indeed, the consequences of impaired performance and the lack of insight due to sleep loss can be catastrophic. In order to cope with the effects of social expediencies on biological imperatives, identification of biological (including genetic) and behavioral markers of sleep loss vulnerability as well as development of technological approaches for fatigue management are critical.
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Affiliation(s)
- Andrea M Spaeth
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Namni Goel
- Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David F Dinges
- Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Zhou X, Ferguson SA, Matthews RW, Sargent C, Darwent D, Kennaway DJ, Roach GD. Mismatch between subjective alertness and objective performance under sleep restriction is greatest during the biological night. J Sleep Res 2011; 21:40-9. [PMID: 21564364 DOI: 10.1111/j.1365-2869.2011.00924.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Subjective alertness may provide some insight into reduced performance capacity under conditions suboptimal to neurobehavioural functioning, yet the accuracy of this insight remains unclear. We therefore investigated whether subjective alertness reflects the full extent of neurobehavioural impairment during the biological night when sleep is restricted. Twenty-seven young healthy males were assigned to a standard forced desynchrony (FD) protocol (n = 13; 9.33 h in bed/28 h day) or a sleep-restricted FD protocol (n = 14; 4.67 h in bed/28 h day). For both protocols, subjective alertness and neurobehavioural performance were measured using a visual analogue scale (VAS) and the psychomotor vigilance task (PVT), respectively; both measures were given at various combinations of prior wake and circadian phase (biological night versus biological day). Scores on both measures were standardized within individuals against their respective baseline average and standard deviation. We found that PVT performance and VAS rating deviated from their respective baseline to a similar extent during the standard protocol, yet a greater deviation was observed for PVT performance than VAS rating during the sleep-restricted protocol. The discrepancy between the two measures during the sleep-restricted protocol was particularly prominent during the biological night compared with the biological day. Thus, subjective alertness did not reflect the full extent of performance impairment when sleep was restricted, particularly during the biological night. Given that subjective alertness is often the only available information upon which performance capacity is assessed, our results suggest that sleep-restricted individuals are likely to under-estimate neurobehavioural impairment, particularly during the biological night.
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Affiliation(s)
- Xuan Zhou
- Centre for Sleep Research, University of South Australia, Frome Road, Adelaide, SA, Australia.
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