Fatigue in ferry crews: a pilot study

Since the 1950s, the shipping industry has undergone profound changes, comparable in scale to those resulting from the advent of steam in the last century. This transformation has been shaped by many historical events and facilitated by the introduction of new technology and new commercial, operational and managerial practices, and it has clear implications for current research into the causality of marine accidents; technological developments, for example, have led to the so-called ‘radar-assisted collisions’. It is often said in the industry that 70-80% of maritime accidents are attributable to human error. What is less well known, however, is that in the majority of these cases, the factor which has consistently been identified as a major contributory link in the chain of events leading to an accident, is fatigue. Because of this, it is important to continue research into the causes and incidence of fatigue in seafarers. The objectives of this pilot study were: to investigate the quality and quantity of sleep among crew employed on the short-sea ferry sector; to evaluate the extent to which poor quality sleep occurs; and to identify the factors contributing to poor sleep quality. The subjects of the study were 12 crew members of different rank and with different work patterns from two UK-flagged short-sea pax/ro ferries. Background information on the participants was collected via questionnaires. Data on the duration and quality of sleep were collected by the use of wrist-worn actimeters and by self-report sleep logs, while self reports of alertness were collected at two-hourly intervals during each wakeful period. All the above data were collected during a complete tour of duty comprising one week at sea followed by one week of leave. The week-on / week-off work schedule allowed comparisons to be made between the sleep patterns of a working week at sea and those of a rest week at home. The findings indicate that differences in both sleep quality and duration of sleep between the work and non-work weeks were greater for those crew members required to work split shifts. Furthermore, they experienced greater sleep disturbance and generally shorter sleep periods than crew members who worked a single shift every 24 hours. The statistical analyses presented in the current study show a significant difference in the total number of hours sleep between the home and work schedules, and reveal a similar difference in the incidence of sleep disturbance. While further and more substantial examination into different shift patterns is required, there are already clear indications of a need to reappraise traditional watch regimes on board. This pilot study is the first phase of an extensive investigation into sleep and fatigue in seafarers’ work patterns, which is being carried out under the name of SEAFATIGUE. It is to include personal and environmental factors and is to be conducted within different shipping sectors of deep-sea and coastal trade. The final objective of the SEAFATIGUE project is to provide the maritime industry with a resource of detailed technical data on fatigue among seafarers, in order to facilitate the formulation and implementation of sound, proactive policies in areas of employment practices, manning levels, shipboard ergonomics, shiftwork patterns and the training of seafarers in fatigue management. This pilot study is the result of a joint collaborative project between the Sleep Research Laboratory at Loughborough University and the Seafarers International Research Centre at the University of Wales, Cardiff

Experimental studies of driver sleepiness in young adults

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At home and away measuring the sleep of Australian truck drivers /

The causes of fatigue in truck drivers related to work hours have been studied extensively and are reasonably well understood. However, much less is known about how rest opportunities can be structured to optimise recovery from fatigue. The nature of the road transport industry often requires that rest be taken in various locations. New investigation in this area, focusing on sleep obtained in truck cabs and other non-home environments is critically important to complement existing understanding. This study examined sleep at home and in truck cabs, in truck drivers who were actively working during the time of the study. Thirty-seven male drivers aged between 24 and 63 years (age: 48.7 ± 9.0 years; mean ± SD) wore activity monitors (also known as ‘sleep watches’) and completed work and sleep diaries for a period of 21 days, recording their subjective fatigue levels before, during and after work shifts, and before and after sleep periods. They also self-rated their sleep quality and noted the number of times they woke during sleep periods. Analyses focused on home versus in-truck sleep periods. The subjective data suggested that a greater quantity (P < .001) and quality (P < .05) of sleep was obtained at home than in the truck, and that sleeping at home more effectively reduced fatigue levels (P < .001). The objective data showed trends towards longer sleep length at home, but other variables, including total sleep per 24 h and sleep quality, showed no significant differences. This study demonstrates that measuring sleep quantity and quality in operational road transport environments is feasible. The findings caution against over-reliance on laboratory and simulator studies since there are critical aspects of the operating environment that cannot be validly studied in artificially controlled settings. This study is unique in its direct examination of sleep quantity and quality in truck drivers sleeping at home and away from home

At home and away : measuring the sleep of Australian truck drivers

The causes of fatigue in truck drivers related to work hours have been studied extensively and are reasonably well understood. However, much less is known about how rest opportunities can be structured to optimise recovery from fatigue. The nature of the road transport industry often requires that rest be taken in various locations. New investigation in this area, focusing on sleep obtained in truck cabs and other non-home environments is critically important to complement existing understanding. This study examined sleep at home and in truck cabs, in truck drivers who were actively working during the time of the study. Thirty-seven male drivers aged between 24 and 63 years (age: 48.7 ± 9.0 years; mean ± SD) wore activity monitors (also known as ‘sleep watches’) and completed work and sleep diaries for a period of 21 days, recording their subjective fatigue levels before, during and after work shifts, and before and after sleep periods. They also self-rated their sleep quality and noted the number of times they woke during sleep periods. Analyses focused on home versus in-truck sleep periods. The subjective data suggested that a greater quantity (P < .001) and quality (P < .05) of sleep was obtained at home than in the truck, and that sleeping at home more effectively reduced fatigue levels (P < .001). The objective data showed trends towards longer sleep length at home, but other variables, including total sleep per 24 h and sleep quality, showed no significant differences. This study demonstrates that measuring sleep quantity and quality in operational road transport environments is feasible. The findings caution against over-reliance on laboratory and simulator studies since there are critical aspects of the operating environment that cannot be validly studied in artificially controlled settings. This study is unique in its direct examination of sleep quantity and quality in truck drivers sleeping at home and away from home

Work hours, workload, sleep and fatigue in Australian Rail Industry employees

Dawson, D ORCiD: 0000-0001-7385-5630Research suggests that less than 5 h sleep in the 24 h prior to work and/or more than 16 h of wakefulness can significantly increase the likelihood of fatigue-related impairment and error at work. Studies have also shown exponential safety declines with time on shift, with roughly double the likelihood of accident or injury after 10 h relative to the first 8 h. While it is acknowledged that reduced sleep, increased wakefulness and longer work hours produce work-related fatigue, few studies have examined the impact of workload on this relationship. Studies in the rail industry have focused on drivers. This study investigated fatigue in a large sample of Australian Rail Industry Employees. Participants were from four companies (n ¼ 90: 85m, 5f; mean age 40.2 8.6 y). Data was analysed for a total of 713 shifts. Subjects wore wrist actigraphs and completed sleep and work diaries for 14-days. They also completed the SamnePerelli Fatigue Scale at the beginning and end of shifts, and the NASA-TLX workload scale at least twice during each shift. Average ( SD) sleep length (7.2 2.6 h), prior wake at shift end (12.0 4.7 h), shift duration (8.0 1.3) and fatigue (4.1 1.3, “a little tired, less than fresh”) were within limits generally considered acceptable from a fatigue perspective. However, participants received 5 h or less sleep in the prior 24 h on 13%, were awake for at least 16 h at the end of 16% and worked at least 10 h on 7% of shifts. Subjects reported that they felt “extremely tired, very difficult to concentrate,” or “completely exhausted, unable to function effectively” on 13% of shifts. Sleep length (OR ¼ 0.88, p < 0.01), shift duration (OR ¼ 1.18, p < 0.05), night shift (REF¼ morning shift, OR ¼ 2.12, p < 0.05) and workload ratings (OR ¼ 1.2, p < 0.05) were significant predictors of ratings of extreme tiredness/ exhaustion (yes/no). While on average, sleep loss, extended wakefulness, longer work hours and workrelated fatigue do not appear problematic in this sample, there is still a notable percentage of shifts that are likely to be associated with high levels of work-related fatigue. Given the size of the Australian Rail Industry, with thousands of shifts occurring each day, this is potentially of operational concern. Further, results indicate that, in addition to sleep length, wakefulness and work hours, workload significantly influences fatigue. This has possible implications for bio-mathematical predictions of fatigue and for fatigue management more generally

Work hours, workload, sleep and fatigue in Australian Rail Industry employees

Research suggests that less than 5 h sleep in the 24 h prior to work and/or more than 16 h of wakefulness can significantly increase the likelihood of fatigue-related impairment and error at work. Studies have also shown exponential safety declines with time on shift, with roughly double the likelihood of accident or injury after 10 h relative to the first 8 h. While it is acknowledged that reduced sleep, increased wakefulness and longer work hours produce work-related fatigue, few studies have examined the impact of workload on this relationship. Studies in the rail industry have focused on drivers. This study investigated fatigue in a large sample of Australian Rail Industry Employees. Participants were from four companies (n ¼ 90: 85m, 5f; mean age 40.2 8.6 y). Data was analysed for a total of 713 shifts. Subjects wore wrist actigraphs and completed sleep and work diaries for 14-days. They also completed the SamnePerelli Fatigue Scale at the beginning and end of shifts, and the NASA-TLX workload scale at least twice during each shift. Average ( SD) sleep length (7.2 2.6 h), prior wake at shift end (12.0 4.7 h), shift duration (8.0 1.3) and fatigue (4.1 1.3, “a little tired, less than fresh”) were within limits generally considered acceptable from a fatigue perspective. However, participants received 5 h or less sleep in the prior 24 h on 13%, were awake for at least 16 h at the end of 16% and worked at least 10 h on 7% of shifts. Subjects reported that they felt “extremely tired, very difficult to concentrate,” or “completely exhausted, unable to function effectively” on 13% of shifts. Sleep length (OR ¼ 0.88, p < 0.01), shift duration (OR ¼ 1.18, p < 0.05), night shift (REF¼ morning shift, OR ¼ 2.12, p < 0.05) and workload ratings (OR ¼ 1.2, p < 0.05) were significant predictors of ratings of extreme tiredness/ exhaustion (yes/no). While on average, sleep loss, extended wakefulness, longer work hours and workrelated fatigue do not appear problematic in this sample, there is still a notable percentage of shifts that are likely to be associated with high levels of work-related fatigue. Given the size of the Australian Rail Industry, with thousands of shifts occurring each day, this is potentially of operational concern. Further, results indicate that, in addition to sleep length, wakefulness and work hours, workload significantly influences fatigue. This has possible implications for bio-mathematical predictions of fatigue and for fatigue management more generally

Strategies for developing sleep research

The Australasian Sleep Association (ASA) is seeking to develop a strategic research plan to improve the sleep health of Australians and New Zealanders, and to contribute to scientific understanding and clinical practice worldwide. To develop the plan, the ASA Research Committee undertook two projects: (i) a membership survey to establish the research activities, interests, and priorities of members; and (ii) compilation of an electronic library of citations of sleep-related research that involved one or more Australia-based or New Zealand-based researchers. Although the intent had been to develop an investigator-initiated research agenda for the ASA, these two projects revealed that such an approach would not provide a comprehensive and systematic research base to improve sleep health in Australasia. In particular, membership research interests were considered insufficient to adequately address public health issues relevant to the populations of Australia and New Zealand, clinical research for non-respiratory sleep disorders, and pediatric sleep research. The identification of these gaps raises a tension. If the ASA is to endorse additional research priority areas that are not major interests among its members, then additional research funding needs to be found, to avoid competing with the interests of members for limited existing research funding. To address this problem, a series of recommendations are offered to improve the proportion of existing health research funding that is directed towards sleep research, and to develop sources of new funding for sleep research

Spychomotor Vigilance and Driving Simulator Performance in shift workers and patients with obstructive sleep apnoea

Obstructive sleep apnoea syndrome (OSAS) is associated with increased risk of motor vehicle accidents (MVAs), excessive sleepiness and chronic affective and cognitive impairment. The long-term effect of chronic shift-work on these domains remains undetermined

A field study of sleep and fatigue in a regular rotating 12-h shift system

The aim of this study was to examine a regular rotating 12-h shift system (2D2N4Off) at an Australian Smelter. Sleep behavior, subjective fatigue and neurobehavioral performance were investigated over a 14-day period for 20 employees. Activity monitors, sleep/wake diaries, and 5-min psychomotor vigilance tasks were used. Sleep data showed differences between day and night shifts. While sleep prior to night1 was increased relative to day shifts, a reduced sleep length carried into the period leading to night2. Total wakefulness at the end of shift, and subjective fatigue were increased for night shifts, particularly night1. Decrements in performance data supported these findings. Both prior wakefulness and prior sleep are important in a 12-h shift system. Employees may “sleep in” after day shifts, rather than taking extra sleep prior to night work. Thus, sleep between day and night shifts is based on recovery rather than preparation.

Managing driver fatigue: Quantifying real world performance impairment

ATSB Research And Analysis Report. Road Safety Research Grant – 2006/01Driver fatigue remains a major cause of road accidents worldwide. Research has demonstrated that fatigue is comparable to alcohol in terms of performance impairment and risks to road safety. It has been well established that increased wakefulness causes driving impairment, both in simulated and on-road driving. Fatigue management systems have used simple performance tests (such as visual reaction time), in an attempt to quantify the risk of impairment to performance in the real world. Little is known however, about the relationship between such measures. The primary objectives of this study were: (1) To measure the decrements in performance caused by increasing levels of fatigue using a simple test of visual reaction time (PVT) and an interactive driving simulation task; and (2) To provide a link between simple and complex measures of performance. Secondary aims were: (a) examine the effects of fatigue on perception of performance; and (b) examine the effects of gender on fatigue, driving performance and perception thereof. Fifteen subjects (7 male, 8 female) aged 22-56 years (mean 33.6y), underwent 26 hours of supervised wakefulness (i.e. one night without sleep) before an 8 hour recovery sleep opportunity. During this time, subjects were present in the laboratory, and tested using (a) a 30-minute interactive driving simulation test, bracketed before and after by (b) a 10-minute standard PVT reaction time test. Testing periods were repeated throughout the protocol (at approx. 3, 8, 18 and 24 hours of wakefulness, and after the 8-hour recovery sleep). Extended wakefulness caused significant decrements in PVT and driving performance, as well as subjective sleepiness and perceptions of performance. While subjective measures normalised following recovery sleep, objective performance measures did not. Results suggest that although objective measures of both simple and complex performance are clearly linked, driving simulation cannot be replaced by a simple reaction time test. Gender differences were found in PVT performance and perceptions of driving ability, with females responding more slowly, and rating their driving as worse than males. Further research is needed to examine links between objective performance measures and to move closer to accurate assessments of fitness to drive. A cognitive-behavioural approach to driver fatigue countermeasures may be beneficial.Stuart D Baulk, Sarah Biggs, Cameron van den Heuvel, Kathryn Reid and Drew Dawso