Rescheduling a three shift system at a steel rolling mill: effects of a one hour delay of shift starting times on sleep and alertness in younger and older workers.

OBJECTIVE: To evaluate a new work schedule at a Finnish steel mill with special attention to effects on older workers. The schedule was designed to improve sleep before the morning shift, and alertness during the morning shift, by delaying shift start and end times. METHODS: Evaluation was by a shiftwork health and safety questionnaire, recordings of work-rest-sleep cycles with activity monitors worn on the wrist, daily diaries, and on site computerised testing of fatigue and alertness by the NIOSH fatigue test battery. RESULTS: The one hour delay in shift starting times improved sleep before the morning shift, and improved waking fatigue, sleepiness, and performance during the morning shift. Evening and night shift sleep and fatigue or sleepiness, however, were affected negatively by the new work schedule, but the results for those shifts were less consistent across the various measures. Despite the improvements, most workers were not satisfied with the new schedule because of social concerns. Few interactions of age with the new work schedule were found, suggesting that the effects of the work schedule were uniform across age groups. CONCLUSION: A change of as little as one hour in shift starting times can improve morning shift sleep and alertness, but there are trade offs from these improvements in terms of night shift effects and social considerations. It seems, then, that optimal shift start and end times for an entire organisation are difficult to institute on a wide scale. Tailoring shift schedules to subgroups within an organisation is suggested.     

The Influence of Break Timing on the Sleep Quantity and Quality of Fly-in, Fly-out Shiftworkers

Although shift and break timing is known to affect the sleep of shiftworkers, this has not been demonstrated in Fly-in, Fly-out (FIFO) settings which, compared to residential based settings, may be favourable for sleep. This study investigated the sleep quantity and quality of shiftworkers working a FIFO operation comprising of shifts, and therefore breaks, across the 24-h day. The sleep of 24 males (50.43 ± 8.57 yr) was measured using actigraphy and sleep diaries. Morning breaks were associated with less sleep (09:00–12:00 h; 4.4 ± 1.3 h) and a poorer sleep quality (06:00–09:00 h; 3.1 ± 1.0, “average”) compared to breaks beginning between 00:00 h and 03:00 h (6.8 ± 1.7 h; 2.2 ± 0.9, “good”). Sleep efficiency remained constant regardless of break timing (85.9 ± 5.0% to 89.9 ± 3.5%). Results indicate that even in operations such as FIFO where sleeping conditions are near-optimal and the break duration is held constant, the influence of the endogenous circadian pacemaker on sleep duration is evident.     

Cardiopulmonary exercise testing for personalized job reintegration after acute cardiovascular attacks: a pilot cross-sectional study

Background:Cardiovascular diseases (CVD), particularly the ischemic heart disease, are a growing public health issue. In addition, the return to work after an acute cardiovascular attack represents a complex challenge.Objectives:To evaluate utility and safety of cardiopulmonary exercise testing (CPET), particularly performed “on site”, to promote a return to work in line with the residual working capacity.Methods:Fifty-nine workers affected by a major cardiovascular event, aged 18-63 years, have been enrolled between 2015 and 2018. All the patients underwent a CPET in outpatient clinic. Eleven workers also underwent the “on site” CPET, recorded during their working activities.Results:Outpatient clinic CPET outcomes (i.e. normal, mild impairment or moderate/severe impairment of cardiopulmonary function) were associated with the subjective perception of workers’ health status after returning to work. The “on site” CPET was found to be safe and reliable to promote a personalized return to work of patients. In 7 out of 11 patients, the values of O₂ consumption (VO₂) during the working activity were higher than 40% of VO₂ max as obtained from laboratory CPET.Conclusions:This study provides evidence for safety and usefulness of “on site” CPET for a personalized statement of fitness for work. This may facilitate the job retention of patients characterized by a high risk of unnecessary job loss. The use of CPET represents a first step of energy expenditure evaluation associated with specific working tasks.Key words: Acute coronary syndrome, cardiopulmonary exercise testing, return to work     

Alertness management in 24/7 settings: lessons from aviation

Round-the-clock operational requirements pose physiological challenges for human operators. Fatigue due to sleep loss and circadian disruption can reduce safety, performance quality, and alertness. The authors describe the physiological factors underlying fatigue and provide examples from NASA research in aviation settings that demonstrate how fatigue affects real-world operations. A comprehensive alertness management approach to address fatigue effectively includes education, alertness strategies, scheduling, policy, and healthy sleep components. There is a need for cultural change that will encourage attitudes, behaviors, and practices that will reduce fatigue-related risks and improve safety, performance, and alertness in 24/7 operational settings.     

Effects of direction of rotation in continuous and discontinuous 8 hour shift systems

OBJECTIVES—Previous research has produced conflicting evidence on the relative merits of advancing and delaying shift systems. The current study assessed the effects of the direction of shift rotation within 8 hour systems, upon a range of measures including sleep, on shift alertness, physical health, and psychological wellbeing.
METHODS—An abridged version of the standard shiftwork index which included retrospective alertness ratings was completed by four groups of industrial shiftworkers on relatively rapidly rotating 8 hour systems (n=611). Two groups worked continuous systems that were either advancing or delaying; the other two groups worked discontinuous systems that were either advancing or delaying.
RESULTS—Few effects were found of direction of rotation on chronic measures of health and wellbeing, even when the systems incorporated "quick returns" (a break of only 8 hours when changing from one shift to another). This was despite the use of measures previously shown to be sensitive to the effects of a broad range of features of shift systems. However, advancing continuous systems seemed to be associated with marginally steeper declines in alertness across the shift (F (3,1080)=2.87, p<0.05). They were also associated with shorter sleeps between morning shifts (F (1,404)=4.01, p<0.05), but longer sleeps between afternoons (F (1,424)=4.16, p<0.05).
CONCLUSIONS—The absence of negative effects of advancing shifts upon the chronic outcome measures accorded with previous evidence that advancing shifts may not be as harmful as early research indicated. However, this interpretation is tempered by the possibility that difficult shift systems self select those workers most able to cope with their deleterious effects. The presence of quick returns in advancing continuous systems seemed to impact upon some of the acute measures such as duration of sleep, although the associated effects on alertness seemed to be marginal.


Keywords: shift rotation; health; alertness     

Effect of MSDs and scope of ergonomic interventions among rubber processing workers: a systematic review

Background:The rubber processing workers experience various types of musculoskeletal disorders (MSDs) due to awkward postures, repetitive movements, and manual loads etc. Research on MSDs and ergonomic interventions in this area is limited. Therefore, the present systematic review aims to (i) identify various operations done by rubber processing workers and their associated MSDs, (ii) explore the ergonomic intervention and post-intervention study and its impact among the workers, (iii) identify the research gaps in MSDs and ergonomic interventions through bibliometric analysis.Methods:Comprehensive electronic searches were conducted in Web of Science, ScienceDirect and PubMed for the search term “Ergonomics” or “Musculoskeletal disorder” and “Rubber” for the article published before 2020. Eleven papers were identified for the review of MSDs and ergonomic interventions; data were extracted to summarize sample size, data collection methods, analyzing tools, various operations, MSDs, and ergonomic interventions.Results:The reviewed article is classified according to various operations such as rubber tapping, latex collection, rubber sheeting and sheet pressing. The review reveals that most of the workers experience lower back pain, which involved a traditional way of operating. Every author is trying to recommend some interventions, but post-intervention studies are limited.Conclusions:Due to the limited post-intervention study, there is a scope of ergonomic interventions in every operation. So, the implementation of a proper ergonomic tool with adequate awareness improves the MSDs among the rubber processing workers. The review will help to identify the various intervention gaps in different operations associated with rubber farming.     

Gastric cancer mortality rates by occupation and industry among male and female workers aged 25–64 years in Japan

Differences in risk for gastric cancer exist among occupations and industries in Japan. Using a 2015 national dataset, we estimated the mortality rates due to gastric cancer in Japanese male and female workers aged 25–64 yr. Regression models were used to estimate the mortality rate ratios separately for men and women with adjustment for age. The occupation with the highest risk ratio was “Service” in men (2.06, 95% confidence interval: 1.63–2.61) and “Construction and Mining” in women compared with “Sales”. For industries, workers in “Mining”, “Electricity, Gas, Heat supply and Water”, “Fisheries”, “Agriculture and Forestry”, and “Construction” had a higher mortality risk. Our results showed that occupations and industries with higher mortality rates in men had the same trend as the results from 2010, and occupations and industries with higher mortality rates in women were almost the same as those in men. The analyses also indicated that managerial and professional workers in Japan had higher mortality as opposed to developed Western countries. In conclusion, this study suggests that occupations and industries still impact men and women’s health in terms of mortality due to gastric cancer in Japan.     

Job stress and poor sleep quality: data from an American sample of full-time workers

Given the associations between poor quality sleep and health, it is important to consider whether job stressors are related to sleep-related outcomes. Studies from Europe and Japan suggest that these stressors negatively impact sleep, but there are few studies of job stressors and sleep quality that draw upon large representative samples of workers in the USA. Using data collected via telephone interviews from a nationally representative random sample of 1715 American full-time employees, this research considers three dependent variables of past-month poor sleep quality: number of days the respondent had difficulty initiating sleep, number of days of difficulty maintaining sleep, and number of days of non-restorative sleep. Negative binomial regression was used to estimate a count data model of the associations between the frequency of these three types of poor sleep quality and the job stressors of work overload, role conflict, autonomy, and repetitive tasks, while controlling for socio-demographic characteristics. The average American worker reported 5.3 days of difficulty falling asleep, 6.6 days of trouble staying asleep, and 5.0 days of trouble waking up for work in the past month. Across the three types of poor sleep quality, work overload was positively associated with the frequency of poor sleep quality. Role conflict was positively associated with difficulty initiating sleep and non-restorative sleep. Repetitive tasks were associated with more days of difficulty initiating sleep and maintaining sleep. Job autonomy was negatively associated with non-restorative sleep. Given that sleep quality is associated with other health outcomes, future research should continue to explore the associations between job-related stressors, sleep quality, and workers' health status.     

Alternate Day Fasting Combined with a Low Carbohydrate Diet: Effect on Sleep Quality,Duration, Insomnia Severity and Risk of Obstructive Sleep Apnea in Adults with Obesity

Background: Alternate day fasting combined with a low carbohydrate diet (ADF-LC) is an effective weight loss regimen. Whether the weight loss induced by ADF-LC can improve sleep, remains unknown. Objective: This study examined the effect an ADF-LC diet on sleep quality, duration, insomnia severity and the risk of obstructive sleep apnea. Methods: Adults with obesity (n = 31) participated in ADF (600 kcal “fast day”; ad libitum intake “feast day”) with a low-carbohydrate diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period. Results: Reductions in body weight (−5 ± 1 kg, p < 0.001) and fat mass (−4 ± 1 kg, p < 0.01) were noted during the weight loss period, and these reductions were sustained during the weight maintenance period. Lean mass and visceral fat remained unchanged. The Pittsburgh Sleep Quality Index (PSQI) score indicated poor sleep quality at baseline (6.4 ± 0.7) with no change by month 3 or 6, versus baseline. ISI score indicated subthreshold insomnia at baseline (8.5 ± 1.0), with no change by month 3 or 6, versus baseline. The percent of subjects with high risk of obstructive sleep apnea at baseline was 45%, with no change by month 3 or 6. Wake time, bedtime, and sleep duration remained unchanged. Conclusion: The ADF-LC diet does not impact sleep quality, duration, insomnia severity or the risk of obstructive sleep apnea in adults with obesity.     

Effects of diurnal and seasonal sleep deficiency on work effort and fatigue of shift workers

Summary This study was designed to assess and compare the quantity and quality of sleep of morning, afternoon, and night shift workers during the winter and summer seasons, and to evaluate the effects of sleep deficiency on the work effort and fatigue of the workers. The subjects studied consisted of a sample of 150 textile workers, working on a monthly rotating 3-shift system: morning shift (06.00–11.00 and 14.00–17.00) afternoon shift (11.00–14.00 and 17.00–22.00), and night shift (22.00–06.00). Information concerning quantity and quality of sleep were registered daily over a week for every subject. The Ratings of Perceived Effort scale and the Feeling and Symptoms of Fatigue scale were used to collect information about feeling of effort and fatigue of the subjects. The results showed that the duration of sleep length is longest in the afternoon and shortest in the night shift both during summer and winter. The amount of sleep is shorter during summer during all three shifts. The workers spent more effort and felt more fatigued during summer than winter. The shift workers, particularly of the tropical region, like Bangladesh, seem to be worst affected in terms of quantity and quality of sleep, health and well-being due to extremely high temperature (30–45° Celsius) during summer than winter (5–25° Celsius). The workers think that the problems of shift work could be minimized by improving the quality of working and living conditions, reducing cycle of rotation, shortening working day and closing night shift during peak summer.     

Open access: a giant leap towards bridging health inequities

Access to health research publications is an essential requirement in securing the chain of communication from the researcher to the front-line health worker. As the diagram of the knowledge cycle from the Canadian Institutes of Health Research shows, health knowledge generated in the world’s laboratories is passed down the information chain through publications, through its impact and application, its subsequent “translation” into appropriate contexts for different user communities, arriving finally with health workers and the general public. This article focuses on the first link in the chain, from research author to reader, and the free online access to peer-reviewed published articles that are the building blocks for future health innovation developments.     

The impact of extended leave on sleep and alertness in the Australian rail industry

In the past, scientific studies have investigated the effects of shift timing and duration on sleep and alertness in the rail industry. To our knowledge no research has been conducted to determine the effects of extended break lengths (>48 h) on these factors. Hence, this study analyses the work and rest schedules of 304 Australian rail employees (mean age 41.3 yr, standard deviation 7.4 yr) to determine the effect of prior break lengths (12-169 h) on sleep and subjective alertness at work after periods of leave. Extended break periods (>48 h) were found to increase the length of the sleep prior to returning to work and reduce the total wake time to the end of the first shift, but did not influence levels of subjective alertness immediately prior to the commencement of the first shift. Research into the influence of longer break periods (>169 h) is needed in order to make definitive conclusions regarding sensible return to work policies after extended leave within the Australian rail industry.     

Work at sea: a study of sleep,and of circadian rhythms in physiological and psychological functions,in watchkeepers on merchant vessels

The safety of a ship depends substantially on its bridge watchkeepers, whose alertness and efficiency must be maintained at all hours of the day and night. Fatigue, circadian rhythms, and sleep disruption occasioned by the unusual working hours of these personnel may all affect their performance. A methodology for assessing the magnitude of this problem is proposed. The application of this methodology in a large-scale shipboard study of merchant mariners on extended voyages is then described, and details given of the techniques used to measure sleep and activity, and temporal variations in a range of physiological und psychological parameters. A summary of the data collected in the study is provided as a reference point for the reports on the different aspects of the results that follow in subsequent articles.     

Comparing performance on a simulated 12 hour shift rotation in young and older subjects

OBJECTIVES—To simulate a 12 hour shift rotation and measure the difference in performance if any, between older and younger subjects. Significant reductions in neurobehavioural performance during shift work and particularly night work have long been recognised. There are conflicting reports of the effects of 12 hour shifts on performance, alertness, and safety. Furthermore, research suggests that older shift workers have more sleep disruption and maladaption to shift work. When this is combined with longer hours at work there may be considerable reductions in performance for older compared with younger workers.
METHODS—Thirty two subjects were allocated to groups according to age. Group one had 16 subjects with a mean (SD) age of 21.2 (2.7) years, and group two had 16 subjects with a mean (SD) age of 43.9 (6.8) years. Subjects came to the laboratory for six consecutive days and completed a simulated 12 hour shift rotation consisting of two 12 hour day shifts (0700-1900), followed by two 12 hour night shifts (1900-0700). During the work period subjects completed a computer administered neurobehavioural performance task every hour.
RESULTS—Performance for the older subjects was consistently lower than for the younger subjects. There was a significant difference in performance across the shift between older and younger subjects. There was a significant change in performance across the shifts in the older subjects, such that performance significantly increased across the day shifts and decreased across the night shifts. By contrast, the younger subjects were able to maintain performance across both day shifts and the second night shift.
CONCLUSIONS—There are significant differences in performance of older and younger subjects during a simulated 12 hour shift rotation. Future studies both in the field and the laboratory would be useful in determining whether this is typical and if there are any important consequences for the older worker on 12 hour shifts.


Keywords: 12 hour shifts; performance; age; sleep reduction; circadian rhythms; night work     

Caffeine withdrawal,sleepiness, and driving performance: What does the research really tell us?

Abstract

As a psychostimulant, caffeine is thought to reduce road accidents by keeping drivers alert and wakeful. Studies have found that caffeine can improve performance on vigilance tasks and in driving simulators under normal sleeping conditions and after sleep restriction or deprivation. However, there is increasing evidence that these beneficial effects of caffeine are due to withdrawal reversal. Studies comparing the effects of caffeine versus placebo on driving performance have tested habitual caffeine consumers deprived of caffeine from the evening before the test day. The conclusion from this review is, therefore, that improvements in driving performance and alertness after caffeine are likely to represent withdrawal reversal rather than a net beneficial effect of caffeine. Further research using designs that control for caffeine withdrawal are necessary and, accordingly, advice given to the public on use of caffeine as an antidote to tiredness and impaired performance should be reviewed.     

脑力劳动人群职业紧张与睡眠质量的关系研究

目的 了解脑力劳动目标人群职业紧张和睡眠质量状况,并分析两者之间的关系。方法 采用分层整群抽样方法抽取乌鲁木齐市脑力劳动者1 500人,使用工作紧张测量问卷和匹兹堡睡眠质量指数量表进行问卷调查。结果 不同人口学特征的脑力劳动者职业紧张状况不同(P＜0.05);此次调查的脑力劳动人群睡眠问题发生率为27.46%,其睡眠质量得分与国内常模比较,除睡眠时间外,其余各因子得分均高于国内常模,差异有统计学意义(P＜0.05);且控制一般人口学特征因素后对职业紧张与睡眠质量进行偏相关分析,结果显示职业紧张各维度与睡眠质量各因子间均存在一定相关性(P＜0.05),进一步进行Logistic回归分析发现,在调整了一般人口学特征因素的影响后,工作紧张强度和频度每改变一个单位,发生睡眠问题的危险性分别增加2.064倍和4.623倍。结论 脑力劳动人群职业紧张和睡眠质量状况较差,除一般人口学因素的影响外,职业紧张会对脑力劳动者的睡眠造成不良影响,且会增加职业人群发生睡眠问题的风险,应该注意防治。     

The Relationship Between Thiamine Intake and Long Sleep Duration: Results From the Korea National Health and Nutrition Examination Survey

Objectives:Thiamine is thought to modify sleeping patterns, while alcohol use diminishes internal thiamine levels. We investigated the association between thiamine intake and sleep duration and explored possible heterogeneity in the effect according to alcohol use.Methods:In total, 15 384 participants aged 19-64 were obtained from the Korea National Health and Nutrition Examination Survey 2012-2016. Nutrient intake, including thiamine, was measured using a food frequency questionnaire. Sleep duration was measured by a self-reported questionnaire. The highest thiamine intake quartile was set as the reference group. Participants were divided into 3 groups, with 7-8 hours of daily sleep as a reference group and those who slept more or less than that as “oversleeping” and “insufficient sleeping,” respectively. Multivariate logistic regression was used, adjusting for socioeconomic, medical, and nutritional factors. Additionally, participants were stratified according to high-risk alcohol use defined by the World Health Organization standards on alcohol use.Results:Low thiamine intake was associated with oversleeping (Q3: odds ratio [OR], 1.06; 95% confidence interval [CI], 0.86 to 1.32; Q2: OR, 1.24; 95% CI, 0.99 to 1.55; Q1: OR, 1.49; 95% CI, 1.16 to 1.91) and showed a significant trend for higher ORs at lower intake levels (p-trend<0.001). The effect was stronger in the high-risk alcohol use group (Q1: OR, 1.78; 95% CI, 1.28 to 2.49).Conclusions:Low thiamine intake was associated with oversleeping, and alcohol use intensified that association. These results were found in a context where overt clinical symptoms due to thiamine deficiency are considered rare. More awareness of the potential relationship of thiamine intake with oversleeping and its related risks should be considered.     

Effects of Diet and Lifestyle on Audio-Vestibular Dysfunction in the Elderly: A Literature Review

Background: The world’s age-related health concerns continue to rise. Audio-vestibular disorders, such as hearing loss, tinnitus, and vertigo, are common complaints in the elderly and are associated with social and public health burdens. Various preventative measures can ease their impact, including healthy food consumption, nutritional supplementation, and lifestyle modification. We aim to provide a comprehensive summary of current possible strategies for preventing the age-related audio-vestibular dysfunction. Methods: A PubMed, Embase, and Cochrane review databases search was conducted to identify the relationship between diet, lifestyle, and audio-vestibular dysfunction. “Diet”, “nutritional supplement”, “lifestyle”, “exercise”, “physical activity”, “tinnitus”, “vertigo” and “age-related hearing loss” were used as keywords. Results: Audio-vestibular dysfunction develops and progresses as a result of age-related inflammation and oxidative stress. Diets with anti-inflammatory and antioxidant effects have been proposed to alleviate this illness. A high-fat diet may induce oxidative stress and low protein intake is associated with hearing discomfort in the elderly. Increased carbohydrate and sugar intake positively correlate with the incidence of audio-vestibular dysfunction, whereas a Mediterranean-style diet can protect against the disease. Antioxidants in the form of vitamins A, C, and E; physical activity; good sleep quality; smoking cessation; moderate alcohol consumption; and avoiding noise exposure are also beneficial. Conclusions: Adequate diet or nutritional interventions with lifestyle modification may protect against developing audio-vestibular dysfunction in elderly individuals.     

On-call work and health: a review

Many professions in the fields of engineering, aviation and medicine employ this form of scheduling. However, on-call work has received significantly less research attention than other work patterns such as shift work and overtime hours. This paper reviews the current body of peer-reviewed, published research conducted on the health effects of on-call work The health effects studies done in the area of on-call work are limited to mental health, job stress, sleep disturbances and personal safety. The reviewed research suggests that on-call work scheduling can pose a risk to health, although there are critical gaps in the literature.