Do sleep, stress, and illness explain daily variations in fatigue? A prospective study

Personality Pathology and Momentary Stress Processes

The expression of personality pathology differs between people and within a person in day-to-day life. Personality pathology may reflect, in part, dysregulation in basic behavioral processes. Thus, a useful approach for studying maladaptive trait expression comes from literature on stress and daily hassles, which provide dynamic accounts for the relations between individual differences and maladaptive dysregulation. This study sought to integrate maladaptive traits and dynamic stress processes to further dynamic models of personality pathology. In a combined clinical/community sample (N=297) oversampled for interpersonal problems, we used ecological momentary assessment (observation N=19,968) to investigate how maladaptive traits moderated the processes of stress generation, stress reactivity, and affective spillover/inertia. Tests of our preregistered hypotheses provided a mix of supportive and null findings for stress processes identified in past research, and mixed support for the moderating role of personality. The results provide insights into the relations between everyday stressors and personality pathology.

Mentally Demanding Work and Strain: Effects of Study Duration on Fatigue, Vigor, and Distress in Undergraduate Medical Students

AIMS

The impact of the extent of mentally demanding work on the next-day's strain is largely unknown, as existing studies generally investigate consequences of extended versus normal workdays. The present study sought to fill this gap by investigating how short work periods of mentally demanding academic work impact strain reactions in medical students preparing for an exam, using days of no work as reference category.

METHOD

The observational design involved students repeatedly self-reporting fatigue, vigor, distress, and the preceding day's study duration. Hours of nocturnal sleep, attending paid work and compulsory classes, gender, and proximity to the exam were controls in the linear model (generalized estimating equations). Forty-nine students provided 411 self-reports (M = 8.6, SD = 7.0 self-reports/student).

RESULTS

Engaging in mentally demanding work was associated with increased distress and work periods > 4 h with increased fatigue. Distress, vigor loss, and fatigue increased in proximity to the exam.

CONCLUSION

Despite students' high control of their schedule, even short periods of mentally highly demanding work may impair next-day's well-being when task motivation is high. Freelancers and students might require health-promoting scheduling of work and leisure to avoid an accumulation of strain.

Satisfaction with activity-support and physical home-workspace characteristics in relation to mental health during the COVID-19 pandemic

Previous research indicates that employees' mental health might be influenced by their satisfaction with physical office characteristics, such as noise, daylight, and ventilation. However, similar research on mental health in relation to working from home (WFH) is limited. Therefore, this study aimed to identify the relationships between satisfaction with physical home workspace characteristics and support of work activities and mental health while WFH during the COVID-19 pandemic. Relationships were analysed using a path analysis approach, based on a sample of 1219 office workers, who had to work fully from home. The internal relationships between the ten considered mental health variables were also studied. Results showed that satisfaction with daylight, artificial light, greenery, and views outside were directly related to one of the mental health variables and indirectly to several others. Surprisingly, satisfaction with temperature, noise, ventilation, and air quality did not seem to play a role at the home workplace. In addition, unlike at the office, personal characteristics did not relate to workspace satisfaction nor perceived support of activities at home. Furthermore, all mental health variables were related to at least one other mental health variable. Workplace managers could use these insights to formulate recommendations for employees on how to design their home-workspace.

Smartphone keyboard interaction monitoring as an unobtrusive method to approximate rest-activity patterns: Inter-individual and metric-specific variations (Preprint)

BACKGROUND

Sleep is an important determinant of individuals' health and behavior during the wake phase. Novel research methods for field assessments are required to enable the monitoring of sleep over a prolonged period and across a large number of people. The ubiquity of smartphones offers new avenues for detecting rest-activity patterns in everyday life in a noninvasive an inexpensive manner and on a large scale. Recent studies provided evidence for the potential of smartphone interaction monitoring as a novel tracking method to approximate rest-activity patterns based on the timing of smartphone activity and inactivity throughout the 24-hour day. These findings require further replication and more detailed insights into interindividual variations in the associations and deviations with commonly used metrics for monitoring rest-activity patterns in everyday life.

OBJECTIVE

This study aimed to replicate and expand on earlier findings regarding the associations and deviations between smartphone keyboard-derived and self-reported estimates of the timing of the onset of the rest and active periods and the duration of the rest period. Moreover, we aimed to quantify interindividual variations in the associations and time differences between the 2 assessment modalities and to investigate to what extent general sleep quality, chronotype, and trait self-control moderate these associations and deviations.

METHODS

Students were recruited to participate in a 7-day experience sampling study with parallel smartphone keyboard interaction monitoring. Multilevel modeling was used to analyze the data.

RESULTS

In total, 157 students participated in the study, with an overall response rate of 88.9% for the diaries. The results revealed moderate to strong relationships between the keyboard-derived and self-reported estimates, with stronger associations for the timing-related estimates (β ranging from .61 to .78) than for the duration-related estimates (β=.51 and β=.52). The relational strength between the time-related estimates was lower, but did not substantially differ for the duration-related estimates, among students experiencing more disturbances in their general sleep quality. Time differences between the keyboard-derived and self-reported estimates were, on average, small (<0.5 hours); however, large discrepancies were also registered for quite some nights. The time differences between the 2 assessment modalities were larger for both timing-related and rest duration-related estimates among students who reported more disturbances in their general sleep quality. Chronotype and trait self-control did not significantly moderate the associations and deviations between the 2 assessment modalities.

CONCLUSIONS

We replicated the positive potential of smartphone keyboard interaction monitoring for estimating rest-activity patterns among populations of regular smartphone users. Chronotype and trait self-control did not significantly influence the metrics' accuracy, whereas general sleep quality did: the behavioral proxies obtained from smartphone interactions appeared to be less powerful among students who experienced lower general sleep quality. The generalization and underlying process of these findings require further investigation.

Evaluation on the automotive skill competency test through 'discontinuity' model and the competency test management of vocational education school in Central Java, Indonesia

This article provides an alternative competency test model for vocational education schools in Central Java, Indonesia which particularly for automotive skill competency in order to replace the current competency test model that has been implemented for several decades which the author's concern about the students' accomplishment during the competency test, aimed to improve competency test results to increase the students' job opportunity in the labor market. Currently, the applied competency test model is the ‘Continuity’ model, where the students are given five tasks and should be finished within five hours with limited break time. This model tends to increase students' fatigue and stress levels. Consequently, the students lose their focus and concentration which adversely impacts their competency test results. In this study, the new competency test model namely the ‘Discontinuity’ competency test model was proposed aiming to overcome the issue of the ‘Continuity’ model. To research the effect of the ‘Discontinuity’ model implementation on the students' competency test results and vocational school competency test management, a study was done among 100 students and 50 teachers in 10 vocational education schools around Central Java, Indonesia. The results show that the ‘Discontinuity’ competency test model gives a significant improvement in the students' competency test scores. This reasonably happened due to the implementation of the ‘Discontinuity’ model gives the students time to break for an hour of each competency task. Without this break time, fatigue and stress levels of the students will significantly increase which adversely affect the students' competency final score. In addition, the new management of the competency test was proposed in this research.

Precarious Work Schedules and Sleep: A Study of Unionized Full-Time Workers

Unlike precarious employment which is temporary and insecure, with inadequate pay, benefits, and legal protections, precarious work schedules can affect workers with permanent full-time jobs in sectors where employment has historically been secure, well-compensated, and even unionized. Precarious work schedules - characterized by long shifts, non-daytime hours, intensity and unsocial work hours - are increasingly prevalent. Relations between precarious work schedules and poor health are not well understood, and less is known about how to attenuate this relation. We examined the indirect effects of precarious work schedules on fatigue and depressive symptoms through sleep quantity. Two moderators - schedule flexibility and sleep quality - were examined as buffers of these associations. Workers from the Departments of Correction and Transportation in a northeast state (N = 222) took surveys and reported on demographics, work schedule characteristics, schedule flexibility, sleep quality and quantity, fatigue, and depressive symptoms. Results revealed that precarious work schedules had indirect effects on fatigue and depressive symptoms through sleep quantity. Schedule flexibility moderated the relation between precarious work schedules and sleep quantity, such that workers with greater schedule flexibility had more hours of sleep. Sleep quality moderated the association between sleep quantity and fatigue and depressive symptoms, such that workers reported greater fatigue and depressive symptoms when they had poorer sleep quality. Findings have direct applicability for developing initiatives that enhance Total Worker Health® through individual and organizational changes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41542-022-00114-y.

Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: guidance from the American Academy of Sleep Medicine and the Sleep Research Society

CITATION

Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: (1) a recognition of the factors contributing to fatigue and fatigue-related risks; (2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and (3) an informed approach to selecting workplace-specific strategies for managing work hours. We propose a series of guiding principles to assist stakeholders with designing a shift duration decision-making process that effectively balances the need to meet operational demands with the need to manage fatigue-related risks.

Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: guidance from the American Academy of Sleep Medicine and the Sleep Research Society

Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: (1) a recognition of the factors contributing to fatigue and fatigue-related risks; (2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and (3) an informed approach to selecting workplace-specific strategies for managing work hours. We propose a series of guiding principles to assist stakeholders with designing a shift duration decision-making process that effectively balances the need to meet operational demands with the need to manage fatigue-related risks.

Time in Nature Associated with Decreased Fatigue in UK Truck Drivers

Heavy goods vehicle (HGV) driving is recognised as a highly hazardous occupation due to the long periods of sedentary behaviour, low levels of physical activity and unhealthy food options when working. These risk factors combine with shift work and concomitant irregular sleep patterns to increase the prevalence of fatigue. Fatigue is closely linked with stress and, subsequently, poor physiological and psychological health. In parallel, a wealth of evidence has demonstrated the health and wellbeing benefits of spending time in nature. Here, we sought to examine whether spending time in nature was associated with lower levels of fatigue, anxiety and depression in HGV drivers. 89 long-distance drivers (98.9% male, mean ± SD age: 51.0 ± 9 years, body mass index: 29.8 ± 4.7 kg/m²) participating in a wider health promotion programme reported time spent in nature (during and before the Covid-19 pandemic) and symptoms of occupational fatigue, depression and anxiety. After controlling for covariates, truck drivers who visited nature at least once a week exhibited 16% less chronic fatigue prior to the pandemic, and 23% less chronic fatigue and 20% less acute fatigue during the pandemic. No significant differences were observed for either anxiety or depression. As fatigue has a range of physical and mental health sequelae, we propose that increased exposure to natural settings may make a valuable contribution to interventions to promote the health and wellbeing of this underserved group.

Sickness and sleep health predict frustration and affective responses to a frustrating trigger

Fluctuations in health and sleep are common, but we know surprisingly little about how these daily life stressors affect one's level of frustration and sensitivity to becoming frustrated. In this pre-registered study, 517 participants (Mage = 30.4, SD = 10.4) reported their current sickness symptoms, health status, sleepiness, and sleep duration and quality the previous night. They also rated their general frustration and mood before and after a mild frustration-eliciting task. In the task, participants were instructed to copy geometric shapes onto a piece of paper, without lifting the pen from the paper. Participants were given three minutes to copy the eight shapes, but in order to induce frustration half of them were unsolvable. The study was subsequently repeated in an independent sample (N = 113). Frustration increased in response to the task; however, those with the worst sickness symptoms or sleep health reduced or did not change their frustration levels. Instead, across both studies, frustration was already high at baseline for these individuals. These findings indicate that being sick or having poor sleep is related to high general frustration, but resilience to further frustration due to mild frustrating situations.

Workers’ Aging Management—Human Fatigue at Work: An Experimental Offices Study

The aging issue in the work context is becoming a significant element of the future sustainability of service and industrial companies. It is well known that with increasing worker age the problem of maintaining the performance and the safety level when fatigue increases is a crucial point, and fatigue increases with the age. Due to social and political developments, especially in Western countries, the retirement age is increasing and companies operate with a higher workforce mean age. Therefore, the problem of recognizing and measuring fatigue has become a key aspect in the management of aging. Note that in the scientific engineering field, the problem of fatigue evaluation when a worker is performing his/her work activities is an important issue in the industrial and service world and especially in the context of the researchers that are investigating the human reliability assessment. As it is clear from the literature, the industrial operations management are suffering from some misleading concepts that only the medicine scientific context can clarify. Therefore, the aim of this paper is to define what are the open issues and the misleading concepts present in the classical fatigue evaluation methods, and second to define two experimental curves of fatigue that will help the decision makers to minimize the impact of fatigue on the workers, thus maximizing the sustainability of the working tasks assigned. This aim is achieved by examining the medical literature about the measurement of a particular kind of fatigue related to the circadian cycle, i.e., the cognitive one; after that, a survey about the possible technologies for measurements is performed. On the basis of technology selection, an experiment on real work activities is performed and some remarkable results about the fatigue in the workers observed and the technology use and its limitations are defined.

Tonight's Sleep Predicts Tomorrow's Fatigue: A Daily Diary Study of Long-Term Care Employees With Nonwork Caregiving Roles

BACKGROUND AND OBJECTIVES

Long-term care employees and employees with nonwork caregiving roles are at high risk for sleep problems and fatigue. Little is known, however, about relationships between sleep and fatigue among long-term care employees who occupy nonwork caregiving roles. This study examined whether longer sleep duration and better sleep quality reduce fatigue occurrence and severity within and between long-term care employees with nonwork caregiving roles, and investigated nonwork caregiving role occupancy as a moderator of these relationships.

RESEARCH DESIGN AND METHODS

The sample comprised 166 women working in U.S.-based nursing homes. All women had children aged 9-17 years and some also had nonwork caregiving responsibilities for adult relatives. Sleep (duration and quality) and fatigue (occurrence and severity) were assessed via telephone interviews for eight consecutive evenings. Multilevel modeling was used to examine within-person and between-person associations.

RESULTS

At the within-person level, nights characterized by longer-than-usual sleep duration or better-than-usual sleep quality were followed by days with lower odds of reporting fatigue; these same sleep characteristics predicted less severe next-day fatigue. At the between-person level, employees with better average sleep quality, but not longer sleep duration, had lower odds of experiencing fatigue. Relationships between sleep and fatigue were generally similar regardless of nonwork caregiving responsibilities for children or for both children and adults.

DISCUSSION AND IMPLICATIONS

Findings suggest that tonight's sleep predicts tomorrow's fatigue. Given the serious and wide-ranging consequences of fatigue, sleep constitutes a worthwhile intervention target with potential benefits for employees, care recipients, and organizations.

Psychosocial work demands and physical workload decrease with ageing in blue-collar and white-collar workers: a prospective study based on the SLOSH cohort

OBJECTIVES

Psychosocial work demands and physical workload are important causes of ill health. The dramatic demographic changes in society make it important to understand if such factors change with ageing, but this is presently not known. The purpose of the present study was to investigate whether psychosocial work demands and physical workload change across 8 years of ageing, whether occupational groups show different trajectories of change and if such trajectories are reflected in sleep or fatigue.

METHODS

A cohort of 5377 participants (mean age: 47.6±11.6 (SD) years, 43.2% males, 40.2% blue-collar workers) was measured through self-report in five biannual waves across 8 years. Mixed model regression analyses was used to investigate change across ageing.

RESULTS

Psychosocial work demands decreased significantly across 8 years (Coeff: -0.016±0.001), with the strongest decrease in the high white-collar group (Coeff=-0.031±0.003) and the oldest group. Physical workload also decreased significantly (Coeff=-0.032±0.002), particularly in the blue-collar group (Coeff=-0.050±0.004) and in the oldest group. Fatigue decreased, and sleep problems increased with ageing, but with similar slopes in the occupational groups. All effect sizes were small, but extrapolation suggests substantial decreases across a working life career.

CONCLUSIONS

The decrease in psychosocial work demands and physical workload suggests that the burden of work becomes somewhat lighter over 8 years. The mechanism could be 'pure' ageing and/or increased experience or related factors. The gradual improvement in the work situation should be considered in the discussion of the place of older individuals in the labour market, and of a suitable age for retirement. The results also mean that prospective studies of work and health need to consider the improvement in working life with ageing.

Variation, companionship and manageability important for recovery during working hours: A qualitative focus group study

BACKGROUND

Lack of recovery from everyday strains and demands is connected to increased levels of stress-related problems and development of ill-health. There is much research on how to handle and prevent fatigue and stress in leisure time, but research on working time is more scarce. A recent study found that employees' experience of recovery during working hours was related to high self-rated health.

OBJECTIVE

The aim of this study was to explore the concept of recovery during working hours among primary health care workers.

METHODS

Eight focus groups with 50 staff members, men and women, from different professions were conducted in the primary health care sector in southern Sweden. The analysis was inspired by systematic text condensation, a strategy for qualitative analysis.

RESULTS

Three main categories were identified as important factors for experiencing recovery during working hours: variation (including changes in location, tasks and tempo) companionship (including helpfulness, appreciation, social chat and laughter) and manageability (including completion, satisfaction, influence, control and reflection).

CONCLUSIONS

Recovery during working hours is multifaceted. The categories identified in this study will be further elaborated and tested.

A longitudinal analysis of the relationships among daytime dysfunction, fatigue, and depression in college students

OBJECTIVE

To examine the longitudinal trajectory of daytime dysfunction (DD) and its relationship with fatigue by depression status in university students.

PARTICIPANTS

243 students completed online surveys from September- December 2016.

METHODS

Surveys were conducted at three time points over a semester period: the beginning of the semester, the end of mid-term and the end of the semester.

RESULTS

Results indicated that the DD significantly increased in all students over the semester. Students with depression showed a higher initial level of DD and faster rate of change compared to those without depression. A faster rate of change of DD predicted a higher level of end-semester fatigue.

CONCLUSIONS

Depression is related to a higher initial level of DD and its faster rate change which in turn, predicted end-semester fatigue, identifying one of the possible pathways through which depression impacts the functioning and health of affected students.

Contributors to Fatigue of Mine Workers in the South African Gold and Platinum Sector

Background

Mine workers in South Africa face challenges relating to poor health and safety, including fatigue risks, and poor socioeconomic and living conditions. Fatigue results in impaired mental and physical performance. The aim of this study was to assess contributors to fatigue of mine workers in South Africa.

Methods

Data collection took place at four gold mines and one platinum mine in South Africa. A total of 21 focus groups were held with individuals in management, union representatives, and mine workers, and 564 questionnaires were completed by mine workers to gather information about fatigue and potential contributors to fatigue at these mines.

Results

Qualitatively (through focus groups), fatigue was attributed to extended working hours, harsh working conditions, high workloads, production pressure, and resource constraints, along with aspects relating to demographic and socioeconomic factors, living conditions, lifestyle, health, and wellness. Greater fatigue was significantly associated with younger age, indebtedness, a lack of exercise, poor nutrition, less sleep, increased alcohol use, poor self-reported health, more sick leave, higher stress, and lower job satisfaction.

Conclusion

The aim of the study was achieved; numerous work-, sociodemographic-, lifestyle-, and wellness-related factors were linked to fatigue in the participating mine workers. Contributors to fatigue should be addressed to improve health, safety, and sustainability in the industry.

Lifestyle Factors Are Important Contributors to Subjective Memory Complaints among Patients without Objective Memory Impairment or Positive Neurochemical Biomarkers for Alzheimer's Disease

Background/Aims

Many patients presenting to a memory disorders clinic for subjective memory complaints do not show objective evidence of decline on neuropsychological data, have nonpathological biomarkers for Alzheimer's disease, and do not develop a neurodegenerative disorder. Lifestyle variables, including subjective sleep problems and stress, are factors known to affect cognition. Little is known about how these factors contribute to patients' subjective sense of memory decline. Understanding how lifestyle factors are associated with the subjective sense of failing memory that causes patients to seek a formal evaluation is important both for diagnostic workup purposes and for finding appropriate interventions and treatment for these persons, who are not likely in the early stages of a neurodegenerative disease. The current study investigated specific lifestyle variables, such as sleep and stress, to characterize those patients that are unlikely to deteriorate cognitively.

Methods

Two hundred nine patients (mean age 58 years) from a university hospital memory disorders clinic were included.

Results

Sleep problems and having much to do distinguished those with subjective, but not objective, memory complaints and non-pathological biomarkers for Alzheimer's disease.

Conclusions

Lifestyle factors including sleep and stress are useful in characterizing subjective memory complaints from objective problems. Inclusion of these variables could potentially improve health care utilization efficiency and guide interventions.

Sleep problems and fatigue as predictors for the onset of chronic widespread pain over a 5- and 18-year perspective

BACKGROUND

Previous research suggests that sleep problems may be an important predictor for chronic widespread pain (CWP). With this study we investigated both sleep problems and fatigue as predictors for the onset of CWP over a 5-year and an 18-year perspective in a population free from CWP at baseline.

METHODS

To get a more stable classification of CWP, we used a wash-out period, including only individuals who had not reported CWP at baseline (1998) and three years prior baseline (1995). In all, data from 1249 individuals entered the analyses for the 5-year follow-up and 791 entered for the 18-year follow-up. Difficulties initiating sleep, maintaining sleep, early morning awakening, non-restorative sleep and fatigue were investigated as predictors separately and simultaneously in binary logistic regression analyses.

RESULTS

The results showed that problems with initiating sleep, maintaining sleep, early awakening and non-restorative sleep predicted the onset of CWP over a 5-year (OR 1.85 to OR 2.27) and 18-year (OR 1.54 to OR 2.25) perspective irrespective of mental health (assessed by SF-36) at baseline. Also fatigue predicted the onset of CWP over the two-time perspectives (OR 3.70 and OR 2.36 respectively) when adjusting for mental health. Overall the effect of the sleep problems and fatigue on new onset CWP (over a 5-year perspective) was somewhat attenuated when adjusting for pain at baseline but remained significant for problems with early awakening, non-restorative sleep and fatigue. Problems with maintaining sleep predicted CWP 18 years later irrespective of mental health and number of pain regions (OR 1.72). Reporting simultaneous problems with all four aspects of sleep was associated with the onset of CWP over a five-year and 18-yearperspective, irrespective of age, gender, socio economy, mental health and pain at baseline. Sleep problems and fatigue predicted the onset of CWP five years later irrespective of each other.

CONCLUSION

Sleep problems and fatigue were both important predictors for the onset of CWP over a five-year perspective. Sleep problems was a stronger predictor in a longer time-perspective. The results highlight the importance of the assessment of sleep quality and fatigue in the clinic.

Does Stress Explain the Effect of Sleep on Self-Control Difficulties? A Month-Long Daily Diary Study

Insufficient sleep is linked to increased stress and suboptimal self-control; however, no studies have examined stress as a reason for why sleep affects self-control. Moreover, it is unknown if there are individual differences that make people vulnerable to this dynamic. Daily diary entries from 212 university students across 30 days were used in a multilevel path model examining if stress explained how prior night sleep affected next-day self-control difficulties and exploring if individual differences in sleep duration, stress, or self-control qualified this effect. Increased stress partially mediated of the effect of reduced sleep duration on increased next-day self-control difficulty. Moreover, short sleep increased next-day stress more for individuals with higher typical stress. Daytime stress especially amplified self-control difficulty for individuals with shorter typical sleep duration. Findings implicate stress as a substantial factor in how sleep loss undermines self-control and identify individuals particularly susceptible to this effect.

Discriminating Between Fatigue and Sleepiness in the Naval Operational Environment

OBJECTIVE

To assess the similarities and differences between reported levels of fatigue and sleepiness as a consequence of working at sea.

PARTICIPANTS

767 crewmembers of a U.S. Navy ship.

METHODS

Retrospective analysis of a survey to include questions about demographics, caffeine consumption, sleep adequacy, the Epworth Sleepiness Scale (ESS), and the Fatigue Severity Scale (FSS).

RESULTS

ESS scores (8.41 ± 4.66) indicated that 32% of the participants had excessive daytime sleepiness (ESS score > 10), while approximately 7% had an ESS score of 16 or more. FSS scores (average FSS = 3.01 ± 1.37) indicated that 28% of the participants had elevated fatigue (FSS score ≥ 4). Even though ESS and FSS scores were correlated (r = 0.39), their association explained only 15% of the variability observed. In terms of behavioral and lifestyle patterns, crewmembers with elevated fatigue (FSS ≥ 4) reported getting less exercise than those reporting less fatigue. Individuals with excessive sleepiness (ESS > 10) reported higher caffeine consumption. Crewmembers with elevated fatigue and comorbid sleepiness (FSS ≥ 4 and ESS > 10) reported receiving less sleep than other crew members.

CONCLUSIONS

These results suggest that subjective fatigue and subjective sleepiness, as measured by the FSS and ESS scales, are distinct constructs and both are consequences of working at sea. The scores on the two scales correlate differentially with behavioral and lifestyle patterns of the crewmembers.

Time pressure and sleep problems due to thoughts about work as risk factors for future sickness absence

Purpose

This study investigated whether time pressure or sleep problems due to thoughts about work are associated with future sickness absence (SA) among women and men employed in different sectors, also when adjusting for confounders including familial factors (genetics and shared environment).

Methods

The study sample included 16,127 twin individuals (52% women), aged 19–47 years who in 2005 participated in an online survey including questions regarding time pressure, sleep, work and health. Register data on SA (> 14 days) were obtained from the National Social Insurance Agency and individuals were followed from date of survey response until 12/31/2013. Associations between time pressure, sleep problems due to thoughts about work and future SA were investigated using logistic regression analyses to assess odds ratios (OR) with 95% confidence intervals (CI).

Results

In total 5723 (35%) individuals had an incident SA spell during follow-up. Sleep problems due to thoughts about work were associated with SA in the fully adjusted model (OR 1.22, CI 1.10–1.36). Stratified by sector, the highest estimate was found for state employees (OR 1.54, CI 1.11–2.13). Familial factors did not seem to influence the associations. We found no statistically significant associations between time pressure and SA. No sex differences were found.

Conclusions

Results indicated that sleep problems due to thoughts about work is a risk factor for future SA. This follows previous research showing that sleep length and sleep disturbances, regardless of reason, are associated with SA. But, experiences of work-related time pressure seem to have no effect on SA.

Co-variation of fatigue and psychobiological stress in couples' everyday life

OBJECTIVE

There is limited knowledge about how fatigue develops and worsens and what influences fluctuations in daily fatigue. Stress was found to influence fatigue, and being in a relationship seems to either increase or decrease stress depending on the couple interaction. In this study, co-variation of fatigue, self-reported stress, and biological stress markers in couples' everyday lives was investigated. Specifically, we examined a) whether momentary couple interactions moderated dyadic outcomes and b) whether and how stress and relationship measures influenced individual momentary fatigue.

METHODS

Forty heterosexual couples (age: 28 ± 5 years) reported subjective fatigue and stress levels 4 times a day for 5 consecutive days (1600 measures). Furthermore, participants reported whether they had interacted with their partner since the last data entry and, if so, they rated the valence of this interaction. Salivary cortisol (a measure of HPA axis activity) and alpha amylase (a measure of ANS activity) were analyzed as biological stress markers from saliva samples obtained at the same time points. Moment-to-moment data were analyzed using dyadic multilevel models to account for the nested design.

RESULTS

Stress (women and men: p ≤ 0.001) and fatigue (women: p = .003, men: p = .020) showed patterns of co-variation within couples, especially if partners had interacted with each other since the previous data entry. Cortisol was also found to co-vary between partners (women: unstandardized coefficient (UC) = 0.12, p ≤ .001, men: UC = 0.18, p ≤ .001), whereas the regulation of alpha-amylase levels depending on the partner's levels was only present in women (UC = 0.11, p = .002). Valence of couple interaction was negatively associated with fatigue (women: UC = -0.13, p ≤ .001, men: UC = -0.06, p = .011). There was no momentary association of fatigue with an individual's own or the partner's subjective or biological stress markers.

CONCLUSIONS

Fatigue and stress levels during the day seem to co-vary within couples. These associations were particularly strong when the partners had interacted with each other since the last measurement. These data underline the importance of social factors in fatigue and stress in everyday life.

Aging and the Change in Fatigue and Sleep - A Longitudinal Study Across 8 Years in Three Age Groups

Fatigue is prevalent in the population and usually linked to sleep problems, and both are related to age. However, previous studies have been cross-sectional. The purpose of the present study was to investigate the trajectories of sleep and fatigue across 8 years of aging in a large group (N > 8.000) of individuals. A second purpose was to investigate whether fatigue trajectories would differ between age groups, and whether different trajectories of fatigue would be reflected in a corresponding difference in trajectories for sleep variables. Results from mixed model analyses showed that fatigue decreased across 8 years in all age groups, while sleep problems increased, non-restorative sleep decreased, weekend sleep duration decreased, and weekday sleep duration showed different patterns depending on age. Furthermore, the larger the decrease in fatigue, the larger was the increase in sleep duration across years, the lower was the increase of sleep problems, and the larger was the decrease of non-restorative sleep. The results suggest that aging has positive effects on fatigue and sleep and that these changes are linked.

Cross-Cultural Validation of the Korean Version of the Chalder Fatigue Scale

PURPOSE

University students are vulnerable to fatigue. If not adequately dealt with, fatigue might develop into various health problems and negatively affect quality of life (QOL). The present study examined psychometric properties of the Korean version of the Chalder Fatigue Scale (K-CFQ) in university students.

METHOD

Data were obtained from two samples of undergraduate students in Korea. The first dataset (N = 557) was collected in a cross-sectional survey in 2015 and the second dataset (N = 338) from a longitudinal survey with three time points over a semester period in 2016. Participants completed measures of fatigue, QOL, depression, anxiety, and sleep quality.

RESULTS

Three-factor model (physical fatigue, low energy, and mental fatigue) rather than the original two-factor model (physical and mental fatigue) provided a better goodness of fit indices to the data. Internal consistency of the K-CFQ was satisfactory, with Cronbach's α value of 0.88 for the total scale and those of subscales ranging from 0.73 to 0.87. Its convergent validity was supported by its significant association with anxiety, depression, sleep quality, and QOL. Significant association between T1 K-CFQ with physical QOL at T2 and T3 supported its predictive validity. Its known-group validity was proven with higher K-CFQ scores observed in the participants with depression and those with poor sleep quality.

CONCLUSIONS

Current results suggest that K-CFQ is a valid and reliable measure of fatigue, and a better model fit of the three-factor structure of the K-CFQ implies potential cross-cultural differences in the dimensionality of fatigue.

The trait and occasion components of fatigue and their association with sickness absence

OBJECTIVE

Fatigue is an important health outcome in public and occupational health care. To correctly understand and treat high levels of (prolonged) fatigue it is important to disentangle the state of fatigue into a time-varying (occasion) and -invarying (trait) component. Not only for understanding of the construct itself over time but also for its relation with (health) outcomes such as sickness absence.

METHODS

Longitudinal data (n=2316) from the Maastricht Cohort Study (MCS) study was used, which assessed fatigue across 4-month intervals using the Checklist Individual Strength (CIS).

RESULTS

It was found that the occasion component explains 27.60% (95%-CI [25.80%; 29.40%]) of the variance of fatigue and the trait component 71.00% (95%-CI [69.00%; 72.90%]). The trait component was, furthermore, found to be a significant predictor of sickness absence.

CONCLUSION

Fatigue has a considerable time-invariant component. As this component is also related with other adverse health outcomes, preventive measures and interventions should take the difference between the occasion and trait component of fatigue into account.

Within-person fluctuations in wellbeing and task-specific work ability

Purpose

To research within-person fluctuations in occupational health, work ability and wellbeing, we need new measurement strategies. We studied absolute agreement for weekly measurements of task-specific work ability and relationships between wellbeing, work demands and personal factors and task-specific work ability over time.

Methods

Forty-eight Dutch academic researchers answered questions during 12 consecutive weeks. Physical and mental work demands, indicators of wellbeing and task-specific work ability in each week were measured. Intra-class correlation coefficients (ICC) for absolute agreement between task-specific work ability measures were calculated. For application in individual workers, an ICC > 0.90 was regarded as suitable. Multilevel models were used to relate both time-invariant and time-varying predictors to task-specific work ability.

Results

Multiple measurements increased the reliability. Absolute agreement, however, did not reach the optimal level, except for the task ‘ability to conduct data analyses’ which had an ICC value of 0.95 (95% CI 0.91–0.98). Individuals’ leisure time physical activity (p = 0.03) and relational (p = 0.02) and social (p = 0.02) wellbeing were related to their average task-specific work ability. Weekly physical demands (p = 0.01) and personal (p = 0.04) and general wellbeing (p = 0.03) were related to weekly fluctuations in work ability.

Conclusions

We demonstrated intra-individual variability in repeated assessments of task-specific work ability, pointing to the need for multiple measurements when characterizing work ability. The finding that some time-invariant and time-varying predictors can be related to the estimate of aspects of task-specific work ability and its fluctuations is helpful in understanding the dynamics of this concept.

Reviewing the relationship between OSA and cognition: Where do we go from here?

Obstructive sleep apnoea (OSA) is a disorder of breathing during sleep resulting in temporary reduction in cerebral oxygenation and sleep disruption. A growing body of research reveals a relatively consistent pattern of deficits in cognition, particularly in attention, episodic memory, and executive function, which are partially remediated by treatment. This is where the consensus ends. Despite a number of competing explanations regarding how OSA affects cognition, reliable evidence is hard to find, which may relate to the many, common conditions co-morbid with OSA or to the methodological challenges in this field. This paper reviews the evidence for cognitive impairment in OSA, the proposed models of cognitive harm, the impact of co-morbidities and the many methodological and theoretical challenges of exploring the effect of OSA on cognition. To overcome some of these challenges, we end by proposing a number of future directions for the field, including suggesting some core design elements for future studies.

Variance in Mood Symptoms Across Menstrual Cycles: Implications for Premenstrual Dysphoric Disorder

Premenstrual dysphoric disorder (PMDD) remains a controversial diagnosis: Some authors have argued that it pathologizes normal mood changes, and others have questioned the need for daily mood reports across multiple cycles. In the present study, we examined changes in mood among psychologically healthy young participants with regular menstrual cycles. We collected daily reports of negative mood (depression, nervousness, irritability, and fatigue) across two to six consecutive cycles from 27 participants aged 18-35 years, and we used variance decomposition analyses to examine how much of the variance in these daily reports was due to day, cycle, and individual. The majority of variance (79%-98%) was due to daily fluctuations and did not conform to a standard pattern of premenstrual rise/postmenstrual fall. These findings suggest that PMDD is not simply an exaggeration of mood patterns typical for psychologically healthy people. Individual patterns were relatively stable from cycle to cycle; thus tracking deviations from a patient's own normative mood patterns may have greater clinical utility than deviation from a presumptive norm.

Occupational imbalance and the role of perceived stress in predicting stress-related disorders

BACKGROUND

Stress-related disorders are the main reason for sick leave in many European countries. The aim of the present study was to explore whether perceived occupational imbalance predicts stress-related disorders, potential gender differences, and to explore the mediating role of perceived stress.

METHOD

Longitudinal data on 2223 employees in a public organization in Sweden were collected by surveys, and analyzed by logistic regression.

RESULTS

Occupational imbalance predicted stress-related disorders among both women and men. However, what aspects of occupational imbalance which predicted stress-related disorders differ by gender. Perceived stress was not a mediator in these associations.

CONCLUSION AND SIGNIFICANCE

How women and men perceived their occupational balance affected the risk of stress-related disorders. The results may be used to develop effective strategies to decrease stress-related disorders.

Work environment, overtime and sleep among offshore personnel

Personnel working on North Sea oil/gas installations are exposed to remote and potentially hazardous environments, and to extended work schedules (typically, 14×12h shifts). Moreover, overtime (additional to the standard 84-h week) is not uncommon among offshore personnel. Evidence from onshore research suggests that long work hours and adverse environmental characteristics are associated with sleep impairments, and consequently with health and safety risks, including accidents and injuries. However, little is known about the extent to which long hours and a demanding work environment combine synergistically in relation to sleep. The present study sought to address this issue, using survey data collected from offshore day-shift personnel (N=551). The multivariate analysis examined the additive and interactive effects of overtime and measures of the psychosocial/physical work environment (job demands, job control, supervisor support, and physical stressors) as predictors of sleep outcomes during offshore work weeks. Control variables, including age and sleep during leave weeks, were also included in the analysis model. Sleep duration and quality were significantly impaired among those who worked overtime (54% of the participants) relative to those who worked only 12-h shifts. A linear relationship was found between long overtime hours and short sleep duration; personnel who worked >33h/week overtime reported <6h/day sleep. Significant interactions were also found; sleep duration was negatively related to job demands, and positively related to supervisor support, only among personnel who worked overtime. Poor sleep quality was predicted by the additive effects of overtime, low support and an adverse physical environment. These findings highlight the need to further examine the potential health and safety consequences of impaired sleep associated with high overtime rates offshore, and to identify the extent to which adverse effects of overtime can be mitigated by favourable physical and psychosocial work environment characteristics.

Sleep deprivation affects reactivity to positive but not negative stimuli

OBJECTIVE

The current study examined the effects of partial and total sleep deprivation on emotional reactivity.

METHODS

Twenty-eight partially sleep-deprived participants and 31 totally sleep-deprived participants rated their valence and arousal responses to positive and negative pictures across four testing sessions during the day following partial sleep deprivation or during the night under total sleep deprivation.

RESULTS

The results suggest that valence and arousal ratings decreased under both sleep deprivation conditions. In addition, partial and total sleep deprivation had a greater negative effect on positive events than negative events.

CONCLUSION

These results suggest that sleep-deprived persons are more likely to respond less to positive events than negative events. One explanation for the current findings is that negative events could elicit more attentive behavior and thus stable responding under sleep deprivation conditions. As such, sleep deprivation could impact reactivity to emotional stimuli through automated attentional and self-regulatory processes.

Abnormal Resting-State Functional Connectivity in Patients with Chronic Fatigue Syndrome: Results of Seed and Data-Driven Analyses

Although altered resting-state functional connectivity (FC) is a characteristic of many chronic pain conditions, it has not yet been evaluated in patients with chronic fatigue. Our objective was to investigate the association between fatigue and altered resting-state FC in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Thirty-six female subjects, 19 ME/CFS and 17 healthy controls, completed a fatigue inventory before undergoing functional magnetic resonance imaging. Two methods, (1) data driven and (2) model based, were used to estimate and compare the intraregional FC between both groups during the resting state (RS). The first approach using independent component analysis was applied to investigate five RS networks: the default mode network, salience network (SN), left frontoparietal networks (LFPN) and right frontoparietal networks, and the sensory motor network (SMN). The second approach used a priori selected seed regions demonstrating abnormal regional cerebral blood flow (rCBF) in ME/CFS patients at rest. In ME/CFS patients, Method-1 identified decreased intrinsic connectivity among regions within the LFPN. Furthermore, the FC of the left anterior midcingulate with the SMN and the connectivity of the left posterior cingulate cortex with the SN were significantly decreased. For Method-2, five distinct clusters within the right parahippocampus and occipital lobes, demonstrating significant rCBF reductions in ME/CFS patients, were used as seeds. The parahippocampal seed and three occipital lobe seeds showed altered FC with other brain regions. The degree of abnormal connectivity correlated with the level of self-reported fatigue. Our results confirm altered RS FC in patients with ME/CFS, which was significantly correlated with the severity of their chronic fatigue.