Personality factors predicting changes in shift work tolerance: A longitudinal study among nurses working rotating shifts

Abstract

The aim of the present study was to investigate the relationship between personality factors (hardiness, morningness, flexibility, and languidity) and longitudinal changes on different measures of shift work tolerance (fatigue, sleepiness, anxiety and depression) over one year among nurses working rotating shifts. A total of 642 female Norwegian nurses working in a rotating three-shift schedule participated in the study. The cohort was established by age-stratified selection among members of the Norwegian Nurses Association in 2008. Questionnaires were administered in 2008/2009 (T1) and in 2009/2010 (T2). The results showed that hardiness was negatively related to fatigue, anxiety and depression at T2 when controlling for the scores on these constructs at T1. Morningness was not related to any indicators of shift work tolerance at T2 when controlling for shift work tolerance at T1. Flexibility was negatively related to anxiety at T2 when controlling for anxiety at T1. Languidity was positively related to sleepiness and fatigue at T2 when controlling for sleepiness and fatigue at T1. The findings indicate that personality factors, especially hardiness, can predict changes related to shift work tolerance over a period of one year.     

Editorial statement: Stress and work compensation

Shift work has been reported to predict health problems, and a possible explanation is that shift work may lead to poorer health habits, thereby increasing a person's vulnerability to illness. This study examined the association between shift work and health habits, as indicated by smoking, alcohol intake, physical activity and by being overweight. A questionnaire was sent to all 2795 female nurses working in the 10 hospitals of two Finnish health care districts. From the 2299 respondents, we selected those 506 shift workers who reported having always done shift work and those 183 day workers who had never done shift work. Shift workers were found to smoke more and to be overweight more often than day workers. These differences gradually increased in each successive age group, being 1.94 pack-years in smoking and 0.9 kg m^-2 in body mass index among nurses over 45 years of age. Shift work was not associated with alcohol intake or sedentary lifestyle. This evidence is compatible with the possibility that shift work in nurses increases smoking and being overweight to a degree that contributes to health problems, including coronary heart disease.     

Does shift work lead to poorer health habits? A comparison between women who had always done shift work with those who had never done shift work

Shift work has been reported to predict health problems, and a possible explanation is that shift work may lead to poorer health habits, thereby increasing a person's vulnerability to illness. This study examined the association between shift work and health habits, as indicated by smoking, alcohol intake, physical activity and by being overweight. A questionnaire was sent to all 2795 female nurses working in the 10 hospitals of two Finnish health care districts. From the 2299 respondents, we selected those 506 shift workers who reported having always done shift work and those 183 day workers who had never done shift work. Shift workers were found to smoke more and to be overweight more often than day workers. These differences gradually increased in each successive age group, being 1.94 pack-years in smoking and 0.9 kg m^-2 in body mass index among nurses over 45 years of age. Shift work was not associated with alcohol intake or sedentary lifestyle. This evidence is compatible with the possibility that shift work in nurses increases smoking and being overweight to a degree that contributes to health problems, including coronary heart disease.     

Dealing with shift work: Physical fitness, temperature, and napping

This paper reviews the effects of generally controllable factors such as physical conditioning, ambient temperature, and amount of prior sleep in adjustment to night work periods and shift work. One can expect a 5-10% decline in capacity for work in nocturnal work periods as compared to daytime work periods. This decreased capacity would dissipate if workers maintained a consistent sleep-wake routine for 8-16 days after moving to a new shift. Proven means for accelerating this adaptation are currently not available. The ability to perform work also declines as the length of the work period increases but depending upon individual tasks. Physical conditioning improves mood and general well-being, but no strong evidence currently indicates that conditioning increases tolerance or adjustment to shift work.

Increased ambient temperature increases the stress of work, although studies do not address heat as a factor in adjustment to shift work. While lower nocturnal temperature would be assumed to reduce heat stress during night shifts, supporting data does not exist. Studies have not addressed the negative consequences of cold stress or of rotating from night to day shifts with added heat stress.

The proper use of short sleep periods either as preparation for or as a response to a shift change can ameliorate some effects of shift rotation. Data indicate that performance on 'graveyard' shifts can be maintained close to baseline levels following true prophylactic naps while performance may decline by up to 30% when such naps are not taken. While there is evidence that naps or even rest periods without sleep are beneficial in improving mood in normal young adults, these data do not apply to 'replacement' naps. Studies of interjected naps imply that such naps do reduce sleep debt but do not imply that such naps are more beneficial than longer sleep periods. Naps appear to be most advantageous when the accumulated sleep debt is least.     

On-shift and daily variations in self-report and performance measures in rotating-shift and permanent night nurses

An intensive study was conducted of the influence of type of shift system, type of shift, and time-into-shift on a battery of on-shift and daily measures obtained from 61 female nurses over a 28-day period. Thirty-two rotating-shift nurses and 28 permanent night nurses recorded data on a hand-held computer at the start and end of each day, and every 2-h during their shifts. The measures included a sleep diary, self-ratings of mood, workload, and personal disruption, and two cognitive performance tasks. These results suggest that the permanent night nurses were no worse off and for some measures were actually better off than the rotating-shift nurses after controlling for differences in age and shiftwork experience; the night-shift was problematic for the rotating-shift nurses but so was the early shift; mood deteriorated and reaction time got slower over the course of the night-shift but extra long responses (which may correspond to lapses of attention) and rated workload were lower on the night-shift. The relatively large number of consecutive night-shifts worked by the rotating-shift nurses, the uneven distribution of workload between shifts, and the long night-shift may have contributed to these results.     

On-shift and daily variations in self-report and performance measures in rotating-shift and permanent night nurses

Abstract

An intensive study was conducted of the influence of type of shift system, type of shift, and time-into-shift on a battery of on-shift and daily measures obtained from 61 female nurses over a 28-day period. Thirty-two rotating-shift nurses and 28 permanent night nurses recorded data on a hand-held computer at the start and end of each day, and every 2-h during their shifts. The measures included a sleep diary, self-ratings of mood, workload, and personal disruption, and two cognitive performance tasks. These results suggest that the permanent night nurses were no worse off and for some measures were actually better off than the rotating-shift nurses after controlling for differences in age and shiftwork experience; the night-shift was problematic for the rotating-shift nurses but so was the early shift; mood deteriorated and reaction time got slower over the course of the night-shift but extra long responses (which may correspond to lapses of attention) and rated workload were lower on the night-shift. The relatively large number of consecutive night-shifts worked by the rotating-shift nurses, the uneven distribution of workload between shifts, and the long night-shift may have contributed to these results.     

Causes of accidents and the time of day

Abstract

The relationship between accidents and the time of day is not entirely clear. Although there is considerable evidence that performance is poorest in the early morning hours compared to at all other times, the degree to which this is translated into accidents is not understood. In this study work-related fatal accidents were analysed to determine whether the causes of these accidents vary with time. The analysis used a classification and coding system devised to describe the wider circumstances of the causes of fatalities. In terms of absolute numbers, fatalities were most common in the late morning or early afternoon. When these results were expressed in terms of the estimated number of workers at work, the proportion of fatal accidents occurring at night was more than double that occurring during the day. Behavioural factors were the most common cause of fatalities at all times, but most common in the early hours of the morning. Further analysis of the nature of the behavioural involvement showed that errors in automatic processing (skill-based errors) were the most common types of error and did not vary much with time of day. Rule-based errors were most common during the day whereas knowledge-based errors occurred mainly in the afternoon and night shifts. These results cast some doubt on the assumption that there is a direct relationship between the previously observed variations in performance across time and the ultimate safety outcome.     

Countermeasures for night work performance deficits: The effect of napping or caffeine on continuous performance at night

Napping and caffeine consumption, two common strategies for improving alertness and performance on the night shift, were investigated in two separate studies. Performance was measured with a simulated assembly line task (SALT) during a single night work shift. Both strategies proved beneficial. Performance and subjective alertness were improved following either a 2.3-h evening nap or ingestion of caffeine (4 mg/kg) prior to the work shift. The effects were noted particularly at the trough of circadian alertness. Although neither napping nor caffeine countered the strong circadian influence on performance and alertness in the early morning hours, both strategies attenuated their sharp decline. Further research is required to determine the generalizability of these findings beyond a single night shift and in different populations of workers, such as older age groups, or chronic caffeine users.     

Psychological and physiological stress responses during repetitive work at an assembly line

The association between psychological and physiological stress responses was examined in 20 male workers at an assembly line. Each worker was studied during a 2 h period on two consecutive days in their normal job and, in order to obtain physiological baseline values, during a corresponding paid 2 h period off the job on the third day. Self-reports of work demands, mood, etc., measurements of catecholamine and cortisol excretion and of systolic and diastolic blood pressure and heart rate were obtained at the end of each of the three 2 h periods. Work induced a significant elevation in almost all psychological and physiological measurements. Levels were consistently lower in workers reporting a 'good' workday compared to those reporting a 'normal' or a 'bad' day. Correlations between self-reports and physiological values showed that catecholamine and cortisol responses, respectively, tended to be associated selectively with different psychological conditions, catecholamine values being associated with feelings of time pressure and pressure by demands, cortisol values with irritation, tenseness and tiredness. The results show that perceived stress at an assembly line is consistently reflected in cardiovascular and neuroendocrine functions of the workers.     

Does 'hardiness' predict adaptation to shiftwork?

This longitudinal study examined whether the dimensions of hardiness (commitment, control and challenge) predicted psychological symptoms and dissatisfaction with shiftwork, and whether or not the relationships identified were confounded with neuroticism and extraversion. Female nurses were studied during their first 15 months of shiftwork. Thirty-six nurses worked on a 2-shift (day and evening) schedule throughout and 66 transferred from the 2-shift schedule to a 3-shift (day, evening and night) schedule after 6 months. Hardiness, neuroticism, extraversion and symptoms were measured before the respondents began shiftwork (Stage 1). Symptoms and dissatisfaction were measured after 6 months (Stage 2) and 15 months (Stage 3). Multiple regressions indicated that the hardiness dimensions did not predict dissatisfaction at Stages 2 or 3, or symptoms at Stage 3. They also failed to buffer the effect of night-work on symptoms. However, commitment did predict symptoms at Stages 1 and 2 and challenge predicted symptoms at Stage 2. Although these effects were confounded with neuroticism, commitment showed weak evidence of independent prediction. In general, hardiness was a very poor predictor of shiftwork tolerance.     

The psychosocial work environment of district nurses in Sweden

Data were collected from a stratified sample of district nurses in the greater Stockholm area on four occasions during one year using questionnaire techniques (to assess psychosocial working conditions and social networks, and self-reported health sums); as well as physiological measurement techniques. Three groups of district nurses were compared: group A, those working independently in the 'traditional' role but outside primary health care centres; group B, those working independently in the 'traditional' role but in primary health care centres; and group C, those working in the model role as part of primary health care teams. The study focused on the effects of these different work environments on the district nurse's psychological and somatic health, and their physiological state.

The data suggested that district nurses in the primary care teams (group C) had a lower objective work load than those working in the more traditional role. Despite this, they reported a less favourable balance (ratio) of work demands to decision latitude. They reported more 'problems' and 'conflicts' at work than did the other district nurses. However, such 'problems' were diminishing during the study period, which could mean that successive adaptation to the 'new' situation was occurring. The 'conflicts', on the other hand, remained. This may indicate that despite this adaptation, the district nurses in the primary care teams were struggling with their new work roles. It points to the need for organizational support during this important change process. The district nurses in group B (traditional role but in a primary health care centre) had the highest objective work load and showed physiological reactions in terms of elevated plasma cortisol levels in the morning, high systolic blood pressure and sleep disturbances.     

Sleep disturbances in shift-workers: A marker for maladaptation syndrome

Abstract

This study aims to examine whether the relationship between overtime and well-being is influenced by the voluntary vs. involuntary (i.e., compulsory) nature of overtime work and by the presence or absence of rewards for overtime. We also explored the prevalence of these types of overtime and how they were related to work and personal characteristics. A survey was conducted among a representative sample of Dutch full-time employees (N=1612). AN(C)OVA was used to compare rewarded and unrewarded, voluntary and involuntary overtime workers on personal and work characteristics, fatigue, and work satisfaction. Most overtime workers were rewarded (62%). About half of the sample (n=814) could be classified as either voluntary or involuntary overtime workers, or as having “mixed reasons” to work overtime. Voluntary and unrewarded overtime workers had a relatively high income and favourable job characteristics. Involuntary overtime work was associated with relatively high fatigue and low satisfaction, especially for involuntary overtime workers without rewards who can be considered a burnout risk group. Voluntary overtime workers were non-fatigued and satisfied, even without rewards. It can be concluded that control over overtime and rewards for overtime are important for well-being. Moderate overtime work may not be a problem if it is done voluntarily. Moreover, the negative effects of compulsory overtime work may be partly offset by fair compensation for the extra work.     

Using pharmacological aids to improve waking function and sleep while working at night

Non-refreshing or insufficient sleep, and impaired alertness on the job, are two nearly universal consequences of night work. The effects of drugs upon the sleep and alertness of night workers has only recently been studied and much work remains to be done. To date, it is clear that sleep during the day can be improved with sedative-hypnotic compounds, particularly the benzodiazepines. Despite improvement in sleep, alertness at night is improved only mildly, if at all, with short-acting sleeping agents and can be further impaired with long-acting drugs. The limited research examining alertness and performance during night shift hours after administration of CNS stimulants suggests significant benefits. The judicious use of CNS stimulants in this way needs further exploration. Precise pharmacological manipulation of the endogenous sleep/wake rhythm is primarily theoretical at this time but should be pursued.     

Trajectories of effort-reward imbalance in Swedish workers: Differences in demographic and work-related factors and associations with health

ABSTRACT

The aim of the study was to identify trajectories of effort-reward imbalance (ERI), to examine these with respect to demographic (age, gender, socio-economic position) and work-related (employment contract, work hours, shift work, sector) factors, and to investigate associations with different health indicators (self-rated health, depressive symptoms, migraine, sickness absence). The study used four waves of data (N?=?6702), collected biennially within the Swedish Longitudinal Occupational Survey of Health (SLOSH). Using latent class growth modelling, we identified four trajectories: a stable low imbalance trajectory, which comprised 90% of all participants, and three change trajectories including a decreasing trajectory (4% of the participants), an inverted U-shaped trajectory and an increasing imbalance trajectory, both in 3% of the participants. Results indicate that a sizeable proportion of Swedish employees’ experience imbalance between efforts and rewards at work. The most favourable trajectory comprised relatively more men and was characterised by better work-related characteristics than the less favourable ERI trajectories. All change trajectories were dominated by women and employees in the public sector. Health developments followed ERI trajectories, such that less favourable trajectories associated with impaired health and more favourable trajectories associated with better health. Sickness absence increased among all ERI trajectories, most so for the decreasing and increasing ERI trajectory.     

The many meanings of sleep

Reductions in sleep are concomitant with night shift work. Data are presented showing that these robust differences in sleep are even present in experienced permanent night shift workers who most prefer to work nights. A model is presented which relates these reductions to chronic sleep deprivation. This, in turn, may be associated with performance decrements, and lead to accidents and illness. Better work schedule selection, worker training programs, and preventive medical action are unproven but promising approaches to overturning this model.     

Impact of shift work and department type upon strain and attitudinal measures of hospital nurses

The effects of shift work (fixed versus rotating), type of hospital department (intensive care unit versus non-ICU), and job scope on stress and attitudes have been reported previously. The goal of the present study was to examine the interactive, as well as individual, impact of these variables on measures of perceived work stress, strain, work satisfaction and withdrawal intentions. Respondents in the study were nurses in a large general hospital in Israel. None of the two- or three-way interactions received empirical support. However, significant multivariate main effects for each of the three independent measures were found. The negative influence of rotating work shift compared to fixed work shift was supported. Nurses who thought that their job was more enriching were more satisfied and perceived their workload as being lower. Department type affected only burnout level; nurses in non-ICUs were lower in burnout. Several theoretical and practical possible interpretations and possible implications are presented.     

Health, well-being and burnout of ICU nurses on 12- and 8-h shifts

It is generally agreed that some features of shift systems can influence the extent of well-being and health problems experienced by the workers involved. Extended working days (9-12 h) have been found to aggravate some problems associated with shiftwork, especially when the work is mentally and emotionally demanding. The aim of the study was to compare measures of health, sleep, psychological and social well-being, job satisfaction and burnout of ICU nurses on 12- and 8-h shifts. The groups of subjects were matced for age, length of shiftwork experience, marital status and number of hours worked. the 12-h shift nurses, when compared to their 8-h shift colleagues, experienced more chronic fatigue, cognitive anxiety, sleep disturbance and emotional exhaustion. Job satisfaction seems to be independent of the shift duration. The nurses on 12-h shifts reported less social and domestic disruption than those on 8-h shifts. The 12-h shift nurses showed worse indices of health, well-being and burnout tan the 8-h shift nurses. It is suggested that this may be associated with their longer daily exposure to the stress of work. The increased number of rest days of 12-h shift nurses seems tobe insufficient to dissipate the adverse health and well-being effects that built up over their longer shifts.     

Leader support and responses to work in US nurses: A test of alternative theoretical perspectives

A number of theoretical perspectives as well as common wisdom suggest that leader support is important for alleviating or preventing dysfunctional effects of stress at work. Other perspectives suggest that task characteristics also serve a supportive function. In this study, data from 97 nurses in a paediatric hospital were used to compare the utility of the path-goal theory of leadership, social support theory and substitutes for leadership theory for explaining the impact of leader support on satisfaction and anxiety responses of workers. In addition, the relative impact of leader support and enriched tasks on worker affect was explored. Results suggest that social support theory was able to predict most findings regarding leader support, and that leader support is more important than task to predictions of satisfaction of workers and autonomy is more important to relieving anxiety of workers. The study extends findings about the general value of leader support for managing, but the need to clarify the mechanisms through which the effects occur is emphasized.     

Occupational stress and cardiovascular reactivity in blue-collar workers

This study analyses the influence of chronic occupational stress on cardiovascular reactivity (heart rate [HR] and blood pressure [BP] elevation from baseline to maximal challenge) during a standard mental stress test (modified version of the STROOP colour word interference test). The test was applied to a sample of 190 healthy male blue-collar workers at the end of a regular working day. Our research hypothesis was based on the assumption that sustained autonomic activation due to chronic occupational stress may reduce cardiovascular responsiveness to challenge: workers defined by high level of chronic occupational stress exhibited lower maximal HR and BP elevations under challenge as compared to workers with low levels of stress. Three distinct indicators of occupational stress were derived from structured interviews: 'cumulative workload', 'worsening of job conditions', and 'high demand and low job security'. Statistical analysis, using ANOVA, showed that all main effects of chronic stress were in the expected direction (6 of 9 effects were statistically significant at the 0'05 level). These effects remained stable after adjusting for age, hypertensive status, physiological baseline level, cigarette smoking, test performance, and individual style of coping. In summary, cardiovascular reactivity under experimental challenge is modulated by an individual's experience of chronic occupational stress.     

Psychological stress-factors and concentration of immunoglobulins and complement components in Norwegian nurses

Psychological stress produces immunological changes in animals, and increasing evidence suggests that this may also be true for humans. In the present study of 34 nurses in a busy ward of a Norwegian hospital, significant relationships have been demonstrated between die plasma levels of immunoglobulins and complement components and work-related 'stress', anxiety, and cognitive defence strategies. The main components of die work-related stress experience were role-stress and nonparticipation in decision-making.

The results indicate chat immunological parameters may perhaps be used as a psychological stress indicator, but the relationships are complex and can best be understood if individual coping and defence mechanisms are considered. Health symptoms were also examined, but these were not related to stress experience or immunological measures.