Jane Barton

The Standard Shiftwork Index: a battery of questionnaires for assessing shiftwork-related problems

Abstract The lack of standardization in shiftwork research has been recognized. In response, a battery of selfreport questionnaires has been developed, which might usefully be employed in assessing the impact of different types of shift systems on large groups of individuals. The scales included reflect the most pertinent issues within shiftwork research, and were chosen on the basis of being both relatively short, easy to administer, and having good psychometric properties. The scales fall broadly into three main categories: outcomes, relating to the actual problems experienced by the individuals concerned; modifiers, relating to those differences between individuals which may serve to moderate the impact of shiftwork; and general, including work context and shift system details. Suggestions as to how the questionnaires might usefully be employed are offered. Based on the results of a large sample of nurses and midwives, and a second sample of industrial and service workers, the present paper offers: a s...

Choosing to work at night: a moderating influence on individual tolerance to shift work.

The author looked at the impact of choosing to work at night on individual tolerance to shift work. The relative importance of individual circumstances and personality type in influencing this decision was examined. Five hundred eighty-seven nurses and midwives completed measures of physical and psychological health, difficulties with sleep, social and domestic disruption, flexibility of sleeping habits, morning versus evening preferences, and reasons for engaging in shift work. Results high-lighted the advantages of choosing to work at night, rather than engaging in night work as part of a rotating-shift schedule, on tolerance to shift work. The individual circumstances of the shift workers were particularly important in influencing whether they chose to work at night. These results offer some support for the maintenance of permanent night-shift schedules and have implications for the future design of shift systems.

Recovery from work shifts: how long does it take?

Although regulations on work hours usually include a minimum weekly rest period, there is little empirical evidence concerning recovery from work. Shift-working nurses (N = 61) used a handheld computer for 28 days to complete self-ratings, cognitive-performance tasks, and a sleep diary. Many measures were worse on rest days that followed a night shift rather than a day shift and tended to be worse on first rest days compared with subsequent rest days. Alertness was lowest on the 1st rest day following a night shift. Social satisfaction was better on workdays that were preceded by 2 rather than 1 rest day. Reaction time decreased over consecutive night shifts and tended to increase over rest days following night shifts. The results are interpreted as being consistent with the combined adaptive costs of fatigue and adjustment to and from a nocturnal routine. The practical implications for scheduling rest days are considered.

Is there an optimum number of night shifts? Relationship between sleep, health and well-being

By concentrating on the impact of a specific shift-system feature on the well-being of those concerned, rather than on the impact of the shift system as a whole, one might be able to offer more meaningful suggestions as to what constitutes a better form of shift system. The present study focused on the impact of the number of consecutive night shifts worked on the health and well-being of two groups of nurses (permanent night and rotating shift). All nurses completed a copy of the Standard Shiftwork Index, which is a set of questionnaires designed for comparing the effects of different types of shift system on large groups of workers. It includes measurements of psychological ill-health, physical ill-health, chronic fatigue, social and domestic disruption, attitudes towards shiftwork, sleep quality and sleep habits. Results showed clearly the impact of the number of consecutive nights worked on health and well-being, not directly, but indirectly through the impact on sleep duration and sleep quality. Sleep duration was shown to increase with more consecutive nights worked. This in turn was found to predict sleep quality, which in turn was found to be the stronger direct predictor of psychological and physical ill-health i.e. better health was associated with longer and better quality sleeps. Explanations in terms of circadian adaptation are discussed.

Advancing versus delaying shift systems

Two hundred and sixty-one shiftworkers from a range of UK industrial and service organizations, took part in a study to determine the impact of the direction of shift rotation on the health and well-being of the individuals concerned. All the systems were continuous, rotating over three shifts. Systems were classified according to whether they delayed (i.e., rotated in a forward direction) or advanced (i.e., rotated in a backward direction). In addition, advancing systems were divided into those which incorporated a quick return (i.e., a break of only 8 h when changing from one shift to another) and those which did not. The results add some support for the use of delaying as opposed to advancing systems, and highlight the detrimental effects of incorporating a quick return into an advancing system.

A process model of shiftwork and health

The authors developed and tested a process model of adaptation to shiftwork, which hypothesizes that various individual and situational variables influence the development of sleep and social and domestic disturbances. Both types of disturbances trigger various types of coping behavior, leading to several proximal outcomes. The end result is the development of chronic health problems in the form of digestive and cardiovascular symptoms. The model was tested with survey data collected from 2 samples of nurses (N = 1,532) in the United Kingdom and was cross-validated against a 3rd sample of industrial workers (N = 370). Results indicate support for the model across the 3 samples, although some sample-specific and subgroup effects were found. Results have direct implications for the development of shiftwork theory and interventions.

Comparison of eight and 12 hour shifts: impacts on health, wellbeing, and alertness during the shift.

OBJECTIVES: The generally agreed view is that there is no ideal shift system, and that most systems will have both advantages and disadvantages. As such, attention has been placed on trying to identify good and bad features of shift systems, with a view to minimising the possible ill health as a consequence of shiftwork. The present study focuses on the duration of the shift and looks at the implications for individual health, wellbeing, and alertness during the shift of extending the shift from the traditional eight hours to 12. METHODS: Two groups of chemical workers, one working 12 hour shifts and the other working eight hour shifts, took part. All completed a modified version of the standard shiftwork index (SSI), a set of self reported questionnaires related to health and wellbeing. RESULTS: The two groups did not differ on most outcome measures, although the differences that did exist suggested advantages for the 12 hour shift workers over the eight hour shift workers; with the notable exception of rated alertness at certain times of day. CONCLUSIONS: The results are explained in terms of the design of the 12 hour shift system and the specific sequencing of shifts that seem to minimise the potential for the build up of fatigue. Although the current data moderately favour 12 hour shifts, a cautionary note is sounded with regard to the implications of the alertness ratings for performance and safety.

Does individual choice determine shift system acceptability

The relationship between individual control of hours of work and tolerance of shiftwork was examined in a group of nurses and midwives. Two levels of individual control were studied: (i) choosing to work on a regular shift system, e.g. a permanent night shift; and (ii) working on a flexible, rotating shift system where individual choice of shift-sequencing is taken into account. Greater tolerance to shiftwork was found to be associated with more control over hours of work. The advantages of flexible as opposed to irregular shift-rostering, and of choosing to work on a regular permanent night shift were highlighted clearly. The results offer some contribution to the permanent night versus rapidly-rotating shift system debate.

Effects on health of a change from a delaying to an advancing shift system.

OBJECTIVES--Shift work can lead to a range of problems for some people that seem to result from the disturbance of the circadian system, and can broadly be classified as: disturbances of sleep, impaired physical and psychological health, and disturbed social and domestic life. The main attempt to try to reduce these problems has focused on the design of the shift system, and the identification of the most problematic features of the shift system. One such feature is believed to be the direction of shift rotation. Systems that advance are thought to be more problematic than those that delay. The present study examines the change in the direction of shift rotation from a delaying to an advancing system on health and wellbeing. METHODS--Self reported measures of tolerance to shift work were taken two months before and six months after the change. These included sleep difficulties, gastrointestinal problems, psychological ill health, chronic fatigue, social and domestic disruption, job satisfaction, and satisfaction with the shift system. RESULTS--The change from a delaying to an advancing system resulted in an increase in sleep difficulties between successive afternoon shifts, but a decrease in social disruption. There was little evidence of impaired health on the advancing compared with the delaying system. CONCLUSIONS--The increase in sleep difficulties was thought to result from the undesired adaptation of the circadian system to night work, as a result of the afternoon shifts now following a series of night shifts, whereas previously they followed a series of morning shifts. The decrease in social disruption was thought to result from the specific sequence of the shifts and the discontinuous nature of the shift system, in particular, the long week-end off every third week. Lack of reported health related differences are explained in terms of the relatively unharmful nature of the shift system in question, and the relatively short time span over which the study was conducted.

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-...