Compensation for inconvenience: The utility of shift systems

Abstract

This study is part of a larger study airned at the development of a system for quantifying the inconvenience of shift schedules and schedule characteristics. The results can be used to reduce inconvenience (counter-value compensation) and to compute the monetary (counter-weight) compensability of shift schedules. The results presented here show that consensus exists among subjects from different organizations and with different background characteristics on the utility of several features, e.g. working at inconvenient hours, the irregularity of a schedule, and working during the evening (which has a positive value). The opinions slightly differ with respect to some other characteristics, such as very long shifts, work during the weekend and the average sequence length. The differences are possibly due to job characteristics.     

Appropriate use of bright light promotes a durable adaptation to night-shifts and accelerates readjustment during recovery after a period of night-shifts

Abstract

The present study examines the stability of bright light circadian readjustment during two consecutive dim light night-work periods and circadian synchronization during the recovery after a night-shift period. A sample of 10 subjects was divided into 2 groups (control group: 6 subjects; experimental group: 4 subjects). All subjects worked during 5 days, between 23:00 and 07:00 h and then went to sleep. Subjects received 2500-3000 lux between 02:00 and 05:00 h during 5 days for the control group and 3 days for the experimental group. During recovery after the night-shift periods, three cycles of bright light were administered at two different times: 12:00-15:00 h for two of six subjects from the control group and 10:00-13:00 h for all subjects (4) of the experimental group. By the fifth cycle of night-work the maximum of urinary aMT6s excretion that occurs at 05:00 h in the baseline condition was shifted to 12:00 h for the control and experimental groups (delay in hours: 7±1.6 (control); 7±1 (experimental)). This result suggests that three cycles of bright light are sufficient to induce a significant phase delay and that this delay remained stable when night-work proceeded under dim light. The phase delay of the circadian aMT6s excretion by exposure to bright light was accompanied by an improvement of the quality of day sleep and level of cognitive and psychomotor performances for control and experimental groups. No significant difference was observed in the two groups for daytime sleep and nocturnal performance. The two bright light periods used during the three days of recovery induced a complete synchronization in five of six subjects. One subject showed a partial synchronization probably because he remained at the laboratory under dim light during the day and had few family and social contacts.     

Psychophysical conditions of air traffic controllers evaluated by the standard shiftwork index

Abstract

In the ambit of a large epidemiological survey on the Italian population of air traffic controllers, an evaluation of their health conditions was carried out using the Standard Shiftwork Index (SSI). The study took into consideration 572 male air traffic controllers, aged between 23 and 59 years, of whom 301 were engaged in three large Regional Centres, 189 in thirteen Airport Towers and 82. formerly active controllers, were working in administrative offices. The former controllers showed worse health levels, in particular minor psychological disorders and chronic fatigue. Sixteen of them had been transferred to administrative jobs because of health impairment, owing to severe diseases of the nervous, gastrointestinal and cardiovascular systems. Such disorders, and musculoskeletal ones, were mostly reported by the active controllers. The controllers engaged in Regional Centres showed more sleep disturbances than those engaged in towers. Beside age, some personal characteristics appeared to influence health and well-being. Neuroticism was correlated with chronic fatigue, digestive and cardiovascular complaints, minor psychological disorders, cognitive and somatic anxiety. On the other hand, morningness was correlated negatively with sleep disturbances on morning shift, and positively with sleep duration both on morning shift and rest days.     

Men and women who like continuous shiftwork are more ‘hardy’: But what does it mean?

Abstract

Continuous shiftworkers of both genders who like shiftwork and report fewer digestive problems have higher scores on hardiness than those who dislike shiftwork. Whether this is a causal, consequential or accidental relationship requires a longitudinal investigation. It is also not clear how far ‘hardiness’ is a personality measure, a behavioural style, a coping strategy, or a consequence of the stress of shiftwork.     

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.     

Editorial: Women and work

Abstract

When compared to day workers, night-shift workers report that they eat fewer meals, have poorer appetites, are less satisfied with their eating habits, and eat at different times of the day. When demographic variables are held constant, there do not appear to be any significant differences between experienced day and night-shift workers in caffeine or alcohol consumption. Exceptions to and variations in these findings are probably due to the background influences of social and cultural variables. Eating and drinking behaviours do effect human performance and mood, but little relevant data have been gathered from experienced night-shift workers. There are no shiftworker data evaluating the effectiveness of the special diets or dietary recommendations that have been proposed for use by night-shift workers. Thus, attempts to manipulate night-shift worker eating and drinking habits require experimental test.     

Effects of various types of change in shift schedules: A controlled longitudinal study

Abstract

Data from a longitudinal study accompanying changes in shift rotas connected with a shortening of working time in the chemical industry are presented. Altogether 260 subjects forming five experimental groups participated in both the pretest and the posttest. The effects of the change in shift schedules were controlled by the inclusion of five groups in which 139 subjects participated in both tests. Five types of change in shift schedule were investigated. The purpose was to determine to what extent similar, but in some aspects differing, types of change in shift schedule varied from one another in their effects on those involved, and on which factors their attitudes towards the new shift systems depended with regard to various types of schedule change. The effects of a change in shift schedule were tested by means of the 4-group investigation design developed by Solomon (1949). The results confirm that differences in the effects of new shift systems depend on the type of change. Only in three experimental groups were improvements in health and social life observed. One experimental group showed significant signs of deterioration in subjective health. In the analyses of the factors influencing the attitude of the shiftworkers towards the new shift system, differences in the structure of the influencing factors between the experimental groups were observed. The causal analysis was used in order to test how important the factors found in each group were and which of them were dominant. It showed that the most influential factors dominated so much that the disturbances in the less influential ones lost their importance. In spite of the number of indicators analysed regarding their influence on attitude in this study, further important factors seem to exist that have not been analysed here.     

Sleep hygiene practices and sleep duration in rotating-shift shiftworkers

Abstract

Alcohol, caffeine and tobacco intake, exercise, activities on going to bed, and sleep-enhancing measures were assessed in 72 rotating-shift shiftworkers to determine whether these variables differ following day shifts and night-shifts, and which are related to sleep duration. Only alcohol intake and exercise prior to sleep, and feeling drowsy when retiring, differed following the night-shift. Workers generally followed recommendations concerning alcohol intake, sleeping immediately on retiring, and exercising, but acted contrary to recommendations concerning caffeine and nicotine intake. The only behaviour clearly associated with poor sleep was smoking, which reduced sleep duration.     

Relationships among shiftworker eating habits, eating satisfaction, and self-reported health in a population of US miners

As part of a larger study on the health and safety of shiftworkers in the mining population by the US Bureau of Mines, the association between meal frequency, meal regularity, eating satisfaction and a self-reported health index was examined. Although the link between shiftwork and some health complaints, such as gastrointestinal disorders, has been established, the research needed to understand why this occurs has not been fully undertaken. Specifically, academic nutritional research has substantially ignored the question of how working irregular hours affects the eating behavior of industrial workers such as miners. In this study the eating habits of 101 surface mine workers were studied. It was found that working the day, afternoon/evening, and night-shifts was related to the number of meals eaten on those shifts and to the consistency of timing of those meals. The lowest eating satisfaction levels were reported by those who ate at different times on all shifts and who changed the number of meals eaten per day on each shift. Lowest self-reported health ratings were reported by those who changed the number of meals taken on each shift, rather than by those who ate one, two or three meals per day. These results are discussed in relation to the possible mechanisms contributing to gastrointestinal disorders and to coping mechanisms that could be adopted by shiftworkers.     

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.