Fighting fire and fatigue: sleep quantity and quality during multi-day wildfire suppression

This study examined firefighters' sleep quantity and quality throughout multi-day wildfire suppression, and assessed the impact of sleep location, shift length, shift start time and incident severity on these variables. For 4 weeks, 40 volunteer firefighters' sleep was assessed using wrist actigraphy. Analyses revealed that the quantity of sleep obtained on fire days was restricted, and pre- and post-sleep fatigue ratings were higher, compared to non-fire days. On fire days, total sleep time was less when: (i) sleep location was in a tent or vehicle, (ii) shifts were greater than 14 h and (iii) shifts started between 05:00 and 06:00 h. This is the first empirical investigation providing objective evidence that firefighters' sleep is restricted during wildfire suppression. Furthermore, sleep location, shift length and shift start time should be targeted when designing appropriate controls to manage fatigue-related risk and preserve firefighters' health and safety during wildfire events. Practitioner Summary: During multi-day wildfire suppression, firefighters' sleep quantity was restricted, and pre- and post-sleep fatigue ratings were higher, compared to non-fire days. Furthermore, total sleep time was less when: (i) sleep occurred in a tent/vehicle, (ii) shifts were >14 h and (iii) shifts started between 05:00 and 06:00 h.

Associations between firefighters' physical activity across multiple shifts of wildfire suppression

The aim of this study was to examine the associations between firefighters' physical activity levels across consecutive wildfire suppression shifts and to determine whether sleep duration moderated these associations. Forty volunteer firefighters (31 males, 9 females) wore an activity monitor to concurrently measure physical activity and sleep duration. Sedentary time and time spent in light- (LPA), moderate- (MPA), and vigorous-intensity physical activity (VPA) during each shift were determined using monitor-specific cut points. During any given shift, every additional 60 min spent in LPA was associated with 7.2 min more LPA and 27.6 min MPA the following shift. There were no other significant positive or negative associations. No significant moderating effect of total sleep time was observed. Firefighters are able to maintain and/or increase their physical activity intensity between consecutive shifts. Further research is needed to understand firefighters pacing and energy conservation strategies during emergency wildfire deployments. Practitioner Summary: To examine associations between firefighters' physical activity levels across consecutive shifts during a multi-day emergency wildfire and determine whether sleep duration moderated these associations. Firefighters are able to maintain and/or increase their physical activity intensity between consecutive shifts. No significant moderating effect of total sleep time was observed.

Estimating long-haul airline pilots' at-home baseline sleep duration

OBJECTIVE

Characterize the baseline sleep of long-haul airline pilots.

METHODS

Sleep of 332 pilots (median age = 51 years, range = 23-64 years) from 4 airlines was measured by actigraphy while at home and off-duty and by retrospective estimate of the total amount of nighttime sleep usually obtained at home.

RESULTS

Mean actigraphic sleep per 24 hours during baseline periods was 6.8 hours (SD = 1.0 hour), 52 minutes shorter than mean self-reported usual nighttime sleep (7.6 hours, SD = 1.1 hours).

CONCLUSIONS

Pilots' self-reported sleep duration was comparable to weekend sleep of men in general population samples, but their actigraphic baseline sleep was longer than objectively monitored sleep of other samples. Long-haul pilots routinely experience sleep restriction and circadian disruption across trips, both of which are implicated in increased health risks. We recommend that they be educated about the long-term importance for health of obtaining adequate sleep on off-duty days.

The effect of split sleep schedules (6h-on/6h-off) on neurobehavioural performance, sleep and sleepiness

Shorter, more frequent rosters, such as 6h-on/6h-off split shifts, may offer promise to sleep, subjective sleepiness and performance by limiting shift length and by offering opportunities for all workers to obtain some sleep across the biological night. However, there exists a paucity of studies that have examined these shifts using objective measures of sleep and performance. The present study examined neurobehavioural performance, sleepiness and sleep during 6h-on/6h-off split sleep schedules. Sixteen healthy adults (6 males, 26.13 y ± 4.46) participated in a 9-day laboratory study that included two baseline nights (BL, 10h time in bed (TIB), 2200 h-0800 h), 4 days on one of two types of 6h-on/6h-off split sleep schedules with 5h TIB during each 'off' period (6h early: TIB 0300 h-0800 h and 1500 h-20000 h, or 6-h late: TIB 0900 h-1400 h and 2100 h-0200 h), and two recovery nights (10h TIB per night, 2200 h-0800 h). Participants received 10h TIB per 24h in total across both shift schedules. A neurobehavioural test bout was completed every 2 h during wake, which included the Psychomotor Vigilance Task (PVT) and the Karolinska Sleepiness Scale (KSS). Linear mixed effects models were used to assess the effect of day (BL, shift days 1-4), schedule (6h early, 6h late) and trial (numbers 1-6) on PVT lapses (operationalised as the number of reaction times >500 ms), PVT total lapse time, PVT fastest 10% of reaction times and KSS. Analyses were also conducted examining the effect of day and schedule on sleep variables. Overall, PVT lapses and total lapse time did not differ significantly between baseline and shift days, however, peak response speeds were significantly slower on the first shift day when compared to baseline, but only for those in the 6h-late condition. Circadian variations were apparent in performance outcomes, with individuals in the 6h-late condition demonstrated significantly more and longer lapses and slower peak reaction times at the end of their night shift (0730 h) than at any other time during their shifts. In the 6h-early condition, only response speed significantly differed across trials, with slower response speeds occurring at trial 1 (0930 h) than in trials 3 (1330 h) or 4 (2130 h). While subjective sleepiness was higher on shift days than at baseline, sleepiness did not accumulate across days. Total sleep was reduced across split sleep schedules compared to baseline. Overall, these results show that while there was not a cumulative cost to performance across days of splitting sleep, participants obtained less sleep and reported lowered alertness on shift days. Tests near the circadian nadir showed higher sleepiness and increased performance deficits. While this schedule did not produce cumulative impairment, the performance deficits witnessed during the biological night are still of operational concern for industry and workers alike.

Effects of Shift Work on the Postural and Psychomotor Performance of Night Workers

The purpose of the study was to investigate the effects of shift work on the psychomotor and postural performance of night workers. The study included 20 polysomnography technicians working schedule of 12-h night shift by 36-h off. On the first day of protocol, the body mass and height were measured, and an actigraph was placed on the wrist of each participant. On the second day of protocol, sleepiness by Karolinska Sleepiness Scale, postural control by force platform (30 seconds) and psychomotor performance by Psychomotor Vigilance Task (10 minutes) were measured before and after 12-h night work. Results showed that after 12-h night work, sleepiness increased by 59% (p<0.001), postural control variables increased by 9% (p = 0.048), and 14% (p = 0.006). Mean reaction time, and the number of lapses of attention increased by 13% (p = 0.006) and 425% (p = 0.015), respectively, but the mean reciprocal reaction time decreased by 7%. In addition, there were correlations between sleepiness and postural control variables with opened eyes (r = 0.616, 95% confidence interval [CI] = 0.361-0.815; r = 0.538; 95% CI = 0.280-0.748) and closed eyes (r = 0.557; 95% CI = 0.304-0.764, r = 0497; 95% CI = 0.325-0.715) and a pronounced effect of sleepiness on postural sway (R2 = 0.393; 95% CI = 0.001-0.03). Therefore, 12-h night work system and sleepiness showed a negative impact in postural and psychomotor vigilance performance of night workers. As unexpected, the force platform was feasibility to detect sleepiness in this population, underscoring the possibility of using this method in the workplace to prevent occupational injuries and accidents.

Working multiple jobs over a day or a week: Short-term effects on sleep duration

Approximately 10% of the employed population in the United States works in multiple jobs. They are more likely to work long hours and in nonstandard work schedules, factors known to impact sleep duration and quality, and increase the risk of injury. In this study we used multivariate regression models to compare the duration of sleep in a 24-hour period between workers working in multiple jobs (MJHs) with single job holders (SJHs) controlling for other work schedule and demographic factors. We used data from the Bureau of Labor Statistics US American Time Use Survey (ATUS) pooled over a 9-year period (2003-2011). We found that MJHs had significantly reduced sleep duration compared with SJHs due to a number of independent factors, such as working longer hours and more often late at night. Male MJHs, working in their primary job or more than one job on the diary day, also had significantly shorter sleep durations (up to 40 minutes less on a weekend day) than male SJHs, even after controlling for all other factors. Therefore, duration of work hours, time of day working and duration of travel for work may not be the only factors to consider when understanding if male MJHs are able to fit in enough recuperative rest from their busy schedule. Work at night had the greatest impact on sleep duration for females, reducing sleep time by almost an hour compared with females who did not work at night. We also hypothesize that the high frequency or fragmentation of non-leisure activities (e.g. work and travel for work) throughout the day and between jobs may have an additional impact on the duration and quality of sleep for MJHs.

A 30-Minute, but Not a 10-Minute Nighttime Nap is Associated with Sleep Inertia

STUDY OBJECTIVES

To assess sleep inertia following 10-min and 30-min naps during a simulated night shift.

METHODS

Thirty-one healthy adults (aged 21-35 y; 18 females) participated in a 3-day laboratory study that included one baseline (BL) sleep (22:00-07:00) and one experimental night involving randomization to either: total sleep deprivation (NO-NAP), a 10-min nap (10-NAP) or a 30-min nap (30-NAP). Nap opportunities ended at 04:00. A 3-min psychomotor vigilance task (PVT-B), digit-symbol substitution task (DSST), fatigue scale, sleepiness scale, and self-rated performance scale were undertaken pre-nap (03:00) and at 2, 17, 32, and 47 min post-nap.

RESULTS

The 30-NAP (14.7 ± 5.7 min) had more slow wave sleep than the 10-NAP (0.8 ± 1.5 min; P < 0.001) condition. In the NO-NAP condition, PVT-B performance was worse than pre-nap (4.6 ± 0.3 1/sec) at 47 min post-nap (4.1 ± 0.4 1/sec; P < 0.001). There was no change across time in the 10-NAP condition. In the 30-NAP condition, performance immediately deteriorated from pre-nap (4.3 ± 0.3 1/sec) and was still worse at 47 min post-nap (4.0 ± 0.5 1/sec; P < 0.015). DSST performance deteriorated in the NO-NAP (worse than pre-nap from 17 to 47 min; P < 0.008), did not change in the 10-NAP, and was impaired 2 min post-nap in the 30-NAP condition (P = 0.028). All conditions self-rated performance as better than pre-nap for all post-nap test points (P < 0.001).

CONCLUSIONS

This study is the first to show that a 10-min (but not a 30-min) nighttime nap had minimal sleep inertia and helped to mitigate short-term performance impairment during a simulated night shift. Self-rated performance did not reflect objective performance following a nap.

Effects of the Internal Circadian System and Circadian Misalignment on Glucose Tolerance in Chronic Shift Workers

CONTEXT

Shift work is a risk factor for diabetes. The separate effects of the endogenous circadian system and circadian misalignment (ie, misalignment between the central circadian pacemaker and 24-hour environmental/behavioral rhythms such as the light/dark and feeding/fasting cycles) on glucose tolerance in shift workers are unknown.

OBJECTIVE

The objective of the study was to test the hypothesis that the endogenous circadian system and circadian misalignment separately affect glucose tolerance in shift workers, both independently from behavioral cycle effects.

DESIGN

A randomized, crossover study with two 3-day laboratory visits.

SETTING

Center for Clinical Investigation at Brigham and Women's Hospital.

PATIENTS

Healthy chronic shift workers.

INTERVENTION

The intervention included simulated night work comprised of 12-hour inverted behavioral and environmental cycles (circadian misalignment) or simulated day work (circadian alignment).

MAIN OUTCOME MEASURES

Postprandial glucose and insulin responses to identical meals given at 8:00 am and 8:00 pm in both protocols.

RESULTS

Postprandial glucose was 6.5% higher at 8:00 pm than 8:00 am (circadian phase effect), independent of behavioral effects (P = .0041). Circadian misalignment increased postprandial glucose by 5.6%, independent of behavioral and circadian effects (P = .0042). These variations in glucose tolerance appeared to be explained, at least in part, by different insulin mechanisms: during the biological evening by decreased pancreatic β-cell function (18% lower early and late phase insulin; both P ≤ .011) and during circadian misalignment presumably by decreased insulin sensitivity (elevated postprandial glucose despite 10% higher late phase insulin; P = .015) without change in early-phase insulin (P = .38).

CONCLUSIONS

Internal circadian time affects glucose tolerance in shift workers. Separately, circadian misalignment reduces glucose tolerance in shift workers, providing a mechanism to help explain the increased diabetes risk in shift workers.

Stress, shift duty, and eating behavior among nurses in Central Saudi Arabia

OBJECTIVES

To investigate the association between stress, shift work, and eating behavior among non-Saudi female nurses working in Central Saudi Arabia.

METHODS

A sample of 395 non-Saudi female nurses from 2 major hospitals in Riyadh, Kingdom of Saudi Arabia participated in this cross-sectional study. The nurses completed a questionnaire from November 2013 to January 2014 that included items relating to stress and eating behavior using the Dutch Eating Behavior Questionnaire (DEBQ). The questionnaire also contained items pertaining to socio-demographic data, body mass index, shift work, and hours worked per week. 

RESULTS

For all eating styles, stress, and shift duty influenced the amount of food nurses consumed, but was more significant under a restrained eating style. Under this eating style, a significantly higher percentage of nurses reported eating more fast food, snacks, and binging, while fruits and vegetables were the least likely to be eaten under stress. High stressed nurses were more likely to present with abnormal restrained eating (odds ratio [OR]=1.52, p=0.004), emotional (OR=1.24; p=0.001), and external (OR=1.21; p=0.001) DEBQ scores. Working nighttime shift duty was positively associated with restrained eating (OR=1.53; p=0.029) and emotional eating (OR=1.24; p=0.001), but negatively associated with external eating (OR=0.45; p=0.001). 

CONCLUSION

Our findings suggest that stress and shift duty were associated with eating habits.

Blood Pressure, Sleep Quality and Fatigue in Shift Working Police Officers: Effects of a Twelve Hour Roster System on Cardiovascular and Sleep Health

Background: Police officers have been reported to exhibit a high incidence of pathologies, which present prematurely in an otherwise healthy population. Shift work has also been associated with an increased risk of cardiovascular and sleep disorders, attributable to its propensity for circadian rhythm dysfunction. However, contention exists as to whether shift work has a direct effect upon blood pressure (BP) regulation. Methods: This cross-sectional study sought to determine changes in BP and associations with the overall sleep quality and fatigue in 206 general duties police officers (n = 140 males) of the New South Wales Police Force in Australia. The subjects’ BP was assessed before and after their twelve hour shift, during which time they also completed the Lifestyle Appraisal Questionnaire, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale and Fatigue Severity Scale (FSS). Results: Poor sleep quality (PSQI) and fatigue severity (FSS) were found to predominate in the sample (69% and 51% respectively). Although there was no change in BP for male participants, female officers’ systolic blood pressure (SBP) was found to increase significantly across the shift (p < 0.001), but with no change found in females’ diastolic blood pressure (DBP). Finally, higher pre and post-shift SBP (r = −0.26, p = 0.001; r = −0.25, p = 0.001, respectively) and DBP (r = −0.26, p = 0.001; r = −0.26, p = 0.001, respectively) were significantly correlated with lower FSS scores after accounting for age, waist-hip ratio and lifestyle risk factors. Conclusions: Based on these preliminary findings, there was a significant increase in SBP of female police officers after shift work, while BP and fatigue levels in all police officers were strongly related. Moreover, the predominating poor sleep quality and impact of fatigue in this sample remain a concern. Further research is required to ensure the physiological welfare of police officers, while strategies must be implemented to manage the detrimental effects shift work may be having upon their cardiovascular and sleep health.

[WORKLOAD OF PASSENGER TRAIN DRIVER AT DIFFERENT ROADS AND DRIVING REGIMES]

There was performed a chronometer study of the workload of passenger train drivers in the work in the areas of circulation differing in the complexity of the track profile and in working in various modes of conducting the train. As a result of the chronometer study of the workload of passenger train drivers in the work in the areas of circulation differing in the complexity of the track profile there was determined the structure of the workload of the operational activity of drivers and revealed the dependence of the increase in the number of control actions in the complication of the track profile. Analysis of data obtained as a result of the study of patterns of the activity in the manual mode and with the use of the automatic driving system showed a marked decrease in active control actions, but also revealed the growing problem of physical inactivity among train drivers. In addition, the issue of the preservation of movement and motor skills when working with systems of automatic driving trains requires a more detailed study.

[THE AGE AND WORK EXPERIENCE DYNAMICS OF INDICES OF HEALTH OF EMPLOYEES--CRITERIA FOR COMPARISON OF OCCUPATIONAL AND NONOCCUPATIONAL RISKS]

There are reported data of the analysis of parameters of the general morbidity (hypertension, chronic diseases, organs of respiratory and digestive system, adiposity, vertebral osteochondrosis) in dependence on age and work experience of dockers-mechanizators in seaport at various working conditions. Morbidity rate indices were calculated on results of the profound medical examination at annual periodic surveys of workers. There were analyzed ecological and ergonomic indices of working conditions, including an estimation of physiological intensity of the work. The general hygienic assessment of working conditions was executed on the basis of the measurement of rates of gains in the risk of diseases depending on age and the experience of work (an annual gain of risk). The divergence of these rates was used for the determination of occupational and nonoccupational fractions of the general morbidity in employees working in harmful conditions.

[State of vegetative nervous system in workers engaged into multiple shifts work with night shifts]

Occupational activity with night shifts and length of service over 5 years is characterized by prevalent sympathetic influence on cardiac activity, vagosympathetic interaction index (LF/HF) is considerably higher than in workers with lower length of service and 1.5 times exceeding upper normal value. VLF indicator exceeds physiologic normal value due to increased activity of ergotropic and humoral metabolic mechanisms of cardiac rhythm regulation. Sympathetic regulation activity level (LF parameter) is also reliably higher than in workers with lower length of service (p = 0.024). Parasympathetic regulation activity level (HF parameter) is below normal value - that indicates decreased influence of parasympathetic vegetative system on cardiac activity (depression of defence mechanisms). Comparative analysis of vegetative regulation spectrum at rest, in accordance with length of service, demonstrated the most marked changes in workers with length of service over 5 years: lower total spectral capacity (TP, msz), lower share of high-frequency waves (HF, %), increase of average vagosympathetic interaction index (LF/HF) and higher share of very low waves (VLF, %) in the spectrum structure. Ihe data prove intensified ergotropic, humoral, sympathetic influences on cardiac activity and, as a result, higher risk of dysmetabolic processes and cardiovascular diseases.

Fatiguing effect of multiple take-offs and landings in regional airline operations

Fatigue is a risk factor for flight performance and safety in commercial aviation. In US commercial aviation, to help to curb fatigue, the maximum duration of flight duty periods is regulated based on the scheduled start time and the number of flight segments to be flown. There is scientific support for regulating maximum duty duration based on scheduled start time; fatigue is well established to be modulated by circadian rhythms. However, it has not been established scientifically whether the number of flight segments, per se, affects fatigue. To address this science gap, we conducted a randomized, counterbalanced, cross-over study with 24 active-duty regional airline pilots. Objective and subjective fatigue was compared between a 9-hour duty day with multiple take-offs and landings versus a duty day of equal duration with a single take-off and landing. To standardize experimental conditions and isolate the fatiguing effect of the number of segments flown, the entire duty schedules were carried out in a high-fidelity, moving-base, full-flight, regional jet flight simulator. Steps were taken to maintain operational realism, including simulated airplane inspections and acceptance checks, use of realistic dispatch releases and airport charts, real-world air traffic control interactions, etc. During each of the two duty days, 10 fatigue test bouts were administered, which included a 10-minute Psychomotor Vigilance Test (PVT) assessment of objective fatigue and Samn-Perelli (SP) and Karolinska Sleepiness Scale (KSS) assessments of subjective sleepiness/fatigue. Results showed a greater build-up of objective and subjective fatigue in the multi-segment duty day than in the single-segment duty day. With duty start time and duration and other variables that could impact fatigue levels held constant, the greater build-up of fatigue in the multi-segment duty day was attributable specifically to the difference in the number of flight segments flown. Compared to findings in previously published laboratory studies of simulated night shifts and nighttime sleep deprivation, the magnitude of the fatiguing effect of the multiple take-offs and landings was modest. Ratings of flight performance were not significantly reduced for the simulated multi-segment duty day. The US duty and flight time regulations for commercial aviation shorten the maximum duty duration in multi-segment operations by up to 25% depending on the duty start time. The present results represent an important first step in understanding fatigue in multi-segment operations, and provide support for the number of flight segments as a relevant factor in regulating maximum duty duration. Nonetheless, based on our fatigue results, a more moderate reduction in maximum duty duration as a function of the number of flight segments might be considered. However, further research is needed to include investigation of flight safety, and to extend our findings to nighttime operations.

[ASSESSMENT OF EXTREME FACTORS OF SHIFT WORK IN ARCTIC CONDITIONS BY WORKERS WITH DIFFERENT REGULATORY PROCESSES]

A man working on a shift basis in the Arctic, every day is under the influence of various extreme factors which are inevitable for oil and gas indudtry. To adapt to shift work employees use various resources of the individual. The purpose of research is the determination of personal resources of shift workers to overcome the adverse factors of the environment in the Arctic. The study involved 191 builder of main gas pipelines, working in shifts in the Tyumen region (the length of the shift 52 days of arrival) at the age of 23 to 59 (mean age 34.9 ± 8.1) years. Methods: psychological testing, questioning, observation, descriptive statistics, discriminant step by step analysis. There was revealed the correlation between the subjective assessment of the majority of adverse climatic factors in the regulatory process "assessment of results"; production factors--regulatory processes such as flexibility, autonomy, simulation, and the general level of self-regulation; social factors are more associated with the severity of such regulatory processes, flexibility and evaluation of results.

Shift work and the risk of cardiovascular disease among workers in cocoa processing company, Tema

OBJECTIVE

Shift work has been implicated in cardiovascular disease (CVD), a major cause of death globally. The aim of this study was to evaluate the risk of developing CVD in shift work.

DESIGN

A cross-sectional study involving secondary analysis of shift and non-shift work from an industry in Ghana.

PARTICIPANTS

Two hundred (113 shift and 87 non-shift) consecutive workers who consented were recruited into the study. A structured questionnaire was administered to deduce information on participant's age, alcohol consumption pattern, smoking habits, history of diabetes, stroke and hypertension.

RESULTS

Shift workers were found to be associated with higher body mass index (26.9 ± 4.6 vs 25.2 ± 3.3, p = 0.013); fasting blood glucose (5.9 ± 1.8 vs 5.3 ± 0.8, p ≤ 0.0001); glycated haemoglobin (4.9 ± 0.9 vs 4.2 ± 0.8, p ≤ 0.0001); high sensitivity C-reactive protein (2.5 ± 1.1 vs 1.8 ± 1.1, p < 0.0001); total cholesterol (5.9 ± 1.3 vs 5.2 ± 1.7, p = 0.002); triglycerides (1.3 ± 0.8 vs 1.1 ± 0.6, p = 0.015) and LDL cholesterol (3.6 ± 0.9 vs 3.2 ± 1.3, p = 0.04) than controls. Shift work however, had no associations with HDL-cholesterol.

CONCLUSION

It can be concluded that shift work is associated with risk factors of CVD.

Longer shifts mean higher risk of injury among clinicians

EMERGENCY SERVICES staff are at a greater risk of injury and illness the more hours they work, according to a US study, and the risk rises in tandem with the length of a shift.

Job demands and resting and napping opportunities for nurses during night shifts: impact on sleepiness and self-evaluated quality of healthcare

The aim of this field study is to describe night shift resting and napping strategies and to examine their beneficial effects on sleepiness and quality of work. The study was carried out with 16 nurses working in an intensive care unit. Data collected during 20 night shifts were related to job demands (systematic observations), to the duration and timing of rests and naps taken by nurses (systematic observations, sleep diaries), to sleepiness (Karolinska Sleepiness Scale), and to quality of work scores (visual analog scale). The results showed that the number of rests and naps depended on the job demands. Resting and napping lowered the levels of sleepiness at the end of the shift. There was no direct relationship between sleepiness and the quality of work score. Discussions about the choice of indicators for the quality of work are necessary. Suggestions for implementing regulations for prescribed napping during night shifts are presented.

Nonstandard working schedules and health: the systematic search for a comprehensive model

BACKGROUND

Theoretical models on shift work fall short of describing relevant health-related pathways associated with the broader concept of nonstandard working schedules. Shift work models neither combine relevant working time characteristics applicable to nonstandard schedules nor include the role of rest periods and recovery in the development of health complaints. Therefore, this paper aimed to develop a comprehensive model on nonstandard working schedules to address these shortcomings.

METHODS

A literature review was conducted using a systematic search and selection process. Two searches were performed: one associating the working time characteristics time-of-day and working time duration with health and one associating recovery after work with health. Data extracted from the models were used to develop a comprehensive model on nonstandard working schedules and health.

RESULTS

For models on the working time characteristics, the search strategy yielded 3044 references, of which 26 met the inclusion criteria that contained 22 distinctive models. For models on recovery after work, the search strategy yielded 896 references, of which seven met the inclusion criteria containing seven distinctive models. Of the models on the working time characteristics, three combined time-of-day with working time duration, 18 were on time-of-day (i.e. shift work), and one was on working time duration. The model developed in the paper has a comprehensive approach to working hours and other work-related risk factors and proposes that they should be balanced by positive non-work factors to maintain health. Physiological processes leading to health complaints are circadian disruption, sleep deprivation, and activation that should be counterbalanced by (re-)entrainment, restorative sleep, and recovery, respectively, to maintain health.

CONCLUSIONS

A comprehensive model on nonstandard working schedules and health was developed. The model proposes that work and non-work as well as their associated physiological processes need to be balanced to maintain good health. The model gives researchers a useful overview over the various risk factors and pathways associated with health that should be considered when studying any form of nonstandard working schedule.

Quality of Life, Health, and Sleep of Air Traffic Controllers with Different Shift Systems

BACKGROUND

Air traffic controllers (ATC) work shifts and their work schedules vary according to the characteristics of each airport. The human body adapts to shiftwork differently. These adjustments affect the health-disease process, predisposing ATC to risk conditions associated with sleep deprivation and lack of night sleep, which can lead to conditions such as cardiovascular diseases, mood disorders, anxiety, and obesity. This study investigated the characteristics of health, sleep, and quality of life of ATC exposed to 8-h alternate work shifts and 6-h rotational work shifts.

METHODS

The study was cross-sectional with convenience samples consisting of 84 ATC from two international airports in Brazil. We applied questionnaires to collect data about socioeconomic conditions, quality of life, sleep, and physical activity levels. We also collected health data regarding nutritional status, body composition, and blood pressure. We analyzed the differences between ATC from the two airports considering the variables of sleep, quality of life, and health.

RESULTS

Differences were found between the groups in terms of body fat percentage (30.7% and 27.8%), scores of overall quality of life (56.2 and 68), concentration (3.37 and 3.96), energy (3.12 and 3.62), and sleep time on working days (5:20 h and 6:15 h).

CONCLUSION

ATC under 8-h alternate shifts showed lower scores for quality of life, higher body fat, and less sleep time on working days, which characterizes inadequate shiftwork for this population.

A pilot study examining if satisfaction of basic needs can ameliorate negative effects of shift work

The objective of the present study was to investigate if satisfaction of the basic needs of autonomy, competence, and relatedness is related to shift work tolerance, specifically physical and mental fatigue, insomnia, and digestive troubles in a sample of shift workers. This is a cross-sectional pilot questionnaire study, including 252 shift workers employed in a municipality in Norway. Autonomy was negatively related to physical fatigue and digestive troubles, while competence was negatively related to mental fatigue. Relatedness showed significant correlations with insomnia and mental fatigue, but did not reach significance in the regression model controlling for the two other basic needs as well as work scheduling, night work exposure, and sleep medication. Sleep medication was significant in the final regression model for insomnia, but unrelated to fatigue and digestive troubles. The demographic variables, work hours per week, work schedule, and night work exposure were unrelated to all four measures of shift work tolerance. Autonomy and competence may be more important for fatigue and digestive troubles among shift workers than work arrangement variables, night work exposure, and sleep medication use.

Shift work disorder, depression, and anxiety in the transition to rotating shifts: the role of sleep reactivity

AIM

The aim of this study is to investigate premorbid sleep reactivity as a vulnerability to incident shift work disorder (SWD), and related changes in depression as well as anxiety following a transition to a rotating shifts work schedule.

METHODS

This is a longitudinal study with two waves of data collection. The community-based sample included normal sleeping non-shift workers (N = 96; 62.5% female; 47.9 ± 13.3 years) without a lifetime history of insomnia or baseline excessive daytime sleepiness who transitioned to rotating shift work one year later. Participants reported demographic characteristics, trait sleep reactivity on the Ford Insomnia Response to Stress Test, depression symptoms on the Quick Inventory of Depression Symptomatology, and anxiety symptoms on the Beck Anxiety Inventory. SWD was determined based on significant sleep disturbance and/or excessive sleepiness in the context of working in a rotating-shift schedule.

RESULTS

Analyses revealed that the odds were over five times greater for highly sleep-reactive individuals to develop SWD after transitioning to rotating shifts (OR = 5.59, p = 0.04). Nearly 90% of participants who suffered from SWD were accurately identified as high risk at one year before disease onset. Furthermore, individuals who developed SWD reported greater increases in symptoms of depression and anxiety. Finally, analyses revealed significant indirect effects wherein high sleep reactivity increased risk for SWD, which led to greater severity of anxiety and depression symptoms.

CONCLUSIONS

The Ford Insomnia Response to Stress Test (FIRST) accurately identifies a focused target population in which the premorbid psychobiological processes complicit in SWD onset and progression, as well as shift work-related depression and anxiety changes, can be better investigated, thus improving future preventative efforts.