1. SHIFT WORK AND HEALTHCARE PROFESSIONALS
Shift work is an indispensable and essential strategy to ensure continuous health care services in hospitals and residential sites. Globally, one-fifth of the workforce is involved in shift work with almost 20% of people engaged from the European workplace [1]. Patients can come unexpectedly to hospitals or clinics; hence it is impossible for healthcare professionals (HCPs) to work in the health sector without getting involved in shift schedules. These workers dedicate themselves to help people. Looking from another point of view, many research articles pointed out an association between their work time and health problems and disorders [2-4]. This includes sleep disorders, gastrointestinal diseases, cardiovascular diseases, diabetes, metabolic disturbances, cancer, etc. Although the mechanism of how these diseases are caused by shift work is still not well elaborated, it was shown by most of the studies that factors disturbing the circadian rhythm of the workers play a major role [2-4]. Most notably changes in the pattern of sleep, which may be reflected as changes in sleep quality and quantity or as sleep disorders that may differ from shift timing to another. The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) has included these sleep alterations related to shift work among Circadian Rhythm Sleep-Wake Disorders, irregular type, estimating a high prevalence of this disorder among night shift workforce (5%-10% of total work population) in healthcare settings [5]. Studies reported to have detrimental effects of shift work on health from several dimension but the pathological mechanisms in relation with shift work yet to be deciphered. Many HCP suffering from sleep, distress or fatigue disorders are still undermined even though these diseases are frequent [6]. So, in this study, we aim to explore the different shift work impact on sleep among HCPs and its associated underlying mechanisms of how that might contribute.
2. HOW DIFFERENCES IN SHIFT SCHEDULES IN HCPS AFFECT SLEEP
Even though they are working outside the traditional time and their sleep is disturbed more than day workers [7], there are some variations in the schedules of these professionals, leading to varied effects. So, they can be classified into:
These workers have fixed timings and they can be subdivided into three main categories:
As many studies elucidate the adverse effects of night work, only a few were about early-morning work. According to a review published by Åkerstedt et al [8], shift workers including HCPs have worse sleep patterns than night workers. Authors reported these workers to experience reduced sleep quantity due to less stage & rapid eye movement (REM) sleep [6, 9]. Problems in this type of schedules result mainly from the fact that they need to give up their sleep very early in the morning, resulting in a reduction of sleep that accounts to sleepiness in their morning shifts. Moreover, difficulties in working. This is due to the action of the circadian rhythm, more specifically the hormone cortisol that is so low at that time to prevent premature sleep termination. Consequently, their early arousal in the morning gives rise to anticipation stress that causes a decrement in slow wave sleep, sleep disturbance and fatigue [10].
This type of timing is not well studied as compared with the other types. It may appear to be less harmful than the other categories of shift workers, but not as safe as the standard working time (8 am - 4 pm) [3]. Yazdi et al concluded that nurses who are with eveningness orientation have lower sleep quality than those who go to bed and wake up early. However, a meta-analysis drew attention to having an increased sleep duration in evening workers in contrast to night workers [11]. As mentioned before, this category is very poorly studied and there must be more studies focusing on it in the future to further examine its impact.
Although these health providers have fixed working times and they may adjust to their schedules, the majority of studies concluded that this category is in danger of sleep disturbances most importantly decreased quality and quantity of sleep more than day-workers or non-rotating individuals working in the same field [12, 13]. This is attributed to having most of the physiological and psychological variables i.e. melatonin, metabolism, concentration, and performance in their lowest amount or nadir the time he/she starts the shift [8]. As a result, these problems will start the time the HCP starts working and will persist until finishing the shift and sleep. Consequences will be that they will fall asleep after one hour of night shift [14] and they will have a reduction of one to four hours in sleep duration which further results in premature awakening and not getting sufficient sleep, according to EEG (electroencephalogram) studies [15-17]. Due to the sleep deprivation, they are significantly facing drowsiness, fatigue, and difficulties in concentration throughout the day [18-19]. Moreover, they are highly exposed to the irregular type of circadian rhythm sleep- wake disorders (5%–10%) and shift work disorder [5, 20]. These patterns of sleep habitat make night shift HCPs more vulnerable to irritability, somatization, obsessive-compulsive disorder, anxiety, alteration in mood, paranoia, interpersonal sensitivity and consequently impairment on psychological health and social life [21, 22].
These workers do not have fixed schedules and that mainly results in an inability to adjust their circadian clock to work times. Also, other factors including having family can negatively affect it [23]. All of these collectively contribute to having HCPs experiencing more sleep disturbances including decreased sleep duration and drowsiness at work than permanent day/night workers [3]. Additionally, another study on nurses concluded that their rotating schedules caused them to have decreased sleep quality with aggravated mental health [24]. It also indicated that these problems can be reversed if nurses can have two days off or more after their rotating night shifts. As a consequence, this type of schedules should be avoided as it increases the occurrence of accidents or errors at work [25].
This category refers to HCPs that work more than the original duration of eight hours. However, they also work for fewer days in a week which may help them to recover. Studies on nurses [26, 27], clinicians [28] and residents [29] found that this type of working schedules results in decreased vigilance in work and causes accidents. Moreover, prospective trial on interns indicated that those who had extended shifts performed worse than those who had overnight shifts [30]. Many other studies investigated the hazard of this type of schedule and how EW workers may endanger their lives and other people’s lives [31]. On the contrary, a study conducted by Richardson et al on nurses postulates that 12-hour shifts on critical care staff result in an increase in the quality of care and an improvement in dealing with patients or relatives [32]. Another narrative review suggested that sleep problems are not necessarily caused by extending the shift interval from eight to twelve hours [33]. This category is still under controversy and more research is needed in the future.
3.CONCLUSION
HCPs are at an increased risk of developing sleep disturbances due to their shift work. The difference in the shift timings may appear to be an important predictor of the shift hazard. Permanent shift workers were shown to have better results than rotating workers. However, most of the studies were conducted on nurses, which is one of the limitations of the literature. We highly suggest future studies to study that in further. Based on World Health Organization (WHO) definition of shift work, as it increases the risk of many health problems, it is highly suggested to implement ergonomic criteria to attenuate such adverse effects for holistic workplace environment in healthcare settings and promote the well-being of professionals.
