Shift work sleep disorder

Last updated

Shift work sleep disorder
Other namesshift work disorder; SWD
Specialty Neurology, psychology   OOjs UI icon edit-ltr-progressive.svg

Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep or to wake up before the individual has slept enough. [1] About 20% of the working population participates in shift work. SWSD commonly goes undiagnosed, and it is estimated that 10–40% of shift workers have SWSD. [2] [3] The excessive sleepiness appears when the individual has to be productive, awake and alert. [1] Both symptoms are predominant in SWSD. [4] There are numerous shift work schedules, and they may be permanent, intermittent, or rotating; consequently, the manifestations of SWSD are quite variable. Most people with different schedules than the ordinary one (from 8 AM to 6 PM) might have these symptoms but the difference is that SWSD is continual, long-term, and starts to interfere with the individual's life. [1]

Contents

Health effects

There have been many studies suggesting health risks associated with shift work. Many studies have associated sleep disorders with decreased bone mineral density (BMD) and risk for fracture. Researchers have found that those who work long-term in night positions, like nurses, are at a great risk for wrist and hip fractures (RR=1.37). [5] Low fertility and issues during pregnancy are increased in shift workers. [6] Obesity, diabetes, insulin resistance, elevated body fat levels [7] and dyslipidemias were shown to be much higher in those who work night shift. [8] SWSD can increase the risk of mental disorders. [1] Specifically, depression, anxiety, and alcohol use disorder is increased in shift workers. [6] Because the circadian system regulates the rate of chemical substances in the body, when it is impaired, several consequences are possible. [1] Acute sleep loss has been shown to increase the levels of t-tau in blood plasma, which may explain the neurocognitive effects of sleep loss. [9]

Sleep quality

Sleep loss and decreased quality of sleep is another effect of shift work. To promote a healthy lifestyle, the American Academy of Sleep Medicine recommended that an adult have 7 or more hours of sleep per day. [10] Each year, there are almost 100,000 deaths estimated in the U.S. because of medical errors. [10] Sleep deprivation and sleep disorders are factors that contribute significantly to these errors. [10] In the same article, the authors affirm that there is a high prevalence of sleepiness and symptoms of sleep disorders related to the circadian system in medical center nurses. [10] In a study done with around 1100 nurses, almost half of them (49%) reported sleeping less than 7 hours per day, a significant increase compared to national figures, in which 28% of people claimed to sleep less than 7 hours per night. [11] Having a lack of sleep can impact cognitive performance. [1] For example, it might become difficult to stay focused and concentrate, and reaction times might also be slowed down. [12] [1] SWSD might interfere with making decisions quickly, driving, or flying safely. [1] Sleep loss seen in shift workers greatly impairs cognitive performance, being awake for 24 hrs. straight results in a cognitive performance that is equal to a blood-alcohol of 0.10, which is over the legal limit in most states. [6] All of these factors can affect work efficiency and cause accidents. Michael Lee et al. demonstrated that those working night shifts had a significantly higher risk of hazardous driving events when compared to those on a typical day shift schedule. [13] Accidents in the workplace have been found to be 60% higher in shift workers. [6] They can affect the individual's social life and cause a lack of well-being and happiness. [1] Poor sleep quality has also been associated with decreased quality of life, based on a SF-36 assessment. [14]

Sleep and alertness

Although SWD affects many shift workers, its manifestation is still unclear within the general shift-working population. [15] A field study investigating the nature of SWD in an experimental (with SWD) and control (non-SWD) group of Finnish shift workers revealed decreased total sleep time (TST) and increased sleep deficit before morning shifts. [15] Furthermore, the SWD group also exhibited decreased objective sleep efficiency, decrease in sleep compensation over the free days, increased sleep latency, and finally poorer sleep quality was recorded in the SWD group compared to the non-SWD group. [15] Moreover, shift workers with SWD scored significantly higher on the Karolinska Sleepiness Scale (KSS) when assessed at the beginning and the end of morning shifts and at the end of night shifts, while having more attentional lapses at the beginning of night shifts. [15]

Many studies have shown evidence of how partial and total sleep deprivation affects work productivity, absenteeism, fatal workplace accidents, and more. [16] [17] In a study by Akkerstedt et al., those who had a hard time sleeping in the past two weeks were at a greater risk for having a fatal workplace accident (RR=1.89, 95% CI 1.22–2.94). [18] Other sleep disorders, like OSA which are risk factors for SWSD, have also been associated with low productivity, absenteeism, and accidents. [19] At a cognitive level, sleep deprivation has been shown to cause decreased attentiveness, increased micro-sleeps, delayed psychomotor response, performance deterioration, neglect of activities, decline in working memory, and more. [17]

Immune functioning

Partial and total sleep deprivation has been linked to an increase of pro-inflammatory markers, [20] such as IL-6, [21] and a decrease in anti-inflammatory markers, such as IL-10, that plays a role in tumor suppression. [22] Chronic shift work has been associated with decreased immune function in nurses. In a study by Naigi, et al., over the course of a shift, nurses exhibited decreasing levels of Natural Killer cells, an innate immune response that plays a role in infectious disease and tumor suppression. [23] Other researchers have found that less sleep at night increased the risk of developing the common cold. [24] A supporting study by Moher et al. showed that shift workers were more likely to develop infectious diseases after exposure compared to daytime workers. [25] A poorly functioning immune system may leave workers vulnerable for developing occupational illnesses. Sleep loss is also associated with an increase in TNF, a marker of systemic immune functioning. [26]

Cardiovascular disease

Decreased sleep quality and duration have also been associated with other chronic illnesses, such as cardiovascular disease. Many studies have shown that prolonged sleeplessness and sleep disorders, such as OSA, increases systemic levels of CRP, a marker of cardiovascular disease. [20] Many studies have shown that lack of sleep causes blood pressure to increase from the prolonged stimulation of the nervous system. [26] The increase of inflammatory markers, like IL-6, up-regulate the production of CRP. [26]

SWSD in firefighters

SWSD can affect many occupations, but firefighters and Emergency Medical Technicians are at a greater risk because of their extended (24hr) shift and frequent sleep interruptions due to emergencies. Many firefighters have sleep disorders as a result of their extended shift and frequently disrupted sleep. In a study on firefighters by Barger, et al., over a third of study participants screened positive for a sleep disorder, but most had not received a previous medical diagnosis for any sleep disorders. [27] Those with sleep disorders were also at a higher risk for being in a motor vehicle crash (OR=2.0 95% CI 1.29–3.12, p=0.0021), near crash (OR=2.49 95% CI 2.13–2.91, p < 0.0001), and nodding off while driving (OR=2.41 95% CI 2.06–2.82, p < 0.0001). [27]

Symptoms

Cause and prevalence

Insomnia and wake-time sleepiness are related to misalignment between the timing of a non-standard wake–sleep schedule and the endogenous circadian propensity for sleep and wake. In addition to circadian misalignment, attempted sleep at unusual times can be interrupted by noise, social obligations, and other factors. There is an inevitable degree of sleep deprivation associated with sudden transitions in sleep schedule. [28]

The prevalence of SWSD is unclear because it is not often formally diagnosed and its definitions vary in scientific literature. [29] However, SWSD is estimated to affect 2–10% of general population [30] [31] [4] and about 27% of night and rotating workers. [3] The use of the third edition of the International Classification of Sleep Disorders (ICSD-3) criteria has decreased the prevalence estimates of SWSD compared to the old ICSD-2 criteria after 2014. [32] [3]

There are various risk factors, including age. Although SWSD can appear at any age, the highest prevalence is in the 50 years old and above age bracket and even more so in cases of irregular schedules. [4] Gender is also a factor. [33] It may be that female night workers sleep less than their male counterparts. [33] A possible explanation is the social obligations that can increase their vulnerability to SWSD. Female night workers also seem to be more sleepy at work. [33]

Some people are more affected by shift work and sleeplessness than others, and some will be impaired on some tasks while others will always perform well on the same tasks. [34] Some people have a morning preference but others not. [34] Genetic predisposition is an important predictor of which people are vulnerable to SWSD. [34]

Medical field

Cognitive impact

Shift work sleep disorder affects many individuals, especially those within the medical field. Research done by The Journal Of Sleep Research [35] examine the difference in cognitive function using sleep-deprived and well-rested nurses using autobiographical memory skills. The participants underwent the autobiographical memory test, as well as anxiety and depression inventories. The researchers found that a sleep-deprived group of individuals scored significantly higher in the depression score and remembered more negative than positive memories. The sleep-deprived group also scored significantly lower than the well-rested group in autobiographical memory and specific memories. This study is similar to the one done by the National Center for Biotechnology Information, [36] which found that their hypothesis of sleep deprivation and the cognitive impact it has on nurses was strongly supported in 69% of shift workers. The impairment in cognitive performance, such as general intellect, reaction time, and memory, was statistically significant among the staff nurses due to poor sleep quality and decreased alertness while awake.

Patient care

Shift work sleep disorder affects patient care within all aspects of the medical field. Research published in European Review for Medical and Pharmacological Sciences [37] analyzed the correlation between the clinical risk management and the occurrence of medication errors and the effects of the shift work on inpatient nurses. The researchers reviewed 19 out of 217 research articles and focused on the impact of workload, shifts and sleep deprivation on the probability of making medication errors. They found that the main reason behind medication errors are stress, fatigue, increased workload, night shifts, nurse staffing ratio and workflow interruptions.

Mechanism

Brain arousal is stimulated by the circadian system during the day and sleep is usually stimulated at night. [38] The rhythms are maintained in the suprachiasmatic nucleus (SCN), located in the anterior hypothalamus in the brain, and synchronized with the day/night cycle. [38] Gene-transcription feedback loops in individual SCN cells form the molecular basis of biological timekeeping. [38] Circadian phase shifts are dependent on the schedule of light exposure, the intensity, and previous exposure to light. [39] Variations in exposure can advance or delay these rhythms. For example, the rhythms can be delayed due to light exposure at night. [39]

Photoreceptors located in the retina of the eye send information about environmental light through the retinohypothalamic tract to the SCN. [38] [39] The SCN regulates the pineal gland, which secretes the hormone melatonin. [39] Typically, the secretion of melatonin begins two hours before bedtime and ends two hours prior to waking up. [39] A decline in neuronal firing in the SCN is caused by the binding of melatonin to the MT1 and MT2 melatonin receptors. It is believed that the reduction in firing in the SCN stimulates sleep. [38] While day-active individuals produce melatonin at night, night shift workers' production of melatonin is suppressed at night due to light exposure. [39]

Circadian misalignment

Circadian misalignment plays a major role in shift work sleep disorder. Circadian misalignment occurs when there is no complete adaptation to a night shift schedule. [39] The hormones cortisol and melatonin are an important part of the circadian rhythm. [39] In circadian misalignment, cortisol and melatonin lack entrainment to a night oriented schedule and stay on a daytime schedule. [39] Melatonin continues to peak at night during a shift workers awake time and decreases during a shift workers sleep time. [39] Cortisol levels are lower during a shift workers awake time and remain higher during shift workers sleep time. [39]

Diagnosis

The primary symptoms of shift work sleep disorder are insomnia and excessive sleepiness associated with working (and sleeping) at non-standard times. Shift work sleep disorder is also associated with falling asleep at work. Total daily sleep time is usually shortened and sleep quality is less in those who work night shifts compared to those who work day shifts. [28] Sleepiness is manifested as a desire to nap, unintended dozing, impaired mental acuity, irritability, reduced performance, and accident proneness. Shift work is often combined with extended hours of duty, so fatigue can be a compounding factor. [40] The symptoms coincide with the duration of shift work and usually remit with the adoption of a conventional sleep-wake schedule. [40] The boundary between a "normal response" to the rigors of shift work and a diagnosable disorder is not sharp.

There are criteria of SWSD in the International Classification of Diseases (ICD-10), in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), and in the International Classification of Sleep Disorders (ICSD) – Second and Third Editions. The diagnosis requires the following assumptions : [41] [42] [6]

Assessments

There are different tools to assess shift work disorder. [33] Patients can keep a diary. [33] Some questionnaires could be useful as the Morningness-Eveningness Questionnaire. [33] Actigraphy and polysomnography could indicate some interesting patterns. [33] Further studies are needed to see if some phase markers as the body temperature rhythm or the melatonin rhythm are efficient to assess shift work disorder. [33] Decreased sleep quality may be assessed using the Pittsburg Sleep Quality Index (PQSI). [19]

Treatment

Prescribed sleep/wake scheduling

Experts agree that there is no such thing as an "ideal" night work schedule, but some schedules may be better than others. For example, rotating shifts every two weeks in a forward (delaying) direction was found to be easier than rotation in a backward (advancing) direction. [43] Gradual delays ("nudging" the circadian system about an hour per day) has been shown in a laboratory setting to maintain synchrony between sleep and the endogenous circadian rhythms, [44] but this schedule is impractical for most real world settings. Some experts have advocated short runs (1 to 2 days) of night work with time for recovery; however, in the traditional heavy industries, longer (5 to 7 day) runs remain the rule. In the end, scheduling decisions usually involve maximizing leisure time, fairness in labor relations, etc. rather than chronobiological considerations. Shift workers can benefit from adhering to sleep hygiene practices related to sleep/wake scheduling. [12] Symptoms typically only fully resolve once a normal sleep schedule is resumed. [40]

Many night workers take naps during their breaks, and in some industries, planned napping at work (with facilities provided) is beginning to be accepted. A nap before starting a night shift is a logical prophylactic measure. However, naps that are too long (over 30 minutes) may generate sleep inertia, a groggy feeling after awakening that can impair performance. Therefore, brief naps (10 to 30 minutes) are preferred to longer naps (over 30 minutes). Also, long naps may interfere with the main sleep period. [45]

In the transportation industry, safety is a major concern, and mandated hours of service rules attempt to enforce rest times.

Bright light treatment

The light-dark cycle is the most important environmental time cue for entraining circadian rhythms of most species, including humans, and bright artificial light exposure has been developed as a method to improve circadian adaptation in night workers. The timing of bright light exposure is critical for its phase shifting effects. To maximize a delay of the body clock, bright light exposure should occur in the evening or first part of the night, and bright light should be avoided in the morning. Wearing dark goggles [46] (avoiding bright light) or blue-blocking goggles during the morning commute home from work can improve circadian adaptation. For workers who want to use bright light therapy, appropriate fixtures of the type used to treat winter depression are readily available [47] but patients need to be educated regarding their appropriate use, especially the issue of timing. Bright light treatment is not recommended for patients with light sensitivity or ocular disease.

Melatonin treatment

Melatonin is a hormone secreted by the pineal gland in darkness, normally at night. Its production is suppressed by light exposure, [48] principally blue light around 460 to 480 nm. Light restriction, or dark therapy, in the hours before bedtime allows its production. Dark therapy does not require total darkness. Amber or orange colored goggles eliminate blue light to the eyes while allowing vision.

Melatonin is also available as an oral supplement. In the US and Canada, the hormone melatonin is not classified as a drug; it is sold as a dietary supplement. In other countries, it requires a prescription or is unavailable. Although it is not licensed by the FDA as a treatment for any disorder, there have been no serious side effects or complications reported to date.

Melatonin has been shown to accelerate the adaptation of the circadian system to a nighttime work schedule. [49] Melatonin may benefit daytime sleep in night workers by an additional direct sleep promoting mechanism. Melatonin treatment may increase sleep length during both daytime and nighttime sleep in night shift workers. [28]

Medications that promote alertness

Caffeine is the most widely used alerting drug in the world and has been shown to improve alertness in simulated night work. [50] Caffeine and naps before a night shift reduces sleepiness during the shift. [28] Night shift medical field workers report the highest activity, along with the least amount of sleep. These individuals require medication/power naps to function at their best. [51] Modafinil and armodafinil are non-amphetamine alerting drugs originally developed for the treatment of narcolepsy that have been approved by the FDA (the US Food and Drug Administration) for excessive sleepiness associated with SWSD. [52]

Medications that promote daytime sleep

Obtaining enough sleep during the day is a major problem for many night workers. Hypnotics given in the morning can lengthen daytime sleep; however, some studies have shown that nighttime sleepiness may be unaffected. [53] Zopiclone has been shown to be ineffective in increasing sleep in shift workers. [28]

See also

Related Research Articles

<span class="mw-page-title-main">Sleep</span> Naturally recurring resting state of mind and body

Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.

<span class="mw-page-title-main">Sleep disorder</span> Medical disorder of a persons sleep patterns

A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Sleep disorders are frequent and can have serious consequences on patients' health and quality of life. Polysomnography and actigraphy are tests commonly ordered for diagnosing sleep disorders.

<span class="mw-page-title-main">Jet lag</span> Physiological condition caused by travel across time zones

Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones. For example, someone travelling from New York to London, i.e. from west to east, feels as if the time were five hours earlier than local time, and someone travelling from London to New York, i.e. from east to west, feels as if the time were five hours later than local time. The phase shift when travelling from east to west is referred to as phase-delay of the circadian cycle, whereas going west to east is phase-advance of the cycle. Most travellers find that it is harder to adjust time zones when travelling east. Jet lag was previously classified as a circadian rhythm sleep disorder.

<span class="mw-page-title-main">Circadian rhythm</span> Natural internal process that regulates the sleep-wake cycle

A circadian rhythm, or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism and responds to the environment. Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life.

<span class="mw-page-title-main">Delayed sleep phase disorder</span> Chronic sleep disorder

Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is the delaying of a person's circadian rhythm compared to those of societal norms. The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles. People with this disorder are often called night owls.

Advanced Sleep Phase Disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition that is characterized by a recurrent pattern of early evening sleepiness and very early morning awakening. This sleep phase advancement can interfere with daily social and work schedules, and results in shortened sleep duration and excessive daytime sleepiness. The timing of sleep and melatonin levels are regulated by the body's central circadian clock, which is located in the suprachiasmatic nucleus in the hypothalamus.

Shift work is an employment practice designed to keep a service or production line operational at all times. The practice typically sees the day divided into shifts, set periods of time during which different groups of workers perform their duties. The term "shift work" includes both long-term night shifts and work schedules in which employees change or rotate shifts.

Non-24-hour sleep–wake disorder is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising [...] daily delays in sleep onset and wake times in an individual living in a society". Symptoms result when the non-entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature. Although this sleep disorder is more common in blind people, affecting up to 70% of the totally blind, it can also affect sighted people. Non-24 may also be comorbid with bipolar disorder, depression, and traumatic brain injury. The American Academy of Sleep Medicine (AASM) has provided CRSD guidelines since 2007 with the latest update released in 2015.

<span class="mw-page-title-main">Circadian rhythm sleep disorder</span> Family of sleep disorders that affect the timing of sleep

Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep–wake disorders (CRSWD), are a family of sleep disorders that affect the timing of sleep. CRSDs cause a persistent pattern of sleep/wake disturbances that arise either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues. As a result of this misalignment, those affected by circadian rhythm sleep disorders can fall asleep at unconventional time points in the day, or experience excessive daytime sleepiness if they resist. These occurrences often lead to recurring instances of disrupted rest and wakefulness, where individuals affected by the disorder are unable to go to sleep and awaken at "normal" times for work, school, and other social obligations. Delayed sleep phase disorder, advanced sleep phase disorder, non-24-hour sleep–wake disorder and irregular sleep–wake rhythm disorder represents the four main types of CRSD.

Light effects on circadian rhythm are the response of circadian rhythms to light.

<span class="mw-page-title-main">Sleep deprivation</span> Condition of not having enough sleep

Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity. All known animals sleep or exhibit some form of sleep behavior, and the importance of sleep is self-evident for humans, as nearly a third of a person's life is spent sleeping. Sleep deprivation is common as it affects about one-third of the population.

Sundowning, or sundown syndrome, is a neurological phenomenon wherein people with delirium or some form of dementia experience increased confusion and restlessness beginning in the late afternoon and early evening. It is most commonly associated with Alzheimer's disease but is also found in those with other forms of dementia. The term sundowning was coined by nurse Lois K. Evans in 1987 due to the association between the person's increased confusion and the setting of the sun.

<span class="mw-page-title-main">Effects of fatigue on safety</span>

Fatigue is a major safety concern in many fields, but especially in transportation, because fatigue can result in disastrous accidents. Fatigue is considered an internal precondition for unsafe acts because it negatively affects the human operator's internal state. Research has generally focused on pilots, truck drivers, and shift workers.

<span class="mw-page-title-main">Light in school buildings</span>

Light in school buildings traditionally is from a combination of daylight and electric light to illuminate learning spaces, hallways, cafeterias, offices and other interior areas. Light fixtures currently in use usually provide students and teachers with satisfactory visual performance, i.e., the ability to read a book, have lunch, or play basketball in a gymnasium. However, classroom lighting may also affect students' circadian systems, which may in turn affect test scores, attendance and behavior.

Irregular sleep–wake rhythm disorder (ISWRD) is a rare form of circadian rhythm sleep disorder. It is characterized by numerous naps throughout the 24-hour period, no main nighttime sleep episode, and irregularity from day to day. Affected individuals have no pattern of when they are awake or asleep, may have poor quality sleep, and often may be very sleepy while they are awake. The total time asleep per 24 hours is normal for the person's age. The disorder is serious—an invisible disability. It can create social, familial, and work problems, making it hard for a person to maintain relationships and responsibilities, and may make a person home-bound and isolated.

<span class="mw-page-title-main">Charles Czeisler</span> American physician and sleep researcher

Charles Andrew Czeisler is a Hungarian-American physician and sleep and circadian researcher. He is a leading researcher and author in the fields of the effects of light on human physiology, circadian rhythms and sleep medicine.

Studies, which include laboratory investigations and field evaluations of population groups that are analogous to astronauts, provide compelling evidence that working long shifts for extended periods of time contributes to sleep deprivation and can cause performance decrements, health problems, and other detrimental consequences, including accidents, that can affect both the worker and others.

<span class="mw-page-title-main">Sleep deprivation in higher education</span> Health issue in students

Sleep deprivation – the condition of not having enough sleep – is a common health issue for students in higher education. This issue has several underlying and negative consequences, but there are a few helpful improvements that students can make to reduce its frequency and severity.

Dr. Debra J. Skene is a chronobiologist with specific interest in the mammalian circadian rhythm and the consequences of disturbing the circadian system. She is also interested in finding their potential treatments for people who suffer from circadian misalignment. Skene and her team of researchers tackle these questions using animal models, clinical trials, and most recently, liquid chromatography-mass spectrometry. Most notably, Skene is credited for her evidence of a novel photopigment in humans, later discovered to be melanopsin. She was also involved in discovering links between human PER3 genotype and an extremely shifted sleep schedules categorized as extreme diurnal preference. Skene received her Bachelor of Pharmacy, Master of Science, and Ph.D. in South Africa.

Chronodisruption is a concept in the field of circadian biology that refers to the disturbance or alteration of the body's natural biological rhythms, for example the sleep-wake cycle, due to various environmental factors. The human body is synchronized to a 24-hour light-dark cycle, which is essential for maintaining optimal health and well-being. However, modern lifestyles —which involve exposure to artificial light, irregular sleep schedules, and shift work — can disrupt this natural rhythm, leading to a range of adverse physiological outcomes. Chronodisruption has been linked to a variety of health disorders and diseases, including neurodegenerative diseases, diabetes, mood disorders, cardiovascular disease, and cancer. Such disruptors can lead to dysregulation of hormones and neurotransmitters, though researchers continue to investigate the physiological implications of chronodisruption. Indeed, research in chronobiology is rapidly advancing, with an increasing focus on understanding the underlying mechanisms of chronodisruption and developing strategies to prevent or mitigate its adverse effects. This includes the development of pharmacological interventions, as well as lifestyle modifications such as optimizing one's sleeping environment and timing of meals and physical activity.

References

  1. 1 2 3 4 5 6 7 8 9 "Shift Work Disorder Symptoms". National Sleep Foundation. 16 October 2018. Retrieved 2019-06-20.
  2. 1 2 3 4 5 6 "Shift Work Sleep Disorder (SWSD)". Cleveland Clinic. Retrieved 2020-04-12.
  3. 1 2 3 Pallesen S, Bjorvatn B, Waage S, Harris A, Sagoe D (March 2021). "Prevalence of Shift Work Disorder: A Systematic Review and Meta-Analysis". Frontiers in Psychology. 12 (638252): 638252. doi: 10.3389/fpsyg.2021.638252 . PMC   8021760 . PMID   33833721.
  4. 1 2 3 American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders (DSM-5®). American Psychiatric Publications.
  5. Feskanich D, Hankinson SE, Schernhammer ES (April 2009). "Nightshift work and fracture risk: the Nurses' Health Study". Osteoporosis International. 20 (4): 537–42. doi:10.1007/s00198-008-0729-5. PMC   2651998 . PMID   18766292.
  6. 1 2 3 4 5 Wickwire EM, Geiger-Brown J, Scharf SM, Drake CL (May 2017). "Shift Work and Shift Work Sleep Disorder: Clinical and Organizational Perspectives". Chest. 151 (5): 1156–1172. doi:10.1016/j.chest.2016.12.007. PMC   6859247 . PMID   28012806.
  7. Sooriyaarachchi P, Jayawardena R, Pavey T, King N. Shift work and body composition: a systematic review and meta-analysis. Minerva Endocrinology. 2021 Jun https://doi.org/10.23736/s2724-6507.21.03534-x
  8. Ulhôa MA, Marqueze EC, Burgos LG, Moreno CR (2015). "Shift work and endocrine disorders". International Journal of Endocrinology. 2015: 826249. doi: 10.1155/2015/826249 . PMC   4393906 . PMID   25892993.
  9. Benedict C, Blennow K, Zetterberg H, Cedernaes J (2020-03-17). "Effects of acute sleep loss on diurnal plasma dynamics of CNS health biomarkers in young men". Neurology. 94 (11): e1181–e1189. doi: 10.1212/WNL.0000000000008866 . ISSN   0028-3878. PMC   7220231 . PMID   31915189.
  10. 1 2 3 4 "Nurses have increased risk of sleep disorders, sleep deprivation". American Academy of Sleep Medicine – Association for Sleep Clinicians and Researchers. 2019-06-07. Retrieved 2019-06-22.
  11. Christian F, Muppavarapu K, Aston C, Bauer CY, Doshi V (2019-04-13). "0630 Sleep Health of Nursing Staff in an Academic Medical Center: Results of a Survey Study". Sleep. 42 (Supplement_1): A251. doi: 10.1093/sleep/zsz067.628 . ISSN   0161-8105.
  12. 1 2 Jehan S, Zizi F, Pandi-Perumal SR, Myers AK, Auguste E, Jean-Louis G, McFarlane SI (2017). "Shift Work and Sleep: Medical Implications and Management". Sleep Medicine and Disorders. 1 (2). PMC   5836745 . PMID   29517053.
  13. Lee ML, Howard ME, Horrey WJ, Liang Y, Anderson C, Shreeve MS, et al. (January 2016). "High risk of near-crash driving events following night-shift work". Proceedings of the National Academy of Sciences of the United States of America. 113 (1): 176–81. Bibcode:2016PNAS..113..176L. doi: 10.1073/pnas.1510383112 . PMC   4711869 . PMID   26699470.
  14. Lo CM, Lee PH (June 2012). "Prevalence and impacts of poor sleep on quality of life and associated factors of good sleepers in a sample of older Chinese adults". Health and Quality of Life Outcomes. 10 (1): 72. doi: 10.1186/1477-7525-10-72 . PMC   3445836 . PMID   22709334.
  15. 1 2 3 4 Vanttola P, Härmä M, Viitasalo K, Hublin C, Virkkala J, Sallinen M, et al. (May 2019). "Sleep and alertness in shift work disorder: findings of a field study". International Archives of Occupational and Environmental Health. 92 (4): 523–533. Bibcode:2019IAOEH..92..523V. doi:10.1007/s00420-018-1386-4. PMC   6435614 . PMID   30511341.
  16. Kucharczyk ER, Morgan K, Hall AP (December 2012). "The occupational impact of sleep quality and insomnia symptoms". Sleep Medicine Reviews. 16 (6): 547–559. doi:10.1016/j.smrv.2012.01.005. ISSN   1087-0792. PMID   22401983.
  17. 1 2 Goel N, Rao H, Durmer J, Dinges D (September 2009). "Neurocognitive Consequences of Sleep Deprivation". Seminars in Neurology. 29 (4): 320–339. doi:10.1055/s-0029-1237117. ISSN   0271-8235. PMC   3564638 . PMID   19742409.
  18. AKERSTEDT T, FREDLUND P, GILLBERG M, JANSSON B (March 2002). "A prospective study of fatal occupational accidents - relationship to sleeping difficulties and occupational factors". Journal of Sleep Research. 11 (1): 69–71. doi:10.1046/j.1365-2869.2002.00287.x. ISSN   0962-1105. PMID   11869429. S2CID   23727344.
  19. 1 2 Jurado-Gámez B, Guglielmi O, Gude F, Buela-Casal G (May 2015). "Workplace Accidents, Absenteeism and Productivity in Patients With Sleep Apnea". Archivos de Bronconeumología (English Edition). 51 (5): 213–218. doi:10.1016/j.arbr.2014.12.002. ISSN   1579-2129. PMID   25129165. S2CID   25047796.
  20. 1 2 Meier-Ewert HK, Ridker PM, Rifai N, Regan MM, Price NJ, Dinges DF, Mullington JM (February 2004). "Effect of sleep loss on C-reactive protein, an inflammatory marker of cardiovascular risk". Journal of the American College of Cardiology. 43 (4): 678–83. doi: 10.1016/j.jacc.2003.07.050 . PMID   14975482.
  21. Rohleder N, Aringer M, Boentert M (July 2012). "Role of interleukin-6 in stress, sleep, and fatigue". Annals of the New York Academy of Sciences. 1261 (1): 88–96. Bibcode:2012NYASA1261...88R. doi:10.1111/j.1749-6632.2012.06634.x. PMID   22823398. S2CID   31209474.
  22. Taraz M, Khatami MR, Hajiseyedjavadi M, Farrokhian A, Amini M, Khalili H, et al. (July 2013). "Association between antiinflammatory cytokine, IL-10, and sleep quality in patients on maintenance hemodialysis". Hemodialysis International. 17 (3): 382–90. doi:10.1111/hdi.12035. PMID   23490309. S2CID   21036731.
  23. Nagai M, Morikawa Y, Kitaoka K, Nakamura K, Sakurai M, Nishijo M, et al. (September 2011). "Effects of fatigue on immune function in nurses performing shift work". Journal of Occupational Health. 53 (5): 312–9. doi: 10.1539/joh.10-0072-oa . hdl: 2297/37568 . PMID   21778660.
  24. Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB (January 2009). "Sleep habits and susceptibility to the common cold". Archives of Internal Medicine. 169 (1): 62–7. doi:10.1001/archinternmed.2008.505. PMC   2629403 . PMID   19139325.
  25. Mohren DC, Jansen NW, Kant I, Galama JM, van den Brandt PA, Swaen GM (November 2002). "Prevalence of Common Infections Among Employees in Different Work Schedules". Journal of Occupational and Environmental Medicine. 44 (11): 1003–1011. doi:10.1097/00043764-200211000-00005. ISSN   1076-2752. PMID   12449906. S2CID   17166254.
  26. 1 2 3 Mullington JM, Haack M, Toth M, Serrador J, Meier-Ewert H (2009). "Cardiovascular, Inflammatory and Metabolic Consequences of Sleep Deprivation". Progress in Cardiovascular Diseases. 51 (4): 294–302. doi:10.1016/j.pcad.2008.10.003. ISSN   0033-0620. PMC   3403737 . PMID   19110131.
  27. 1 2 Barger LK, Rajaratnam SM, Wang W, O'Brien CS, Sullivan JP, Qadri S, et al. (March 2015). "Common sleep disorders increase risk of motor vehicle crashes and adverse health outcomes in firefighters". Journal of Clinical Sleep Medicine. 11 (3): 233–40. doi:10.5664/jcsm.4534. PMC   4346644 . PMID   25580602.
  28. 1 2 3 4 5 Liira J, Verbeek JH, Costa G, Driscoll TR, Sallinen M, Isotalo LK, Ruotsalainen JH (August 2014). "Pharmacological interventions for sleepiness and sleep disturbances caused by shift work". The Cochrane Database of Systematic Reviews. 2014 (8): CD009776. doi:10.1002/14651858.CD009776.pub2. PMC   10025070 . PMID   25113164.
  29. Vanttola P (2021). Shift Work Disorder: Prevalence, Manifestation, and Recovery; Chapter: Definitions of SWD. Unigrafia. pp. 28–33. ISBN   978-951-51-6959-4.
  30. International Classification of Sleep Disorders 3rd Ed. Darien, IL USA: American Academy of Sleep Medicine. 2014.
  31. Drake CL, Roehrs T, Richardson G, Walsh JK, Roth T (December 2004). "Shift work sleep disorder: prevalence and consequences beyond that of symptomatic day workers". Sleep. 27 (8): 1453–62. doi: 10.1093/sleep/27.8.1453 . PMID   15683134.
  32. Vanttola P, Puttonen S, Karhula K, Oksanen T, Härmä M (June 2020). "Prevalence of shift work disorder among hospital personnel: A cross-sectional study using objective working hour data". Journal of Sleep Research. 29 (e12906): e12906. doi:10.1111/jsr.12906. PMID   31410909. S2CID   199574164.
  33. 1 2 3 4 5 6 7 8 Sack RL, Auckley D, Auger RR, Carskadon MA, Wright KP, Vitiello MV, Zhdanova IV (November 2007). "Circadian rhythm sleep disorders: part I, basic principles, shift work and jet lag disorders. An American Academy of Sleep Medicine review". Sleep. 30 (11): 1460–83. doi:10.1093/sleep/30.11.1460. PMC   2082105 . PMID   18041480.
  34. 1 2 3 Kecklund G, Axelsson J (November 2016). "Health consequences of shift work and insufficient sleep". BMJ. 355: i5210. doi:10.1136/bmj.i5210. PMID   27803010. S2CID   206912413.
  35. Khormizi HZ, Salehinejad MA, Nitsche MA, Nejati V (2019). "Sleep-deprivation and autobiographical memory: evidence from sleep-deprived nurses". Journal of Sleep Research. 28 (1): e12683. doi: 10.1111/jsr.12683 . ISSN   1365-2869. PMID   29624749. S2CID   206156921.
  36. "JCDR - Circadian rhythm, Night shift, Sleep quality". jcdr.net. Retrieved 2021-09-28.
  37. "Can nurses' shift work jeopardize the patient safety? A systematic review" (PDF). European Review for Medical and Pharmacological Sciences.
  38. 1 2 3 4 5 Wright KP, Bogan RK, Wyatt JK (February 2013). "Shift work and the assessment and management of shift work disorder (SWD)". Sleep Medicine Reviews. 17 (1): 41–54. doi:10.1016/j.smrv.2012.02.002. PMID   22560640.
  39. 1 2 3 4 5 6 7 8 9 10 11 Boivin DB, Boudreau P (October 2014). "Impacts of shift work on sleep and circadian rhythms". Pathologie-Biologie. 62 (5): 292–301. doi:10.1016/j.patbio.2014.08.001. PMID   25246026.
  40. 1 2 3 Ker K, Edwards PJ, Felix LM, Blackhall K, Roberts I (May 2010). "Caffeine for the prevention of injuries and errors in shift workers". The Cochrane Database of Systematic Reviews. 2010 (5): CD008508. doi:10.1002/14651858.CD008508. PMC   4160007 . PMID   20464765.
  41. Cheng P, Drake C (August 2019). "Shift Work Disorder". Neurologic Clinics. 37 (3): 563–577. doi:10.1016/j.ncl.2019.03.003. PMID   31256790. S2CID   164490979.
  42. Almeida CM, Malheiro A (2016). "Sleep, immunity and shift workers: A review". Sleep Science. 9 (3): 164–168. doi:10.1016/j.slsci.2016.10.007. PMC   5241621 . PMID   28123655.
  43. Czeisler CA, Moore-Ede MC, Coleman RH (July 1982). "Rotating shift work schedules that disrupt sleep are improved by applying circadian principles". Science. 217 (4558): 460–3. Bibcode:1982Sci...217..460C. doi:10.1126/science.7089576. PMID   7089576.
  44. Gallo LC, Eastman CI (January 1993). "Circadian rhythms during gradually delaying and advancing sleep and light schedules". Physiology & Behavior. 53 (1): 119–26. doi:10.1016/0031-9384(93)90019-C. PMID   8434051. S2CID   32361866.
  45. Kolla BP, Auger RR (October 2011). "Jet lag and shift work sleep disorders: how to help reset the internal clock" (PDF). Cleveland Clinic Journal of Medicine. 78 (10): 675–84. doi:10.3949/ccjm.78a.10083. PMID   21968474. S2CID   33565476.
  46. Eastman CI, Stewart KT, Mahoney MP, Liu L, Fogg LF (September 1994). "Dark goggles and bright light improve circadian rhythm adaptation to night-shift work". Sleep. 17 (6): 535–43. doi: 10.1093/sleep/17.6.535 . PMID   7809567.
  47. "Seasonal affective disorder treatment: Choosing a light box". MayoClinic.com. Retrieved 2010-12-30.
  48. deHaro D, Kines KJ, Sokolowski M, Dauchy RT, Streva VA, Hill SM, et al. (July 2014). "Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night". Nucleic Acids Research. 42 (12): 7694–707. doi:10.1093/nar/gku503. PMC   4081101 . PMID   24914052.
  49. Sack RL, Lewy AJ (December 1997). "Melatonin as a chronobiotic: treatment of circadian desynchrony in night workers and the blind". Journal of Biological Rhythms. 12 (6): 595–603. doi: 10.1177/074873049701200615 . PMID   9406035. S2CID   34215295.
  50. Muehlbach MJ, Walsh JK (January 1995). "The effects of caffeine on simulated night-shift work and subsequent daytime sleep". Sleep. 18 (1): 22–9. doi: 10.1093/sleep/18.1.22 . PMID   7761739.
  51. Chen C, ValizadehAslani T, Rosen GL, Anderson LM, Jungquist CR (2020). "Healthcare Shift Workers' Temporal Habits for Eating, Sleeping, and Light Exposure: A Multi-Instrument Pilot Study". Journal of Circadian Rhythms. 18: 6. doi: 10.5334/jcr.199 . ISSN   1740-3391. PMC   7583716 . PMID   33133210.
  52. Czeisler CA, Walsh JK, Roth T, Hughes RJ, Wright KP, Kingsbury L, et al. (August 2005). "Modafinil for excessive sleepiness associated with shift-work sleep disorder". The New England Journal of Medicine. 353 (5): 476–86. doi: 10.1056/NEJMoa041292 . PMID   16079371.
  53. Walsh JK, Schweitzer PK, Anch AM, Muehlbach MJ, Jenkins NA, Dickins QS (April 1991). "Sleepiness/alertness on a simulated night shift following sleep at home with triazolam". Sleep. 14 (2): 140–6. doi: 10.1093/sleep/14.2.140 . PMID   1866527.