Shift Work Sleep Disorder (aka Shift Work Disorder, Shift Disorder)
Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder that commonly affects individuals who work outside of the standard 9 A.M.–5 P.M. work schedule, including fixed non-standard work hours, rotating shift schedules, oo erratic and on-call work schedules.
It is characterized by an overall decrease in sleep quality, and either:
Symptoms of insomnia such as difficulties in initiating or maintaining sleep (i.e. getting to sleep or staying asleep) when trying to sleep;
Symptoms of excessive sleepiness when needing to be awake (EDS, or excessive daytime sleepiness); or
A combination of both the above.
Recognising the impact of SWSD on shift workers sleep health is important for both individuals and shift working organisations. The sleep deprivation shift work disorder can lead to affects both an individual's health, their quality of life, and their safety and performance in the workplace.
Shift Work And Sleep: What Causes Shift Work Disorder?
Shift work disorder is considered to be a circadian rhythm sleep disorder, a category of sleep disorders that arise owing to a mismatch between the timing of sleep and the timing of the body's internal circadian clock that regulates the sleep-wake cycle. Other circadian rhythm disorders include delayed and advanced sleep-wake phase disorder, irregular sleep-wake rhythm disorder, and jet lag.
The development of shift work sleep disorder is closely tied to the misalignment of the body's internal circadian clock with the external work schedule.
The human body operates on a natural 24-hour cycle known as the circadian rhythm. This rhythm is regulated by a master internal clock, known as the suprachiasmatic nucleus, located in the hypothalamus of the brain.
This clock tells us when to be alert and awake, and when to be less alert and awake. It does this by taking cues from patterns of light and darkness exposure coming through receptors in the eyes.
When it is light outside, the master clock will promote wakeful alertness. When dark, the master clock will promote reduced alertness.
In shift workers, the timing of light exposure and the 24hr sleep-wake schedule is disrupted causing a desynchronization of the internal circadian rhythm (for example, many shift workers work night shifts and are trying to sleep during the day and daylight hours, when the master clock will be sending out a strong alertness signal).
This desynchronization can lead to difficulties falling asleep during the day and in staying awake at night, as the body's natural inclination to sleep conflicts with the demands of the work schedule.
The resulting sleep disruption and irregular sleep schedules contribute to the manifestation of sleep disturbances and shift work disorder.
What Are The Symptoms Of Shift Work Disorder?
As noted earlier, SWSD is associated with both symptoms of insomnia and symptoms of excessive daytime sleepiness. This means common symptoms of shift work sleep disorder encompass a range of sleep-related difficulties and daytime impairments. Individuals with SWSD often experience:
- Poor sleep quality: Shift work can disrupt the natural sleep cycle, causing fragmented and shallow sleep. This poor quality sleep can lead to fatigue and a lack of feeling refreshed upon waking;
- Insomnia: Shift workers often struggle with difficulty falling asleep or staying asleep during their sleep periods, resulting in fatigue and distress (take our insomnia test to assess your insomnia symptoms);
- Persistent non-restorative sleep
- Physical and/or mental fatigue: variable sleep schedules and sleep loss can contribute to persistent fatigue;
- Excessive sleepiness: reduced sleep time can be an issue for some that work rotating shifts, but even when getting enough sleep individuals with SWSD may feel excessively tired and sleepy during their shift owing to body clock misalignment, making it challenging to stay alert and focused.
- Struggles with maintaining alertness during waking hours: in addition to body clock disruption, many shift workers experience shortened sleep durations;
- Difficulties concentrating: SWSD can impair cognitive function, affecting an individual's ability to concentrate, make decisions, and perform tasks effectively.
- Irritability,
- Depression,
- Anxiety
- Gastrointestinal disturbances: Shift workers may experience digestive problems such as indigestion, stomach pain, and bowel irregularities due to disrupted meal times and circadian misalignment.
- Sleep-related motor vehicle accidents (especially after shifts)
- Increased substance use
- Errors and accidents: Lack of sleep and excessive sleepiness can impair motor skills and reaction times, increasing the risk of workplace accidents or accidents around the home;
- Social isolation: Work at night can put an individual's schedule at odds with family members and friends, impacting relationships and opportunities to socialise.
What Is The Prevalence Of Shift Work Sleep Disorder?
The prevalence of shift work disorder is significant and affects a wide range of industries and professions.
Prevalence rates of SWSD among shift workers internationally range from 8% to 54% (American Academy of Sleep Medicine 2014; Di Milia et al. 2013).
A range of scheduling factors affect the likelihood of developing SWSD, such as
the shift type (ranging from most to least detrimental: night shift, rotating shift, early morning shift, afternoon shift or evening shift, day shift);
duration of shift work, including hours per shift (>12 hours per shift); and
years of regular shift work (with a dose-dependent effect meaning more years of shift work increase likelihood of developing SWSD);
direction of rotation (counterclockwise being worse than clockwise);
speed of shift rotation (for rotating shift workers, faster rotation, such as multiple rotations within 1 week, potentially have a more adverse impact than slower rotation).
The tendency of an individual's circadian rhythm may impact their ability to adjust to shift work. For example, people who are "evening types" may seek to become night shift workers, or find it easier to adapt to night shift work or clockwise rotating shift schedules.
On the other hand, certain medical and psychological conditions that are sensitive to irregular sleep, such as bipolar disorder and sleep apnoea, may pose higher risks for developing Shift Work Sleep Disorder (SWSD).
Age may also play a role in the risk of developing SWSD, with older people who work shift work often having more difficulties with sleep disruption, daytime sleepiness, and fatigue.
Health Effects On Shift Workers
Research suggests that there are a range of negative health consequences of shift work (and shift work disorder) resulting from the disruption to natural body rhythms caused by inconsistent or non-standard work schedules. The risk of developing these conditions are more pronounced in long term shift workers. Physical health complications can include increased risk of:
general health conditions;
cardiovascular disease;
gastrointestinal problems;
metabolic disorders such as obesity and diabetes;
reproductive health difficulties
developing other sleep disorders.
Mental health is also impacted and can include:
increased risk of experiencing mental health disorders such as depression,
substance abuse problems
How Is Shift Work Sleep Disorder Diagnosed?
The International Classification Of Sleep Disorders (ICSD3) recommends shift work disorder diagnosis is performed via a comprehensive evaluation of an individual's sleep history, sleep patterns, shift work schedule, and associated sleep problems and symptoms.
Ideally, clinical evaluation and treatment is performed by a clinical sleep specialist familiar with the treatment of circadian rhythm sleep disorders characterized by both sleepiness and insomnia symptoms.
This helps to ensure that the issues are caused by shift work and symptoms are not better explained by another sleep disorder that existed prior to working a nontraditional shift.
Healthcare professionals may utilize various assessments and procedures to diagnose SWSD and develop an appropriate management plan.
Additionally, standardized sleep questionnaires and sleep diaries or sleep logs may be employed to assess the severity and impact of SWSD symptoms on the individual's daily functioning. An overnight sleep study is not required.
Understanding the intricate role of circadian misalignment in the development of SWSD is crucial for devising targeted interventions to alleviate its impact on affected individuals.
How Is Shift Work Sleep Disorder Treated?
Shift Work Sleep Disorder can be treated using a combination of lifestyle changes, good sleep hygiene practices, and medication when needed.
1. Lifestyle Changes and Sleep Hygiene: Treatment may include adapting yourself to work at night and sleep during the day. This may require changing your sleeping schedule gradually and creating an environment that supports daytime sleep (like dark, quiet, and cool environments with no distractions).
2. Medication: Sleeping pills may be prescribed for short term use for troubles sleeping. However, while medications may increase hours of sleep per night, they are unlikely to be a long-term solution as they can lead to further impairment at work. The hormone melatonin may also be prescribed to influence the signals that promote sleep and circadian factors. Wake promoting medications may be prescribed for wake period fatigue and performance concerns.
3. Light Therapy: This involves exposure to a special kind of light that mimics natural outdoor light. The light may help to modify or reset your body’s internal clock, or circadian rhythms.
4. Cognitive Behavioral Therapy : This form of therapy involves changing behavior and dealing with the psychological effects of shift work sleep disorder. Typically we find that elements of CBTi or cognitive behavioural therapy for insomnia is relevant for treating shift work sleep disorder.
5. Regular Exercise and Healthy Diet: Regular exercise can help promote good sleep. Also, maintaining a healthy diet can improve overall wellbeing and improve sleep quality.
6. Napping: Taking short naps before or during shifts can help to reduce sleepiness.
The exact treatment plan may depend on individual factors and should be discussed with a healthcare provider. It's also essential to manage related conditions, such as depression or anxiety, that could be causing sleep issues.
You can find out more about specialist sleep treatments in Auckland, Wellington sleep clinic sleep disorders treatment options, and Christchurch sleep clinic sleep medicine information by clicking the links.
Clinical Comment:
Treating shift work disorder can be complex and is very individualised. Treatment and treatment plans tend to be very specific to an individual because
Different people respond very differently to shiftwork;
People with shift work disorder can experience insomnia or falling asleep at work, or a combination of symptoms, and
the shift worker will likely be working the rotating shift work or night shift schedule that is creating the problem throughout treatment.
Fequently Asked Questions
1. What Is Shift Work Disorder?
Shift work disorder is a specific type of circadian rhythm sleep disorder that primarily affects shift workers. This particular sleep disorder is caused by a work schedule that takes place during the night shift or any shift that requires work when most people sleep (e.g. early morning shift, evening shift, on-call work). Shift workers often have trouble adjusting their clocks to accommodate their work hours, and as a result, they may experience a range of symptoms of shift work disorder, which include excessive sleepiness, insomnia, lack of energy, and difficulty concentrating. According to the American Academy of Sleep Medicine, a significant number of people who work on a shift work schedule experience such problems - studies often suggest 20-50% of shift workers.
2. What Are The Symptoms of Shift Work Disorder?
The symptoms of shift work disorder include difficulties in falling asleep or staying asleep, excessive sleepiness when you need to be awake and alert, lack of energy, difficulty concentrating, and more. These sleep problems can lead to significant sleep loss and severe impairments in overall health, performance, and safety at work. It's important for shift workers to recognize these symptoms early and seek treatment to improve sleep and quality of life.
3. How Does Shift Work Affect Sleep Quality?
Shift work can seriously affect quality of sleep and the circadian rhythm due to inconsistencies in work time and sleep time. It can require shift workers to sleep during the day and work when your body wants to sleep at night. This disrupting their natural circadian rhythm and leading to shift work sleep disorder.
4. What Strategies Can Help To Manage Shift Work Disorder?
Strategies to manage shift work disorder include maintaining a regular sleep schedule as much as possible, optimizing your sleep environment, and practising good sleep hygiene. Trying to keep the same sleep hours on work and non-work days can also help. Seeking professional help may also be necessary if the disorder severely affects day-to-day activities.
5. How Common Is Shift Work Disorder?
Shift work disorder is fairly common among those who work non-traditional hours, especially night and early morning shifts. However, not all shift workers will experience shift work disorder.
Written By: The Better Sleep Clinic Team
Reviewed By: Dan Ford, Sleep Psychologist