Changes

April 2024 — reviewed. A literature search was conducted in March - April 2024 to identify evidence-based guidelines, UK policy, systematic reviews, and key randomized controlled trials published since the last revision of this topic. No significant changes to recommendations have been made. New sections have been added on risk factors and diagnosis.

Update

Goals

To support primary healthcare professionals to:

• Give advice on self-help measures to reduce sleep disturbance and symptoms in people who do shift work.
• Give advice on self-help measures to reduce sleep disturbance and symptoms in people with jet lag.

Outcome measures

Audit criteria

QOF indicators

QIPP - Options for local implementation

NICE quality standards

What is it?

Circadian rhythm sleep-wake disorders (CRSWDs) are disturbances of the sleep-wake cycle (typically manifest as insomnia and/or excessive sleepiness) caused by issues with a person's circadian rhythm (their 'internal clock'). There are six defined disorders, which come into broadly two categories:

• Intrinsic or endogenous CRSWDs, where sleep disturbance comes from alterations to a person's endogenous circadian rhythm system.
  • Delayed sleep-wake phase disorder.
  • Advanced sleep-wake phase disorder.
  • Irregular sleep-wake rhythm disorder.
  • Non-24-hour sleep-wake rhythm disorder.
• Extrinsic or exogenous CRSWDs, where the sleep problems are a result of environmental changes which cause a mismatch between sleep times and internal circadian rhythms.
  
  • Circadian rhythm sleep-wake disorder, shift work type or shift work sleep disorder.
  • Circadian rhythm sleep-wake disorder, jet lag type, or Jet lag disorder.

This topic relates to the extrinsic CRSWDs.

• Shift work disorder is characterised by insomnia and/or sleepiness as a result of work shifts that overlap with all or a portion of conventional night-time sleep periods. It is associated with overall reduction of sleep time. 
  • Symptoms should have persisted for at least several months and result in significant distress or mental, physical, social, occupational or academic impairment for diagnosis.
• Jet lag disorder is defined as a temporary mismatch between the timing of the sleep-wake cycle generated by the endogenous circadian clock and that of the sleep-wake pattern required by travel across at least two time zones.
  • Symptoms include disturbed sleep, sleepiness, fatigue, somatic symptoms (such as gastrointestinal disturbance) and impaired daytime function.
  • Duration and severity of symptoms varies with number of time zones crossed, ability to sleep whilst travelling, exposure to circadian time cues in the new environment, individual adaptability and direction of travel.

For a formal diagnosis of CRSWDs, a sleep diary should be used (and, where possible actigraphy) for a minimum of one week.

[Wilson, 2019; Sun, 2022; WHO, 2024]

How common is it?

There are limited and variable data on the prevalence of shift work disorder and jet lag disorder in the literature, and there are individual differences in people's susceptibility to these conditions.

• Shift work disorder
  • Shift work is common.
    • The European Working Conditions Survey in 2015 found that 21% of all employees reported working shifts, and 19% worked nights at least once a month [Parent-Thirion, 2017]. (The subsequent 2020 survey was disrupted by the COVID-19 pandemic and was more limited in scope.)
    • Information from the Office for National Statistics shows that in 2022, 27% of the workforce worked in the UK during the evening or night (irrespective of whether they also work in the day), equating to around 8.7 million people [ONS, 2023]. 4% of the workforce worked only in the evening or night.
    • The 2013 health survey for England found that around one-third of men and one-fifth of women reported working shift work (defined as working outside the hours of 7 am to 7 pm in their main job) [HSCIC, 2014].
      • This was most common in the 16–24 age group, and least common in those aged over 55.
      • Those in shift work were more likely to report fair or bad health and to have one or more limiting longstanding illnesses, as well as being more likely to be obese, more likely to have diabetes, and more likely to smoke cigarettes.
  • Prevalence data for shift work disorder shows significant disparity in figures due to diagnostic criteria used and sample selection. One systematic review and meta-analysis published in 2021 found an overall prevalence of 26.5% but noted great heterogenicity between prevalence studies for this condition [Pallesen, 2021].
  • A 2016 review found that about 20–30% of shift workers report insufficient sleep and excessive sleepiness in relation to working night and early morning shifts, and that the estimate for the prevalence of shift work disorder is 10-23% in rotating shift and night shift workers [Kecklund, 2016].
• Jet lag disorder
  • The prevalence of jet lag disorder is not known, however anyone who crosses time zones rapidly could be affected [BMJ Best Practice, 2023].
  • A review article states that it is possible that one-third of all travellers do not experience jet lag, and there is variation between people in the rate of adaptation between time zones for those who are affected [Arendt, 2018].
  • Duration of jet lag is partly dependent on how many time zones have been crossed and direction of travel - it is thought to take around half a day per time zone to adjust when travelling West, and 1 day per time zone when travelling East [van Rensburg, 2021].

What are the risk factors?

Shift work disorder

• Shift work disorder occurs in some individuals exposed to shift work and not others. It is not known why some people adapt more easily than others. 
• Factors increasing the risk include:
  • Older age.
  • Short recovery time between shifts and rapidly rotating shift schedules.
  • High number of night shifts.
  • Being unable to sleep during the day or take naps.

[Kecklund, 2016; Richter, 2016; Wilson, 2019; NHS Confederation, 2020]

Jet lag disorder

• Anyone who crosses time zones rapidly may develop jet lag disorder. Some people are more affected than others, and some will adapt more quickly than others.
• Factors which increase the risk, severity or longevity of jet lag disorder include:
  • Number of time zones crossed (Severity increases with number of time zones).
  • Eastbound travel (It is easier to phase-delay rather than to phase-advance one's own circadian cycle).
  • Excess caffeine or alcohol use.
  • Sleep deprivation.
  • Older age.
  • Dehydration.
  • Stress.

[DTB, 2020; Beros, 2021; BMJ Best Practice, 2023; IATA, 2023]

What are the complications?

The potential complications of shift work and jet lag may be linked to altered light exposure impacting on physiological processes, food and diet patterns, fatigue, and sleep patterns and behaviours. An accumulated 'sleep debt' may cause a variety of symptoms in different people [Kecklund, 2016; McKenna, 2018; BMJ Best Practice, 2023]

• Shift work may increase the risk of:
  • Chronic sleep disturbance, such as insomnia.
    • This may be seen with shift schedules with few days off and limited rest time between shifts [Richter, 2016; McKenna, 2018].
    • See the CKS topic on Insomnia for more information.
  • Excessive sleepiness and fatigue.
    • This may be due to acute sleep loss and reduced sleep quality, particularly related to night shifts and early morning shifts, with short day sleeps, short recovery times between shifts, and early wake times [Kecklund, 2016; Richter, 2016; McKenna, 2018].
    • 'Sleep inertia' describes a period of decreased cognitive and motor performance, which may occur after prolonged napping [McKenna, 2018].
  • Cognitive impairment and depression.
    • Cognitive performance worsens during periods of extended wakefulness and after acute restricted sleep [Kecklund, 2016].
    • Features may include reduced attention, poorer working and short-term memory, impaired executive functioning, reduced emotional regulation, and psychosocial stress related to conflict between work, family, and social commitments that negatively affect work-life balance [Kecklund, 2016; Richter, 2016].
    • See the CKS topics on Generalized anxiety disorder and Depression for more information.
  • Reduced performance, work-related errors and accidents, and road traffic collisions.
    • There is an increased safety risk with long waking periods, night shifts, and while driving following night shift. The risk is particularly increased with long, monotonous tasks and lack of work breaks [Kecklund, 2016; Richter, 2016; McKenna, 2018].
    • In a number of well-known industrial workplace accidents, fatigue or sleepiness relating to shift work was quoted as a contributory factor (for example, the Chernobyl and Three Mile Island nuclear power plant incidents, Exxon Valdez oil spill, and the Space Shuttle Challenger explosion) [Steele, 2021].
  • Cardiometabolic conditions.
    • There is an increased risk of type 2 diabetes mellitus, obesity and weight gain, coronary heart disease, and stroke, particularly associated with working night shifts [Kecklund, 2016]. 
      • This may partially be related to factors such as irregular and more frequent eating, eating at the wrong circadian phase (such as eating at night), worse food choices and availability, reduced physical activity and smoking [HSCIC, 2014; Shan, 2018].
      • Cardiometabolic effects of shift work include reduced glucose tolerance and insulin sensitivity, weight gain, increased overnight blood pressure, increased risk factors for cardiovascular disease as circadian rhythms impact on many physiological processes apart from sleep cycles, including neuroendocrine hormone release, homeostatic and metabolic processes such as autonomic control of blood pressure and body temperature [Steele, 2021; Hebl, 2022].
      • See the CKS topics on Angina, Diabetes - type 2, Hypertension - not diabetic, Lipid modification - CVD prevention, Obesity, and Stroke and TIA for more information.
  • Cancer.
    • There is a theoretical increased risk of breast, prostate, and colorectal cancer, in particular. The evidence in the literature is, however, conflicting and may be related to study bias or confounding factors [Kecklund, 2016].
  • Death.
    • There is a theoretical small increased risk for cardiovascular death. The evidence in the literature is, however, conflicting [Kecklund, 2016].
• Jet lag may increase the risk of [BMJ Best Practice, 2023]:
  
  • Sleep disturbance.
    • Typically there is an inability to get to sleep at night after an eastward flight, or early awakening after a westward flight, together with disturbed night-time sleep.
      • There may be excessive daytime sleepiness and fatigue due to acute sleep loss and reduced sleep quality, particularly during and following long-haul flights.
      • This may become longer lasting, leading to insomnia.
      • See the CKS topic on Insomnia for more information.
  • Cognitive impairment and impaired performance [BMJ Best Practice, 2023].
    • Features may include reduced alertness, impaired judgement and performance. This may be particularly relevant for business travellers, airline crew, military workers, and professional athletes [Bin, 2019]. 
      • Although evidence is lacking, an international consensus statement notes that there is agreement that jet lag can have significant impact on athletes' performance and risk of illness and injury [van Rensburg, 2021].
  • Gastrointestinal and bladder disturbance.
    • This includes loss of appetite, inappropriate timing of defecation, constipation, and excessive desire to urinate during the night [Arendt, 2018].
    • These are usually short-lived.

When should I suspect shift work disorder or jet lag disorder?

Shift work disorder

• Suspect shift work disorder in a person who works shifts which overlap with all or a portion of usual nighttime sleep periods and complains of insomnia (when trying to sleep) and/or excessive sleepiness (whilst awake), and a reduction in overall sleep time.
  • The symptoms should have persisted for at least three months and have led to significant distress or functional impairment (mental, physical, social, occupational or academic).
  • No other disorder (such as another medical condition or sleep disorder, side effects from medication, or substance abuse) is present, which better explains the symptoms and impact.

Jet lag disorder

• Jet lag tends not to present to healthcare professionals unless it leads to the destabilising of another medical condition.
• Suspect jet lag disorder in a person who has recently travelled across at least two time zones, and
  • Who complains of disturbed sleep, daytime sleepiness and fatigue, with onset within one or two days of travel.
    • Difficulty initiating sleep is more common with eastward travel.
    • Difficulty maintaining sleep is more common with westward travel.
  • Has significant distress or mental, physical, social, occupational or academic impairment as a result of the disturbed sleep.
• There may also be associated somatic symptoms such as general malaise, muscle cramps and gastrointestinal disturbance (nausea, abdominal distension, constipation).

How should I assess someone with shift work disorder or jet lag disorder?

Shift work disorder

• A thorough history is needed to ensure another disorder does not better explain the symptoms.
• Ask the person about their:
  • Symptoms, history of their symptoms, and impact on their daytime functioning.
  • Shift patterns.
  • Sleep routines and sleep hygiene.
  • Medical history - other medical conditions, other sleep disorders, mental health issues.
    • Consider screening for depression and anxiety. See the sections on the appropriate questionnaires in the CKS topics Depression and Generalized anxiety disorder.
    • Medication and history of substance abuse.
• Examination is not usually necessary unless the history leads to suspicion of another medical condition.
• Ask the person to keep a sleep diary/log for one to two weeks.
  • An example of a 2-week sleep diary is available from the American Academy of Sleep Medicine, or a more detailed example is available from the Sleep Foundation.
• Consider arranging actigraphy if the diagnosis is uncertain. This is a method of assessing sleep patterns, worn as a device on the wrist. Unless available in primary care, this would usually entail referral to a sleep clinic.

Jet lag disorder

• Ask the person about:
  • Details of travel (dates, time zones crossed, departure times).
  • Symptoms.
  • Sleep details (such as difficulties with initiating or maintaining sleep, total sleep duration, timing of onset of sleep disturbance, previous sleep difficulties).
  • Impact on functioning.
  • Details of any associated symptoms (such as bowel or urinary symptoms; consider any possible underlying condition).
• Examination is not usually necessary, unless another condition is suspected from the history (for example, persisting bowel symptoms).
• Investigations are not usually necessary unless another sleep disorder or another condition is suspected from the history.

What else might it be?

Alternative conditions which may present similarly to jet lag disorder or shift work disorder (or be comorbid with them) include:

• Travel fatigue. This is distinguished from jet lag by symptoms of general fatigue, headaches, and weariness, and can result from any long journey whether crossing time zones or not. Sleep is not usually affected and symptoms usually settle after a normal night's sleep.
• Other circadian rhythm sleep-wake disorders (symptoms will have persisted for at least several months and cause significant distress or functional impairment).
  • Delayed sleep-wake phase disorder. There is a persistent delay in the major sleep period, compared to usual sleep times, leading to difficulty falling asleep and difficulty awakening.
  • Advanced sleep-wake phase disorder. The onset of sleep is earlier than usual. There is evening sleepiness earlier than usual bedtimes and earlier awakening than desired.
  • Irregular sleep-wake rhythm disorder. There is a lack of a clearly defined circadian rhythm of sleeping and waking.
  • Non-24-hour sleep-wake rhythm disorder. Sleep onset is delayed by one or two hours, and the circadian sleep-wake cycle is typically longer than 24 hours. 
• Other sleep disorders, such as insomnia, obstructive sleep apnoea syndrome, and restless legs syndrome. See the CKS topics on Insomnia and Obstructive sleep apnoea syndrome for more information.
• Mental health conditions affecting sleep, such as depression or anxiety disorders. See the CKS topics on Depression and Generalized anxiety disorder for more information.
• Other causes of fatigue. See the CKS topic on Tiredness/fatigue in adults for more information.

A careful history will usually separate jet lag disorder and shift work disorder from these possible differentials (although note there may be comorbidity), and further tests are not usually necessary.

Scenario: Shift work

From age 18 years onwards.

Scenario: Jet lag

From age 18 years onwards.

Search strategy

Scope of search

A literature search was conducted for guidelines and systematic reviews on primary care management of sleep disorders - shift work and jet lag.

Search dates

January 2019 - April 2024

Key search terms

The terms listed below are the core search terms that were used for EBSCOhost MEDLINE (searched 15th January 2019). The strategy was adapted for The Cochrane Library databases.

S7    S1 OR S2 OR S3 OR S4 OR S5 OR S6 
S6    (MH "Shift Work Schedule") 
S5    AB ( ((nightshift* or night-shift or (night N0 shift*)) N5 sleep*) ) OR TI ( ((nightshift* or night-shift or (night N0 shift*)) N5 sleep*) ) 
S4    AB ( ((shift-work* or (shift N0 work*) or shiftwork*) N5 sleep*) ) OR TI ( ((shift-work* or (shift N0 work*) or shiftwork*) N5 sleep*) ) 
S3    AB ( (jetlag* or (jet N0 lag*) or jet-lag*) ) OR TI ( (jetlag* or (jet next lag*) or jet-lag*) ) 
S2    AB (circadian rhythm sleep disorder*) OR TI (circadian rhythm sleep disorder*) 
S1    (MH "Sleep Disorders, Circadian Rhythm+")

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• World Health Organization
• Guidelines International Network
• TRIP database
• Agency for Healthcare Research and Quality
• Institute for Clinical Systems Improvement
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work (occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Bandolier
• Drug and Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium (HMIC)

Patient experiences

• Healthtalk
• BMJ - Patient Journeys

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary (BNF)
• electronic Medicines Compendium (eMC)
• European Medicines Agency (EMEA)
• LactMed
• Medicines and Healthcare products Regulatory Agency (MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.