Sleep disorders - shift work and jet lag
Exam Tips
- For shift work disorder exams, anchor diagnosis to: shift overlap with usual night sleep + insomnia/sleepiness + reduced total sleep + functional impairment + persistence (around 3 months) + exclusion of better causes.
- In OSCE history, ask direction of travel and number of time zones: eastbound usually causes sleep-onset difficulty; westbound often causes early waking.
- Sleep diary (and ideally actigraphy) is a high-yield investigation point and often expected in viva questions.
- Management stations score highly when you combine timed light exposure, behavioural scheduling, and cautious short-term pharmacology with explicit safety counselling (especially driving/occupational risk).
- Always mention comorbidity screening (depression/anxiety, OSA, substance use) before labeling a pure circadian disorder.
Definition
Shift work disorder and jet lag disorder are extrinsic circadian rhythm sleep-wake disorders where the internal body clock is misaligned with required sleep and wake times. Shift work disorder causes persistent insomnia and/or excessive sleepiness linked to work hours that overlap usual night sleep (typically for at least 3 months with functional impairment), while jet lag disorder is a short-term syndrome after rapid travel across at least 2 time zones with disturbed sleep, fatigue, and daytime performance decline.
Pathophysiology
Both conditions arise from circadian misalignment between the suprachiasmatic nucleus (SCN)-driven clock and external time cues. Night/rotating shifts and transmeridian travel disrupt light-driven entrainment, melatonin timing, core body temperature rhythm, cortisol rhythm, and peripheral metabolic clocks; this reduces sleep efficiency, shortens total sleep time, and impairs neurocognitive performance. Eastward travel usually causes greater difficulty because phase advance (sleeping earlier) is biologically harder than phase delay; chronic misalignment in shift work is also linked to reduced insulin sensitivity, higher blood pressure during biological night, appetite dysregulation, and mood vulnerability. For visual revision, see a circadian phase-response-curve/light-entrainment figure in a core sleep medicine or physiology textbook.
Risk Factors
- Older age
- Rapidly rotating shifts and short recovery intervals between shifts
- High frequency of night shifts
- Inability to obtain consolidated daytime sleep or naps
- Crossing multiple time zones rapidly
- Eastbound travel
- Sleep deprivation before travel
- Excess alcohol or caffeine use around travel/shift periods
- Dehydration and psychological stress
Clinical Features
Symptoms
- Insomnia symptoms temporally linked to shift pattern or recent long-haul travel
- Excessive daytime sleepiness, non-restorative sleep, and fatigue
- Reduced concentration, slowed thinking, memory lapses, irritability, low mood
- Jet lag pattern: sleep-onset insomnia more common after eastward flights; early waking/sleep maintenance problems more common after westward flights
- Somatic jet lag symptoms such as malaise, myalgia/cramps, abdominal bloating, nausea, constipation
Signs
- Often normal physical examination
- Observable reduced alertness/psychomotor slowing during biological night
- Functional impairment at work/study (errors, near-misses, reduced productivity)
- Possible associated cardiometabolic features over time (weight gain, elevated BP) in long-term shift workers
Investigations
Management
Lifestyle Modifications
- Provide explanation of circadian misalignment and expected adaptation timeline
- Optimise sleep hygiene: fixed sleep window when possible, cool/dark/quiet bedroom, avoid screens and heavy meals pre-sleep
- Timed light management: bright light at desired wake phase and strict light avoidance before intended sleep (sunglasses/blackout strategies)
- Shift-work tactics: forward-rotating rosters where possible, limit consecutive night shifts, protected recovery days, planned short naps before/early in night duty
- Jet lag tactics: pre-shift sleep schedule by 30-60 minutes/day before travel, align meals/activity to destination time, maintain hydration, limit alcohol
- Caffeine as a timed alertness aid (avoid within about 6 hours of planned sleep)
Pharmacological Treatment
Melatonin receptor agonist (chronobiotic)
- Melatonin immediate-release 2-5 mg orally at local bedtime after eastbound travel, usually for up to 2-5 nights
- Melatonin prolonged-release (Circadin) 2 mg orally 1-2 hours before bedtime (licensed in UK for short-term primary insomnia in adults >=55 years; circadian indications commonly off-label)
Most useful for phase-shifting and sleep initiation in jet lag/circadian misalignment. Counsel about drowsiness, avoid driving/operating machinery if affected, and avoid alcohol. Check interactions (notably fluvoxamine can markedly increase melatonin exposure). Use caution in pregnancy/breastfeeding and autoimmune disease; follow local formulary/BNF and specialist advice for off-label use.
Short-term hypnotic (if severe transient insomnia, after non-drug measures)
- Zopiclone 3.75-7.5 mg orally at night for up to 2-4 weeks including taper period
- Temazepam 10-20 mg orally at night for short-term use only
Reserve for brief rescue treatment due to tolerance, dependence, falls, parasomnias, and next-day psychomotor impairment. Contraindications/cautions include significant respiratory depression, sleep apnoea, myasthenia gravis, severe hepatic impairment, and history of substance misuse. Give explicit driving and safety-net advice.
Complications
- Chronic insomnia and persistent sleep debt
- Excessive sleepiness with occupational errors and road traffic collision risk
- Cognitive impairment (attention, working memory, executive dysfunction)
- Mood disturbance including depressive and anxiety symptoms
- Cardiometabolic risk increase: obesity, type 2 diabetes, hypertension, coronary disease, stroke
- Jet lag-related gastrointestinal disturbance and reduced daytime performance
- Possible long-term association with some cancers (evidence inconsistent)
Prognosis
Jet lag is usually self-limiting with re-entrainment over days; typical adaptation is faster westward (about half a day per time zone) and slower eastward (about one day per time zone). Shift work disorder may persist or recur while adverse rosters continue, but symptoms often improve with schedule redesign, circadian strategies, and treatment of comorbid insomnia, mental health issues, or other sleep disorders.
Sources & References
💊BNF Drug References(1)
- Melatonin[management.pharmacological]
✅NICE Guidelines(1)
- Sleep disorders - shift work and jet lag[overview]
📖Textbook References(10)
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 664)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 736)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 664)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 664)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 664)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 736)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 44)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 44)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 43, 44)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 220)[context]