3/11/2012 American Osteopathic College of Occupational and Preventive Medicine 2012 Mid-Year Educational Conference St. Petersburg, Florida Objectives • Identify factors involved w/jet lag & shift Fatigue in Aviation: work sleep disorder Circadian rhythm sleep disorders • Describe the evaluation of circadian rhythm sleep disorders (CRSD) Bascom K. Bradshaw, DO, MPH, MAS • List treatments for jet lag & shift work sleep disorder Outline Fatigue Management Recap • Past fatigue management recap • Fatigue Factors – Circadian Factors • Case presentation – Sleep Factors • Jet lag – Domestic Factors • Shift work sleep disorder • Coping Strategies – Work Schedules • Summary – Alertness Management – Evidence-Base & Operational Considerations Two-process model of sleep regulation Two-process model of sleep regulation Beersma DG, Gordijn MC. Circadian control of the sleep-wake cycle. Physiol Behav 2007;90:190–195 Q-1 3/11/2012 American Osteopathic College of Occupational and Preventive Medicine 2012 Mid-Year Educational Conference St. Petersburg, Florida Case 1 • 45yo female diplomat is going to Europe for a series of conferences • She is scheduled to be away for 21 days • Unremarkable past medical Hx • Reports significant difficulty adjusting to local time when going to Europe – Insomnia at night and sleepiness during the early day for up to 1 week or more • She would like advice on optimizing her adjustment to eastward travel Adapted from: American Academy of Sleep Medicine. International classification of sleep disorders: diagnostic and coding manual. 2nd ed. Westchester, Illinois: American Academy of Sleep Medicine; 2005. Circadian desynchronization Circadian desynchronization • Circadian rhythm sleep disorders • Sleep and wakefulness are conceptually governed by 2 processes – Dyssynchrony b/w body’s internal clock (Borbely & Achermann 1992) and external 24-hr light-dark cycle – “process S” – “process C” – Typically presents w/insomnia or excessive somnolence • Process S – May be an intrinsic disorder (delayed or advanced sleep- – Homeostatic drive to sleep phase disorder) – Proportional to duration of sleep restriction – May be the result of transmeridian air travel or working – Maximal after ~ 40 hrs (Carskadon & Dement 1979) nonstandard shifts • Process C – Symptomatic Tx is available – Creates drive for wakefulness • Tx based on understanding of sleep regulation – Variably opposes process S – Depends on intrinsic circadian rhythms of individual (Beersma & Gordijn – Important to determine circadian phase 2007) • Clinical approach • Neurons of the suprachiasmatic nuclei of the hypothalamus – Coordinates sleep-wake rhythm, as well as numerous other behavioral – Specific interventions can be adjusted and physiologic processes (Ralph et al. 1990; Moore & Eichler 1972) Circadian Rhythm Sleep Disorder Circadian desynchronization Evaluation • Intrinsic human circadian period (Czeisler et al. 1999) • Clinical interview – Slightly longer than 24 hrs – Synchronized, or entrained, to 24-hr day by various – Hx is cornerstone of evaluation environmental inputs, or zeitgebers • Jet lag disorder Hx: – Most important zeitgebers is light exposure (Waterhouse & DeCoursey 2004) – Degree of sleep deprivation before and during travel • Misalignment of internal clock w/the sun – Innate circadian preference, “night owl” or “early bird” – Daytime anergia – Alcohol and caffeine intake – Alternating complaints of insomnia and hypersomnia – Emotional disturbances • Shift work disorder Hx: – Gastrointestinal distress – Sleep-wake schedule on working days vs nonworking • Intrinsic clock unable to adjust rapidly w/long-distance air days travel or nocturnal work schedule – Jet lag sleep disorder or shift work sleep disorder – External contributors to poor sleep Q-2 3/11/2012 American Osteopathic College of Occupational and Preventive Medicine 2012 Mid-Year Educational Conference St. Petersburg, Florida Circadian Rhythm Sleep Disorder Circadian Rhythm Sleep Disorder Evaluation Evaluation • Sleep diary or sleep log • Actigraphy – Record time of naps, consolidated sleep, wake – Wristwatch-size motion detector/light exposure time – Typically worn continuously for 7 days or longer – Record estimated sleep latency, awakening after – Surrogate measure of various sleep-wake sleep onset, time in bed, medication and caffeine variables (Morgenthaler et al. 2007) intake, and restorative quality of sleep – Valuable in assessing Tx response • Insight into counteractive sleep-related • Either sleep diary or actigraphy can demonstrate stability of sleep patterns and behaviors and sleep/wake misperceptions circadian preference – Compliance is often limited – Actigraphy typically generates more reliable data – Best used in conjunction w/actigraphy (Bradshaw DA et al. 2007) Circadian Rhythm Sleep Disorder Circadian Rhythm Sleep Disorder Evaluation Evaluation • Morningness-Eveningness questionnaire • Polysomnography – 19 items – Used primarily to rule out sleep-disordered – Night owls tend to score lower than early birds breathing (Horne & Ostberg 1976) – Not indicated for routine evaluation of • Assist w/identifying non-optimal work shifts circadian rhythm sleep disorders – “Early bird” on permanent night-shift schedule Circadian Rhythm Sleep Disorder Evaluation • Minimum core body temperature & peak melatonin secretion (6-sulphatoxymelatonin) Back to Case 1… – Follow a 24-hour cycle. – Often used in research – Not routinely used in clinical practice Q-3 3/11/2012 American Osteopathic College of Occupational and Preventive Medicine 2012 Mid-Year Educational Conference St. Petersburg, Florida Jet Lag Sleep Disorder Jet Lag Sleep Disorder • Results from air travel across multiple time • Rapid travel across 1 or 2 time zones – Only transient sxs zones • Westward travel is normally less severe than eastward • Discordance b/w internal circadian clock – Requires later adjustment of internal clock and destination’s light-dark cycle • Circadian period tends to exceed 24 hours – Internal clock can move later ~2 hrs/day • Sleeping poorly at night and feeling groggy – Can move earlier 1-1.5 hrs/day during the day (Waterhouse et al. 2007; Eastman et al. 2005) • More time zones crossed • Experience general malaise and – Longer-lasting and more severe sxs gastrointestinal distress – Longer re-entrainment required for circadian pacemaker Jet Lag Sleep Disorder/ Jet Lag Sleep Disorder Light exposure • Age effects on severity of jet lag is not yet known • Light exposure (Sack et al. 2007; Burgess et al. 2002; Lewy et al. 1998) – Methodologic differences preclude direct comparisons of studies – Primary influence in shifting circadian clock – Direction of shift depends on timing of the exposure • Study of simulated jet lag (requiring 6-hr advance) • Core body temperature (Moline et al. 1992) – Lowest point ~ 2-3 hrs before habitualy wake time – Subjects ages 37-52 > fragmented sleep than ages 18-25 • Phase delay (Desirable for westward travel) – Older group also > impairment in daytime alertness – Exposure to bright light in hours leading up to core body temp minimum – Sets internal clock later • Decrease in phase tolerance? • Phase advance (Desirable for eastward travel) • Decrease in ability to sleep at an abnormal time in circadian cycle – Exposure to bright light after core body temp minimum • 2 field studies involving both eastward and westward travel – Sets internal clock earlier yielded opposite results • “Antidromic re-entrainment” (Waterhouse et al. 2002; Tresguerres et al. 2001; Sack et al. – Inadvertent shifting of circadian phase in wrong direction 2007) – Delays circadian reacclimation – Older age protective against jet lag (?) – Prolongs jet lag sxs Human phase-response curve to Jet Lag Sleep Disorder light and exogenous melatonin • Example of “Antidromic re-entrainment” – Flight from Chicago to Paris (7 time zones) • Arrives in Paris 8AM local time • Traveler’s internal clock, 1AM – Core body temp minimum ~ 4AM Chicago time, or 11AM Paris time – Light exposure immediately after landing (Daan & Lewy 1984) • Promotes phase delay (not desired) • Prolongs circadian re-entrainment Burgess HJ, et al. Bright light, dark, and melatonin can promote circadian adaptation in night shift workers. Sleep Med Rev 2002;6:407-420 Q-4 3/11/2012 American Osteopathic College of Occupational and Preventive Medicine 2012 Mid-Year Educational Conference St. Petersburg, Florida Jet Lag Sleep Disorder Jet lag plan for 7 time zones east • Other factors (typically, transient effects) – Sleep deprivation (before flight or en route) – Acute discomfort at cruising altitude (Muhm et al. 2007) – Excessive alcohol or caffeine intake inflight Burgess HJ, Eastman CT. Prevention of Jet Lag. American College of Physicians, 2010. http://pier.acponline.org/physicians/screning /prev1015/prev1015.html. Jet Lag Sleep Disorder/ Jet Lag Sleep Disorder/ Nondrug therapies Nondrug therapies • Business travel • If traveler intends to remain at destination for – Often requires frequent shifts to different time extended period zones – Optimal adjustment via strategic avoidance/exposure – May benefit from keeping home-based schedule to light (Daan & Lewy 1984) – Avoid antidromic shift • Home-based sleep hrs vs. local sleep hrs (Lowden & Akerstedt 1998) • Burgess & Eastman (2010; 2009) – Phase delay vs. phase advance (?) – 2-day stay after 9-hr westward flight – Depends on number of time zones crossed – Travelers sleeping on home-based hrs were – Shifts earlier in time are required for eastward flights less sleepy and reported