Circadian Rhythms and Shift Work 1 Vicken Y. Totten MD: Vicken Y. Totten MD: Emergency Physician Emergency Physician and Career-long Shift Worker and Career-long

Circadian Rhythms and Shift WorkCircadian Rhythms and Shift Work 11

Circadian Rhythms Circadian Rhythms and and

Shift WorkShift Work

Circadian Rhythms Circadian Rhythms and and

Shift WorkShift Work

Vicken Y. Totten MD:Vicken Y. Totten MD: Emergency Physician Emergency Physician

and Career-long Shift Workerand Career-long Shift Worker



SLEEP in literatureSLEEP in literatureSLEEP in literatureSLEEP in literature

Sleep, that knits the ravell'd sleave of care,Sleep, that knits the ravell'd sleave of care, The death of each day's life, sore labour's bath,The death of each day's life, sore labour's bath, Balm of hurt minds, great nature's second Balm of hurt minds, great nature's second

course,course, Chief nourisher in life's feast.Chief nourisher in life's feast.

• - Shakespeare, Macbeth, Act II, Scene I- Shakespeare, Macbeth, Act II, Scene I



Goals and Objectives: Goals and Objectives: Goals and Objectives: Goals and Objectives:

Describe normal sleep structure Describe normal sleep structure Discuss Circadian Rhythm Disorders Discuss Circadian Rhythm Disorders Describe types of shift work patternsDescribe types of shift work patterns Offer concrete shiftwork suggestionsOffer concrete shiftwork suggestions Provide a resource list Provide a resource list


Biologic Rhythm ControlBiologic Rhythm Control

Innate rhythms poly-genetically Innate rhythms poly-genetically determined determined

Master clock in suprachiasmatic nucleus Master clock in suprachiasmatic nucleus of the rostro-ventral hypothalamus. of the rostro-ventral hypothalamus.

Mediated by light/dark cycles via Mediated by light/dark cycles via cryptopsin receptors in retina, skin and cryptopsin receptors in retina, skin and possibly pituitarypossibly pituitary

Humans: Day = alert / Night = sleep. Humans: Day = alert / Night = sleep.


Biologic rhythmsBiologic rhythms

All body systems change All body systems change rhythmicallyrhythmically

90 minute alertness cycle90 minute alertness cycle Monthly fertility cycleMonthly fertility cycle Sleep/wake generally 23-26 hour Sleep/wake generally 23-26 hour

cyclecycle



Rhythm disordersRhythm disorders

Normally, biologic cycles kept in synch Normally, biologic cycles kept in synch by signal substances such as by signal substances such as melatonin, cortisol and othersmelatonin, cortisol and others

Disruption in these systems have Disruption in these systems have profound health implications. profound health implications.

Disrupted by both internal and Disrupted by both internal and external signalsexternal signals

Cycles re-synchronize at different Cycles re-synchronize at different ratesrates


Circadian disruption Circadian disruption

De-synchronization of innate De-synchronization of innate biologic / circadian cycles. biologic / circadian cycles.

Chronically in shiftwork and briefly Chronically in shiftwork and briefly from jetlag. from jetlag.

Medicine is far behind industry in Medicine is far behind industry in recognizing the implications of shift recognizing the implications of shift work work


Causes of circadian rhythm Causes of circadian rhythm disorders disorders

GeneticsGenetics Medications Medications PregnancyPregnancy Shift work Shift work time zone changes time zone changes


Normal Sleep Architecture: Normal Sleep Architecture: Stages of sleepStages of sleep

Normal Sleep Architecture: Normal Sleep Architecture: Stages of sleepStages of sleep

Non-REM (NREM) sleep - Stages I-IV Non-REM (NREM) sleep - Stages I-IV brain idle, body mobile brain idle, body mobile

REM - Body paralyzed, Brain active REM - Body paralyzed, Brain active (more metabolically active than (more metabolically active than during waking)during waking)


Stage 1 - transition period. Stage 1 - transition period. Stage 1 - transition period. Stage 1 - transition period.

Normally 10 minutes. Eyes rove. Normally 10 minutes. Eyes rove. Most people awakened during Stage Most people awakened during Stage

1 claim they are not asleep.1 claim they are not asleep. ““Micro-Sleeps” Micro-Sleeps” Driving while fatiguedDriving while fatigued


Stage 2 - Deeper, fewer eye Stage 2 - Deeper, fewer eye movements. movements.

Stage 2 - Deeper, fewer eye Stage 2 - Deeper, fewer eye movements. movements.

Shallowest restorative sleep. Shallowest restorative sleep. About half of adult sleep in Stage 2. About half of adult sleep in Stage 2. 20 min. before progressing to next 20 min. before progressing to next

stage. stage.


Stages 3/4 - Slow wave Stages 3/4 - Slow wave sleep (SWS), (delta sleep) sleep (SWS), (delta sleep) Stages 3/4 - Slow wave Stages 3/4 - Slow wave

sleep (SWS), (delta sleep) sleep (SWS), (delta sleep) Most restorative & restful; vital for Most restorative & restful; vital for

physical recuperation. physical recuperation. Majority occurs early in the sleep Majority occurs early in the sleep

period.period. Difficult to arouse from SWS.Difficult to arouse from SWS. First stage to be “made up” after sleep First stage to be “made up” after sleep

deprivation.deprivation. SWS deprivation causes fatigue, SWS deprivation causes fatigue,

muscle aches. muscle aches.


REM sleepREM sleepREM sleepREM sleep brain on, body off. brain on, body off. Vital for psychological well-being; Vital for psychological well-being; Isolated REM deprivation -> 1Isolated REM deprivation -> 1stst

irritability -> psychosis -> death irritability -> psychosis -> death EEG similar to wakefulness. EEG similar to wakefulness. Dreams, irregular pulse, respiration, Dreams, irregular pulse, respiration,

increased BP, loss of muscle tone, increased BP, loss of muscle tone, and absent spinal reflexes. and absent spinal reflexes.


REM sleepREM sleepREM sleepREM sleep First episode occurs after 90-120 minutes First episode occurs after 90-120 minutes

of NREM sleep. of NREM sleep. Recurs in about 90 minute cycles, getting Recurs in about 90 minute cycles, getting

more frequent towards awakeningmore frequent towards awakening REM periods become longer as night REM periods become longer as night

progresses. progresses. REM disorders include sleepwalking / REM disorders include sleepwalking /

talking / night terrorstalking / night terrors


““Core Sleep” Core Sleep” ““Core Sleep” Core Sleep”

Horne: first three SWS cycles with Horne: first three SWS cycles with their REM periods their REM periods

"optional" sleep the rest of the night: "optional" sleep the rest of the night: more REM, less SWS more REM, less SWS

Core sleep: about 5 hours for most Core sleep: about 5 hours for most personspersons

Only core sleep made up.Only core sleep made up.


““Sleepiness”Sleepiness”““Sleepiness”Sleepiness”

2 components: core versus optional2 components: core versus optional missing core sleep (physiologic) -- missing core sleep (physiologic) --

disrupts physiologic systems disrupts physiologic systems missing optional sleep missing optional sleep

(psychological) -- mostly (psychological) -- mostly psychological / mood effectspsychological / mood effects


Excess Sleepiness in Shift Excess Sleepiness in Shift WorkersWorkers

Up to 36% of rotating-shift workers experience ES.

Up to 45% of night-shift workers experience ES.


Circadian disruptionCircadian disruptionCircadian disruptionCircadian disruption Day /awake and night / sleep are the Day /awake and night / sleep are the

normal human condition. normal human condition. When switching to a day / sleep and When switching to a day / sleep and

night / awake, various physiologic night / awake, various physiologic cycles become desynchronizedcycles become desynchronized

Hospitalization with loss of ‘Zeitgibers”Hospitalization with loss of ‘Zeitgibers” Re-synchronization at different ratesRe-synchronization at different rates Generally, all systems can shift 1 hr Generally, all systems can shift 1 hr

per day. per day.



Adverse Health effects of Adverse Health effects of shiftworkshiftwork

Breast Cancer, Endometrial Cancer : increased Breast Cancer, Endometrial Cancer : increased in women who are not exposed to enough in women who are not exposed to enough darkness; mechanism unclear; proposed darkness; mechanism unclear; proposed mechanism is melatonin deficiency.mechanism is melatonin deficiency.

Prostate Cancer: increased most in rotating Prostate Cancer: increased most in rotating shift workers when compared to fixed-night shift workers when compared to fixed-night shift-workers, who have an extremely minimal shift-workers, who have an extremely minimal risk. risk.

Peptic Ulcer Disease /Obesity / Cardiovascular Peptic Ulcer Disease /Obesity / Cardiovascular DiseaseDisease

Pregnancy Issues: night work and high work Pregnancy Issues: night work and high work load increase the risk of spontaneous abortionload increase the risk of spontaneous abortion


Inter-relationships are Inter-relationships are complexcomplex

Obesity, pregnancy, high fat diets Obesity, pregnancy, high fat diets and circadian rhythmand circadian rhythm

Npas2 is a key organizer of the Npas2 is a key organizer of the circadian system; if maternal diet is circadian system; if maternal diet is high fat, the fetal liver fetal histone high fat, the fetal liver fetal histone code is mal-transcribed, and leads to code is mal-transcribed, and leads to appetite and circadian disorders in appetite and circadian disorders in the offspring. the offspring.

www.bcm.edu/obgyn/index.cfm?pmidwww.bcm.edu/obgyn/index.cfm?pmid=11856=11856


Common Circadian Rhythm Common Circadian Rhythm DisordersDisorders

Common Circadian Rhythm Common Circadian Rhythm DisordersDisorders

Jet Lag or Rapid Time Zone Change Jet Lag or Rapid Time Zone Change Syndrome:Syndrome:

Delayed Sleep Phase Syndrome Delayed Sleep Phase Syndrome (DSPS)(DSPS)

Advanced Sleep Phase Syndrome Advanced Sleep Phase Syndrome (ASPD)(ASPD)

Shift Work Sleep Disorder (SWSD)Shift Work Sleep Disorder (SWSD)


Jet Lag / Shift workJet Lag / Shift work

Personal cycles out of synchrony with Personal cycles out of synchrony with local conditions. local conditions.

Sleepy when alertness is required; Sleepy when alertness is required; alert when sleep requiredalert when sleep required

Caused by travel across time zones, Caused by travel across time zones, shift work and sometimes by shift work and sometimes by adolesnceadolesnce

Can cause chronodysruption, since Can cause chronodysruption, since different systems re-synchronize at different systems re-synchronize at different rates. different rates.


Zeitgibers Zeitgibers (from Gr. “Time Tellers”)

Zeitgibers Zeitgibers (from Gr. “Time Tellers”)

the physical and social clues which the physical and social clues which tell us what time it is.tell us what time it is.

Most powerful is light. Most powerful is light. Others include taste and Others include taste and smell of usual breakfast smell of usual breakfast food, going to work, food, going to work, sound of daytime activitiessound of daytime activities


Night Owls vs. Morning LarksNight Owls vs. Morning LarksNight Owls vs. Morning LarksNight Owls vs. Morning Larks Night people = easier adjustment to shift Night people = easier adjustment to shift

workwork Tend to be phase delayed Tend to be phase delayed Day people = harder with shift change; Day people = harder with shift change;

more stable once adjustedmore stable once adjusted Tend to be more synchronized and more Tend to be more synchronized and more

resistant to re-settingresistant to re-setting Residency survey: EP s have more night Residency survey: EP s have more night

types than normal populationstypes than normal populations


Delayed Sleep Phase Delayed Sleep Phase Syndrome (DSPS)Syndrome (DSPS)

A disorder of sleep timing. A disorder of sleep timing. People with DSPS tend to fall asleep People with DSPS tend to fall asleep

very late very late Difficulty waking up in time for work, Difficulty waking up in time for work,

school, or social engagementsschool, or social engagements Common, perhaps normal in Common, perhaps normal in

adolescenceadolescence ““Owls”Owls”


Advanced sleep-phase Advanced sleep-phase syndrome (ASPS)syndrome (ASPS)

ASPS persistent early evening sleep onset ASPS persistent early evening sleep onset time (between 6:00 pm and 9:00 pm) and time (between 6:00 pm and 9:00 pm) and spontaneous early morning wake-up time spontaneous early morning wake-up time (between 3:00 am and 5:00 am).(between 3:00 am and 5:00 am).

Variably associated with inadquate sleep.Variably associated with inadquate sleep. Less common than DSPS Less common than DSPS Associated with extreme age and Associated with extreme age and

depression.depression. ““Larks”Larks”


Non 24-Hour Sleep Wake Non 24-Hour Sleep Wake Disorder (N24HS/W disorder): Disorder (N24HS/W disorder):

Innate 23-25 hr cycles constantly Innate 23-25 hr cycles constantly reset by zeitgibersreset by zeitgibers

Normal sleep pattern but inate cylce Normal sleep pattern but inate cylce is neither firm nor maintained. is neither firm nor maintained.

Struggles with “Free cycling” Struggles with “Free cycling” Inconsistent Inconsistent insomniainsomnia that occurs at that occurs at

different times each night. different times each night.


Definitions Definitions for for

Emergency Emergency MedicineMedicine

Definitions Definitions for for

Emergency Emergency MedicineMedicine

On - call On - call On dutyOn duty Sleep deprivationSleep deprivation ChronodisruptionChronodisruption


On Call versus On DutyOn Call versus On DutyOn Call versus On DutyOn Call versus On Duty

““On call”: night work between working On call”: night work between working days = pure sleep deprivationdays = pure sleep deprivation

Possibility of sleep while on callPossibility of sleep while on call Usually does not cause circadian rhythm Usually does not cause circadian rhythm

disruptions -- body cycles remain in phasedisruptions -- body cycles remain in phase ““On duty” implies expected time of usual On duty” implies expected time of usual

type of worktype of work Isolated night shifts “on duty” (less than Isolated night shifts “on duty” (less than

once per week) physiologically function as once per week) physiologically function as ‘on call’‘on call’


Sleep deprivation Sleep deprivation Sleep deprivation Sleep deprivation

loss of "optional sleep" (sleeping less loss of "optional sleep" (sleeping less than one's habit) causes drowsiness, than one's habit) causes drowsiness, no other serious effects no other serious effects

"core sleep" deprivation (less than 5 "core sleep" deprivation (less than 5 hours of slow wave sleep)hours of slow wave sleep)

Sleep deprivation causes both Sleep deprivation causes both physiologic and psychological ill physiologic and psychological ill effectseffects


Shift work prevalenceShift work prevalenceShift work prevalenceShift work prevalence

Not a new phenomenon, but now Not a new phenomenon, but now vastly more frequent. vastly more frequent.

25% of American workers are shift 25% of American workers are shift workers at some point in their lives.workers at some point in their lives.

Invention of the light bulb: 1883Invention of the light bulb: 1883


Shift work definitionShift work definitionShift work definitionShift work definition

Work a defined period of time, then Work a defined period of time, then off for a periodoff for a period

Working time can be at any time of Working time can be at any time of the 24-hr daythe 24-hr day

Fixed shifts -- working the same time Fixed shifts -- working the same time every dayevery day

Rotating shifts -- working time of day Rotating shifts -- working time of day changes from time to timechanges from time to time


Shift lengthShift lengthShift lengthShift length

length of shift: most common is 8 length of shift: most common is 8 hourshours

others are 10, 12 and 6 hoursothers are 10, 12 and 6 hours more mistakes made in the last 4 more mistakes made in the last 4

hours of a 12 hour shift than in the hours of a 12 hour shift than in the first 8 hoursfirst 8 hours

Shift changes become more difficult Shift changes become more difficult after age 40after age 40


Serious adverse health Serious adverse health consequences of shift workconsequences of shift work

Serious adverse health Serious adverse health consequences of shift workconsequences of shift work

20% decrease in life span20% decrease in life span 62% sleep disturbance62% sleep disturbance higher rate of accidents on the jobhigher rate of accidents on the job high risks of fatal commuting high risks of fatal commuting

accidentsaccidents 800% risk of ulcers 800% risk of ulcers 1500% incidence of depression and 1500% incidence of depression and

mood swings mood swings


Shift work is also linked to: Shift work is also linked to: Shift work is also linked to: Shift work is also linked to:

drug and alcohol abusedrug and alcohol abuse altered immune responsealtered immune response infertility in womeninfertility in women high divorce rate.high divorce rate.


Cardiovascular effects of Cardiovascular effects of shift work is ...shift work is ...

Cardiovascular effects of Cardiovascular effects of shift work is ...shift work is ...

linked to chronic hypertensionlinked to chronic hypertension increased cardiovascular mortality increased cardiovascular mortality (risk worse than smoking a pack of (risk worse than smoking a pack of

cigarettes per day)cigarettes per day) risk for dysrhythmias (PVC, MAT, risk for dysrhythmias (PVC, MAT,

SVT)SVT) risk of sinus arrest (up to 12 sec in risk of sinus arrest (up to 12 sec in

one study)one study)


Tolerance to shift workTolerance to shift workTolerance to shift workTolerance to shift work Better in younger persons (under 40, or Better in younger persons (under 40, or

pre-menopausal)pre-menopausal) Better in childless personsBetter in childless persons Better in natural owls than natural larks Better in natural owls than natural larks 20% of people have no trouble 20% of people have no trouble

changing shifts, changing shifts, 60% have moderate hardship, and 60% have moderate hardship, and 20% have extreme difficulty. 20% have extreme difficulty.


Shift work patternsShift work patternsShift work patternsShift work patterns most work has been done on 8 hour most work has been done on 8 hour

shiftsshifts 12 hour shifts no longer permitted in 12 hour shifts no longer permitted in

most industriesmost industries rotating shiftsrotating shifts isolated shiftsisolated shifts random shiftsrandom shifts


Shift schedulesShift schedulesShift schedulesShift schedules

Optimum: days only; in synchronous Optimum: days only; in synchronous with your own best working timewith your own best working time

Next best: same shift every day, Next best: same shift every day, even if not most suited to your even if not most suited to your optimal time; or isolated nightsoptimal time; or isolated nights

Worst: randomly rotating shiftsWorst: randomly rotating shifts


Rotation patterns: Swing Rotation patterns: Swing shiftsshifts

Rotation patterns: Swing Rotation patterns: Swing shiftsshifts

Phase advance: one week days, one Phase advance: one week days, one week evenings, one week nightsweek evenings, one week nights

Phase retreat: (Southern Swing): one Phase retreat: (Southern Swing): one week days, one week nights, one week days, one week nights, one week eveningsweek evenings

Of the two, phase advance is more Of the two, phase advance is more physiologic and more easily toleratedphysiologic and more easily tolerated



Randomly changingRandomly changingRandomly changingRandomly changing

almost universally condemnedalmost universally condemned forbidden by most unionsforbidden by most unions highest physiologic risk and stresshighest physiologic risk and stress practiced mostly by physicianspracticed mostly by physicians


Isolated nightsIsolated nightsIsolated nightsIsolated nights

defined as less than one night per defined as less than one night per weekweek

equivalent to a bad night on callequivalent to a bad night on call



Important!Important!Important!Important! One can adjust by 1-2 hrs. / 24, or one One can adjust by 1-2 hrs. / 24, or one

week to move forward by one (8 hr) shiftweek to move forward by one (8 hr) shift Therefore, maintain the same schedule Therefore, maintain the same schedule

when not workingwhen not working most permanent night workers switch to most permanent night workers switch to

day-life when not at work and reap the day-life when not at work and reap the same ill effects as random-shift changerssame ill effects as random-shift changers

Optimal: one month or more between Optimal: one month or more between changeschanges


What about physicians?What about physicians?What about physicians?What about physicians?

MD = Maximum DenialMD = Maximum Denial Socialized to ignore their own needsSocialized to ignore their own needs Trained to be ‘tough’Trained to be ‘tough’ poor role modelspoor role models


Cardiovascular effects in Cardiovascular effects in physicians: physicians:

Cardiovascular effects in Cardiovascular effects in physicians: physicians:

palpitations and dysrhythmias palpitations and dysrhythmias Brodsky M, Wu D, Denes P, Kanakis C, Brodsky M, Wu D, Denes P, Kanakis C,

Rosen KM: Arrhythmias documented Rosen KM: Arrhythmias documented by 24 hour continuous by 24 hour continuous electrocardiographic monitoring in 50 electrocardiographic monitoring in 50 male medical students without male medical students without apparent heart disease. Am J apparent heart disease. Am J Cardiology 1977;39:390-395Cardiology 1977;39:390-395


Cardiovascular effectsCardiovascular effectsCardiovascular effectsCardiovascular effects

sinus arrest with syncope in sinus arrest with syncope in residentsresidents

Guilleminault C, Pool P, Motta J, Gillis Guilleminault C, Pool P, Motta J, Gillis AM: Sinus arrest during REM sleep in AM: Sinus arrest during REM sleep in young adults. NEJM: 1984;311:1006-young adults. NEJM: 1984;311:1006-1010



More studiesMore studiesMore studiesMore studies Physicians aren’t immune to poor Physicians aren’t immune to poor

health effects of shift workhealth effects of shift work Åkerstedt T, Knutsson A, Alfredsson L, Theorell T: Åkerstedt T, Knutsson A, Alfredsson L, Theorell T:

Shift work and cardiovascular disease. J Work Shift work and cardiovascular disease. J Work Environ Health: 1984; 10:409-414Environ Health: 1984; 10:409-414

Åkerstedt T. Psychological and psychophysiological Åkerstedt T. Psychological and psychophysiological effects of shift work. Scand J Work Environ Health. effects of shift work. Scand J Work Environ Health. 1990;16(suppl 1):67-73 1990;16(suppl 1):67-73


Performance of physiciansPerformance of physiciansPerformance of physiciansPerformance of physicians

Poor performance with micro-sleeps (non-Poor performance with micro-sleeps (non-restorative) during rote tasksrestorative) during rote tasks

Documented micro and mini-sleeps during Documented micro and mini-sleeps during drive home even in those who did not drive home even in those who did not think they had sleptthink they had slept

Åkerstedt et al: Physicians during and following Åkerstedt et al: Physicians during and following night call duty--41 hour ambulatory recording of night call duty--41 hour ambulatory recording of sleep. Electroencephalography & Clinical sleep. Electroencephalography & Clinical Neurophysiology: 1990; (76) 193-196Neurophysiology: 1990; (76) 193-196


Physician learningPhysician learningPhysician learningPhysician learning

Decreased performance, learning of Decreased performance, learning of deleterious habits and physiologic deleterious habits and physiologic harm.harm.

Asken MJ, Raham DC: Resident Asken MJ, Raham DC: Resident Performance and Sleep Deprivation: Performance and Sleep Deprivation: A Review. J. Med Educ 1983;58:382-A Review. J. Med Educ 1983;58:382-388388


Overall performance Overall performance Overall performance Overall performance

Found that shift work affected rote Found that shift work affected rote tasks and the highest intellectual tasks tasks and the highest intellectual tasks equally as much; moderately equally as much; moderately challenging but well known tasks challenging but well known tasks suffered least. Implication for suffered least. Implication for physicians: we make more mistakes physicians: we make more mistakes on the more serious caseson the more serious cases

Tilley et al The sleep and performance of Tilley et al The sleep and performance of shift workers. Human Factors, 1982; 24: shift workers. Human Factors, 1982; 24: 624-41624-41


Exercise tolerance Exercise tolerance Exercise tolerance Exercise tolerance

Sleep deprivation had little effect on Sleep deprivation had little effect on acute exercise tolerance in normal acute exercise tolerance in normal personspersons

Chen H: Effects of 30-h sleep loss on Chen H: Effects of 30-h sleep loss on cardiorespiratory functions at rest and in cardiorespiratory functions at rest and in exercise. Med Sci Sports and Exerc: 1991; exercise. Med Sci Sports and Exerc: 1991; 23(2):193-19823(2):193-198


Shift lengthShift lengthShift lengthShift length Used temperature as a marker for Used temperature as a marker for

slowing of physiologic activitiesslowing of physiologic activities Concluded that 12 hour shifts lead to Concluded that 12 hour shifts lead to

increased mistakes poorer per-hour increased mistakes poorer per-hour productivity productivity

Daniel J, Potasova A; Oral temperature Daniel J, Potasova A; Oral temperature and performance in 8 h and 12 h and performance in 8 h and 12 h shifts . Ergonomics 32(7):689-96 , 1989 shifts . Ergonomics 32(7):689-96 , 1989 Jul.Jul.


Strategies to improve health Strategies to improve health for shift workersfor shift workers

Strategies to improve health Strategies to improve health for shift workersfor shift workers

sleep hygiene sleep hygiene napping at worknapping at work shift rotation patternsshift rotation patterns food & exercisefood & exercise social lifesocial life


If you must be a shift If you must be a shift worker:worker:

If you must be a shift If you must be a shift worker:worker:

Learn how to sleep wellLearn how to sleep well Learn how to change your circadian Learn how to change your circadian

rhythms smoothlyrhythms smoothly Use circadian principles to make your Use circadian principles to make your

work and home life betterwork and home life better Educate your schedule-makerEducate your schedule-maker Educate and enlist your familyEducate and enlist your family


Living the Strategic LifeLiving the Strategic Life

Avoid vigorous exercise at least 4 Avoid vigorous exercise at least 4 hours prior to bedtime (Regular hours prior to bedtime (Regular exercise is recommended.)exercise is recommended.)

Avoid cigarettes, alcohol, and Avoid cigarettes, alcohol, and caffeine 4-6 hours prior to bedtimecaffeine 4-6 hours prior to bedtime

Avoiding large meals and excessive Avoiding large meals and excessive fluids just before bedtimefluids just before bedtime


Light therapy: Light therapy:

Timing of lightTiming of light Minimum of 30-60 minutes not long after Minimum of 30-60 minutes not long after

wakening to promote adaptation and wakening to promote adaptation and wakefullnesswakefullness

Re-synchronising ASPS light in the early Re-synchronising ASPS light in the early evening and nighttime hours delays the evening and nighttime hours delays the cyclecycle

DSPS light therapy in the early morning DSPS light therapy in the early morning hours stimulates morning alertness and an hours stimulates morning alertness and an earlier bedtime. earlier bedtime.


Environmental controlEnvironmental control

Light – adequate at work (6,000-Light – adequate at work (6,000-7,000 Lux) 7,000 Lux)

Dark – during sleep time (less than Dark – during sleep time (less than full moon) (consider eye shades)full moon) (consider eye shades)

Noise – shut out during sleep. Isolate Noise – shut out during sleep. Isolate sleep room, use earplugssleep room, use earplugs

Room temperature – warm sleepers Room temperature – warm sleepers vs cool sleepersvs cool sleepers

Exercise, DietExercise, Diet


Sleep HygieneSleep HygieneSleep HygieneSleep Hygiene

Temperature: between 22 - 24 CTemperature: between 22 - 24 C Bedroom: Condition yourself that Bed Bedroom: Condition yourself that Bed

= Sleep time= Sleep time Ritual: helps to create a ‘stimulus-Ritual: helps to create a ‘stimulus-

response’ conditioning response’ conditioning Keep sleep time sacred, and Keep sleep time sacred, and

minimize care-giving responsibilities minimize care-giving responsibilities during that time.during that time.



Diet Diet Diet Diet

troubled by early awakening? => try troubled by early awakening? => try bedtime snack. bedtime snack.

Milk products seem to improve sleep. Milk products seem to improve sleep. Alcohol: a single drink can help tense Alcohol: a single drink can help tense

people relax, but alcohol actually people relax, but alcohol actually alters sleep structure by postponing alters sleep structure by postponing REMREM

Great care to eat appropriately during Great care to eat appropriately during the working / waking timethe working / waking time



Exercise Exercise Exercise Exercise

Athletes: get more delta Athletes: get more delta (SWS, restorative) sleep. (SWS, restorative) sleep.

Time of day important: Time of day important: pm exercise has more pm exercise has more effect.effect.

Exercise should be Exercise should be completed more than one completed more than one hour before sleep timehour before sleep time



Light – most important for Light – most important for humanshumans

Light – most important for Light – most important for humanshumans

intensity is important: 7,000 Luxintensity is important: 7,000 Lux about the same as a heavily overcast dayabout the same as a heavily overcast day most indoor lighting is inadequatemost indoor lighting is inadequate new ‘energy saving’ fixtures are even more new ‘energy saving’ fixtures are even more

inadequateinadequate implication to hospital administration: high implication to hospital administration: high

intensity lights over physicians / nurses intensity lights over physicians / nurses working areas improves productivity and working areas improves productivity and minimizes mistakes.minimizes mistakes.



Timing of light pulses is Timing of light pulses is importantimportant

Timing of light pulses is Timing of light pulses is importantimportant

2-3 hours of high intensity light 2-3 hours of high intensity light within one hour of awakeningwithin one hour of awakening

implication for shift workers: either implication for shift workers: either go outside while the sun is still up go outside while the sun is still up before going to work the night shift, before going to work the night shift, or buy and use a high intensity light or buy and use a high intensity light at homeat home

Fluorescents in windows.Fluorescents in windows.


Drugs and Pharmacology Drugs and Pharmacology Drugs and Pharmacology Drugs and Pharmacology

Drugs to sleep or to wake or re-Drugs to sleep or to wake or re-synchronizesynchronize

MDs: temptation and access to non-MDs: temptation and access to non-legal drug uselegal drug use

health care shift workers are at high health care shift workers are at high risk for drug addictionrisk for drug addiction


MelatoninMelatonin

Melatonin is a re-synchronizerMelatonin is a re-synchronizer used in the treatment of circadian used in the treatment of circadian

rhythm sleep disorder especially in rhythm sleep disorder especially in blind personsblind persons

OTC “diet supplement” dosing OTC “diet supplement” dosing guidelines not established. My use: guidelines not established. My use: 6-6-3-36-6-3-3


Melatonin Melatonin Melatonin Melatonin

3-6 mg, taken one hour prior to 3-6 mg, taken one hour prior to desired (new) sleep timedesired (new) sleep time

Diminished (genetically?) in aging. Diminished (genetically?) in aging. Full effects of chronic exposure not Full effects of chronic exposure not

yet known. yet known. Not FDA regulated, but seems to be Not FDA regulated, but seems to be

extremely safe for brief use as in extremely safe for brief use as in phase adjustment. phase adjustment.


Melatonin stimulant Melatonin stimulant RamelteonRamelteon ((RozeremRozerem) )

Rx only. Rx only. stimulates melatonin releasestimulates melatonin release Ramelteon promotes the onset of Ramelteon promotes the onset of

sleep and helps normalize circadian sleep and helps normalize circadian rhythm disorders. rhythm disorders.

Ramelteon is approved by the Ramelteon is approved by the Food and Drug AdministrationFood and Drug Administration (FDA) (FDA) for insomnia characterized by for insomnia characterized by difficulty falling asleep.difficulty falling asleep.


Hypnotics: BenzodiazipinesHypnotics: Benzodiazipines

Benzodiazepines: short acting for Benzodiazepines: short acting for sleep onset or napping. Triazolam sleep onset or napping. Triazolam (Halcion) (Halcion)

Medium or long-acting: for sleep Medium or long-acting: for sleep maintenance. estazolam [ProSom] maintenance. estazolam [ProSom] quazepam [Doral]quazepam [Doral]

Possibility of rebound insomniaPossibility of rebound insomnia


Benzodiazepines side Benzodiazepines side effectseffects

Benzodiazepines side Benzodiazepines side effectseffects

can disrupt sleep architecturecan disrupt sleep architecture may have residual sedative effects may have residual sedative effects

lasting into the next working periodlasting into the next working period many are fat soluble and will leach many are fat soluble and will leach

out over many daysout over many days illegal in some working environmentsillegal in some working environments


Non-benzodiazepine Non-benzodiazepine hypnoticshypnotics

Less effect on sleep architecture Less effect on sleep architecture than benzos, less rebound insomnia than benzos, less rebound insomnia

Zolpidem (Ambien) moderate to long Zolpidem (Ambien) moderate to long actingacting

Eszopicline (Lunesta) moderate Eszopicline (Lunesta) moderate duragionduragion

Zaleplon (Sonata) short actingZaleplon (Sonata) short acting


OTC hypnoticsOTC hypnotics

Benadryl – 25-50mg. TachyphylaxisBenadryl – 25-50mg. Tachyphylaxis Alcohol – disrupts sleep architecture Alcohol – disrupts sleep architecture Herbs: hops, valerian, passion flower Herbs: hops, valerian, passion flower Marijuana – legal issues, prolonged Marijuana – legal issues, prolonged

effectseffects


Diphenhydramine / sedative Diphenhydramine / sedative antihistaminesantihistamines

Diphenhydramine / sedative Diphenhydramine / sedative antihistaminesantihistamines

sedative antihistamines help induce sedative antihistamines help induce sleep, and in some, help maintain sleepsleep, and in some, help maintain sleep

effect on sleep architecture is minimaleffect on sleep architecture is minimal tachyphylaxis: effects wane within daystachyphylaxis: effects wane within days may produce prolonged sedation, may produce prolonged sedation,

interfering with performance and interfering with performance and maintenance of new schedule when not maintenance of new schedule when not at workat work



AlcoholAlcoholAlcoholAlcohol

disrupts sleep architecturedisrupts sleep architecture delays REM sleepdelays REM sleep variable effect on sleep latencyvariable effect on sleep latency recommendation for shift workers: recommendation for shift workers:

finish your alcohol more than one finish your alcohol more than one hour before scheduled sleep timehour before scheduled sleep time


Cheat Sleep: stimulants Cheat Sleep: stimulants

OTC: primarily caffeineOTC: primarily caffeine Illegal: Cocaine, “Speed” and various Illegal: Cocaine, “Speed” and various

“uppers”“uppers” Legal: Legal:

• amphetamines and amphetamine –like amphetamines and amphetamine –like drugs drugs

• Ampakines and their sucessorsAmpakines and their sucessors


Amphetamines Amphetamines

methylphenidate (Ritalin, Metadate, methylphenidate (Ritalin, Metadate, Concerta)Concerta)

dextroamphetamine Plus dextroamphetamine Plus amphetamine (Adderall)amphetamine (Adderall)

DextroamphetamineDextroamphetamine (Dexedrine) (Dexedrine) lisdexamfetamine dimesylate – lisdexamfetamine dimesylate –

metabolized to methamphetamine metabolized to methamphetamine ((Vyvanse) Vyvanse)


Ampakines and their Ampakines and their successorssuccessors

Modafinil (Modafinil (ProvigilProvigil, Alertec, Modavigil, , Alertec, Modavigil, Modalert, Modiodal, Modafinilo, Carim, Modalert, Modiodal, Modafinilo, Carim, Vigia) Vigia)

analeptic drug manufactured by Cephalon, analeptic drug manufactured by Cephalon, and is approved by the FDA for shift and is approved by the FDA for shift workersworkers

Armodafinil (Nuvigil) is the active (−)-(Armodafinil (Nuvigil) is the active (−)-(RR)-)-enantiomer of the racemic drug modafinil enantiomer of the racemic drug modafinil

Side effects include potentially cognitive Side effects include potentially cognitive enhancement, and loss of effect of BCPsenhancement, and loss of effect of BCPs


CaffeineCaffeineCaffeineCaffeine

harmless in small dosesharmless in small doses taking caffeine to get through the taking caffeine to get through the

night shift may interfere with day night shift may interfere with day sleepsleep

careful with timing of caffeine intakecareful with timing of caffeine intake


Optimal phase adjustment Optimal phase adjustment strategiesstrategies

Optimal phase adjustment Optimal phase adjustment strategiesstrategies

bright light early in waking timebright light early in waking time significant exercise later in waking period significant exercise later in waking period optimize sleeping conditions: aluminum-optimize sleeping conditions: aluminum-

foil on the windows, ear plugs, eye foil on the windows, ear plugs, eye shades, fanshades, fan

stay on the same schedule without stay on the same schedule without varying by more than an hour as long as varying by more than an hour as long as you canyou can

Consider Melatonin.Consider Melatonin.


SummarySummarySummarySummary

American society is more 24 / 7American society is more 24 / 7 EM always 24 / 7EM always 24 / 7 Use circadian principles to improve Use circadian principles to improve

your well being and prolong your your well being and prolong your professional life and your personal professional life and your personal lifelife


ResourcesResources

American Academy of Sleep MedicineAmerican Academy of Sleep MedicineOne Westbrook Corporate Center, One Westbrook Corporate Center, Suite 920Suite 920Westchester, IL 60154Westchester, IL 60154(708) 492-0930(708) 492-0930

National Sleep FoundationNational Sleep Foundation1522 K Street, NW, Suite 5001522 K Street, NW, Suite 500Washington, DC 20005Washington, DC 20005


Enhancing adaptionEnhancing adaptionEnhancing adaptionEnhancing adaption

Rotating shiftwork schedules: can we Rotating shiftwork schedules: can we enhance physician adaptation to enhance physician adaptation to night shifts?night shifts?Smith-Coggins R , Rosekind MR , Smith-Coggins R , Rosekind MR , Buccino KR , Dinges DF , Moser RP Buccino KR , Dinges DF , Moser RP Acad Emerg Med 1997 Acad Emerg Med 1997 Oct;4(10):951-61 Oct;4(10):951-61


Best single reference Best single reference Best single reference Best single reference

"Why we Sleep" by James Horne. "Why we Sleep" by James Horne. Published by Oxford University Published by Oxford University Press Walton St Oxford OX2 6DP Press Walton St Oxford OX2 6DP 19881988

a classic overall referencea classic overall reference


Web LinksWeb Links Northwestern University, Center for Sleep Northwestern University, Center for Sleep

& Circadian Biology, & Circadian Biology, About Circadian RhythmsAbout Circadian Rhythms

National Sleep Foundation, National Sleep Foundation, Strategies for Shift WorkersStrategies for Shift Workers National Sleep Foundation, National Sleep Foundation, Sleep and the TravelerSleep and the Traveler National Institute of Mental HealthNational Institute of Mental Health, ,

How Biological Clocks WorkHow Biological Clocks Work Sleepnet.comSleepnet.com

Documents

Circadian Rhythms and Shift Work 1 Vicken Y. Totten MD: Vicken Y. Totten MD: Emergency Physician Emergency Physician and Career-long Shift Worker and Career-long