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feeling tired?

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Shiftwork and Fatigue

Once, a pilot crashed after 16 hours on duty because he read an altimeter incorrectly.

He had been flying safely for 15 hours, and suddenly he couldn't read an altimeter?

This is hard to believe. That's fatigue.

Fatigue is a loss of alertness which eventually ends in sleep

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Fatigue is a serious issue• Fatigued operators can cause accidents, (eg Three Mile

Island, Bhopal, Space Shuttle Challenger, Exxon Valdez and Chernobyl)

• USA – cost of sleep-related accidents estimated to be between $43 - $56 billion

• UK – annual cost of work accidents caused by sleepiness estimated to be £115 – 240 million

• 25% of fatal truck crashes are due to fatigue • 7% of motor vehicle accidents may be attributed to

fatigue, a figure that rises to 15% for motorway accidents

• pilot fatigue is implicated in upwards of 20% of near-accidents in aviation

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The Sleep Quiz

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I’m safe at work so it doesn’t matter if I’m sleepy?

False…being sleepy can cause:• slower reaction time• impaired judgements and decision making• decline in attention• decreased alertness• increased moodiness and aggressive behaviour• difficulty in remembering things

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I can tell when I’m going to fall asleepFalse….• People do not know how sleepy they

are• The more tired you become, the less

able you are to make a good judgement about your ability to remain awake

• Being awake for 18 hours is as great a risk as driving drunk

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Signs of tiredness

The signs include:• not feeling refreshed after sleep• difficulty keeping your eyes open and focussed• greater tendency to fall asleep while at work• more frequent naps during leisure hours• lots of yawning• extended sleep during days off• increased errors and loss of concentration at work• feeling irritable, restless and impatient

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Lack of sleep is the only cause of fatigue...

False… but it is the only cure

Causes of fatigue include:

• Workload

• Social factors

• Individual factors – e.g., age, diet, fitness etc

• Shift work

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The older you get, the fewer hours of sleep you needFalse• Sleep needs remain unchanged throughout

adulthood• Older people wake more frequently through

the night• Shift work becomes harder with age (40–50

yrs)• Ability to cope with ‘early starts’ may improve

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Most people need 8 hours of sleep to function at their bestTrue• 7 – 8 hours is recognised as an average and normal

need• Less than this and you build up a sleep debt• Sleep comprises several stages which must follow a

certain pattern if you are to feel fully rested and alert– Stage 1 and 2: transitional phase between waking and

sleeping – Stage 3 and 4: deep sleep– Rapid Eye Movement (REM) sleep

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If I sleep a lot now, I won’t need to sleep much later

False

• Sleep is not like money – you can’t save it up and you can’t borrow it

• While napping is an effective means of managing alertness it is not a substitute for regular sleep

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Everyone has a “biological clock”True• We have evolved own internal body clock /

circadian rhythm• It controls a number of internal rhythms, eg,

sleep/wake cycle, body temperature• It is this body clock that makes us feel

sleepier and less alert when we try and work at times normally reserved for sleep

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The human body can adjust to nightshift workFalse• Our body clock programmes us to feel most sleepy

when it is dark• Eating meals at times normally reserved for sleep

means they are less well digested• On night shifts you tend to get less sleep and it is of

a poorer quality (e.g., after one week of night shifts, workers had lost the equivalent of one night’s sleep)

• Successive night shifts, eg, 4, result in an increase in accident risk

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Features of shiftwork that lead to fatigue

• Timing of shifts (earlies, lates and nights)

• Duration of shifts

• Rotation of shifts

• Rest and recovery periods

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Early Starts• Associated with a reduction in duration of

sleep• Sleep periods prior to early start are on

average 3 hours shorter• Difficult to compensate with earlier bedtime:

– Social pressures– ‘Forbidden zone’ – Fear of not waking up early

• Successive early starts – cumulative sleep deficit

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Snoring is not harmful as long as it does not disturb sleep

False

• Chronic snoring may indicate sleep apnoea, a sleep disorder

• Other common sleep disorders are:– Insomnia– Restless leg syndrome

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Drinking coffee cures drowsinessFalse…• Caffeine has a short term effect• Caffeine should be used carefully as it will

disrupt sleep• Other measures such as opening windows

and putting on the radio are not effective• The only cure for drowsiness is to get some

sleep

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Conclusions

• Being tired impact on our performance and increases the risks of an accident

• The amount and quality of sleep are important factors in ensuring you wake up feeling fully rested

• Shift work makes us more prone to fatigue because it makes us work against out natural circadian rhythms

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Coping with Shiftwork

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Sleep Strategies• Managing your work time • Use naps to improve alertness• Create a good sleep environment• Establish a regular pre-sleep routine• Establish a regular bedtime and wake-up schedule• Manage your caffeine intake• Other advice:

– Avoid alcohol– Take regular exercise– Manage your diet

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Managing Your Work Time

• There are different tips for managing fatigue depending on your shift pattern and the type of shift you have just finished.

• Example: managing night shifts– Go to bed as soon as you get home– Have an afternoon nap– Avoid exposure to daylight– Eat 3 regular meal with “lunch” during your night

shift

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Creating a good sleep environment

• Quiet

• Dark

• Warm/cool

• Comfortable bed that you associate with sleep

• Fresh air

• Free from interruptions

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Pre-sleep routine

• You can learn that it is time to relax and go to sleep

• Establish a pre-sleep routine to provide specific cues:– Reading– Listening to music– Getting dressed for bed

• Only get into bed when your tired

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Napping – Not to be used whilst at work• Limit naps to about 30 – 45 minutes including

the time it takes to fall asleep• Naps of 15 – 20 mins are most restorative• Give yourself time to get over sleep inertia• There is no minimum time period for effective

napping• Improved alertness may last for several hours

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Caffeine

• It is a stimulant so it can keep you awake but it can also disrupt sleep

• Use caffeine in moderation and when it is most needed

• Avoid it for several hours before sleep• Don’t quit “cold turkey”, cut back

gradually• How much caffeine is okay?