1. feeling tired?
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2. Fatigue is a loss of alertness which eventually ends in sleep
Shiftwork and Fatigue
Fatigue is a loss of alertness which eventually ends in sleep
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.
Why is fatigue a problem?
What causes fatigue?
Workload
Individual factors - eg, age, diet, fitness etc.
Social factors
Internal body clock
Sleep patterns / Shiftwork
When is an operator fatigued?
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3. 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
Major accidents tend to happen at night
Exxon Valdez
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4. The Sleep Quiz
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5. 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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6. I can tell when I’m going to fall asleep
False….
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
Hlaf the drivers involved in drowsy-driving crashes said they felt “only slightly sleepy” or “not at all sleepy” right before the crash.
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7. 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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8. 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
Individuals require different amounts of sleep
Age:
Need less sleep but less have flexibility
Shiftwork becomes harder with age (40–50 yrs)
Ability to cope with ‘early starts’ may improve
Personality:
Morning vs evening types (former less tolerant to shiftwork but latter have more health complaints)
Flexible vs rigid types (former can sleep at unusual times, no preference for meal times; latter struggle to sleep in/late, maintain meal times when possible)
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9. The older you get, the fewer hours of sleep you need
False
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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10. Most people need 8 hours of sleep to function at their best
True
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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11. 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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12. 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
We have evolved in a world subject to 24-hour changes in light and temperature
Advantageous to anticipate these changes
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13. The human body can adjust to nightshift work
False
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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14. 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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15. 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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16. 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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17. Drinking coffee cures drowsiness
False…
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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18. 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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19. Coping with Shiftwork
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20. 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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21. 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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22. 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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23. 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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24. 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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25. 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?
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