feeling tired? 11/12/2003 1

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? 11/12/2003 2

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 11/12/2003 3

The Sleep Quiz 11/12/2003 4

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 11/12/2003 5

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. 11/12/2003 6

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 11/12/2003 7

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) 11/12/2003 8

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 11/12/2003 9

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 11/12/2003 10

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 11/12/2003 11

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 11/12/2003 12

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 11/12/2003 13

Features of shiftwork that lead to fatigue Timing of shifts (earlies, lates and nights) Duration of shifts Rotation of shifts Rest and recovery periods 11/12/2003 14

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 11/12/2003 15

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 11/12/2003 16

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 11/12/2003 17

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 11/12/2003 18

Coping with Shiftwork 11/12/2003 19

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 11/12/2003 20

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 11/12/2003 21

Creating a good sleep environment Quiet Dark Warm/cool Comfortable bed that you associate with sleep Fresh air Free from interruptions 11/12/2003 22

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 11/12/2003 23

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 11/12/2003 24

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? 11/12/2003 25