Shiftwork Laurence Hartley

8/10/2019 Shiftwork Laurence Hartley

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The risks of shift and extendedwork hours

Laurence Hartley

Murdoch University


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This talk

First half presents the hazards of

shiftwork

Second half presents the hazards of

extended work hours


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What is shift work?

Shift work: the alternation of teams ofworkers, usually performing the same tasks,so work can continue for longer than one workperiod

Some or all, work will occur outside of daytimehours

Work hours can be f ixed orro tate(change)and rotation can befast or s low


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Whats the problem for

shiftworkers?The rhythms of alertness & sleepiness


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The daily circadian rhythms

Rhythms driven by clock in brain

Alertness is max during the day

Sleepiness increases during the night

Maximum sleepiness in pre-dawn Clock is mainly set by day light

So clock time cannot be easily changed

So workers do not adapt much toshiftwork


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The 4 Hazards of Shiftwork

1. Increased risk of errors & accidents

when working or driving at night

2 Insufficient daytime sleep leads

to increased fatigue & sleepiness

3. Increase in health problems

4. Increase in social and domestic

problems


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1. Daytime sleep is

insufficient for night

shiftworkers


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alertness daytime sleep

Circadian rhythms(daily rhythms)in

body clock keeps body awake and alert

during the day; daytime not suitable forsleep!

Circadian rhythm of alertness meansnight workers are most sleepy at work

and driving home


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shiftwork sleep problems

Other disturbances during the day eg.noise, light, heat

Body rhythms and external

disturbances combine so that day

sleep is shorter (1-2hrs) and of poorer

quality than night sleep

Early shift start times cut down night

sleep


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sleep loss shiftwork

Insufficient sleep (


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Sleep loss leads to microsleeps

Insufficient sleep increases the likelihoodof microsleepsand nodding offoccurring

People are unaware of microsleeps

Loss of awareness and control ofsurroundings . an accident canhappen!


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2. More errors and

accidents at night


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Folkard (2003) Mean relative

risk across 3 shifts

SHIFT

Night (22-06)Af ternoon (14-22)Morning (06-14)

1.4

1.3

1.2

1.1

1.0

.9


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Folkard (2003) Mean relative risk

over 4 successive night shifts

Success ive Night Shifts

4321

1.5

1.4

1.3

1.2

1.1

1.0

.9

( ) f


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Folkard (2003) Relative risk of

different blocks of successive

night shifts

No of Successive Nights

7654321

1.5

1.4

1.3

1.2

1.1

1.0

.9


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driving

Three times risk of a crash with less 6 h sleep

Night workers are more likely to fal l asleepat the

wheel, and to have a crashor near-miss than dayworkers

Night workers are at 6 timesthe risk of a carcrash than day workers, especially at dawn

Fatigue and shift work is a major workplace road

safety issue


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staying awake and BAC

Long hours awake without sleep canimpair performance to a similar/greater

level than acceptable BAC for driving

17hrs awake leads to performance similar to

BAC 0.05%

20-25hrs awake leads to performance similarto BAC 0.1%


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3. More health problems

on the night shift


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adverse health concerns

Gastrointest inal complaints

- 20-75% night shift workers

- 10-20% day & evening workers

Card iovascu lar Disease

- a 40% increased risk for developingcardiovascular disease for shiftworkers


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4. Social and Domestic

Problems for the night

shift


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family and friends

Shift workers can have less suitabletime off and less quality time off

Shift workers often curtail their sleeptime to be with family and friends;this means they can be awake for along period of time, and they do notget enough sleep


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isks of extended hours

of work


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Folkard (2003) Relative risk

over hours on duty

Hours on Shift

121110987654321

2.5

2.0

1.5

1.0

.5

0.0


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Folkard (2003) Estimated relative

risk on different lengths of shift

Length of Shift (hours)

121110987654321

1.3

1.2

1.1

1.0

.9

.8

.7

.6

.5

.4


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Folkard (2003) Estimated relative

risk on different spans of 8, 12 h

No of Successive Nights

7654321

1.8

1.6

1.4

1.2

1.0

.8

8-hour

12-hour

H f k l ti t t


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Hours of work-relative transport

crash risk. Folkard, (1997)

H f k U S F M C S A


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Hours of work -U.S. F.M.C.S.A.


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Shift work hazard control

strategies


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Three Essential Shi f t Work

Hazard Con trol Measu res

1. Adequate, good quality sleep

2. Suitable shift work schedules

3. Appropriate work conditions


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1. Adequate, good qualitysleep


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sleep hygiene rules

Maintain pre-sleep routines similar to nightsleep

Bedroom dark and quiet

Avoid caffeine for 5 hrs before sleep

Avoid alcohol before sleep

Avoid exercise before sleep


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napping

Naps can help maintain alertness,

performance, and safety

Naps can supplement insufficient sleep,

but

BESTif taken after7-8hrs main sleep and

beforefeel ing fat igued:

Nap at home before night shift

Nap early in the night shift

Nap before driving home after night shift


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2. Suitable shift work

schedules


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shift work schedules

No one best shift work system

Employers should consider their

worker population and work tasks,and decide, in collaboration withworkers, on the most suitable

schedule for their work place

Then evaluate the schedule


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Recommendations

Rapid rotations are preferred to slow rotations

No more than 2 consecutive night shifts

Forward (clockwise) rotation of shifts

8hr shift length; 12hrs maximum

5-7 consecutive work days maximumFewer if shifts >8hrs or night shifts


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recommendations

2 days off minimum after a block of shifts

More if shifts >8hrs or night shifts

11hrs off minimum between

consecutive shifts

Keep schedules regular and predictable, butallow flexibility


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3. Appropriate work

conditions


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rest breaks

Regular rest breaks reduce accidents

Incorporate movement, stretching or

light exercise, social interaction

A proper meal break away from work

duties


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work schedule

Employers should tailor work tasksaccording to shi f t t ime; some tasks are

not suitable for night shift

Work tasks should vary during the shift

Schedule tasks so monotonous, boring,

dangerous, and safety critical tasks are

done early in the night shift


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work environment

Bright lighting, comfortable temperature,

and good ventilation

Background music may help temporarily

Appropriate facilities for healthy eating

Napping facilities


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Summary

Shift work is an OH&S hazard

employers and employees have a

du ty of careto control or minimisethe hazards

Mutual responsibility is essential


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Employersduty of care to provide an

appropriate work schedule and workenvironment, and continuing education

and training for workers about coping

strategies

Employeesduty of care to follow the

recommended strategies to manage their

sleep, health, and family life

Shiftwork Laurence Hartley

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