2. The risks of shift and extended work hours
Laurence Hartley
Murdoch University

3. This talk First half presents the hazards of shiftwork
Second half presents the hazards of extended work hours

4. What is shift work?
Shift work: the alternation of teams of workers, usually performing the same tasks, so work can continue for longer than one work period
Some or all, work will occur outside of daytime hours
Work hours can be fixed or rotate (change) and rotation can be fast or slow

5. What’s the problem for shiftworkers
What’s the problem for shiftworkers? The rhythms of alertness & sleepiness

6. 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 to shiftwork

7. 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

8. 1. Daytime sleep is insufficient for night shiftworkers

9. alertness &daytime sleep
Circadian rhythms (daily rhythms) in body clock keeps body awake and alert during the day; daytime not suitable for sleep!
Circadian rhythm of alertness means night workers are most sleepy at work and driving home

10. 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

11. sleep loss & shiftwork
Insufficient sleep (<7-8hrs) or poor quality sleep leads to sleepiness & fatigue, and decreased alertness & performance
A “sleep debt” of ~ 2 h per night shift accumulates; 3 night shifts = 1 lost sleep.
2-3 nights needed to recover from debt.
Workers may not realise how sleepy they are at work (masking) till driving home

12. Sleep loss leads to microsleeps
Insufficient sleep increases the likelihood of “microsleeps” and ‘nodding off’ occurring
People are unaware of microsleeps
Loss of awareness and control of surroundings ……. an accident can happen!

13. 2. More errors and accidents at night

14. Folkard (2003) Mean relative risk across 3 shifts

15. Folkard (2003) Mean relative risk over 4 successive night shifts

16. Folkard (2003) Relative risk of different blocks of successive night shifts

17. driving Three times risk of a crash with less 6 h sleep
Night workers are more likely to fall asleep at the wheel, and to have a crash or near-miss than day workers
Night workers are at 6 times the risk of a car crash than day workers, especially at dawn
Fatigue and shift work is a major workplace road safety issue

18. staying awake and BAC
Long hours awake without sleep can impair 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 similar to BAC 0.1%

19. 3. More health problems on the night shift

20. adverse health concerns
Gastrointestinal complaints
% night shift workers
% day & evening workers
Cardiovascular Disease
- a 40% increased risk for developing cardiovascular disease for shift workers

21. 4. Social and Domestic Problems for the night shift

22. family and friends
Shift workers can have less ‘suitable’ time off and less ‘quality’ time off
Shift workers often curtail their sleep time to be with family and friends; this means they can be awake for a long period of time, and they do not get enough sleep

23. Risks of extended hours of work

24. Folkard (2003) Relative risk over hours on duty

25. Folkard (2003) Estimated relative risk on different lengths of shift

26. Folkard (2003) Estimated relative risk on different spans of 8, 12 h

27. Hours of work-relative transport crash risk. Folkard, (1997)

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

29. Shift work hazard control strategies

30. Three Essential Shift Work Hazard Control Measures
1. Adequate, good quality sleep
2. Suitable shift work schedules
3. Appropriate work conditions

31. 1. Adequate, good quality sleep

32. sleep hygiene rules Maintain pre-sleep routines similar to night sleep
Bedroom dark and quiet
Avoid caffeine for 5 hrs before sleep
Avoid alcohol before sleep
Avoid exercise before sleep

33. napping Naps can help maintain alertness, performance, and safety
Naps can supplement insufficient sleep, but …
BEST if taken after 7-8hrs main sleep and before feeling fatigued:
Nap at home before night shift
Nap early in the night shift
Nap before driving home after night shift

34. 2. Suitable shift work schedules

35. shift work schedules No “one best” shift work system
Employers should consider their worker population and work tasks, and decide, in collaboration with workers, on the most suitable schedule for their work place
Then evaluate the schedule

36. 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 maximum
Fewer if shifts >8hrs or night shifts

37. 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, but allow flexibility

38. 3. Appropriate work conditions

39. rest breaks Regular rest breaks reduce accidents
Incorporate movement, stretching or light exercise, social interaction
A proper meal break away from work duties

40. work schedule
Employers should tailor work tasks according to shift time; 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

41. work environment
Bright lighting, comfortable temperature, and good ventilation
Background music may help temporarily
Appropriate facilities for healthy eating
Napping facilities

42. Summary
Shift work is an OH&S hazard – employers and employees have a duty of care to control or minimise the hazards
Mutual responsibility is essential

43. Employers – duty of care to provide an appropriate work schedule and work environment, and continuing education and training for workers about coping strategies
Employees – duty of care to follow the recommended strategies to manage their sleep, health, and family life