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E67: Designing safer and healthier shift work systems/rosters · Safe As Podcast

• 0:07
  How do we design for occupational fatigue?
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  Let's look at risk factors, scheduling principles, and more.
• 0:15
  Good everyone. I'm Ben Hutchinson and This is
• 0:17
  Safe as a podcast unpacking safety and risk research.
• 0:21
  Visit safetheinsights.org for more research.
• 0:25
  Today's sources are QNG 16 Guidance Note for fatigue Risk
• 0:30
  Management from the Department of Natural Resources, Mines and
• 0:33
  Energy 2013 and from Peter Canout 1996.
• 0:38
  Designing better shift systems in Applied Urbanomics.
• 0:43
  First, there's no single optimum shift system.
• 0:48
  It's really a game of compromises where you may trade
• 0:51
  off gains or losses or risks in one area of the schedule for
• 0:55
  other risks elsewhere. But there are lots of modifiable
• 0:59
  risk factors that we can change to make a given schedule by use
• 1:03
  of a fatigue risk management system more favourable for more
• 1:07
  workers. First, let's jump into the
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  blueprints for scheduling. The primary concern in shift
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  design addresses the biological clock.
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  Firstly, night work should be reduced as much as possible.
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  When night work is necessary, the speed of the rotation is
• 1:25
  key. The body circadian clock
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  typically can't adjust to night work within around one week.
• 1:32
  Consequently, quickly rotating shift systems are generally
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  preferable to slowly rotating ones, as the least disturbance
• 1:41
  of circadian physiological functions is observed in their
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  rapidly rotating systems. So for instance, moving between
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  morning afternoons and nights pretty rapidly rather than
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  really long periods like a 7 days of morning, 7 days of
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  afternoons. So the faster is more
• 1:58
  preferable. Permanent night work is
• 2:01
  generally not recommended for the majority of workers because
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  it can isolate them socially and humans are diurnal.
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  We're generally meant to be awake at daytime and sleep at
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  night. There's quite a lot of research
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  which is found that even people who identify as night owls and
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  they typically like working nights can still have quite
• 2:21
  impaired biological markers, so poor health indices.
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  Also the direction of the change in the cycle also matters.
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  So the forward rotation, which is morning, evening, night shift
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  is more preferred than the backwards rotation.
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  Nights to evenings to mornings. Forward rotation tends to align
• 2:42
  better with our internal circadian rhythm.
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  Conversely, backward rotation, again the nights to evenings to
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  mornings is often listed as a more high potential contributing
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  risk factor for scheduling has been linked to high levels of
• 2:56
  fatigue and increased sleep disturbances.
• 2:59
  Next we'll look at duration and breaks.
• 3:02
  Effective schedules must place firm limits on the length of
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  work and ensure sufficient time for recovery between shifts.
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  If you recall for one of the previous pods when I said that
• 3:13
  fatigue is about sleep and it actually is primarily about
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  sleep. So the shift in roster lengths
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  extended work days, so over around 9 to 12 hours may be
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  actually considered, but preferably if the work nature
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  and the workload are suitable and the system minimises fatigue
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  accumulation. However, exceeding certain
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  thresholds presents a higher potential for fatigue risk.
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  A shift involving more than 12 hours in a day, including call
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  outs, is considered a higher potential risk, though whether
• 3:43
  12 hour shifts are inherently more risky compared to other
• 3:47
  ones really depends on the context.
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  So even compressed work weeks where you work, say, 4 * 12 hour
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  shifts, aren't necessarily riskier than other schedules.
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  And in fact, some have actually argued that reducing the driving
• 4:00
  exposure may be worth a slightly elevated risk during the 12 hour
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  shifts. Total weekly hours working hours
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  of active work that exceeds 72 hours in any seven days carries
• 4:11
  a higher risk. Work schedules exceeding 242
• 4:14
  hours in any 28 day period are higher potential risks and
• 4:18
  consecutive days. So to avoid accumulating
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  fatigue, the number of consecutive working days should
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  be limited to around 5 to 7. Exceeding 7 consecutive shifts
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  worked is a higher potential risk.
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  Of course, anyone that works mining or any sort of fly in fly
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  out, you know that these sorts of extended work schedules are
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  really common. They're here to stay, but that
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  doesn't mean we can make optimizations to make them
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  healthier. Next we have to look at the
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  sleep opportunity and recovery breaks.
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  Recovery time must be carefully managed, so quick change overs
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  such as moving directly from a night shift to an afternoon
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  shift on the same day must be minimised or avoided as much as
• 4:58
  possible. Scheduling systems with only an
• 5:01
  8 hour break between shifts are known to reduce sleep
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  opportunity and thus increase the expected fatigue, so
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  providing as much opportunity for people to catch up on their
• 5:11
  sleep between shifts is advisable.
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  Providing less than 7 hours of sleep opportunity between shifts
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  or less than 50 hours of sleep opportunity in any seven day
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  period is a higher risk and consecutive night shifts.
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  Again, we're generally supposed to be asleep at night, so higher
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  risk applies if a worker completes more than six
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  consecutive 8 hour night shifts, more than five consecutive 10
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  hour night shifts, or more than 4 consecutive 12 hour night
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  shifts. Failing to allow less than 48
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  hours break after four or more consecutive night shifts is also
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  a higher potential risk. And for work lasting 10 hours,
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  providing less than 30 minutes in total for breaks is a higher
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  potential risk. So while in shift breaks can't
• 5:55
  actually overcome the biological need for sleep, it can help
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  reduce the amount of accumulated like time on task fatigue during
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  a task. It can help people who slowly
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  free up their cognitive resources.
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  And generally, every scheduling system should include some free
• 6:10
  weekends with at least two consecutive days off over the
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  swing. Next we'll look at timing,
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  environment, individual risk factors, two final direct risk
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  factors, a shift timing and the commute time.
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  An early start for the morning shift should be avoided.
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  Shift starting out of before 6:00 AM, especially with a one
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  hour longer commute, pose a medium to high risk potential.
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  In fact, some other research found that the best predictor of
• 6:36
  sleep length was actually the shift start time.
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  For instance, on day shifts, the early morning start is likely to
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  be the major cause of sleep disruption.
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  This is likely because people don't necessarily compensate for
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  the early start times by going to bed earlier than not before.
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  So starting the morning shifts at a later time is likely to
• 6:57
  yield better fatigue reduction than many other interventions.
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  Remember, a fatigue clock starts when you wake up, not when you
• 7:04
  start your shift. As Dorset and McCulloch argued,
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  fatigue is about sleep and talking about this idea of
• 7:11
  compromises with schedules. When do you finish a night
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  shift? Earlier in the night, say 3:00
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  AM to allow more deep restorative sleep, or later in
• 7:21
  the morning to avoid the circadian Nadia.
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  This is when the alertness is lowest and sleepiness is often
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  highest anyway. Regarding commuting, driving
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  more than two hours to arrive home at the end of the roster or
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  commuting 2 hours or longer in each direction daily.
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  A high potential risk that directly reduce sleep
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  opportunity and of course expose people to one of the most
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  dangerous thing most of us do every day, drive our cars.
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  And lastly, a few other factors, task design and mental demand.
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  So fatigue onset is increased by jobs that involve high demand
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  but low control, high vigilance or concentration, or repetitive
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  or monotonous work like whole truck driving.
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  And we often combine monotonous tasks like someone operating a
• 8:06
  terminal remedy control centre during night shifts.
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  The scheduling of safety critical tasks when a worker's
• 8:12
  been awake for more than 16 hours is also a high potential
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  risk. Also, physical environmental
• 8:18
  stresses have to be considered. Tasks that are physically or
• 8:21
  mentally strenuous contribute to fatigue.
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  Adverse working conditions such as exposure to cold, heat, noise
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  or whole body vibration increase the need for recovery and
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  contribute to fatigue onset. There's also a range of
• 8:34
  individual and sight factors. So the lighting and use of
• 8:39
  particular lighting like in control centres, so some
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  lighting often blocking the blue light wavelengths can increase
• 8:46
  alertness while minimising circadian disruption since some
• 8:50
  of these wavelengths can impact melatonin production.
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  Now of course, there's a whole range of individual factors.
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  So fatigue is experienced differently between individuals
• 9:00
  and some people tend to be night owls and and we have to consider
• 9:05
  underlying health issues. So for instance, people with
• 9:08
  severe sleep disorders, obstructive sleep apnea, chronic
• 9:11
  fatigue syndrome. In fact, there's quite a bit of
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  research which has found that long distance truck drivers tend
• 9:17
  to have a hat trick of risk factors, overweight, high body
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  mass indexes and waist circumferences, higher neck
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  circumferences and breathing obstructions and critically
• 9:27
  sleep disorders like obstructive sleep apnea.
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  It's all compound to increase the risks in highly vulnerable
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  groups that operate on our roads.
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  There's also a bunch of site management factors, so the
• 9:38
  quality of the accommodation must also be controlled as poor
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  quality of accommodation, like in mining camps and whatnot,
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  which don't have very good insulation from noise, can
• 9:48
  negatively influence sleep quality and opportunity.
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  Something really important here is called sleep hygiene.
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  This is things like the environment that people sleep
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  in, the darkness, even little bits of light penetrating into
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  the room can disrupt people's melatonin and their sleep
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  levels. The noise obviously is
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  disruptive, the temperature can be optimised.
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  There's a whole range of things that we should be doing to
• 10:09
  improve the accommodation. There's heaps of other stuff we
• 10:12
  can cover, but that's really all the time I have for today.
• 10:15
  That's it on Safe As I'm Ben Hutchinson.
• 10:18
  Please help share, rate and review and
• 10:21
  checkoutsafetyinsightsorg for more research.
• 10:24
  Finally, feel free to support Safe ads by shouting a coffee
• 10:28
  link in the show notes.