H&S Tech Tip: Worker Fatigue

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Fatigue is the state of feeling very tired, weary or sleepy resulting from insufficient sleep, prolonged mental or physical work. Boring or repetitive tasks can intensify feelings of fatigue.

The Health and Safety at Work Act (General Risk and Workplace Management) Regulations 2016 impose duties on PCBUs – employers and the like; in relation to the management of risks to health and safety.

Not only does it present a risk to individuals, but may also affect organisations through:

  • increased sick time, absenteeism, rate of turnover
  • increased medical costs
  • increased incident rates

Fatigue is such that a may be considered a form or impairment, which presents a risk and as such must be managed effectively. 

People responsible for planning work routines, particularly for shift workers, must ensure that workers are not exposed to unnecessarily long shifts.

They must be proactive in the management of fatigue by abiding by the following precautions and expectations: 

  • Allow for regular and adequate rest breaks
  • Provide facilities for workers to take their rest periods away from the ‘coal-face’
  • Plan work journeys, taking into account pre-journey work duties, the length of the trip and post-journey commitments
  • Prohibit the use of drugs, including medicinal drugs that cause drowsiness if workers are driving or operating machinery
  • Manage the risks associated with remote or isolated work
  • Causes of fatigue

    There are many, many causes of fatigue.

    Work-related factors may include long work hours, long hours of physical or mental activity, insufficient break time between shifts, changes to jobs or shift rotations, inadequate rest, excessive stress, having multiple jobs, or a combination of these factors.

    Changes to home environments can also impact sleep such as a new baby, change in patterns and routines, new or changing caregiver roles.

    Sometimes, a sleep disorder may cause fatigue. People suspected of having a sleep disorder should be encouraged to consult with a doctor or health professional for more information.

    Research has shown that the number of hours awake can be similar to blood alcohol levels. One study reports the following:

  • Signs and symptoms of fatigue

    Signs and symptoms of fatigue may include:

    • weariness, tiredness, and sleepiness, including falling asleep against your will (“micro” sleeps),
    • irritability,
    • reduced alertness, concentration and memory,
    • lack of motivation, and depression,
    • loss of appetite, or other digestive problems, and
    • increased susceptibility to illness
  • Effects of fatigue

    The effects of fatigue include:

    • reduced decision making ability
    • reduced ability to do complex planning
    • reduced communication skills
    • reduced productivity or performance
    • reduced attention and vigilance
    • reduced ability to handle stress on the job
    • reduced reaction time – both in speed and thought
    • loss of memory or the ability to recall details
    • increased tendency for risk-taking
    • increased forgetfulness
  • Types of Fatigue

    Fatigue can be described as either acute or chronic.

    Acute fatigue results from short-term sleep loss or from short periods of heavy physical or mental work. The effects of acute fatigue are of short duration and can be reversed by sleep and relaxation.

    Chronic fatigue syndrome is the constant severe state of tiredness that is not relieved by rest. The symptoms of chronic fatigue are flu-like, in that they may last longer than six months and may interfere with certain activities.

    Research reports that most incidents occur when people are more likely to want sleep - between midnight and 6 am, and between 1 to 3 pm.

  • Getting a good night’s sleep

    There is no one way to get a good sleep - what works for one person may not work for another. In general, suggestions include:

    • Go to bed and get up at the same time every day - do not watch television, read or do work in bed)
    • Exercise regularly
    • Eat at regular intervals and consume a balanced diet of fruits, vegetables, whole grains, healthy fats and protein
    • If you are not sleepy, do not try to go to bed. Get up and read or do something quiet instead
    • Avoid caffeine, tobacco or alcohol - especially before bed time
    • Turn off the telephone ringer and answering machine speaker
    • Ask family members to be respectful if one person is sleeping
    • Make the room as dark and quiet as possible. Use heavy, dark curtains, blinds, or a sleeping eye mask. Soundproof the room where possible or use ear plugs
    • Most people sleep better when the room is cool. Consider using an air conditioner or fan in the summer months
  • How much sleep do people need?

    It varies, but on average studies say we need at least 7 to 9 hours every day.

    Studies have reported that most night workers get about 5 to 7 hours less sleep per week than the day shift. (You can accumulate a sleep "debt", but not a surplus.)

    Humans follow an "internal" or "biological clock" cycle of sleep, wakefulness, and alertness.

    Although these circadian rhythms are influenced by external clues such as the sun setting and rising, it is the brain that sets your pattern. Most cycles are 23-25 hours long and there are natural dips or periods when you feel tired or less alert - even for those who are well-rested.

Hours awake

17 Equivalent to a blood alcohol content of 0.05 (the legal limit in NZ)
21 Equivalent to a blood alcohol content of 0.08
24-25 Equivalent to a blood alcohol content of 0.10 (twice the legal limit)