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Fatigue - A guide for health and safety representatives

Issue date


An introduction for union health and safety representatives

PDF available here

What is fatigue?

Fatigue is usually defined as the decline in mental and/or physical performance that results from prolonged exertion, sleep loss or disruption of the internal clock.

The word “fatigue” is usually used to refer to a more chronic (long-term) condition than just sleepiness or acute fatigue (also called somnolence) which is generally caused by not enough proper, restful sleep, or a lack of stimulation.

People who suffer from fatigue feel they lack motivation and energy. Even though fatigue and drowsiness are not the same, drowsiness, or the desire to sleep, is a common effect that people with fatigue experience. Apathy may also accompany fatigue.

Fatigue, both long term chronic fatigue and acute fatigue or sleepiness, is a major problem for many workers. In the transport sector it is estimated that 20% of road accidents are a result of fatigue, and there are similar concerns in sectors like rail, aviation and shipping. However any organisation can have an issue with fatigue and it can be a problem with any sector where there are long hours, high demands, monotonous work, shift work or where low pay forces workers to take on addition part-time work. It can lead to accidents, poor production and considerable health problems.

Because it is often identified as a cause of accidents, employers will tend to blame the worker if they have an accident when suffering from fatigue. In fact most fatigue is caused by the demands placed on people by the employer and can be prevented by ensuring that workers are not fatigued or having systems in place to stop them working when fatigued.


The main cause of fatigue is a loss of sleep, either “acute” from the night before, or “cumulative” as a result of lack of sufficient regular sleep over a longer period. It can also be caused by poor quality sleep or changes in sleep patterns.

There can be medical reasons for fatigue, or it could be a result of personal issues such as a new-born child, but often it is work related. Long working hours, or poorly-designed shift work can lead to fatigue and of course stress can also be a significant cause of sleep loss. Among the causes of fatigue that are related to work or the work environment are:

·    Duration of shifts, split shifts, time off between shifts and changes to shift patterns.

·    Ability to sleep on rest days, the quality of sleep, and sleeping disorders.

·    Scheduling and quality of rest breaks during a shift.

·    Cold starts and inadequate recovery times.

·    Commuting time to and from the workplace.

·    Workload and responsibilities both physical and mental including repetitive, monotonous, demanding or strenuous work

·    The impact of second or multiple jobs

·    Stress at work.

·    A working environment which can encourage through being too warm, dark or quiet.

·    Pressures from “digital life”, including the pressure to respond to emails when not at work.

Certain factors can make fatigue worse. These include having to work at a ‘low point’ in the day e.g. early hours of the morning, mid to late afternoon and after a meal and inadequate breaks during the working day

In addition, a number of long term health disorders can cause fatigue.


Compared with their normal state, a person who is either acutely or chronically fatigued is likely to:

·    Find it hard to concentrate, make clear decisions or take in and act on information

·    Have more frequent lapses of attention or memory

·    React more slowly (for example, to hazards arising in the workplace)

·    Make more errors

·    Occasionally fall asleep at work – momentarily or for several minutes

·    Have little motivation or interest in their work

·    Be irritable

This means that people with fatigue are not only likely to be performing badly, they can also pose a danger to themselves and others. Over time, they also risk damaging their health. The long term effects of fatigue can be similar to stress and often people who are suffering from fatigue think they are stressed. Of course work can cause both stress and fatigue and they often go together.

Among the symptoms are:

  • Insomnia (often people with fatigue are simply unable to return to usual sleep patterns even if they try to)
  • Depression and anxiety
  • Headaches
  • Confusion
  • Dizziness
  • Blurred vision
  • Unexplained weight loss or gain
  • Digestive problems

The law

There is a legal duty on employers to manage any risks from fatigue that arise from work. Fatigue needs to be managed, like any other hazard, through risk assessment and risk management. Simply complying with the Working Time Regulations alone is insufficient to manage the risks of fatigue. Nor can an employer claim that a person willingly worked additional hours or shifts. The employer must ensure that they are aware of the hours a person works and take action to prevent any risk to the worker or to others.

In addition there is a legal requirement to consult with the workplace, either directly or through the health and safety representatives if they recognise a trade union.

The HSE has produced detailed guidance for employers on complying with the law and also a ‘fatigue risk index’ which is a useful tool that employers can use (see resources for details).

HSE advice

In a briefing note on fatigue, the HSE gave the following advice on how to manage fatigue.

·    Working hours are not too long

·    Employees get enough rest between shifts

·    Employees don’t work too many night shifts in a row

·    Managers negotiate with staff about overtime or double shift working

·    Managers fit in with individuals’ preferences – some people prefer nights

·    Employees avoid critical jobs at the ends of shifts or at ‘low points’ in the day or night e.g. 3a.m.

·    Shifts rotate ‘forwards’ that is, mornings, then afternoons, then nights

·    Employees take quality rest breaks in their work

·    Anyone can report fatigue problems to management and the company will make improvements

·    The environment doesn’t cause drowsiness (it’s light with visual interest, not too hot and there is always variation in the level of sound)

·    There are contingency plans to avoid overloading one person with overtime or double shifts

·    Incidents or accidents where fatigue may be responsible are thoroughly investigated

In addition to these recommendations from the HSE, the TUC believes that it is important that employers ensure that they involve the workers, through their union if they recognise one.

Role of Unions

If you think that fatigue is an issue in your workplace then try surveying your members to find out what the causes are and raise it with your employer. You can also raise awareness of the dangers of fatigue and work with employers to try to develop an environment where workers can report when they are fatigued without fear of repercussions.

In addition unions can ensure that they are supporting members who feel they are fatigued by ensuring that they get their employer to refer them to an occupational health provider for help if they are ill as a result. However in most cases the best support you can give is to ensure that the causes of the fatigue are removed.

Trade unions can have a positive role in preventing workplace fatigue. In many industries, including rail, road transport, aviation, oil and gas extraction, manufacturing, power generation and shipping trade unions have sought to work with employers to ensure that the demands of work and shift patterns do not risk the health of workers or the public. Many unions will have their own resources on fatigue, so check the website. The HSE guidance and their fatigue index calculator are a good starting point.

Finally unions should support members who are threatened with disciplinary action because the employer claims they have made a mistake or underperformed as a result of fatigue.  Employers have a responsibility to prevent workers from getting fatigued through work and, where there is a safety critical job, they also need procedures to be in place to monitor the risk of a fatigued worker placing themselves and others at risk, even if the fatigue is a result of factors outside their work. If a mistake happens because a worker is fatigued, it is because these procedures have failed and they should not scapegoat the worker.

Useful resources

HSE fatigue pages

H.S.E. – Fatigue Index Calculator.

ORR – Managing Rail Fatigue

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