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Fatigue at Work

To work together to create positive change, we need to share a common understanding of fatigue and shift work.  A science-based definition is that fatigue is a physiological state of reduced mental or physical performance capability, caused by: 

  • not getting enough sleep
  • by staying awake too long, and
  • by trying to sleep and work in the wrong parts of the circadian body clock cycle. 

It can impair your level of alertness and your ability to carry out work safely and efficiently.  Notice that fatigue is more than a sign of being tired or exhausted, and is not a sign of reduced motivation or laziness.  Shift work is a recognised cause of fatigue.



The new Health and Safety at Work Act considers fatigue as a cause of hazards, which are defined as factors that affect a person's behaviour. In other words, the Act also sees fatigue as a cause of reduced mental and physical performance capability. The Act clarifies responsibilities for health and safety and imposes greater penalties for those who do not meet their obligations. This project is designed to help nurses, their managers and DHBs meet their requirements under the Act.



People experience a range of symptoms that they associate with being fatigued. These can include being less able to pay attention, slower reaction times, poorer coordination, forgetting, finding it harder to regulation your emotional responses, being slower to process information, and being less creative in problem solving, particular under time pressure.

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More fatigue facts

The importance of sleep

Shift work and the body clock

Fatigue countermeasures