Fatigue as a Safety Hazard

Fatigue as a Safety Hazard

This past weekend, Nova Scotia and most of the rest of North America entered daylight savings time. The loss of an hour of sleep on Saturday night can lead to greater instances of fatigue at work on Monday morning, as we all try to cope with the change. But for some, fatigue can be an issue whether there is a change to time or not. So this week, Paragon Safety Ltd. will discuss fatigue as a safety hazard

Types of Fatigue

Most of this article will be based on the chapter on fatigue from “Fitting the Task to the Human” by Kroemer and Grandjean. We all feel fatigue from time to time. Staying up to late or doing physically demanding work has an impact on the body. Even after a long night’s sleep, we may still wake up tired.

There are different kinds of fatigue that can affect us. With the time changes in spring and fall, the type of fatigue is called circadian fatigue. This type of fatigue results from changes in our natural sleep pattern. If you work shift work, going from day to night shift and back again also causes this type of fatigue. The circadian rhythm refers the twenty-four hour natural cycle, which can be disrupted from this. Other types of fatigue include:

  • eye fatigue (from straining the visual system),
  • general body fatigue (from physically overloading the body),
  • mental (from intellectual work),
  • nervous fatigue (caused by overstressing one part of the psychomotor system, such as on an assembly line),
  • and chronic fatigue (which is a build up of long term effect)

Symptoms of Fatigue

If you are wondering if the people you are working with are suffering from fatigue, there are symptoms that you can observe. The first of these is sluggish thinking. As a safety hazard, sluggish thinking would be a great concern. Reaction to anything will be slower if the person is suffering from fatigue. This can also tie in to another symptom, reduced alertness. By not paying attention to what is happening, a worker can cause an accident that may lead to injury to themselves or others. Poor and slow perception is another symptom of fatigue that can lead to safety issues on the jobsite. When you are on most jobsites, especially when using or working near heavy equipment or other workers, you need to be able to have the focus on what is happening around you. These symptoms have an impact on your ability to function and mean that you could be putting yourself and other at risk.

There are two other symptoms identified by Kroemer and Grandjean. These are unwillingness to work and decline in mental and physical performance. Decline in mental performance could be serious if a worker, while suffering from fatigue, does not use his/her PPE properly, such as not properly attaching their safety lanyard to an anchor point. Unwillingness to work, while not really a safety hazard, could put pressure on the worker, and lead to added stress on the job.


While we adjust this week to the time change, let us remember that some people, either because of their work or other reason, will suffer from fatigue all year. Another important thing to remember is that fatigue can also be the symptom of a serious medical condition and it may be necessary to see you doctor in order to determine what can be done about the fatigue that you are suffering from. For supervisors and managers, remember that fatigue as a safety hazard is something that you need to be aware of and to watch for the symptoms to prevent an accident at you worksite.

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