Focus on Fatigue

How Accurate is Fatigue Self-Monitoring?

By April 11, 2023 No Comments

Issue #76 – March 23

Welcome to Focus on Fatigue!

Sleep is not always the easiest thing to come by, especially for those working long or night shifts. When we are deprived of adequate sleep, many of us are faced with a number of important questions. How tired am I? Can I continue working? Is my work performance suffering? Am I putting myself or others at increased risk? We all like to think we can accurately identify our level of fatigue and how we’re being affected by it, but is this actually the case? Do we know how tired we really are? Is fatigue self-monitoring an effective fatigue risk management strategy? This is the question we’ll be investigating in this month’s Focus on Fatigue.

The FRMS Team


Views expressed in articles and links provided are those of the individual authors, and do not necessarily represent the views of InterDynamics (except where directly attributed).

How Accurate is Fatigue Self-Monitoring?

Do we know how tired we really are?

Many shift workers rely on self-monitoring to assess their fatigue levels. But the question arises, how good are individuals at assessing their own level of fatigue and whether fatigue is impacting their performance?

Tired at work - person yawning

Self-monitoring of fatigue levels: moderately good but not perfect

Studies have found that people are fairly good at recognizing when sleep deprivation is affecting their performance on simple tasks. However, one study of Australian fire fighters found that this ability to self-monitor performance begins to deteriorate after prolonged periods of wakefulness. Moreover, people tend to either over or under-estimate the degree that fatigue is hampering their performance. The ability to self-monitor fatigue can also be reduced during a person’s biological night (when our circadian rhythm is telling us we should be asleep).

Post-work evaluations are more accurate than predictions

Generally, people are better at evaluating their performance after completing a task, than predicting their performance before starting it. However, when it comes to risk management, pre-performance assessments are more valuable in reducing the risk of accidents or injuries. Feedback during the completion of a task can also lead to more accurate evaluation of performance.

Global predictions are more accurate

People tend to be better at making global predictions about our performance than they are at predicting how well they’ll do on particular tasks. For example, one study found that after a week of simulated night-shifts, participants were better able to predict their performance overall, than they were able to predict their performance for specific shifts.

This means that we aren’t necessarily great at identifying which tasks will be affected by our levels of fatigue. Considering that sleep deprivation does not affect all types of activities equally, such global predictions mean that we may not be good at adjusting our prediction of how well we will perform based on the type of activity we will be performing.

Acknowledging fatigue won’t help improve our performance – much

There can be a tendency to think that if we acknowledge how fatigued we are, then we can improve our performance by ‘trying harder.’ To a certain degree this is true. Studies have found that motivation to do well can make a difference to performance in people who are sleep-deprived (this depends heavily on the severity of the deprivation). However, it is important to remember that the best way to deal with fatigue, especially when we are able to recognize that fatigue is affecting our work performance, is to stop working and take a break or, preferably, have a sleep.

Work culture is also important

Fatigue will most commonly be apparent to a worker long before they cease to be ‘capable’ of working. Therefore, a person who acknowledges they are experiencing a high level of fatigue is not necessarily saying ‘I can’t continue working’ but may actually be saying ‘I believe it may be unsafe for me to continue working.’ It is imperative that workplace culture supports individuals who recognize that fatigue is impeding their work performance and wish to take steps to rectify the situation.

One useful tool

Overall, research tells us that self-monitoring can be one useful tool to assist in determining fatigue risk in the event of sleep deprivation. However, because our own assessment of fatigue has its limitations and is not necessarily as accurate as we would like to think it is, we should also be using the other tools at our disposal to assess risks that might be present as a result of fatigue.


  • Armstrong, T. A., Cvirn, M., Ferguson, S. A., Christoforou, T. and Smith, B. (2013) Can Australian bush fire fighters accurately self-monitor their cognitive performance during a 3-day simulated fire-ground campaign? Sleep, performance and well-being in adults and adolescents, 18-23. 10th Annual Meeting, Australiasian Chronobiology Society: Adelaide.
  • Baranksi, J. V., Pigeau, R. A., and Angus, R. G. (1994) On the ability to self-monitor cognitive performance during sleep deprivation: A calibration study. Journal of Sleep Research, 3(1), 36-44.
  • Dorrian, J., Lamond, N., Holmes, A. L., Burgess, H. J., Roach, G. D., Fletcher, A., and Dawson, D. (2003) The ability to self-monitor performance during a week of simulated night shifts. Sleep, 26(7), 871-877.
  • Muldoon, N., Sargent, C., Zhou, X., Kosmadopoulos, A., Darwent, D. and Roach, G. D. (2013) The efficacy of subjective ratings is limited during the biological night. Sleep, performance and well-being in adults and adolescents, 7-12. 10th Annual Meeting, Australiasian Chronobiology Society: Adelaide.
  • Dorrian, J., Lamond, N. and Dawson, D. (2000) The ability to self-monitor performance when fatigued. Journal of Sleep Research, 9, 137-144.

In The News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Drowsy driving - blurry road at night

Drowsy drivers just won’t stop soon enough, AAA study finds

Gary Gastelu, Fox News, March 2023

A new study found that not enough drivers are taking a hint from their bodies and continuing for too long on their journeys when they should be stopping to rest. About 75% of tired drivers kept going despite the risks.


Human brain looks years ‘older’ after just one night without sleep, small study shows

Rebecca Sohn, Live Science, February 2023

A study suggests that just one night of sleep deprivation may be linked to structural changes in the brain, similar to those seen in aging.


Ignoring fatigue a slippery slope for health and safety on the farm

Erin Kelly, Wellington Advertiser, March 2023

We often hear farmers say, “I’ll sleep when the busy season is over.” But that overlook, even if intended jokingly, is a slippery slope for health and safety considerations.

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