“Fatigue does not have an affect on me” Is there any truth to this statement?

By Clinton Marquardt - Sleep & Fatigue Specialist

July 27, 2020

fatigue, fatigue countermeasure, fatigue management, human performance, performance and fatigue, sleep and performance, sleepy

bright eyes sleepy eyes

We used to push through fatigue and wear our success as a badge of honour.  Accepting an extra long duty and then pushing through the head nods or drifts out of your lane on the highway and making it home in one piece made us feel strong, like we conquered a worthy challenge.  Plus, if others could do it, why can’t you?  Statements like “Fatigue does not have an affect on me” or “I can stay awake forever and still be fine” would make you feel weak if you could not.  Our beliefs are slowly changing and we are realizing that pushing through these risks is too dangerous to our safety, health and performance.

But it turns out that some people are more resilient to the effects of fatigue than others. Their overall performance is better on night duties or during extended periods of wakefulness[1]. The problem is that it is very difficult to know who is more susceptible to experiencing performance decrements due to fatigue. It can be done, but it takes sophisticated statistical techniques based on assumptions around biology and genetics.  Bio-mathematical modeling of fatigue and performance is getting better at incorporating these techniques.  However, it still takes quite a bit of pretesting of a person’s sleep, fatigue and performance to be able to use bio-mathematical modeling to accurately predict the best candidates for night work and long duties[2].

This means we still do not have a quick and easy way to figure out how safe any one particular shift-worker will be.  Simply leaving it up to people to judge their own fatigue and performance is not a good idea either. We are not very good at doing either one. The safest bet is still to err on the side of caution and assume that most people won’t do as well when they are fatigued than when they are fully alert and to ensure they know when to use appropriate fatigue countermeasures.


[1] See for examples:

(A)   Van Dongen, H., Baynard, M., Maislin, G., & Dinges, D. (2004). Systematic interindividual differences in neurobehavioral impairment         from sleep loss: Evidence of trait-like differential vulnerability. Sleep 27(3), 423-433. 

(B)   Van Dongen, H., Bender, A., & Dinges, D. (2012).  Systematic individual differences in sleep homeostatic and circadian rhythm                  contributions to neurobehavioral impairment during sleep deprivation. Accident Analysis and Prevention, 45(Suppl.), 11-16.

[2] See for example:  Van Dongen, H., Mott, C., Huang, J., Mollicone, D., McKenzie, F., & Dinges, D. (2007). Optimization of biomathematical model predictions for cognitive performance impairment in individuals: Accounting for unknown traits and uncertain states in homeostatic and circadian processes. Sleep 30(9), 1125-1139.

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