What causes fatigue?

Answer

Fatigue has different causes. A distinction is often made between sleep-related fatigue and task-related fatigue [1]. Sleep-related fatigue for instance involves

  • structural or once-only sleep deprivation;
  • poor sleep quality, for example because of numerous interruptions, too much noise, being too hot;
  • sleep disorders such as sleep apnoea and narcolepsy;
  • being up and active at times when the body wants to sleep (biological clock).

Task-related fatigue for instance involves

  • being physically or mentally active over long stretches of time (time-on-task);
  • having performed/having to perform too many or too complicated tasks over long stretches of time (excessive workload);
  • having performed/having to perform too few or too simple tasks over long stretches of time (too low workload).

To what degree these circumstances lead to fatigue, or to what degree fatigue manifests itself, depends on several other factors, such as physical condition, age and ambient temperature [2] [3].

The diversity of fatigue causes means that almost all people, and therefore almost all road users, are sometimes tired. Spending prolonged stretches of time behind the wheel is just one of the causes. The often voiced assumption that in countries such as the Netherlands, where distances are relatively short, fatigue in traffic will be a minor factor compared to countries where distances are longer, does therefore not hold water.

Part of fact sheet

Fatigue

Driver fatigue is estimated to be a (contributing) factor in 15 to 20% of crashes, but estimates in individual studies vary widely.

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