ABSTRACT
As currently construed by much of the scientific, professional, and lay communities, “fatigue” is a physiological and/or psychological state caused by a variety of factors (e.g., time on task, boredom or disengagement from the task at hand, sleep debt, circadian desynchrony, etc.). This broad conceptualisation of fatigue has in some ways proven useful since it implies that almost anything that potentially impairs operational performance is in the wheelhouse of “fatigue risk management” researchers and practitioners. However, there is a downside: The more expansive the definition of fatigue, the more ambiguous (and thus less meaningful and actionable) that definition becomes. Two well-known and widely used definitions of fatigue are critiqued and contrasted with a more concise, recently proposed definition. It is concluded that the time has come for the fatigue management community to adopt a narrower and clearer definition of “fatigue”—–especially one that does not conflate “fatigue” with “sleepiness”.
