Nonfatigue

Nonfatigue is a term used informally to denote the absence or reduction of fatigue, particularly in physical, mental, or occupational contexts. Fatigue refers to a decline in physical or cognitive performance and a subjective sense of tiredness that can result from prolonged activity, sleep loss, or illness. Nonfatigue, therefore, describes a state in which fatigue is absent or minimized, allowing sustained energy and performance.

In practice, fatigue is studied as physical fatigue (reduced muscle power and endurance) and mental or cognitive fatigue (decreased attention, slower processing, and weaker decision-making). Nonfatigue is not a formal diagnosis or condition with established criteria; its assessment relies on self-reported fatigue measures and objective performance tests. Common fatigue instruments include questionnaires such as the Chalder Fatigue Questionnaire and the Fatigue Severity Scale, along with tasks that measure endurance, reaction time, or cognitive throughput. Because fatigue is multifactorial, distinguishing true nonfatigue from inadequate assessment can be challenging.

Management and implications vary by context. In health and athletics, reducing fatigue involves adequate sleep, balanced nutrition, hydration, and appropriate conditioning or pacing strategies. Addressing underlying medical or psychiatric conditions is also important. In work settings, fatigue management may include workload adjustment, break scheduling, and energy-conserving practices. In engineering, fatigue is a formal concept describing failure under cyclic loading; the term nonfatigue is uncommon and nonstandard, with fatigue resistance used as the precise descriptor.