ABSTRACT
According to EN ISO 6385, work fatigue is a mental or physical, local or general non-pathological manifestation of excessive strain, completely reversible with rest. Therefore, assuming fatigue is measurable, it can be used to gauge the severity of the work. It is presumed that fatigue manifests itself as a decline in or the loss of alertness (Joteyko J., 1939), however, this state is also achieved as a part of natural processes that shape a person’s capacity to perform work. A person’s ability to work is not steady throughout the day, it can vary according to seasons of the year, and is subject to fluctuations due to factors that are work-related as well as those resulting from biological rhythms and other disrupting factors such as an illness or family problems. This creates methodological problems, since the assessment of fatigue contains simultaneously occurring non-specific phenomena, including the worker’s lifestyle, diet, individual predisposition and many other factors. An assessment of fatigue on the basis of symptoms, even though its subject to such a large margin of error, is necessary when it is not possible to conduct detailed observations of working processes as is the case for bituminous coal miners.
