[Stress and fatigue]

Investigations into fatigue are very important for development of labour and sports physiology. Many occupations in modern industry do not often show apparent fatigue. This is the reason for the interest shown for occupational strain sgudies. Occupational strain has proved to have laws of optimum. In some occupational situations work is performed at a different than the optimum, level. It is important to take into consideration general and local strain as well as specific and unspecific components of strain. The fatigue level is a significant sign characterizing the occupational strain.