Various professional sports have reached a high level of development. Stress at athletes’ work partly characterizes quality of psycho-emotional work environment. Psychological effects caused by stress frequently change into physical effects. At the same time, it should be noted that athletes do not receive adequate attention from the occupational health and safety point of view. The aim of the research was to investigate influence of work stress and physical load on professional volleyball athletes during trainings in comparison with volleyball competitions. The results reveal that the volleyball players are generally exposed to physical load (94%) and 82% - to work stress and other psycho-emotional risks. Heart rate measurements proved that athletes are subjected to significant overload during competitions since it is increased by accumulated workload during trainings as well as by psychological strain during competitions. Work stress and physical load (intense physical activity, forced postures) affect work performance and physiological parameters of the body during the trainings and competitions. This can increasingly contribute to sports injuries.