The extreme physical effort and psychological stress are everyday challenges faced by athletes. The regular training results in adaptation to increasing physical effort. It contributes to changes in various organs and metabolic processes. Intense physical training has been shown to affect numerous body systems including the immune system. The aim of this paper is to present the influence of extreme physical activity on various aspects of immune response. The changes in the immune system of athletes include not only those related to blood leukocytes, but those in connection to respiratory and gut associated lymphoid tissue as well. Moreover, the immune cells play an important role in muscle regeneration after sustaining training injury. The mmunology of physicial activity – mainly extreme physical activity – is a new, not fully recognized yet field of research. The understanding of these interactions facilitates a proper training planning for different groups of athletes.
