[The more effective immune system of women against infectious agents].

Even the reactions of the immunological system are dependent on the sex. Estrogens are the natural stimulants of the general resistance. On the other hand, androgens especially testosterone have an anabolic effect on the voluntary muscles but they inhibit the immunological system. Therefore, women show more resistance to the most infectious agents with the exception of intestinal parasites. To some extent the higher expectation of life of women may be due to that stronger female resistance to infectious agents. It is true, sport is able to decrease the cardiovascular mortality. However, the training of the voluntary muscles is a burden to the resistance especially in the second half of the life. There is therefore some probability that sport is not prolonging the life.