L’Accademia del Fitness
Immune system and
physical exercise
Many studies have demonstrated that different aspects of the immune function are depressed for some time after intense and prolonged physical exercise. This generates a sort of “open window” (which may last from 3 to 72 hours – open window theory) where the protection against viruses and bacteria is reduced, so the risk of developing an infection increases. Several epidemiologic studies have demonstrated that the athletes involved in marathons and/or ultra marathons have an increased risk of infections in the upper respiratory tract (URTI) and a study which involved top sailors has recently proved that infective episodes were preceded by a drop in the levels of salivary immunoglobulin A (IgA). The incidence of infection was inversely correlated to the salivary IgA also in two studies which involved swimmers and American football players from American colleges. These and other studies show that in athletes who undergo high physical workloads, the incidence of diseases, in particular of URTI, can be higher due to an alteration in the immune function.
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Other factors, such as psychological stress, lack of sleep and inappropriate nutrition may depress immunity and lead to an increased risk of infection (Picture 1). Increased exposure to pathogens Pulmonary ventilation, skin abrasion, constant trips abroad Increased susceptibility to infections
Psichological stress, physiological stress, environmental stress, poor diet, lack of sleep
immunosuppression
But what happens in the immune system during intense physical exercise?? The function of T cells is reduced, there is a reduction of the IgA, the activity of neutrophils is suppressed, the NK cells increase. The number and functional capacities of the leucocytes in circulation can be reduced by repeated sessions of prolonged and