Exercise and Infection

Abstract

In brief: Many athletes believe that exercise improves their resistance to infection, but no epidemiological data support this claim. Studies of various host defense mechanisms have produced inconclusive results. Transient lymphocytosis and polymorphonuclear leukocytosis occur with exercise, but they may not be functionally significant. Levels of interleukin-1, an immunostimulant, rise with exercise; this area warrants further study. Both athletes and sedentary individuals are subject to the same infections and can be treated in the same way. However, athletes should be cautioned against strenuous exertion when they are febrile or systemically ill, and should substitute gentle stretching exercises until they have recovered. This article is the third in a series on internal medicine. The first discussed exercise, lymphokines, calories, and cancer (June, page 109); the second discussed management of exercise-induced gastrointestinal problems (September, page 112).