Results C-EX mice demonstrated the lowest severity of infection, assessed by body weight loss and food intake. There was less virus in the lungs at day 5 after infection in C-EX and A-EX mice compared with NON-EX mice (P=.02) and less virus at day 2 after infection only in C-EX mice (P=.07). Soon after infection (day 2), interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 1β, and tumor necrosis factor α in the bronchoalveolar lavage (BAL) fluid were lower in C-EX and A-EX than in NON-EX mice. At day 5 after infection, the BAL fluid from C-EX (but not A-EX) mice had less IL-6, interleukin 12p40, granulocyte colony-stimulating factor, keratinococyte-derived chemokine, and MCP-1 than that from NON-EX mice. A trend toward reduced immunopathologic response was found in C-EX mice
Conclusions Chronic exercise resulted in reduced symptoms, virus load, and levels of inflammatory cytokine and chemokines. Acute exercise also showed some benefit, which was limited to the early phase of infection