CAN REGULAR PHYSICAL ACTIVITY ATTENUATE ALTERATIONS IN THE IMMUNE SYSTEM RELATED TO AGING?

Abstract

Immune function declines with advancing age and physical exercise might provide a tool to restore or modulate the immunosenescence. The data in humans suggest that exercise training may need to be long-term and of sufficient volume to induce changes in body weight and fitness, before any change in immunity can be expected in old age. PURPOSE To investigate the premise that exercise might be considered an immune-restorative intervention. METHODS We performed a cross-sectional study comparing 20 elderly male runners(R)(aging varying from 61 to 80 years) that had been training for at 23±9 years and their 20 sedentary peers(C). Participants were advised to not exercise for at least 48 h before blood samples were drawn. Venous blood was analyzed for leukocyte counts, lymphocytes subsets(CD19,CD56,CD3,CD4,CD8 and CD45RA,CD45RO,CD95 and CD28 on CD3+, CD4+ and CD8+ cells) by flow cytometry, T cell mitogenic proliferation, and IL-2,IL-3,IL-4,IL-6,IL-10,IL-12 production by peripheral mononuclear cells. RESULTS Elderly runners had a body fat content of 19.2±0.7%, and a peak aerobic power of 38.5±1.1 ml kg-1 min-1 significantly different from the sedentary group (body fat=24±1.2% and peak aerobic power =25.5±0.8ml kg-1 min-1), p = 0.002 and p < 0.001 respectively. No significant differences were observed in the numbers of leukocytes, or T cell subsets in runners subjects as compared with elderly controls. But, the R subjects showed a significantly higher OKT3-induced lymphoproliferative response (Stimulation index=111.71±11.95 for R and 78.26±10.51 for C subjects),p = 0.045 and significantly higher stimulated IL-2 production,(R:594.92±78.44 pg/ml and C:321.92±59.92pg/ml),p = 0.002. CONCLUSION Although the runners did not show significant peripheral blood lymphocyte phenotype differences, they presented functional differences in comparison to their sedentary controls. Supported by a grant from Fundação Médica (LIM 56), Faculdade de Medicina da Universidade de São Paulo.