Effect of Tai Chi Exercise on Immune Function in Middle-aged and Elderly Women

Objective: The purpose of this study was to investigate the effect of Tai Chi (TC) exercise on immune functions among middle-aged and elderly women, and to evaluate the relationship between immune modulation of Natural Killer T (NKT) cells and Dendritic Cells (DCs) and T Helper (Th) 1 /Th2 immune response. Methods: Sixty healthy middle-aged and elderly women were randomly assigned into 2 groups: Tai Chi (TC) group (n=30) and control (CON) group (n=30). Subjects in TC group participated in TC exercise for 6 months, 60 minutes a day, four times a week. Meanwhile, subjects in CON group maintained their normal physical activity levels during the whole study period. Peripheral blood samples were collected right before, and after 4 and 6 months of the exercise program, and the sampled were analyzed within 24 hours after collection. Results: After the 6-month TC exercise program, the percentage of CD4+ T lymphocytes, the CD4+:CD8+ ratio, and the percentage of NK and NKT cells in TC group significantly increased (p 0.05) of exercise. The percentage of CD123+ DCs and CD11c+ DCs also significantly increased after the 6-month program (p<0.01), with the percentage of CD11c+ cells increasing much more dramatically than CD123+ DCs. However, the CON group did not show any significant changes in these parameters. Conclusion: Regular TC exercise favors the development of Th1 immune responses in middle-aged and elderly women. TC-induced changes in Th1 and Th2 immune responses are associated with the immune modulation of NKT cells and DCs and their reciprocal interactions.