Effect of Tai Chi Exercise on DNA Damage, Antioxidant Enzymes, and Oxidative Stress in Middle-Age Adults

Background: The biochemical mechanisms involving oxidative stress to explain the relationship between exercise and healthy aging are still unclear. Methods: Tai Chi participants and matched sedentary volunteers age 45 and above were enrolled. Glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities; levels of DNA damage using the comet assay; and malondialdehyde (MDA) and advanced glycation end products (AGE) were determined at 0, 6, and 12 months. Results: Tai Chi subjects had decreased normal and increased mildly damaged DNA with elevated GPx activity after 6 months (n = 25). Plasma MDA and AGE concentrations decreased significantly after 12 months (n = 15) accompanied by increased SOD activity. This may be attributed to the hormesis effect, whereby mild induction of oxidative stress at the first 6 months of exercise resulted in stimulation of antioxidant defenses. These parameters were unchanged in the sedentary subjects in the first 6 months (n = 27) except for elevated SOD activity. After 12 months, the sedentary subjects (n = 17) had decreased normal DNA and increased severely damaged DNA with unaltered MDA and AGE levels while SOD and GPx activities were significantly elevated. Conclusion: Regular Tai Chi exercise stimulated endogenous antioxidant enzymes and reduced oxidative damage markers.