Regular exercise attenuates oxidative stress in aging rat tissues: A possible mechanism toward anti-aging medicine

Regular exercise is known to exhibit various health benefits in reducing risks of age-related diseases such as cardiovascular diseases, type 2 diabetes, cancer, and neuronal disorders. It is interesting to note that beneficial effects appear more pronounced in the elderly than in younger adults despite the fact that aging is accompanied by increased oxidative stress that is suggested to be a major cause of aging and age-related diseases. Mechanisms behind this apparent paradox are not well understood. Regular training and acute bouts of exercise upregulate activities of antioxidant enzymes and thereby can reduce oxidative stress. We have studied the effects of regular exercise on oxidative stress in the liver and brain of middle-aged and old rats. Protein carbonyl was significantly reduced and proteasome activity was upregulated in the brain with improved cognitive function by swimming training. The binding of transcription factor NF-κB to the target DNA was reduced with concomitant increase of reduced glutathione in the liver of old rats by regular treadmill running, suggesting that inflammatory reactions are alleviated in these animals due to reduced oxidative stress. A similar exercise regimen was able to reduce 8-oxodeoxyguanosine (8-oxodG) in the nuclear and mitochondrial DNA of the liver of old rats. Based on these findings and reports by other investigators in which moderate exercise is suggested to be beneficial while excessive exercise is harmful, a hormesis-like mechanism by reactive oxygen species may be proposed that is likely to be a major mechanism of anti-aging effects and reduces risk of age-related diseases by regular exercise.