Researchers at McMaster University have demonstrated that regular exercise, even if moderate, can very significantly slow aging in mice. Per the article:
"The results showed that after five months (when the mice were the equivalent of 60 human years) the exercising mice looked like wild-type mice: younger and healthier and more active than the non-exercising mice, which were almost immobile and had lost much of their hair. The non-exercising mice were also less sociable and less fertile than the exercisers. The researchers said every tissue and every organ they examined was better in the exercising mice than in those that did not exercise, including the hair, skin, ovaries, testicles, spleen, kidneys, and liver. In the non-exercisers their brains had shrunk and hearts were enlarged, but they were normal size in the exercisers. The anti-aging effects were "unprecedented" and protected every part of the body. The muscle structure in the exercising mice was normal, while in the sedentary mice it appeared damaged. The mitochondria in the exercising mice appeared young and healthy, while those in the sedentary mice looked old and damaged. This result was the most surprising because mitochondria have their own DNA, and the accumulation of mutations in their DNA has been thought responsible for the gradual decline in tissue functions during aging, and for conditions such as cancer, diabetes, Parkinson’s disease and Alzheimer’s disease."
The findings have been published in the journal, Proceedings of the National Academy of Science.