Exercise, Mitochondrial DNA, and Brain Fitness
One very influential theory of why our physical and mental functions decline with age holds that changes in our DNA accumulate over time so that out cells don’t work any more. Perhaps the most important part of our DNA exists in every cell in a special part called the mitochondia. Mitochondria are especially important because they are the part of the cell that helps it generate energy. DNA contains the programs that generate energy, but over time errors accumulate in the programs until eventually they don’t work very well any more. Errors in the programs that run our cells happen all the time — but when we’re younger the cells can fix themselves. As we get older, the cells don’t fix themselves as well. The result: our bodies don’t work as well as they used to. Over time, things start breaking and can’t be fixed. Eventually . . .
A recent study reported in the Proceedings of the National Academy of Science reports on a way to reduce the errors, at least in mice who are prone to an increased number of DNA errors. These mice have an increased number of errors in their DNA, and even early in life start to show signs of aging that are eerily similar to those seen in humans: hair loss, graying, low of body weight, and problems in mobility. Researchers at McMaster University in Ontario, Canada, compared mice with the increased number of errors to regular mice, and looked at what happened if some of the error-prone mice spent time exercising.
The group of the mice who had DNA errors exercised for 45 minutes on three days a week for 5 months. The researchers then compared the three groups: (1) DNA error-prone who didn’t exercise, (2) DNA error-prone who exercised, and (3) regualr mice who had normal DNA. Result: The error-prone mice who exercised looked the same as the regular mice. They weren’t just stronger, or in better shape, or able to run longer. They “lacked visible features of the accelerated aging phenotype (alopecia and graying hair) and were visually indistinguishable from age-matched … littermates” (page 4135).
Does this mean that if you start exercising regularly you can reverse aging? Probably not. But good research continues to accumulate that shows that exercise can improve cognition and keep the effects of aging to a minimum.
You can find an abstract for the article here. To read the full article, you will need a subscription to the journal.
