According to research recently published in The Journal of Neuroscience, scientists at Emory University and the Atlanta Veterans Administration Medical Center tested mice by making a group of them run on little treadmills for about an hour a day and another group stay sedentary. After two weeks, they exposed half of the mice in each group to a searingly bright light for four hours, while the others stayed in dimly lit cages. The light exposure is a known way of inducing retinal degeneration in animals, comparable to what happens to humans as we age — though with us, it’s a much slower process.
The sedentary mice, by the end of the experiment, had failing vision: Almost 75 percent of the light-detecting neurons in their retinas had died. While obviously mice aren’t people, this does suggest that exercise could reduce the risk of macular degeneration, which is when neurons in the central part of the retina deteriorate. The researchers are currently trying to find ways to test this theory on humans, but it could take years. Still, the strong connection could add one more thing to the long list of reasons for why you should keep up your workout routine.