Below is an article I received in a health-related news letter: http://www.bottomlinepublications.com/content/article/diet-a-exercise/aerobi c-exercise-protects-eyes-from-macular-degeneration-and-other-retina-problems Aerobic Exercise Protects Eyes from Macular Degeneration and Other Retina Problems Even for people with healthy eyes, protecting eyesight should be a primary concern. That's because as we age, we are increasingly vulnerable to degenerative eye diseases such as age-related macular degeneration (AMD). These diseases can strike anyone...are very tough to treat...and can lead to severely impaired vision, or even blindness, sometimes with horrifying speed. Good news: A recent study suggests a simple (and even enjoyable) way to help protect against AMD and other retinal problems. It's something that your eye doctor probably won't think to mention...but it might do your eyes a world of good by directly benefiting your retinas. This new study used healthy mice. Some of the mice were given treadmills and trained to exercise for one hour, five days each week, at a moderate pace. For comparison's sake, other mice had identical living conditions-except that their treadmills did not move, so they were mostly inactive. After two weeks, the mice were intentionally exposed to a bright light for four hours. The light exposure was intended to damage the light-sensing photoreceptors of the retina in a way that's similar to the retinal neuron degeneration that occurs in humans who have AMD or a less common condition called retinitis pigmentosa. Next, the mice were put back on the same exercise program (or lack thereof) for two more weeks. Halfway through and at the end of that time period, the researchers did some tests. What they discovered... After being exposed to the damaging bright light, the mice that had exercised showed two times greater retinal function, based on measurements of electrical activity of the retina, compared with the inactive mice. Examination of the retinas showed that, even though numerous photoreceptors had indeed been damaged by the bright light exposure, the mice that exercised had more than twice as many healthy photoreceptors as the inactive mice. The fact that the test results remained consistent two weeks after the exposure to the damaging light suggests that exercise's beneficial effects have some power to persist...and may help slow the progression of vision-destroying degenerative retinal diseases. EXERCISE'S EYE BENEFITS EXPLAINED What could account for such dramatic vision benefits from exercise? Part of the answer may come from another portion of the experiment that involved measuring the levels of brain-derived neurotrophic factor (BDNF), a protein involved in nerve growth. In a different set of mice, some exercised for nine days and the others did not. Then researchers tested BDNF levels in the retinas, brains and blood of the mice-and found that, in all three areas, the active mice had significantly higher levels of BDNF than the inactive mice. There's no known cure for AMD...and the treatments that can help slow its progress are anxiety-provoking and uncomfortable, involving injections of drugs directly into the eyes. Compared to that, aerobic exercise seems like a pleasurable walk in the park-quite literally! Get motivated, get moving: This study makes a strong case that aerobic exercise directly benefits the retina and plays a significant role in protecting photoreceptors. Of course, an animal study can't prove that what's good for mouse eyes also is good for human eyes, particularly after just two weeks of regular aerobic exercise...but it certainly could be true. Besides, we do know beyond a shadow of a doubt that aerobic exercise is highly beneficial to people's bodies and brains. If you care about protecting your eyesight (and who doesn't?), let this study serve as yet one more excellent reason to add some aerobic exercise to your day-to-day routine (with your primary-care physician's OK)-whether or not your eye doctor thinks to recommend it. Sources: Machelle T. Pardue, PhD, associate professor, and Jeffrey H. Boatright, PhD, professor, department of ophthalmology, Emory University School of Medicine, and the Atlanta VA Center for Visual and Neurocognitive Rehabilitation, both in Atlanta. Their study was published in The Journal of Neuroscience.