We know exercise is a good thing. It improves everything from cardiovascular disease to one’s cognitive health. Observational studies have also seen physical activity lessen age-related vision loss, but until now it hasn’t been clear how causal that relationship has been. New research from the University of Virginia (UVA) is offering the first experimental evidence to show how exercise can directly slow, or even prevent, macular degeneration.
“There has long been a question about whether maintaining a healthy lifestyle can delay or prevent the development of macular degeneration,” says Bradley Gelfand, a researcher working on the new study. “The way that question has historically been answered has been by taking surveys of people, asking them what they are eating and how much exercise they are performing.”
But those kinds of studies are prone to self-reporting errors. And as Gelfand notes, even if there is an observed association between increased physical activity and reduced vision loss, it doesn’t necessarily imply a causal link. After all, as people get older and their vision declines they naturally exercise and move about less.
So Gelfand and the UVA team set up a series of mouse experiments to investigate whether exercise directly affects macular degeneration. Two groups of mice were compared, one group with an exercise wheel in the cage, and another group sans the wheel. The voluntary nature of the exercise was important as forced exercise exerts a number of stress responses that could negatively influence the results.