GAINESVILLE, FLORIDA — Over the past few years untreated hearing loss in older adults has been linked to a growing list of conditions, including cognitive decline, depression and heart disease. Now research is beginning to surface that healthier lifestyle choices could stave off the effects of hearing loss. Although most of the research in this area has been confined to animal studies, those studies are encouraging.
In the November 2 issue of Journal of Neuroscience, University of Florida researchers found that sedentary mice lost hair cells and strial capillaries within the cochlea at a much higher rate than mice that exercised. This resulted in a roughly 20% reduction in hearing in sedentary mice compared with a 5% reduction in hearing in mice that exercised.
Tiny Earphones and Elliptical Machines Not Needed
To test how exercise affects the loss of strial capillaries and hair cells inside the cochlea, researchers separated mice into two groups: mice that had access to a running wheel and mice that did not have access to it. The mice were also housed individually so that the researchers could keep track of how far the mice ran on their running wheels. The exercise regimen for the mice peaked when the animals were six months old, which is the equivalent of 25 human years. As the mice aged—to 24 months, or 60 human years—their exercise levels decreased.
At their peak, the mice were running about 7.6 miles per day, but at the lowest, the mice were still running about 2.5 miles per day. At autopsy, the group of exercising mice was then compared with a control group of non-exercising mice. Their findings suggest that exercise may provide protection again stage-related inflammation damage to the capillaries and hair cells of the cochlea.
“Exercise likely releases some growth factors yet to be discovered that maintain capillary density as compared to the control animals who were not exercising. Also, exercise may release other beneficial factors, but can also attenuate and blunt negative factors, such as inflammation,” —Christiaan Leeuwenburgh, Professor and Vice Chair of Research for the Institute on Aging
While past epidemiological studies have shown a link between hearing sensitivity and exercise, this is thought to be the first research suggesting regular exercise can prevent age related hearing loss in mice. According to the researchers, their findings translate well to humans.
Images courtesy: Odyssey, medassoc
