Exercise improves hearing

Even people who don’t exercise know that exercise is good for you. We know that exercise builds muscle, strengthens bones, enhances the function of the mind and is good for your heart. Even the most ardent exercise fan, though, is probably not doing it with the thought that they are improving their hearing — but according to a new study that is exactly what you are doing.

We live in an increasingly noisy world and we know that age-related hearing loss will affect many of us. In Australia, hearing loss is the third most prevalent age-related disability after arthritis and high blood pressure in adults over age 45. This age-related loss of hearing occurs when there is loss of hair cells, strial capillaries and spiral ganglion in the cochlea of the ear. Hair cells sense sound, strial capillaries feed the hearing apparatus with oxygen and the spiral ganglion are a group of nerve cells responsible for sending sound from the cochlea to the brain.

In the new study, a group of mice were divided into two groups. One group had access to a running wheel while the other did not. The researchers kept the mice housed individually so that they could measure exactly how far they ran on their running wheels.

The exercise regimen for the mice peaked at about 6 months old (equivalent to 25 in human years) and as they aged to 24 months (60 in human years) the exercise decreased. At their peak, the mice were running about 12km a day, and at their lowest the mice were still running 4km daily.

When comparing the two groups, the researchers found that the sedentary mice lost hair cells and strial capillaries in the cochlea at a much more rapid rate than their active counterparts. The result of this was a 20 per cent hearing loss as they aged for inactive mice compared to only a 5 per cent hearing loss for the active mice.

It would seem the health message about exercise really is worth hearing.

Source: Journal of Neuroscience