Move More, Hear More?

No matter who you are, engaging in regular exercise clearly benefits your overall well-being in many ways.  A new study conducted by researchers at the University of Florida indicates that it may also help stave off hearing loss.  While past research has associated hearing loss with decreased physical function in older adults, this is believed to be the first to suggest that regular exercise can prevent age related hearing loss – in mice.

That’s right, as is often the case, the studie’s participants weren’t humans, but mice. Mice often play the role of, er, guinea pig, in scientific studies for a variety of reasons.  They’re relatively easy to care for, they adapt well to new surroundings, they reproduce quickly, and they have short lifespans of about two to three years, thus enabling several generations of mice to be studied over a relatively short period of time.  Another key reason is that their genetic and biological characteristics are very similar to those of humans. 

In this case, scientists separated the mice into two groups – one group had access to a running wheel, the other did not.  The researchers also kept track of how far the active mice ran on their running wheels.  Activity peaked at 7.6 miles a day when the animals were 6 months old, which correlates to 25 human years.  As the mice aged to 24 months (60 human years) their exercise levels decreased to about 2.5 miles per day.

At the study’s conclusion, researchers found that the sedentary mice experienced a roughly 20% reduction in hearing as compared to a 5% reduction in the mice that exercised.  I presume that the active mice also looked better in their skinny jeans.

So, what’s the deal?  Why did the active mice fare better than their sedentary counterparts in terms of hearing?  It turns out that the less active mice lost more hair cells and strial capillaries, two very important components of the auditory system, at a much higher rate than the active mice.  The researchers theorize that age-related inflammation damages hair cells and capillaries over time, and that exercise can provide some protection against this kind of inflammation.

References:

http://news.ufl.edu/articles/2016/11/whats-that-exercise-is-also-good-for-hearing.php

http://www.jneurosci.org/content/36/44/11308

http://www.livescience.com/32860-why-do-medical-researchers-use-mice.html