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Why Exercise Protects Against Hearing Loss

Peter Lucier, HIS

With the new year upon us and resolutions abounding, you may find yourself inclined to spend more time exercising this season. And if you happen to be on the fence about it, or are encountering that familiar sense of resistance towards heading to the gym, you might be happy to know that exercise continues to reveal its benefits for hearing health. Just in case you need another reason to get going…

In case you’re wondering just how exercise affects your hearing at all, the answer is actually quite interesting. In one study, researchers noted that mice who were trained to exercise regularly showed significantly less degradation of hearing structures over time compared to a group of mice that lived sedentary lives. The structures that were evaluated were analogous to our own human hearing structures: hair cells and strial capillaries, which are known to be damaged over time due to noise and age-related reasons in both mice and humans. This study showed that the mice who didn’t exercise lost twenty percent of their hearing ability over time, as opposed to the mere five percent of hearing lost by the active mice.

These results revealed more protection from exercise than the researchers expected, but upon analysis, they concluded that it’s likely due to the improved circulation that exercise provides. The cochlea organ that is situated inside our inner ears, and houses those aforementioned hair cells and strial capillaries, is processing an enormous amount of data and is consequently a high-energy demanding organ. In order for the hair cells to do their job, and convert the movement they sense from sound waves into electrical signals to the auditory nerve, they need oxygen. A lot of oxygen.

Luckily, those strial capillaries deliver oxygen via the oxygen-rich blood pumping through them. Since our hearing is always “on,” it means the cochlea is always hungry for oxygen in order to perform well and maintain its hearing capacity.

Interestingly, not only did the mice that were trained to exercise show improved circulation throughout their bodies (including those critical-for-hearing strial capillaries), but the exercise also proved to protect those delicate hair cells and strial capillaries from systemic inflammation. In the control group of sedentary mice, inflammation throughout their bodies was determined to be a major source of damage to their inner ears. In comparison, the markers for inflammation in the exercising group of mice were half of what was measured in the control group.

Considering that age-related hearing loss affects about seventy percent of adults over the age of seventy, gaining a better understanding of protective measures before and even after that hearing loss begins is crucial for improvement in preventative and treatment measures. Researchers from this study are looking further into how growth factors released during exercise affect capillary density and health, while simultaneously keeping inflammation at bay.

While this study may have clarified more detail about the mechanism behind exercise and hearing health, the link between them is not as new. In fact, you may have even been encouraged by your own hearing professional or doctor to keep an exercise routine for this very reason. And the many studies out there that support this logic are based in our understanding of how the health of our heart is related to the health of our hearing.

Our understanding of this relationship has evolved enough that doctors can now even evaluate your hearing to measure your heart’s health- and vice versa. Again, this comes back to the high oxygen needs of those delicate and hard-working hair cells within the cochlea. Better cardiovascular health results in better circulation of oxygen-rich blood and thus keeps those hair cells fed and happy. In fact, it’s not uncommon to find very fit fifty year-olds with the hearing capacity of a thirty year-old, according to researchers who study the link between the heart and hearing. The best part is that based on the research thus far, it seems that those who do not partake in much exercise currently need only to increase their activity level to a moderate degree (such as a 30 minute walk) in order to create the heart rate and level of circulation that is considered protective for hearing.

So hopefully, with these additional details about the benefits of exercise, you’ll find yourself more eager to hit the treadmill and get that heart pumping. If our tiny little hair cells can work overtime for us, surely we can set aside 30 minutes for them!