There was recently an excellent article by the BBC about the results of a survey put out by the non-profit organization Action on Hearing Loss. The survey showed that most British adults are taking dangerous risks with their hearing: almost a third played music above the recommended volume and a full two-thirds left noisy venues with ringing in their ears. It may seem harmless to enjoy noisy concerts, but it can and does irrecoverably damage your hearing. But how, exactly, does it do that? And how loud can you listen to music without being at risk?
Let’s start with the second question. You’re at risk of hearing loss if you subject yourself to sounds above 85 decibels. For reference, that’s about as loud as a food processor or blender, and most music players will warn if you try to play music much louder than that. They will, however, sometimes play music up to 110 dB, which is roughly the equivalent of someone starting a chainsaw in your ear and verges on painful. And that is absolutely loud enough to damage your hearing.
Hearing damage is permanent and progressive. Inside your inner ear are tiny, hair-shaped cells. These sway back and forth as the fluid of your inner ear is compressed by sound-waves. It’s a bit like seaweed being pulled back and forth by waves, but on a smaller scale and much, much faster. As these hair cells brush back and forth they create and transmit electrical impulses that are sent to the brain and interpreted as sound. The most delicate part of this process is those tiny hair cells. They’re very sensitive. Which is good, because it means that we’re able to detect noise well, but also bad, because they’re very easy to damage. In fish and birds, that damage can heal over time. In mammals, it can not. Once your hair cells are damaged, they can no longer transmit sound and you lose that part of the signal permanently. There’s a certain amount of unavoidable wear and tear on the system. Even if you do avoid loud noises, you’re still slowly losing parts of your hearing as you and your hair cells age, especially in the upper frequencies. But loud music will accelerate that process drastically. Listen to loud enough music long enough and it will slowly take away at your ability to hear it.
But that doesn’t necessarily mean you should avoid loud environments altogether. As with all things, moderation is key. One noisy concert won’t leave you hard of hearing. (In fact, your body has limited defence mechanisms for sustained loud noises, including temporarily shifting the bones of your inner ear so that less acoustic energy is transmitted.) The best things you can do for your ears are to avoid exposure to very loud sounds and, if you have to be in a noisy environment, wear protection. It’s also possible that magnesium supplements might help to reduce the damage to the auditory system, but when it comes to protecting your hearing, the best treatment is prevention.