While conversations about earbud-induced hearing loss have mostly faded away, people are becoming seriously concerned that volume levels at work, in restaurants, and on the street can cause permanent hearing loss. So, how loud is too loud?
Long Story Short, You Should Avoid 85+ dB
With extended and repeated exposure, sounds that exceed 85 decibels can cause permanent hearing loss. And while 85 dB may sound like a lot, there’s a good chance that you’re exposed to 85 dB of sound every day. As an example, every time you open your car window while driving at 50 mph, you’re being exposed to about 89 dB of sound.
Now, before you get too nervous, consider how long and how often you’re being exposed. Most doctors agree that you can get away with about eight hours of exposure to 85 dB of sound. But even after those hellish eight hours of mowing a lawn or driving with the windows down, there’s a decent chance that you won’t sustain permanent hearing loss.
See, there are little hairs inside of your ear called sterocilia. These hairs vibrate when sound waves enter your ear, and those vibrations are turned into neural information that your brain can understand. With extended exposure to loud sounds (say, an eight-hour lawn mowing session), your little ear hairs get depressed, like blades of grass that have been stepped on. When depressed, these hairs stop vibrating, which means that your brain doesn’t receive any sound signals.
But, like blades of grass, your little ear hairs can spring back up overnight. Occasional long term exposure isn’t a big deal—it’s repeated long term exposure that will ruin your ears. Every time those ear hairs get depressed, they also get a little less spry. Eventually, they stop bouncing back at all, and you’re left with permanent hearing loss.
It’s also important to note that, just because you’ve sustained hearing loss, doesn’t mean that you have a higher volume tolerance. 85 dB is the universal threshold for hearing loss, even if your ears are already blown out.
At the 85 dB range, open-window drivers and lawncare amateurs don’t have much to worry about. Most people that endure repeated eight-hour exposures to 85 dB are construction workers, employees at bars, and sound engineers. That’s not to say that you’re safe from noise-induced hearing loss—you just don’t have to worry about the 85 dB threshold as much as someone who works in a loud environment.
What Happens After 85 dB?
The way that we measure sound can be a little misleading. You’d assume that 80 dB would be twice as loud as 40 dB, but that’s not the case. Volume level doubles with every 10 dB gain, so 80 dB is eight times as loud as 40 dB. In that way, it’s similar to earthquake measurements on the Richter scale.
As volume level increases, your noise tolerance decreases at a similar rate. At 90 dB, four hours of exposure time will cause permanent hearing loss. Go up to 95 dB, and your ears can only handle two hours of exposure. Push it up to 110 dB, and your ears can only take 1 minute and 29 seconds.