DID YOU KNOW that one-third of hearing loss cases are completely preventable? The most common cause of permanent hearing loss in the world is exposure to loud noise1. Once the damage has been done, there is no going back. Loud noise permanently damages the structures of the inner ear.
The human ear has 3 main components: the outer, middle, and inner ear. Each play a unique role in transmitting sound to the brain so we can hear. When sound hits the ear, it travels through the outer ear, causing the eardrum to vibrate. This sets the tiny bones in the middle ear into motion. Their purpose is to amplify the sound enough so that it can reach the inner ear. In the inner ear is a structure called the cochlea. The cochlea is a bony structure shaped like a snail that is responsible for converting sound into electrical energy so it can be sent to the brain.
In the cochlea is a layer called the basilar membrane that is covered in tiny hair cells. As sound passes through the inner ear, these hair cells cause the basilar membrane to move up and down, which allows the auditory nerve fibers attached to the hair cells to send the signal to the brain. The cochlea is arranged a bit like a piano, with high pitched sounds at the entrance and low pitched sounds at the apex.
As sound travels through the cochlea over time, the hair cells begin to wear down, which eventually leads to hearing loss. The louder the sound and the longer you are exposed to it, the more damage is caused to the hair cells in your ear and the higher the likelihood that you will experience hearing loss. Once these cells are gone, they do not regenerate, and once hearing has been lost it can only get worse.1
The likelihood of hearing loss increases with the length of the noise exposure and the intensity of the noise. In general, the louder the noise, the less time it takes to damage your hearing. The World Health Organization and the US Environmental Protection Agency both recommend maintaining sound levels below 70 dB over a 24-hour period to prevent hearing loss from noise exposure. This is about the level of a dishwasher or a washing machine. Anything over 85 dB (about the same volume as a leaf blower or a noisy restaurant) will damage your hearing over time.2
Just because a noise doesn’t sound unbearably loud does not mean it will not cause damage to your hearing. Sound intensity is measured in decibels (dB), which does not directly correspond to loudness. Two sounds that have the same loudness may not necessarily have the same intensity. In general, for every 10 dB increase in intensity the perceived volume doubles2! In general, the best way to make sure the noise in your environment is at a safe level is to use a sound level meter to determine the dB level of your environment. You can purchase one from Amazon for only $20-30, or download a free smartphone app such as the NIOSH Sound Level Meter app.
The amount of time you spend in noisy environments also affects the likelihood of damage to your hearing. At 85 dB, it will take about 2 hours of exposure to damage your hearing, but once the sound reaches 100 dB the damage is possible after only 15 minutes. If you like to listen to loud music, you may want to take steps to protect your hearing, because headphones at maximum volume and concert venues can damage your hearing in only 5 minutes! Sounds at levels of 120 dB and higher, such as a jet engine or gunshot, can cause immediate damage.
The good news is that noise-induced hearing loss is 100% preventable. If you know that you will be in a noisy environment for any period of time, you should plan to wear appropriate hearing protection so your hearing will not be damaged. The best time to stop hearing loss is before it happens in the first place. Damage from noise exposure is cumulative, so even if you don’t feel like your hearing is being impacted now, you will have more and more issues as time goes on. By reducing your exposure to loud noise as well as wearing appropriate hearing protection during noise exposure, you can ensure you will be hearing clearly for years to come.
Some strategies you can use to reduce your exposure to harmful noise levels include:
For more information about hearing protection, stay tuned for next week’s blog where we will talk about the different types of hearing protection that are available and how to use them effectively.
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