Noise is everywhere and you're exposed to it during work and leisure activities. You may suffer noise-exposure hearing loss while commuting in traffic or working at your job. The symptoms of noise-exposure hearing loss are mild and slow, and you may not realize the problem. Noise-induced hearing loss makes it hard to follow conversations, impacting your job and social interactions. Avoiding the causes of noise-induced hearing loss can protect you from deafness.
What Is Noise-Exposure Hearing Loss?
Noise-exposure hearing loss is permanent hearing loss caused by loud sounds. It can occur after brief loud noises like explosions and gunshots. More commonly, it is caused by exposure to loud noises over a long period of time.
Noise-exposure hearing loss (also known as noise-induced hearing loss) is unfortunately common. Both recreational and work-related noise exposure causes it. About 6% of adults have poor hearing due to exposure to loud noises.
How Does Noise Damage Hearing?
Your ears funnel sound waves into the ear canal to the eardrum. The eardrum vibrates, and sends the vibrations to the middle ear. The middle ear amplifies the sound vibrations and passes them along to the inner ear. Within the inner ear is the cochlea, a delicate structure with hair cells inside. Hair cells convert the vibrations into electrical impulses that the auditory nerve sends to your brain, and your brain interprets as sound.
Loud noise damages the hair cells in the cochlea. Prolonged exposure to loud noise causes the death of some of these cells. As more and more hair cells die, your hearing gets worse. Loud noise can also damage the auditory nerve.
Hearing loss depends on the intensity of the sound exposure, how long the exposure lasts, and whether your ears get time to recover between successive exposures. If the exposure is not too intense or prolonged, your hearing can return to normal. But loud, intense sound exposure can destroy some hair cells in your ear, causing permanent damage even if some healthy hair cells remain and you can hear well enough. With more of such exposure, you will lose more hair cells until permanent hearing loss happens.
Symptoms of Noise-Induced Hearing Loss
Noise-induced hearing loss is a quiet condition with no pain or other obvious warning signs.
Symptoms of noise-exposure hearing loss include feeling pressure in the ears or hearing a ringing sound in otherwise quiet environments. In early hearing loss, you'll find you can't hear high-pitched sounds like birds chirping. If your exposure to noise has been brief, these symptoms last only a short while.
As your hearing loss worsens, you will have difficulty hearing lower pitched sounds like human voices. Other peoples' voices may sound muffled or like they are mumbling, especially on the telephone or in a loud environment like a crowd. When you notice any of these symptoms, you should talk to your doctor about a hearing test.
Causes of Noise-Induced Hearing Loss
Many kinds of sounds can cause noise-induced hearing loss. The louder the sounds, the sooner hearing loss will happen.
Here are some common sources of loud noise that may cause hearing loss over time:
Recreational-activity noises. Concerts, nightclubs, truck shows and car races, target shooting, hunting, sporting events, motorcycles, and listening to loud music through earbuds or headphones.
At-home noises. Children's toys, lawnmowers, leaf blowers, woodworking tools, and stereo systems or televisions at high volume.
Work-related noises. Power tools, sirens, firearms and firecrackers, and gas-powered lawnmowers.
Sound is expressed in decibels, which measure the sound energy in a closed space. A whisper is about 30 decibels, a washing machine or dishwasher generates about 70 decibels, and gas-powered lawnmowers or leaf blowers produce 80 to 90 decibels. Exposure to 80 to 90 decibels continuously for two hours may damage your hearing.
Louder sounds can damage your hearing quickly. Approaching subway trains, car horns, sporting events, and even some power tools reach 100 decibels, and just 15 minutes of exposure can damage your hearing. Stereo headsets at full volume (110 decibels) and rock music concerts (120 decibels) also harm your ears in just a few minutes.
Precautions Against Noise-Induced Hearing Loss
You should be aware of the noise levels at places you visit regularly. Your workplace is the most important since you spend several hours at a stretch there.
Workplaces using machine tools should measure their decibel levels. Remember that the decibel scale is not linear, but logarithmic. A 20 decibel sound is not twice as loud as 10 decibels. It's 10 times louder.
You can measure the noise level in your surroundings with a sound level meter. Sound level meters are also available as smartphone apps. As a rough guide, if you can't talk normally to someone at arm's length and need to raise your voice, the noise intensity is probably over 85 decibels. This level of noise will harm your hearing after prolonged exposure.
The National Institute for Occupational Safety and Health recommends 85 decibels as the upper level of noise exposure for workers. It's assumed that exposure will be for eight hours a day, five days a week, and that workers will spend their other time in quieter places.
Here are some precautions to take to prevent noise-induced hearing loss:
- Wear earmuffs in your noisy work environment.
- Choose quieter leisure activities to give your ears time to recover.
- Wear foam earplugs when expecting loud exposure. They can reduce noise exposure by up to 25 decibels.
- Quieten your home. Drapes, curtains, and double-pane windows can reduce outside noise, while carpets and mats under loud appliances reduce inside noise.
- Get used to playing stereo systems, televisions, and personal music systems at a low volume.
- If you can't protect yourself from noise, move away from it.
- Protect the ears of children too young to do it themselves.
Noise-Induced Hearing Loss Treatment
Permanent hearing loss can't be reversed. When you notice difficulty hearing everyday sounds, you should report it to your doctor. They will arrange a hearing test (audiometry) for you. Such tests can show the degree of your hearing loss (mild, moderate, or profound). They also show whether you have lost hearing in high frequencies, low frequencies, or all frequencies.
Detecting hearing loss early is essential for treatment. If loud noise exposure is a part of your day, have your hearing checked at regular intervals. If you find you do have hearing loss, take steps to avoid more noise exposure so the hearing loss doesn't worsen.
Your physician may advise a hearing aid. This device, worn in your ear, helps you hear better by magnifying sound. For more severe hearing loss, your doctor might recommend cochlear implants. Cochlear implants are electronic devices that require surgery to implant and send signals to your brain.