What is noise-induced hearing loss?
Every day, we experience sound in our environment, such as the sounds from television and radio, household appliances, and traffic. Normally, these sounds are at safe levels that don’t damage our hearing. But sounds can be harmful when they are too loud, even for a brief time, or when they are both loud and long-lasting. These sounds can damage sensitive structures in the inner ear and cause noise-induced hearing loss (NIHL).
NIHL can be immediate or it can take a long time to be noticeable. It can be temporary or permanent, and it can affect one ear or both ears. Even if you can’t tell that you are damaging your hearing, you could have trouble hearing in the future, such as not being able to understand other people when they talk, especially on the phone or in a noisy room. Regardless of how it might affect you, one thing is certain: noise-induced hearing loss is something you can prevent.
Who is affected by NIHL?
Exposure to harmful noise can happen at any age. People of all ages, including children, teens, young adults, and older people, can develop NIHL. Based on a 2011-2012 CDC study involving hearing tests and interviews with participants, at least 10 million adults (6 percent) in the U.S. under age 70—and perhaps as many as 40 million adults (24 percent)—have features of their hearing test that suggest hearing loss in one or both ears from exposure to loud noise. Researchers have also estimated that as many as 17 percent of teens (ages 12 to 19) have features of their hearing test suggestive of NIHL in one or both ears (Pediatrics 2011(link is external)), based on data from 2005-2006.
What causes NIHL?
NIHL can be caused by a one-time exposure to an intense “impulse” sound, such as an explosion, or by continuous exposure to loud sounds over an extended period of time, such as noise generated in a woodworking shop.
Recreational activities that can put you at risk for NIHL include target shooting and hunting, snowmobile riding, listening to MP3 players at high volume through earbuds or headphones, playing in a band, and attending loud concerts. Harmful noises at home may come from sources including lawnmowers, leaf blowers, and woodworking tools.
Sound is measured in units called decibels. Sounds of less than 75 decibels, even after long exposure, are unlikely to cause hearing loss. However, long or repeated exposure to sounds at or above 85 decibels can cause hearing loss. The louder the sound, the shorter the amount of time it takes for NIHL to happen.
Here are the average decibel ratings of some familiar sounds:
- The humming of a refrigerator
- Normal conversation
- Noise from heavy city traffic
- An MP3 player at maximum volume
- Firecrackers and firearms
Your distance from the source of the sound and the length of time you are exposed to the sound are also important factors in protecting your hearing. A good rule of thumb is to avoid noises that are too loud, too close, or last too long.