MedNews #04-39
October 8, 2004
Article MN043908

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HEALTHWATCH: Take Care of Your Hearing Health

By: Lt. Cmdr. P. L. Pentin, Naval Hospital Bremerton

BREMERTON, Calif. - Long exposure to excessive noise can damage hearing.

Cells and nerves in the inner ear are destroyed by continuous or repeated exposure to loud sounds. If enough cells and nerves are destroyed, hearing is permanently lost.

Whether noise harms your hearing depends on the loudness, the pitch and the length of time you are exposed to the noise. The loudness of a sound is measured in decibels (dB). The loudness and the length of exposure are related – the louder the sound, the shorter the exposure can be before damage occurs. For example, 8 hours of exposure to 85 dB noise on a daily basis can begin to damage a person’s ears over time. Using power tools (at about 100 dB), listening to a stereo headset (at about 110 dB), attending a rock concert (at about 120 dB) or hearing a gunshot (at 140-170 dB) may damage the hearing of some people after only a few times.

People often fail to notice the danger of noise because it doesn’t produce many symptoms. Hearing loss is rarely painful. The symptoms are usually vague feelings of pressure or fullness in the ears, speech that seems to be muffled or far away, or a ringing sound in the ears that you notice when you are in quiet places. These symptoms may go away minutes, hours or days after the exposure to noise ends.

People assume that if their symptoms go away, their ears have bounced back to normal, but this isn’t really true. Even without symptoms some of the cells of the inner ear may have been destroyed by the noise. Your hearing will return to normal if enough healthy cells are left, but you can develop lasting hearing loss if the noise exposure is repeated and more cells are destroyed.

The first sign of noise-induced hearing loss is not being able to hear high-pitched sounds, like the singing of birds or the voices of women and small children. If the damage goes on, hearing declines further, and lower-pitched sounds like men’s voices become hard to understand.

You can help to prevent hearing loss by reducing your exposure to noise. This step is especially important for people who work in noisy places or who commute to work in noisy traffic or construction. If you can’t help where you work, choose quiet leisure activities instead of noisy ones.

Develop the habit of wearing earplugs when you know you will be exposed to noise for a long time. Disposable foam earplugs cost about $2 a pair and are available in commercial drugstores. These earplugs quiet about 25 dB of sound and can mean the difference between a dangerous and a safe level of noise. Consider wearing earplugs when using power tools, lawn mowers, when riding a motorcycle, or when attending a rock concert.

Try not to use several noisy machines at the same time. Try to keep television sets, stereos and headsets low in volume. Loudness is a habit that can be broken.