In an era when some people think nothing of spending hours on end listening to their MP3 players at high volume, the risk to your hearing from everyday activities might be greater than you think. Someone whose day includes a workout at a noisy gym while listening to music on an MP3 player, lunch at a clamorous restaurant, a subway ride, a few hours of mechanized yard work, and a night out with friends at a dance club can easily end up with a dose of noise exposure that over time can be damaging.
That is more than just a theoretical concern. About 30 million Americans have hearing loss. Studies show that roughly 15 percent of American teenagers are showing early signs of that condition, at an age when their hearing should be almost perfect.
"We are prematurely aging our ears," says Brian Fligor, Sc.D., director of diagnostic audiology at Children's Hospital in Boston.
Here's how to tell whether your lifestyle is putting your own hearing at risk and what you can do about it if it is:
How hearing loss happens
Loud noises can temporarily or permanently damage the microscopic hair cells in the inner ear that convey sound to the brain. Those cells can bounce back from an occasional assault, such as that Metallica concert you went to last year. But if you live a habitually loud life, some of those cells might eventually stop working for good.
Hearing loss might progress for many years before you become aware of the problem. It usually starts with a loss of soft consonant sounds such as "f" and "sh," making speech more difficult to understand. But it can grow into a very serious condition that can isolate people from family and friends, leading to depression and other psychosocial problems.
How much noise is too much?
That's more difficult to answer than you might imagine because some ears can withstand loud noises better than others, and individuals' exposures are so variable and difficult to track.
Noise is measured in decibels, with 0 being the quietest sound a person can hear, 60 a normal conversation, and 140 (a gunshot at close range) a level that can cause immediate, permanent damage. Every additional 10 points on the scale represents a doubling of perceived loudness. At loud volumes over long periods, an increase of even a few decibels adds to your risk of hearing loss.
Our health and safety experts, after studying existing guidelines and scientific research on hearing loss, have concluded that almost everyone can safely be exposed to 70 decibels, about as loud as your morning shower, indefinitely without harm. But you should do everything you can to avoid or minimize exposure to noise above 100 decibels. That's a sound level that can be exceeded by rock concerts, sporting events, movie theaters, and some MP3 players when played at maximum volume.
As for the decibels in between, it all depends. Particularly if your hearing is already deteriorating or you are exposed to significant noise on the job or recreationally, try to avoid other prolonged exposure to noise between 75 and 85 decibels. Above that, everyone should limit prolonged exposure or use hearing protection. For instance, if you're going to spend time operating a 90-decibel lawn mower, wear earplugs or earmuffs.
As for MP3 players, Fligor's research shows that most people listen at safe volumes in quiet settings. But in a louder place, such as an airplane cabin, a gym, or a city street, a large majority of listeners dial the volume up to risky levels to drown out ambient noise.
