Deaf to the dangers of noise
From fitness classes to a night at the movies, the everyday sounds we take for granted are seriously damaging our ears

By Sean Davidson

The Toronto subway train makes a hard left turn on the way into Union Station, setting off a painfully loud metal-on-metal screech as it rounds the bend. Near College Street and Spadina Avenue, the tat-tat-tat of a jackhammer almost, but not quite, drowns out the traffic noise, an ambulance siren, two barking dogs and a car alarm, all of which are sounding off during the morning rush hour.

At a park in the city's west end, two city workers are shouting directly into each other's ears to be heard over the racket of their gas-powered lawn mowers. And at System Sound Bar, in Toronto's nightclub district, the techno pounding out of the speakers is so loud you can feel every bass beat deep down in your bones.

But Phil, a 24-year-old clubgoer, likes it loud. "What's the point of going if you can't really hear it? If the music isn't really loud?" he says, waiting in line. Yes, he has noticed a faint but permanent ringing in his ears. And yes, he says, sounds do seem muffled when he comes out of the club. But no, he isn't worried that it could hurt his hearing.

Maybe he should be. Evidence is piling up that all that banging, barking and bass is doing gradual, irreversible damage to our hearing.

"The world is getting noisier," says Arline Bronzaft, a retired professor and antinoise activist. "We've created a society that associates noise with glamour and excitement. There are so many noise sources, every time I think I've heard it all, I get another call asking for help."

Bronzaft has been researching and lecturing about noise, and its ill effects on health, for 25 years across the United States and Canada. And, like many in her field, she warns about the dangers of so-called "toxic noise."

"We need stronger data," she concedes, "but it's safe to assume that the increasingly noisy environment we're all subjected to is taking its toll."

Recent studies suggest that people — most notably baby boomers and Gen Xers — are losing their hearing sooner and in greater numbers than expected. A 1999 federal study in the United States found a 26-per-cent increase in hearing loss among people aged 46 to 64, and a 17-per-cent jump in 18 to 44 year olds.

That same year in Britain, researchers reported a hearing-loss increase among regular concert- and clubgoers of 72 and 62 per cent respectively, prompting one official to warn that the country's youth were "roller-coastering towards an epidemic."

Statistics for Canada are scarce, but Dr. Margaret Cheesman of the National Centre for Audiology at the University of Western Ontario, agrees that there's a lot of anecdotal evidence that hearing loss is on the rise. She warns that many everyday activities can be dangerously noisy.

"Have you been in a movie theatre lately?" she asks, lamenting the painfully loud sound systems at the big, flashy megaplexes. "Or fitness classes? The fitness craze is good for a lot of reasons but not necessarily for the ears. They're notorious for having their sound levels too high."

Dr. Cheesman says technological changes have made our lives, and our free time, a lot louder. "It could be a leaf blower, it could be a Walkman or jet skis, snowmobiles, dirt bikes, arcades," she says. "Thirty years ago you had to go out to a concert to really get blasted, now we do it to ourselves on a regular basis."

Doctors say hearing loss, once caused mainly by age or disease, is now increasingly self-inflicted. But because the damage is so gradual, and because most adults don't get tested until middle age, a problem can get quite bad before it's noticed.

Warning signs such as tinnitus, a sometimes permanent ringing or whooshing in the ears, often go unheeded, say doctors. As nerve cells in the ear die off, sufferers lose their hearing, starting with high-frequency sounds, such as voices.

Other problems can also develop. Sufferers can lose the ability to focus on particular sounds, such as a conversation in a noisy room or, in a condition known as hyperacusis, relatively mild sounds such as running water or a ringing phone can seem painfully loud.

"Hairs [on the nerve cells] swell, then they glue together and break off and then the cell dies," explains Dr. Cheesman. "If you're exposed for just a short time those hairs may recover a bit but they'll never be normal or perfect again."

Even moderate noise can continue to do damage. "Ears do not get tougher," says Tommy Choo, senior audiologist at the Canadian Hearing Society. "You don't get used to noise. Once you have hearing loss, it doesn't mean you won't get more."

What's doing all this damage? Audiologists stress that it can't be pinned down to a single source, but most agree that electrically amplified sound — introduced to the baby boomers with home stereos and loud concerts, and passed on to the Gen Xers with Walkmans, surround-sound theatres and really loud concerts — is a leading cause.

Early critics of rock music may have been wrong about a great many things, but it seems they were at least partly right about the long-term damage loud music can do to human ears. At concerts or inside nightclubs, the sound can climb as high as a punishing 120 decibels.

How loud is that? On the decibel scale, a whisper is 30, a normal speaking voice is 60, traffic noise is 80, most power tools clock in at 110 and a jackhammer is 120. At 130, noise causes physical pain in the ears. A jet airliner puts out 160.

In most of Canada and the world, 85 decibels is considered the safe limit for an eight-hour workday. Anything over that — more noise or longer exposure — can cause permanent damage. At 88 decibels, the safe limit is four hours. At 91, two hours. At more than 120 decibels, damage can set in after just a few minutes.

"A rule of thumb," says Dr. Cheesman, "is if you can't carry on a conversation — if you're a metre away from someone and you have to shout to be heard — that's more than 85 decibels."

Portable stereos such as Walkmans also pose a unique danger, says Marshall Chasin, co-founder of the Musicians Clinics of Canada, because users often crank up the volume to drown out loud background noise such as subways or construction.

"They're a major element," he says. "We routinely see children coming in who listen to portable stereos, and their hearing in the higher pitches is decreasing." His clinics in Hamilton and Toronto have treated more than 5,000 music-related hearing disorders since opening in 1986.

But household sounds pose a risk too, according to Hans Kunov, a professor at the University of Toronto and researcher at its Institute of Biomaterials and Biomedical Engineering. He says even a common hammer should not be used without hearing protection.

Sounds such as hammering are very hard on the ears, he explains. A single hammer strike puts out roughly 140 decibels. But because each sound is extremely brief, the brain doesn't realize that it's also perilously loud.

"In the old days, blacksmiths went deaf all the time," he says. "A 40-year-old blacksmith would be hard of hearing and a retired blacksmith was always deaf."

He adds that power tools, or even a hair dryer, pose risks. "My wife uses a hair dryer every morning for 20 minutes," he remarks. "It's really very loud. It's right next to her ears and it's really very . . ." He stops, frowns, and says, "I should test that thing and see how loud it is."

Doctors say the only recourse is to avoid excess noise or, failing that, to wear protection such as ear plugs, available for a few dollars at any drug store. Preventing hearing loss is simple, they say. The hard part is getting people to take it seriously and listen, while they still can, to the warning signs.

"People need to know what the consequences are," says Dr. Chessman, and to understand that seemingly harmless sounds can come back, years later, as premature hearing loss.

"It would be a lot easier if, when you got hearing loss, blood gushed out of your ears," says Mr. Chasin. "It certainly wouldn't be known as the 'invisible handicap.'"

Back outside System Sound Bar, Phil hustles down the steps and into the club. A young woman follows him. "My ears don't hurt or anything," she says, "so I figure they must be okay."

The Globe and Mail
October 16, 2001