Exposure to loud noise is an ear buster. Scientists and researchers have long known that exposure to loud noise, especially over an extended period, will cause hearing loss. We even know the many causes of hearing loss.
One known cause of hearing loss is exposure to loud noise, which causes the hearing mechanism’s bits and pieces to generate free radicals. Now, free radicals are naturally produced by the body and are, in fact, associated with the aging process. These acidic molecules corrode the body at the cellular level.
To combat the negative effects of free radicals on hearing and the rest of the body, nutritionists recommend that we consume anti-oxidants, which combat free radicals and lessen their negative impact on hearing loss and even the overall aging process itself. While the jury is still out on the extent to which anti-oxidants combat the negative effects of free radicals, lab science indicates that there is a relationship – one you can take advantage of by eating foods high in anti-oxidants.
Noise-induced hearing loss
When you’re exposed to loud noise over a long time – say in your work environment – damage to hearing can be measured at specific frequencies within the hearing spectrum.
Most persons exposed to long term noise, will develop hearing loss in the high frequencies. Research has shown the hearing mechanism is most sensitive to damage in this frequency range due to the structure of the cochlea and hair cells – the tiny hair-like nerve receptors responsible for converting sound into electrical signals to the brain. Most persons think noise-induced hearing loss is solely influenced by how loud a sound is that one is exposed to; however, it is also dependent upon the length of time the ears are exposed to the loud noise. The combined effect of loudness and length of exposure time is what influences the likelihood of damage occurring.
So, how much noise is too much noise?
|It's a noisy world we live in|
According to Dr. Brain Fligor, Sc.D., CCC-A, Director of Diagnostic Audiology at Children's Hospital in Boston and leading research on noise-induced hearing loss, explained in a previous article on MP3 players and hearing loss on Healthy Hearing “…anything up to 75 dB is safe. That is the maximum for safe listening no matter how long you listen". Once you exceed 75 dB, the amount of time one is listening to the noise becomes part of the ballgame.
How loud is 75 dB? Common sounds that are around 75 dB include garbage disposals and city traffic noise - something we all live with each day.
According to Fligor, any noise above 75 dB is potentially dangerous. Worth noting, especially if your work or lifestyle exposes you to loud noise over time. Hearing experts recommend if you are exposed to sounds above 75 dB for long periods of time to wear ear protection and give your ears a break from time to time. For example, you might consider unplugging your MP3 player for a while to give your ears a break if you have been jamming at high levels.
But there’s more to hearing damage than MP3s. You live in a noisy world, no matter where you live. If you live in the city, there’s ambient noise around you every time you take to the sidewalk. Live out on the farm? Well, that tractor produces a lot of noise that can easily damage the hearing apparatus that nature provided. Live in the suburbs? The lawn mower exposes you to +90 dB sound and depending upon how large your yard is – you could be exposed for multiple hours each week.
So, with all of these opportunities to damage our hearing, how come we aren’t all deaf? Well one reason is hearing damage from excessive noise often does not show up until later in life when the aging effects also kick in. However recent lab research has also shown that the ear has its own natural mechanism to protect hearing – even after exposure to loud noise over a long time.
Research, conducted at the Center for Sensory Biology at the Institute for Basic Biomedical Sciences at the Johns Hopkins School of Medicine, has revealed that lab rats can be genetically altered to withstand higher levels of sound for longer periods. Dr. Paul Fuchs, who wrote up the study, stated "We don't really know how things work in the ear at a cellular and molecular level. We're just starting to make those discoveries."
The research indicates that the ear has the ability to block certain frequencies when potential damage might be done to the individual’s ability to hear. As Dr. Fuchs stated in U.S. News and World Report, "Say you're in a factory where there's lots of loud, low-frequency noise from the machinery. It's conceivable that this [natural protection] could turn down the part of the cochlea hit by low frequencies."
The cochlea is a snail-shaped organ deep within the ear. It’s filled with fluid and lined with millions of tiny, hair-like projections that transmit sound signals to the brain for interpretation. It’s the interaction between brain and ear that may be at the center of this natural protection. The findings of the Fuchs study are resonating throughout the hearing health community. The U.S. News report quotes Robert D. Frisina, who’s the associate director of the University of Rochester’s (NY) International Center for Hearing and Speech Research:
“The findings might also lead to drugs that could prevent noise-induced hearing loss, one of the most common forms of acquired, permanent hearing loss, as can occur in recreational activities, such as hunting or shooting, and from occupational settings, including factory or military work.”
So No More Worries?
|Earplugs - still our best defense|
Ummm, no, there are still worries about hearing loss and exposure to noise. In fact, you’d be well advised to take precautions to protect your hearing from exposure to any loud noise. Nature’s ear plugs can only do so much in the way of protecting your hearing from sounds within a specific frequency range.
The interaction between the cochlea and the brain can modify and protect hearing to a degree but it’s foolish to misinterpret these test results. The fact is that exposure to loud noise does cause damage – permanent, irreversible damage – to human hearing in many millions of cases.
However, the results do hold out the promise of drugs in the future that can protect hearing when other means aren’t appropriate or desirable. Indeed, the best protection is some kind of ear protection (ear plugs or ears muffs) that actually prevents damaging noise from entering the ear.
This research does show that, through genetic manipulation, laboratory rats are better able to withstand loud noise without permanent damage. A “stronger” hearing system, in other words. However, none of the experts who reported on Dr. Fuchs’ study suggested that a cure for hearing loss was at hand. Hardly.
But, there is hope that, someday, researchers will have pharmaceutical weapons designed specifically to address hearing loss in patients with damaged hearing mechanisms within certain frequency ranges. But that day is still a long way off.
The best advice, regardless of the promising results of Dr. Fuchs’ study, is to protect what you’ve got and hope that further research leads to improved medications to address existing hearing loss.
So, unplug yourself from that MP3 player and wear ear protection whenever you’re exposed to noises as the lawn mower. That is the best way to protect your ability to hear today and in to the future.
While the Johns Hopkins study should be seen as a hopeful message to those with hearing loss, the study does NOT suggest that hearing loss is a thing of the past. Far from it. Chances are, you’ll do some damage to your hearing sometime today.
Turn it down. And hope that science can develop preventative solutions to existing hearing loss.