Life, Running, & Medicine.
Notes on life as I see it.

Sunday, June 15, 2008

Running, the iPod, and Hearing Loss

Since my wife got me an iPod Nano some 2 1/2 years ago I have been hooked.  Only recently did I fill up the 2 GB memory and have begun picking "favorites" with my music and leaving some music on the PC out of necessity.  The iPod has been there for most all of my running, in fact until only recently I found it difficult to run any distance without it.  I feel like the iPod definitely keeps my spirits up and helps to pass the time when things get tough on the road.
 
So when my ear buds went dead (from sweat I think) I felt it was the perfect time to replace them with an upgrade.  Of course in my professional life I am constantly dealing with the effects of my patients' hearing loss, and know about the warnings associated with headphones and loud "leisure noise".  Non-professionally I like the earbuds but wish they fit a little more snug.
 
Noise and Hearing Loss:
It is well known that loud noise causes hearing loss.  Generally this is loud noise over a sustained period of time, but sometimes a single close "gunshot" can cause permanent damage.  OSHA has set some safety guidelines for workplace noise exposure that is a decent guide but unfortunately a little arbitrary and non-scientific.  OSHA limits are 8 hours @ 90dB OR 4 hours @ 95dB OR 2 hours @ 100dB OR 1 hour @ 105dB.  Some estimate that hearing loss can happen with sustained volumes of only 85dB.
 
For example, a quiet room is about 30dB, normal talking about 60dB, major highway 90dB, jackhammer 100dB, jet engine 50m away 150dB.
 
The iPod's earbuds get up to a volume of about 115dB at maximum volume.  As you can see, at this volume this is way too loud for safe sustained listening.  There are no well studied recommendations for "maximum personal listening device volume".  However, the best rule of thumb is to never listen so loud that you can't hear people talking around you.  In other words, if you can't carry on a normal conversation while listening, then you are probably turned up too loud.
 
There are a few good studies out there that seem to indict "personal listening devices" as culprits in early hearing loss (here and here).  In science it is extremely difficult to prove a causal relationship - for example we still can't prove that tobacco causes cancer.  Most of the studies look at hearing tests of young adults that are frequent listeners compared to those that are not.  They find that frequent listeners have some decline in their very high frequency hearing (4KHz and above).  There is not much that we listen to in these very high frequencies but it has been established that most sensorineural hearing loss starts very high and then works its way down into the more moderate frequencies as it progresses.  So this very high frequency loss is the first sign of damage.
 
Choosing Earbuds:
I swapped out my older iPod plastic molded buds for Skullcandy-brand.  The Skullcandy's come with three sets of silicone molds that can be exchanged to get a secure fit in the ear canal.  I thought this would be great for running and exercising because it provides a "tight fit".  But ahhh I forget so quickly about the occlusion effect - when you plug your ears (say with your fingers) every noise from your body gets LOUDER, and of course the outside world is silenced.  While the medium earbuds fit the most snug and comfortable, the noises of my breathing, chewing, talking, the earbud wire rubbing on my neck were overwhelming.  Wearing this while running sounds like a freight train.
 
The occlusion effect also amplifies the music by up to 20dB (which is 100-fold, as the spl scale is logarithmic).  The net effect is that if you use these while running you are probably listening at around 100dB or greater to overcome the "personal noise" and forget about hearing the outside world.  They do a good job of "noise reducing" but while road running not hearing your surroundings is unsafe.
 
I wound up switching our the silicone mold to the smallest ones which do a good job of holding the bud secure but does not cause too much occlusion effect.
 
Honestly the classic iPod buds may be the best for running if they fit your ears.  Nike also has the Vapor and Flow headphones which utilize a behind-the-ear anchor like a Blutooth cell phone headset.  If these stay on while running they may do the best at protecting your ears as the mechanics are not forcing the bud into the ear canal and it allows you to hear plenty of background sounds.
 
Safety of iPods on the Road:
The USATF has recently taken the position to ban personal listening devices during their sanctioned races (Rule 159).  They cite the physical danger of running while being distracted (and possibly deafened) as well as the concern that some elite athletes will disguise communication devices and get an "edge up" on the competition.  They also claim that runners will not be able to listen to race instructions or listen for important notices along the way.  Personally I think this is a strong and unfortunate position they are taking.
 
I have never had a problem running with headphones in on suburban streets.  I can't find any studies about headphones making you more prone to getting run over by cars.  I keep the volume low enough that I can still hear cars approaching and still talk to my running buddies.  The music is just there in the background.  In a race scenario this would even be safer as the course is closed to traffic, and it's not like you can do much to stay out of the way of an aberrant fellow jogger anyway.  I will admit that I usually don't wear headphones when I do my 5pm downtown Atlanta runs from work.  I would worry a little about getting distracted.
 
The bit about not hearing race instructions is bologna.  Keep the volume to an acceptably low level and you're good to go.
 
As for the elite runners using headphones to cheat... I may have an answer:  Only actively disqualify headphone users from the top spots (ie money or placements).  This will allow the 98% of other slower runners who don't care about placing to keep using.  (This is more or less what the USTAF has been doing as they are not actively disqualifying average runners yet).  Just make it a rule that you can get an official time but not place.
 
I think there are a lot of folks out there who would be fatter and slower if it weren't for the iPod.  Lets not discourage its use.  Some simple adaptations can keep you listening safely for a lifetime.

6 comments:

pengo said...

1. Your playlist rocks.

2. I swear by Nike Lightweight Sport Headphones. They have a stiff spine that wraps around the back of your head, with a single cord trailing down your neck. They do not plug your ears, they sit comfortably on top of your "pinna" (I think I have that right) an give with the natural movements of your body but very rarely fall out.

They are also pretty sweat resistant, the few I have had to replace are because of shorts in the cable due to natural wear and tear. And they sound great.

3. You should look up information on getting struck by lightning while wearing headphones. They do not increase the chance of getting struck, which are pretty rare anyhow - but the results are pretty gruesome. Just a tip.

Get it together!

John at Hella Sound said...

This is a fantastic post--thank you for putting the time into the research as well as sharing your insight.

i moved from the default iPod buds to some Sennheiser buds for what I hoped to be improved sound quality about a year ago. Unfortunately, the occlusion effect is truly irritating, and it drives me nuts. Also, the silicon pieces have a habit of coming off in my gym bag and getting lost, so I'm down to the tiniest ones provided. I notice (but have not researched) the bass response difference between the small molds and the larger ones--I believe the larger ones offer more space for the bass frequency to develop in the ear.

Anyway, since I'm back looking for new earbuds, I'll likely share what I find on my site (HellaSound.com), and will link to this post for background reference. Great post!

Tiffany said...

I’m working with Takkle.com, a social networking site for sports. Members can post photos, videos, share stats and schedules, and a whole lot more with others throughout the community. Takkle is a place where students, athletes, coaches, and fans can share their passion for sports.

I feel that your site is very useful. I would love to know if you could link to our social networking resource.

hearingaustintx said...

hearing loss because of music players is getting very common now a day. I think we must be more curious about that stuff. We don't want to happen that someday almost all of us lose its hearing.

Mike said...

Is this true? I walk and run every morning with my iPod ear piece on my ear. I think I need to stop using iPod. I don't want to lose my hearing.

Earbuds For Running said...

The iPod has been there for most all of my running, in fact until only ... earbudsrunning.blogspot.com