Taking care of your ears requires more than a Q-tip. Did you know that one-third of all hearing loss is completely preventable?

Let's take a look at the ear and how your hearing works.

How do we hear?
Sound waves travel into the ear canal until they reach the eardrum. The eardrum passes the vibrations through the middle ear bones or ossicles into the inner ear. The inner ear is shaped like a snail and is also called the cochlea. Inside the cochlea, there are thousands of tiny hair cells. Hair cells change the vibrations into electrical signals that are sent to the brain through the hearing nerve. The brain tells you that you are hearing a sound and what that sound is.

Each hair cell has a small patch of stereocilia sticking up out of the top it. Sound makes the stereocilia rock back and forth. If the sound is too loud, the stereocilia can be bent or broken. This will cause the hair cell to die and it can no longer send sound signals to the brain. In people, once a hair cell dies, it will never grow back. The high frequency hair cells are most easily damaged, so people with hearing loss from loud sounds often have problems hearing high pitched things like crickets or birds chirping.

When we talk about noise-induced hearing loss - hearing loss that occurs because of overexposure to noise - we must address the ideas of time and intensity. The louder a sound is, the shorter the time of exposure must be in order to remain safe. With every 3 decibel (dB) increase in sound, the safe exposure time reduces in half.

85 dB(A) = 8 hours of safe exposure time
88 dB(A) = 4 hours
91 dB(A) = 2 hours
94 dB(A) = 1 hour
97 dB(A) = 30 minutes
100 dB(A) = 15 minutes
103 dB(A) = 7.5 minutes
106 dB(A) = 3.75 minutes
109 dB(A) = 1.8 minutes
112 d(B) = less than 1 minute

Some sounds are loud enough to immediately damage hearing, such a gunshot blast. Hunters, for instance, should always wear hearing protection.

Three tips to protecting your hearing:

1)	If possible, avoid loud noise. Walk away.
2)	Turn it down and limit your time. TVs, iPods, toys, anything with a volume control should be at 60 percent of the maximum volume.
3)	Protect your hearing. Wear earplugs or other hearing protection when around loud environments, such as when mowing the lawn or attending a concert.

April 25, 2007, is International Noise Awareness Day, a day dedicated to educating the public about the dangers of noise to hearing and health. In Minnesota, the Sight & Hearing Association has coordinated free hearing screenings. Click here for a list of screening locations.