Wednesday, July 8, 2015
Off
We hear sound when delicate hair cells in our inner ear vibrate, creating nerve signals that the brain understands as sound. But just as we can overload an electrical circuit, we also can overload these vibrating hair cells. Loud noise damages these delicate hair cells, resulting in sensorineural hearing loss and often tinnitus (ringing in the ears). The cells that are the first to be damaged or die are those that vibrate most quickly—those that allow us to hear higher-frequency sounds clearly, like the sounds of birds singing and children speaking.
Sound volume is measured in decibels, with the softest sound a normal hearing human can hear measuring at 0 dBA. Any sounds above 85 dBA for 8 or more hours are considered unsafe. Most firecrackers produce sounds starting at 125 dB peak SPL, presenting the risk of irreversible ear damage.
Repeated exposure to loud noise, over an extended period of time, presents serious risks to hearing health as well. If you have to shout over the noise to be heard by someone within arm’s length, the noise is probably in the dangerous range. Here are the warning signs:
- You have pain in your ears after leaving a noisy area.
- You hear ringing or buzzing (tinnitus) in your ears immediately after exposure to noise.
- You suddenly have difficulty understanding speech after exposure to noise; you can hear people talking but can’t understand them.
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http://www.betterhearing.org.
