Background sound is a constant in our busy lives. Normally, background noises are at safe levels that won’t impact our hearing, but repeated exposure to noise above 85 decibels (dL) can cause hearing loss. Noise induced hearing loss, as a matter of fact, is the second most common form of hearing loss (ranking behind presbycusis, hearing loss related to normal aging), and is the most preventable type.
Facts About NIHL
Hearing loss is often perceived as “a disease of the elderly,” but noise induced hearing loss shatters that stereotype because it can affect people of all ages, including children, teenagers, and adults young and old.
It is estimated that 15 percent of Americans between the ages of 20 and 69 are experiencing hearing loss that is the result of exposure to excessive noise either at work or through recreational activities. High-risk pursuits include hunting, riding motorcycles and snowmobiles, attending rock concerts, listening to music at high volume through ear buds or headphones, and even mowing the lawn or using a leaf blower.
This type of hearing loss is caused when there is damage to the microscopic hair cells found inside the cochlea. These cells respond to mechanical sound vibrations by sending an electrical signal to the auditory nerve. Different groups of hair cells are responsible for different frequencies (rate of vibrations). The healthy human ear can hear frequencies ranging from 20Hz to 20,000 Hz. Over time, the hair cell’s hair-like stereocilia may get damaged or broken. If enough of them are damaged, hearing loss results. The high frequency area of the cochlea is often damaged by loud sound.
Sound pressure is measured in decibels (dB). The average person can hear sounds down to about 0 dB, which is the level of rustling leaves. Some people with very good hearing can hear sounds down to -15 dB. If a sound reaches 85 dB or higher, it can cause permanent damage to your hearing. The amount of time you listen to a sound affects how much damage it will cause. The quieter the sound, the longer you can listen to it safely. With extended exposure, noises that reach a decibel level of 85 can cause permanent damage to the hair cells in the inner ear, which then leads to hearing loss. Many common sounds are louder than you may think.
- A typical conversation occurs at 60 dB – not loud enough to cause damage.
- A bulldozer that is idling (note that this is idling, not actively bulldozing) is loud enough at 85 dB that it can cause permanent damage after only one day of work (8 hours).
- Personal music system with stock earphones at a maximum volume produce sounds as high as 100 dB. This is loud enough to begin causing permanent damage after just 15 minutes!
- A clap of thunder from a nearby storm (120 dB) or a gunshot (140-190 dB, depending on weapon), can both cause immediate damage.
Noise is the most common occupational hazard facing people today. It is estimated that as many as 30 million Americans are exposed to potentially harmful sounds at work. Even outside of work, many people participate in recreational activities that can produce harmful noise, such as using power tools or attending a concert.
Signs & Prevention
Hearing loss often develops gradually, and may not be immediately noticeable. If conversations and other noises sound distorted or muffled, you may be experiencing early symptoms. Other signs include frequently asking people to repeat themselves when speaking, and watching TV or listening to the radio with the volume set at a level uncomfortable to others.
Many times exposure to loud noise causes a temporary hearing loss that disappears within 48 hours, but over time this may lead to long-term hearing damage. The good news? Noise induced hearing loss is 100 percent preventable.
An awareness of activities that can cause hearing damage is key. When exposed to loud noise, be sure to wear earplugs or other protective devices. Many audiologists carry custom earplugs designed for specific activities such as hunting and listening to live music. Keep the volume at a reasonable level on your MP3 player. Regular hearing tests can help identify problems early, reducing your risk of developing long-term damage.
Call Hearing Health Centers at (712) 262-7774 for more information or to schedule an appointment.