Keep still for a moment. Listen to everything you can hear. Cars passing, phones ringing, the kid next door crying, the neighbour mowing his lawn. It never stops. To escape the ‘madness’ we go to gyms, clubs, bars, sports matches, music concerts, and so forth. But all we’re doing is adding to our daily noise intake.
Studies show that noise heightens stress levels and irritation, but how much noise can the ear tolerate before actual damage is caused?
According to the American Academy of Otolaryngology (AAO), three factors contribute to hearing loss:
- the volume/intensity of the sound
- the time you are exposed to the sound
- the distance you are from the source of the sound
How sound affects your hearing
Sound is measured in decibels (dB). The scale runs from the faintest sound the human ear can detect (0dB) to the noise on a rocket pad during launch (more than 180dB). Normal speech rates at about 65dB and busy city traffic at 85dB.
Various sources (see below) agree that sounds that are 85dB or louder can permanently damage your hearing, and the louder the sound, the less time it takes to cause the damage. Decibels are measured on an exponential scale, meaning that for every three decibels over 85dB, the allowed exposure time before damage is caused is cut in half. In other words, the suggested exposure time for 85dB is eight hours, for 88dB it is just four hours, and only two hours for 91db, etc.
Everyday hearing hazards
Listening to your iPod at maximum volume or being a regular patron of rock concerts will have obvious negative effects on your hearing. But even those who don’t seek out loud noises are at risk of damaging their hearing while being exposed to everyday noises. Here are some day-to-day noises to beware of:
- Musical toys, rattles and squeaky toys for infants can reach up to 140dB
- Electric garden tools can attain levels of 130dB
- The sound levels at movie theatres have been measured at 95dB – especially action movies
- A Royal National Institute of the Deaf and Hearing study of nightclubs has found the noise level on most dance floors to be between 90 and 110dB
- Uncomfortably loud noise levels have been recorded at gyms, especially during fitness classes, a study by the Swedish Institute of Working Life shows
What is too loud?
The AAO believe that when the background noise is so loud that you have to raise your voice to be heard during a have a face-to-face conversation, the noise has the potential of damaging your hearing.
How will I know if my hearing has been affected?
A website dedicated to hearing, hear-it.org, warns that people do not feel that their hearing has been overtaxed before the damage is done. They advise people to be aware of the following signs:
- Ringing, whining or buzzing noises in your ears
- Pain in your ears
- Feeling as if you have cotton wool in your ears
- Difficulty hearing after the music stops
These signs show that your hearing has already been affected, and no treatment, medicine, surgery, or even a hearing aid can completely restore hearing once it has been damaged by noise, the AAO stresses. If you suspect that you’ve suffered hearing loss, consult a doctor who can diagnose your hearing problem and advise you on the best way to manage it.
– (Wilma Stassen, Health24, updated April 2010)
American Academy of Otolaryngology (AAO)