(RxWiki News) The most dangerous threat to your hearing health might very well be in your pocket or purse right now: your MP3 player.
Loud noise exposure that could lead to hearing loss more frequently comes from MP3 players and stereo use than even loud work environments or mass transit sounds, according to a new study from the University of Michigan.
"Limit loud music exposure to prevent hearing loss."
Robyn Gershon, a professor with the Philip R. Lee Institute for Health Policy Studies at the University of California, San Francisco, led a study to determine what activities contribute most to the loud noise exposures of 4,500 New York City residents who use public transportation.
Listening to the stereo or to music through headphones did not add up to much noise exposure each year for residents compared to other noises, but it was the primary source of hazardous levels of noise for most people surveyed.
Two thirds of those surveyed get the majority of their excessive noise exposure from music, according to Rick Neitzel, assistant professor in the University of Michigan School of Public Health and the Risk Science Center and a co-author of the paper.
Overall, 90 percent of people using public transportation and 87 percent of nonusers of mass transit are exposed annually to noise levels exceeding the recommended limits.
The researchers investigated five major sources of noise: mass transit use, occupational and non-occupational activities, MP3 player and stereo use and time at home doing other miscellaneous activities.
Typical noise from the New York subway ranges from 72 to 81 decibels, and a busy street corner is about 80. The threshold of pain ranges is estimated at about 125 decibels.
Neitzel said growing evidence about other health problems that could be caused by noise mean that the public should be better educated about the impact of loud noise.
"A growing number of studies show noise causes stress, sleep disturbance and heart disease," Neitzel said. "It may be the noise which we haven't historically paid much attention to is actually contributing to some of the top health problems in developed countries today."
The study appears online in the December Environmental Science and Technology.