We used to associate harmful noise levels with workplaces like factories but it turns out that leisure activities have become even worse.
Researchers at the University of Michigan (UM) found that noise from mp3 players and stereo use causes even more problems than loud work environments, said Rick Neitzel, assistant professor in the UM School of Public Health and the Risk Science Center. Robyn Gershon, a professor with the Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco was the principal investigator on the study.
This proved true even though mp3 player and stereo listening made up just a small fraction of each person’s total annual noise exposure. Neitzel said he was surprised by the findings. As an occupational hygienist, he expected regular users of trains and buses along with work-related activities to be the chief culprits in excessive noise exposure.
The study’s authors found that one in 10 transit users had noise exposures exceeding the recommended limits from transit use alone. But when they estimated the total annual exposure from all sources, 90% of transit users and 87% of nonusers exceeded the recommended limits, primarily due to mp33 and stereo usage.
“That two out of three people get the majority of noise exposure from music is pretty striking,” Neitzel said. “I’ve always viewed the workplace as a primary risk for noise exposure. But this would suggest that just focusing our efforts on the workplace isn’t enough, since there’s lots of noise exposure happening elsewhere.”
The implications are startling, said Neitzel.
“I do think it’s a serious problem, there aren’t really any other experiences where we would tolerate having nine out of 10 people exposed at a level we know is hazardous. We certainly wouldn’t tolerate this with another agent, such as something that caused cancer or chronic disease. Yet for some reason we do for noise.”
Initially, the researchers set out to examine the contribution of common noise sources to total annual noise exposures among urban residents for mass transit usage; occupational and non-occupational activities, mp3 player and stereo use; and time at home doing other miscellaneous activities. They looked at what caused the majority of potentially harmful exposures in 4,500 residents in New York City who used public transportation.
With any environmental exposure, until scientists know the length of exposure, the exposure level means nothing. The average New York transit user spends about 380 or so hours either waiting for or riding transit, which has average noise levels of 72-81 decibels. For comparison, the average speaking level is 60 decibels, a busy street corner is 80, a circular saw is 90, a baby crying 115. The threshold for pain is about 125, and even a brief, one-time exposure above that level can cause permanent hearing loss.
“Lots of people appear to be exposed at hazardous levels,” Neitzel said. “A growing number of studies show noise causes stress, sleep disturbance, and heart disease. 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. This begs for a public health education program.”
As wellness providers, we’re not really positioned to address this problem directly (although regular chiropractic adjustments can improve a person’s overall health and might provide some protection against hearing loss). However, one indirect measure might be to be mindful of the noise level in our practices. Gentle, soothing music instead of loud radio programs can give patients (and staff members) a break from the constant noise that surrounds them every day. Getting people used to being in a quiet environment may also help them realize they don’t need to have an earphone piping sound into their heads every moment of the day.