BERLIN — People who use personal audio players should consider limiting their use to one hour a day and turn down the volume to prevent permanent hearing loss, the World Health Organization said Friday.
The U.N. agency said young people are particularly at risk. with data from middle- and high-income countries showing that almost half of all 12- to 35-year-olds listen to their personal audio devices or cellphones at unsafe volumes. About 40 percent of young people are also exposed to damaging sound levels at nightclubs, bars and sporting events.
"As the intensity of sound increases, the permissible time for safe exposure reduces," said Dr. Shelly Chadha, a WHO expert on hearing loss.
Volumes of 85 decibels — equivalent to being stuck in traffic — can be safely endured for up to eight hours, she said. But the safe exposure time halves with every three additional decibels, so volumes of 100 decibels are safe for only 15 minutes.
"Teenagers and young people can better protect their hearing by keeping the volume down on personal audio devices, wearing earplugs when visiting noisy venues, and using carefully fitted, and, if possible, noise-cancelling earphones or headphones," WHO said, urging them take short listening breaks and restrict the daily use of personal audio devices to less than one hour.
Chadha noted that many people don't realize how loud the volume on their device is. She said someone who turns up the volume on his personal music player to 95 decibels for a 30-minute subway commute "is going to get irreversibly damaged (hearing) in a couple of years' time."
Chadha also said manufacturers should consider displaying the intensity level on devices.
As a general rule, "where you cannot understand conversation around you, you know that this is too loud," she said.
Some 360 million people worldwide live with disabling hearing loss caused by a variety of factors, including chronic infection, rubella and exposure to noise, according to WHO.