NEW YORK - Listening to loud music with earphones on a digital music player for more than 90 minutes a day can damage hearing, a study shows.

The study of 100 doctoral students concluded that people who listened to music at 80 per cent of volume capacity, at which point the sound is considered loud, should stick to under 90 minutes a day.

"If a person exceeds that on a particular day and happens not to use their headphones for the rest of the week, they're at no higher risk," study author Brian Fligor said. "I'm talking about someone who's exceeding 80 per cent for 90 minutes day after day, month after month, for years."

The study also found no problems for people who listened to music at 10 per cent to 50 per cent of maximum volume for extended periods. It found, however, that anyone who listened at 100 per cent for more than five minutes faced the risk of hearing loss.

The findings of the study, co-authored by doctoral candidate Cory Portunff, applies to children and adults - although it was not clear if children were more susceptible to hearing loss than adults.

The scientists found no differences in sound levels between brands of digital music players or between the genres of music tested, ranging from rock, R&B, country to dance.

Dr Fligor, an audiologist at the Children's Hospital of Boston and faculty of Harvard Medical School, said people who consistently listened to high levels of volume did not realise hearing loss could take up to 10 years to show up.

"I worry about the teenager who's going to be 23, 24, 25 and has a measurable noise-induced hearing loss and now has another 60-something years to live with his hearing, which is only going to get worse," he said.

Dr Fligor will also present that study as well as the findings of another study, co-authored by Terri Ives of Pennsylvania's College of Optometry's School of Audiology, at a conference in Cincinnati today that found in-ear earphones are no more dangerous than headphones that are placed over the ears.

- REUTERS