Listening to an MP3 player at its highest volume for one hour a day is enough to seriously damage people's hearing, according to a study for European politicians.
It claims being exposed to loud music could lead to people getting tinnitus, or ringing in the ears.
The condition already affects more than 3 million people in the UK and it's feared a million more are at risk. Studies by charities working with deaf people estimate that two thirds of 16 to 34-year-olds listen to music at very high volumes without knowing the risks.
David Brinn is 33 and from Chippenham in Wiltshire. Until a few years ago he loved listening to music on his MP3 players and would use his for around three hours a day. He admits he would turn his up high.
"In the gym when you are on the treadmill and your favourite song comes on I'd turn it up as loud as it goes," he said.
David owned half a dozen MP3 players, buying new ones hoping they would be louder. Three years ago doctors diagnosed him with tinnitus. He describes his condition as a "whistle blowing" in his ear constantly, when he's eating, sleeping and working.