Turning the volume up too high on your earphones may damage nerve cells that carry signals to the brain, researchers have warned.
University of Leicester research found that earphones or headphones on personal music players can reach noise levels similar to those of jet engines.
Noises louder than 110 decibels are known to cause hearing problems such as temporary deafness and tinnitus (ringing in the ears), but the study for the first time observed the underlying cell damage.
"The research allows us to understand the pathway from exposure to loud noises to hearing loss. Dissecting the cellular mechanisms underlying this condition is likely to bring a very significant healthcare benefit to a wide population," lead researcher, Dr Martine Hamann, said.
Nerve cells that carry electrical signals from the ears to the brain have a coating called the myelin sheath, which helps the electrical signals travel along the cell.
Exposure to loud noises - noise over 110 decibels - can strip the cells of this coating, disrupting the electrical signals.
This means the nerves can no longer efficiently transmit information from the ears to the brain.
However, the coating surrounding the nerve cells can reform, letting the cells function again as normal.
This means hearing loss can be temporary, and full hearing can return, the researchers said in a statement.
"We now understand why hearing loss can be reversible in certain cases. We showed that the sheath around the auditory nerve is lost in about half of the cells we looked at, a bit like stripping the electrical cable linking an amplifier to the loudspeaker. The effect is reversible and after three months, hearing has recovered and so has the sheath around the auditory nerve," Hamann said.
The study has been published in the Proceedings of the National Academy of Sciences.
