Modern life is noisy and can damage hearing. Prolonged exposure to loud noise can hurt your ears and may cause hearing loss even by middle age.
One of the most important steps you can take to look after your hearing is to turn down that MP3 player. Better yet: turn it off! (Parents of teenagers, take special note.) MP3 players are OK for your ears at 50% of their maximum volume or lower. But set higher than that – beware.
Here's what happens at higher volumes:
At 60% volume: you can listen to music for 5 hrs before your hearing is damaged.
At 90% volume: your ears can only stand 10-15 minutes, and they’ll need a rest period afterwards to recover.
It makes one wonder: why aren’t MP3 players rather made to play at only 50% of their current ear-blasting maximum?
Generally speaking, your ears can withstand about 8 hours listening to music at 90 decibels (equivalent to the noise level of a lawnmower or a busy highway) before cells in the inner ear start to suffer injury and definite hearing loss occurs. For every five decibels above this, safe listening time is halved, i.e. you can only tolerate four hours exposure at 95 decibels and two hours at 100 decibels. At 120 decibels and above: instant, irreversible damage.
(Olivia Rose-Innes, Health24, September 2011)