How Loud is Too Loud?

I am a self-professed loud music listener. I use my iPod at the gym, and I love it. Ever wonder how loud is too loud? Ever wonder how much hearing loss your iPod is causing? Music has evolved. Loud gets attention, and sells records. How this is associated with hearing loss depends on the person. It depends on how long you are listening, and it depends on the level at which you are setting your iPod. There is huge variation in how people are affected by loud sound. Certainly a huge part of this is underlying genetics. Put that aside and physiologically, noise-induced hearing loss is caused by damage deep inside the ear. The primary area where the ear is damaged is not the eardrum, not the part of the ear that you can see and not the bones that make up the middle ear — it is actually even deeper inside. It is where the nerve that brings the sound message up to the brain connects with the inner ear, and it involves some very specialized cells. These are hair cells, and specifically we are looking at the outer hair cells. When they are overexposed or stimulated at too high a level for too long a duration, they end up being metabolically exhausted. They are simply overworked. Once fatigued, they temporarily lose their function. What do we do to compensate? We turn up the volume. Sound has to be made louder in order for you to hear it. Ever got into your car and immediately had to turn the radio down? This is the perfect example of hair cell fatigue. In your prior car ride, you had become use to the volume of the radio and did not perceive it as loud anymore. After letting your hair cells rest, re-visiting that level of volume was startling, even uncomfortable. Your hair cells can recover after a single exposure, but if you overexpose them often enough, they end up dying. Once this happens you lose that functional ability inside your inner ear. The cells that die are not replaceable.

As far as a rule of thumb goes, the figures show that people using their iPod could listen at about 80% of maximum volume for 90 minutes per day or less without increasing their risk for noise-induced hearing loss. But the louder the volume, the shorter your duration should be. At maximum volume, you should listen for only about 5 minutes a day. Below is a chart which visually illustrates this relationship.