Walk through any gym, and you’re likely to see people on the treadmill or working out, listening to music through a set of ear buds. Most people don’t realize it, but the combination of exercise and loud music can cause you to slowly go deaf.

We have been working out to music for decades. Years ago, music was a shared experience, played in the background. In fact, some based membership decisions on the type of music played at the gym.

MP3 players like the Walkman and then the iPod came around, and everything changed. These devices, when used with ear buds, block out extraneous noise while delivering music directly down the ear canal. Seems like a great idea, but ear buds have been shown to be able to wreak havoc on the inner ear.

When young, I mistakenly thought that when people became deaf, it was because their eardrum popped. Whereas this can happen with an extremely loud noise, such as an explosion, this “all or none” effect isn’t the typical way one loses their hearing. More commonly, it’s a slow, insidious process, called noise-induced hearing loss (NIHL). This form of deterioration can begin at any age from childhood through old age. This is a preventable form of hearing loss that occurs from repeated exposure to excessively loud sound.

NIHL is a common condition. The National Institutes of Health report that approximately one out of seven Americans (15%) aged 20 to 69 have hearing loss related to occupational or leisure activities, presumably from chronic exposure to loud noise and/or music. People with this form of hearing degeneration initially present with the inability to discriminate between different sounds or a hypersensitivity to certain sounds. Ringing in the ears, referred to as tinnitus, can also occur. Eventually, a hearing aid is needed.

Hearing requires more than just an intact eardrum.

The ear is the first part of an apparatus that first converts vibrational waves of energy into mechanical vibration and following, into electrical impulses which travel from the inner ear to the brain. The brain is where we interpret this information as something we call “sound”. The switch from mechanical vibration to electrical impulse occurs within a structure of the inner ear called the cochlea.

The cochlea is filled with fluid and contains a collection of cells with tiny protruding hairs called cilia. Mechanical vibrations transmitted within the fluid cause the cilia to vibrate. The cells housing the cilia change this mechanical information into an electrical nerve impulse which is then transmitted to the brain.

Each time we are exposed to excessively loud noise, tiny blood vessels that supply the cells in the cochlea constrict, diminishing its blood supply. If the blood supply is reduced too drastically, the cells sporting the cilia can die. Once they’re gone, they’re gone. They can’t grow back.

Where does exercise fit in?

During exercise, blood is diverted to the body’s active muscles that need oxygen and nutrients. This redirection of blood will cause a decrease in blood flow to the cochlea. By itself, this is not a problem for the cells in the cochlea. But mix loud music with exercise, and there is a compounding effect on the blood vessel constriction, doubling the risk for damage. More damage leads to more eventual hearing loss.

The maximum sound intensity that is safe under normal activity and health is 80 decibels. This equates to the noise level generated by running the vacuum cleaner or garbage disposal. Sounds over 85 dB can cause hearing loss. In general, if you are wearing ear buds and can’t hear when someone is talking to you in a normal tone voice, the volume is probably turned up to loud.

Listening to music while exercising can give an energy boost. We become entrained with the music and as a result, it motivates us to move and perform with the rhythm. The good news is that the music doesn’t need to be loud to receive this beneficial effect.