Hearing loss is now the third most-common chronic physical affliction among adults, according to the Centers for Disease Control and Prevention. New research from the CDC shows nearly 20 percent of twenty-somethings may have some form of hearing loss, and many don’t even know it.

To understand hearing loss, you must understand how we hear. The ear is made up of three parts: The outer ear, middle ear and inner ear. Sound waves pass through the outer ear, vibrating the eardrum. The eardrum amplifies these vibrations and moves them through the middle ear to a small snail-shaped structure called the cochlea in the inner ear. When the vibrations reach the cochlea [COKE-lee-ah], they are translated into electrical signals that are transmitted to the brain, which recognizes the vibrations as sound.

What causes hearing loss? Damage to the inner ear occurs through exposure of loud noises. According to the new research from the CDC, everyday activities that generate loud noises such as traffic, operating a lawnmower or power tools, or attending loud concerts damage hearing, but we don’t always realize it. Hearing loss can also be caused by buildup of earwax in the ear canal, or an infection in the middle or outer ear.

How can we protect ourselves against hearing loss? When attending loud concerts or operating machinery, wear earplugs. When in loud traffic, roll up your car windows. If you think your hearing may be jeopardized by earwax or an infection, visit an ear, nose and throat specialist. They can work with you to remove earwax buildup, heal infections and help ensure your hearing is as crystal clear as possible for years to come.