Motorcycle season is almost here, meaning it's almost time to get back in the saddle. Making sure you're prepared is important, as over the winter both mind and machine can rust... For many of us being prepared means checking gear: helmets, leathers, boots that may or may not last one more season, but most of the time an extremely important element is left out, hearing protection.
Hearing loss is a silent threat that impacts motorcyclists of all types and ages. OSHA defines 85 decibels (dB) as the sound level at which permanent hearing damage is possible, and 130 dB as the average pain threshold for sound. Wind noise over 40 mph (regardless of bike type) becomes the predominant sound for riders. Even with a full-face helmet, wind buffeting at highway speeds can reach noise levels in excess of 100 dB, roughly the same level as a chainsaw. Riders not wearing a helmet are at the greatest risk, with noise levels multiplying up to 10 times (110 dB).
|National Institute for Occupational Safety and Health, etymotic.com|
Running the Numbers
According to the Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health (NIOSH), unprotected exposure at 100 dB can cause permanent hearing loss after 1.25 cumulative hours over a 1-week period. And at 110 dB, permanent damage can occur in as little as 5 (cumulative) minutes. To understand why, it's important to understand how the ear works. Ears absorb noise like a shock wave, inside the canal the eardrum converts air waves (sound) into physical vibrations that impact three small bones in the middle ear (the hammer, anvil and stirrup). The vibrations then travel to the fluid-filled bone structure (cochlea) of the inner ear, which is connected to small hair-like cells called stereocilia. The stereocilia turns the vibrations’ mechanical stimuli into electrical stimuli, which is then what stimulates our auditory nerves. After prolonged excessive exposure though these cilia can become fatigued though and actually "lay down" or become permanently bent, resulting in irreversible hearing damage.