The leaves are starting to turn shades of red, yellow, and orange and fall to the ground. October means pumpkins on doorsteps and ghouls on porches. However, many people don’t know that October also means it is time to think about noise. This and every October is protecting your hearing month, a national campaign led by the National Institute on Deafness and Other Communication Disorders (NIDCD) to raise awareness around the risks of loud noise.
Sound vs. Noise
Sounds can be relaxing. The sound of the wind through the trees or a babbling brook can bring joy. However, if you’ve been exposed to too much sound you may not even be able to hear these subtle sounds. As the sound level rises, it can quickly turn to noise and can cause irritability, unrealized stress and even hearing loss. Our world is increasingly noisy, and this can result in noise pollution in our daily lives.
The problem with noise pollution is that many can’t escape the sounds around them. It could be coming from a busy intersection outside your home, full of traffic and construction which fluctuates through the day. It could also occur on your commute, at work or even when you relax. The problem with too much noise is that it can trigger a stress response in the amygdala, a region of the brainstem which learns over time what sounds might signal impending danger.
When extreme sounds are detected, the amygdala triggers a release of cortisol, which is a stress hormone. The secretion of cortisol results in increased heart rate, blood pressure, and a rapid release of energy in the bloodstream. It can take a toll on our body when cortisol is constantly being released due to exposure to noise.
How Does Noise Induced Hearing Loss Occur?
Noise doesn’t only affect our stress levels but our ability to hear. To understand how noise induced hearing loss occurs, we must first explore the systems of the ear. Generally, sound is collected by the outer ear and sent through the eardrum, and the tiniest bones in the body through vibration. The vibrations then reach the cochlea, which is a tiny snail shaped organ filled with fluid. Within the cochlea, tiny hair-like cells called stereocilia respond to the ripples of fluid and convert this information into electrical pulses. These pulses are in turn sent to the brain, to be processed. When sound becomes too loud, the intensity of vibrations causes the stereocilia to break against the membrane walls which hold them. This can cause damage or destruction to stereocilia which impedes the delivery of sound information to the brain.
How Loud Is Too Loud?
The intensity of sound is measured in decibels (dB). Any decibel reading over 85dB can start to cause permanent hearing loss. However, it is not just the level of the decibel but the length of exposure. The CDC explains that “The decibel scale is logarithmic, which means that loudness is not directly proportional to sound intensity. Instead, the intensity of a sound grows very fast. This means that a sound at 20 dB is 10 times more intense than a sound at 10dB. Also, the intensity of a sound at 100 dB is one billion times more powerful compared to a sound at 10dB.” An exposure of 85dB will take about 8 hours of constant exposure for damage to incur but at 88dB, it will only take 4 hours.
Protect Your Hearing
Understanding when your hearing is at risk is key to protection. Using a free app available on most smart devices, will allow you to detect the decibel levels in the places you frequent most, such as your home, car, work and hobbies. If you detect a decibel reading which is consistently over 85dB it is important that you take a few precautions. Because the length of exposure affects the amount of damage, take listening breaks when you can. Step away for about 15 minutes. If this is not an option, you can try to lower decibel levels. The most common solution is to wear hearing protection. Most earplugs and protective headphones can lower the decibel level by 15-33dB.