Have you ever been on an airplane with an inconsolable baby? Or have you walked past a quiet construction site when all of a sudden a jackhammer starts drilling away? In each situation, you were probably startled, stressed or felt the urge to cover your ears.
Noise can be a pesky thing. While the ability to perceive sound – also known as hearing – is a major component of how we make sense of and interact with the world, any unwanted sound is defined as noise. Experiencing noise can initiate a stress response and can potentially cause noise-induced hearing loss depending on the length of exposure to or loudness of the sound.
Noise and the stress response
Researchers and experts know that the sympathetic nervous system (SNS), which initiates the adrenaline-fueled “flight or fight response,” was especially important for our early ancestors who were living in very different conditions. But it has evolved to stick with us today, and is still useful in many circumstances.
Noise is a big trigger for the stress response. Whenever we perceive a threat, whether imagined or imminent, our SNS kicks into high gear, releasing hormones to begin several metabolic processes to immediately prep the body to deal with the threat. Here are the steps:
- The adrenal glands release adrenaline or epinephrine, which increases heart rate, breathing and blood pressure.
- This process moves oxygen-rich blood to the brain very quickly, as well as to the muscles, to prep them for fight or flight.
- Adrenaline also causes rapid release of glucose and fatty acids into the bloodstream, to give the body plenty of energy.
- The body becomes less pain-sensitive and the senses are keener.
- Other hormones shut down or put on hold the immune system, growth and reproduction to divert energy to the stress response.
This stress response is good for an actual threat, but sometimes it takes the body a long time to “shut off” the cortisol and adrenaline, through the calming processes of the parasympathetic nervous system (PNS).
Researchers have found in several studies that both adults and children in noise-polluted areas – such as those living near airports or heavy traffic – have higher levels of cortisol in their bodies. And according to a 2000 study in Noise Health, noise-induced cortisol increases can lead to many health problems associated with stress, including poor cardiovascular health. This can affect people even when sleeping because the auditory system is permanently open and responds to noise signals.
Noise-induced hearing loss
There is also much evidence that excessive or loud noises can cause hearing loss or tinnitus. Any noises 85 decibels and above – heavy city traffic can be as loud as 85 dB, for example – have the potential to damage your hearing. For example, fireworks and firearms can reach 150 dB, which can be instantly damaging during close exposure if one’s ears aren’t protected. Motorcycles can reach 95 dB and ambulance sirens can be as loud as 120 dB at their closest distance.
The problems of excessive noise are many and include stress and hearing loss. However, thankfully, there are many things you can do to protect yourself:
- Purchase foam earplugs and keep a pair with you at all times. If you live in a high-noise environment, wear them at night to protect your body while you sleep.
- Check out the Occupational Safety and Health Administration’s standards for safe levels of noise exposure to learn more. Be informed so you feel confident talking to your boss if your place of employment has potential noise hazards.
- Invest in high-quality noise-canceling headphones, which are good to use on a flight or in other noisy situations.
- If your community is too noisy, see your local council person to work on a noise-reducing initiative.
- Remove yourself from noisy situations when possible.