Noise exposure causes more problems than hearing loss. It's considered an underestimated threat to public health by medical organizations, including the World Health Organization, potentially contributing to cardiovascular problems, disruptions in sleep, mental well-being, work and school performance and more.
How does noise do this? Like other types of pollution and environmental stressors that build up in our bodies and can contribute to chronic disease -- it's complicated. But a lot of it may come down to how we perceive noise and the cascading stress responses it causes in our bodies.
And all of this flows back to the heart. Dr. Rachel Bond, a board-certified cardiologist and the system director of women's heart health with Dignity Health, says chronic exposure to noise releases stress hormones in our body, which leads to inflammation, which can lead to damaged vessels in the body and increase the risk of heart disease. An increased focus on noise pollution as its own source of inflammation and stress join better-known factors that tip the scale of heart health, like cholesterol, blood sugar and blood pressure.
"We know that there are traditional risk factors that often increase one's risk of cardiovascular disease," Bond said. "Now we're looking at things that are less traditional."
Most research on the link between noise and health outcomes has been on the "unpleasant stuff," like traffic or transportation noise -- specifically as it's related to heart health. But according to a 2021 policy statement by the American Public Health Association, noise pollution also includes sound from outdoor power tools, consumer products and things we use for recreation or leisure -- which means even your blender or lawn mower could be considered pollution, in some cases.
Per the APHA, about 145 million Americans may be at risk for hypertension (high blood pressure) as it's related to noise, which puts them at risk for stroke and death from heart disease. What's more, noise exposure as a pollutant in the environment can run hand-in-hand with other stressors, compounding a higher risk of disease in some people, including those who live in busier neighborhoods or work an industrial job.
Noise pollution, Bond said, "really highlights the importance of realizing our ZIP code can dictate our overall health."
"Our environment 100% affects our overall health," she added, even if that means it's too loud.
But because it's complicated, as many health matters of the heart are, it's important to untangle the effects of noise and sound. As we tune into our environment, we can learn ways to tune out noise that makes subtle but harmful impacts on our health. Here's what to know.
Noise vs. sound: How loud is too loud?
We use noise and sound interchangeably to describe how loud something is, but "noise" is technically reserved for unwanted or unpleasant sounds, like the rumblings coming from a nearby airport or the sound of a drill. While knowing the decibel where the threat of hearing damage kicks in (70 decibels over long periods of time) is useful for staving off hearing loss, a specific threshold for health is less clear. Research has linked airport noise as low as 45 decibels to reduced sleeping time, for example, but different factors can affect how our ear perceives sound and how harmful it is.
The way to measure what we call "too loud" is by decibels, or sound intensity. But this also introduces some gray area: what's too loud for your ears and may lead to hearing loss over time may have different levels of pleasantness. This means that not everything fits neatly into the "noise pollution" category that's mitigated by agencies like the Occupational Safety and Health Administration, which sets guidance for workplaces to follow.
For example, 100 dB of your favorite band blasted through your headphones causes the same type of damage to your ears as 100 dB from an approaching subway. We know by looking at trends of hearing loss among musicians that liking or even experiencing euphoria from sound doesn't protect your ears from overexposure. But more enjoyable loud sounds haven't been directly studied for their other health risks, in the way that noise pollution from cars has been linked to cardiovascular disease, for example.
Research is needed to compare the heart health effects of "more enjoyable" noise versus noise noise, Bond says, but given what experts know about the stress response to noise, one could conclude that obnoxious sound is more harmful than pleasant sound that's equally as loud.
"But until we have a study that looks at that, it's just a postulation and an assumption," she said.
The stress response and its link to heart health
As The New York Times reported, there's some research that suggests "jarring" sounds that have more variation (e.g. trains passing versus the steady hum of the highway) cause more harm, even if it's the same level of "loud."
A 2019 study published in the European Heart Journal found that more transportation noise exposure meant more activity in the amygdala, the part of the brain that responds to feelings like stress or fear. The study also linked exposure to noise to inflammation in the blood vessels, which is linked to heart health, and found that chronic exposure increased the risk of someone having a major cardiac event (like a stroke or heart attack).
If something is so loud or disruptive that it's causing you stress, assume that it's no good for your health.
"Stress in and of itself is a risk factor for heart disease," Bond said. Living in a constant "fight or flight" state where your body is releasing cortisol and adrenaline cause inflammation, which can lead to plaque build-up and heart disease.
Heart disease, the No. 1 killer in the US, has a lot of contributing factors that can tip the scale in risk, varying from physical activity, nutrition, stress, air pollution and even blood type. But anyone who's ever felt their blood pressure rise from the noise outside their bedroom while they're trying to get some shut-eye can speak to noise's potential impact on another crucial mediator of our well-being: sleep.
Read more: Lower Your Risk of Heart Disease With These Tips
A study published in Environmental Health Perspectives looked at the association between how close someone lives to an airport and their sleep quality. It found a link between how close people in the study lived to an airport and how long they slept, but it also found that the noise of the nearby airport didn't have to be that loud to have an impact.
This builds on existing evidence on the relationship between sleep and noise. According to the Sleep Foundation, noise can decrease slow wave and REM sleep (which is crucial for mood, memory and brain development) and may also cause extra production of stress hormones.
Read more: REM vs. Deep Sleep: Why Both Are Critical for Your Sleep Hygiene
How to combat the noise (or at least make it less stressful)
There's lots of health advice on what's too loud when it comes to hearing damage, down to the decibel. And for healthy sleep, the WHO recommends keeping noise outside your bedroom below 40 db. But let's be honest, it's not realistic to clock the decibel level in every environment you step in to, or skip out on important errands or events just because they may be irritatingly loud. If you live in a loud neighborhood or close to an airport, it may also not be feasible for you to just up and move. For these reasons, reducing the stress and disruptiveness associated with sound may be more actionable for most people.
For starters, and you probably already know this one, protect your ears if you're going to be spending time in loud environments, especially if you're in them often. In addition to protecting your hearing, earplugs and noise-canceling headphones can make an irritating noise level less irritating, hopefully reducing your stress.
For sleeping more soundly at night, there are also headphones and earplugs designed specifically for sleep.
In terms of quieting your environment, there are some things you can do to try to muffle or disguise sound. Here are a few home hacks to try:
- For smoothing over sound and creating a more relaxing environment for sleeping, try a white noise machines. You can read more about the different frequencies of background noise here, and what may be more helpful to you. Personally, I get really bothered by background noise when I'm trying to sleep or focus, and after experimenting (and instead of a whitenoise machine), I found another noise savior and have the hook-up down to a T: I use my Bose Bluetooth speaker to play this "commercial airliner" sound on the Calm app during the night, which perfectly matches the frequency and pitch of my neighbor's TV and stereo.
- You may also consider investing in some sound-absorbing material that may dampen noise coming from outside. We haven't tested them, but products like these noise-blocking curtains are available and marketed as being able to add a little more silence to your room.
Knowing your individual risk factor for inflammation or heart disease is also important when cutting down the effects of noise pollution. People with autoimmune conditions and people who eat a lot of processed foods may have more inflammation in their bodies and have a greater risk, Bond said, in addition to people with an existing health condition, like diabetes or high cholesterol. Making sure you stay active and eat a heart healthy diet are things you can do to improve your overall being as well as potentially mitigate burden of noise on your body.
"It is extremely important to know what your inflammatory markers are," Bond said.
For more information on winding down and creating a less-stressful home environment, try these tips for the evening, organizing your room so it feels more relaxing to you and getting started practicing meditation and mindfulness.