How our noisy world is seriously damaging our health

We are surrounded by an invisible killer—one so common that we barely notice it shortening our lives. It is causing heart attacks, type 2 diabetes, and studies now even link it to dementia. Can you guess what it is? The answer is noise, and its impact on the human body goes far beyond damaging hearing.

"It is a public health crisis. We've got huge numbers of people exposed to it in their everyday lives," says Prof. Charlotte Clark from St George's, University of London. It’s a crisis we don’t talk about.

I have been investigating when noise becomes dangerous, speaking with people whose health is suffering, and exploring ways to overcome our noisy world. I started by meeting Prof. Clark in an eerily silent sound laboratory. I was outfitted with a device resembling a chunky smartwatch that measures my heart rate and how much my skin sweats. You can join in too if you have some headphones. Think about how these five sounds make you feel.

From the hustle of Bangladeshi traffic to barking dogs, how do these noises affect your emotions? I listened to five different noises in under a minute. The one I found particularly grating was the traffic noise from Dhaka, Bangladesh, known as the noisiest city in the world. I immediately felt like I was stuck in a gigantic, stressful traffic jam. My sensors registered my agitation: my heart rate shot up, and my skin began to sweat.

"There's substantial evidence that traffic noise affects your heart health," says Prof. Clark as she prepares the next sound. Only the joyful sounds of a playground produce a calming effect on my body. In contrast, the barking dogs and the neighbor's party in the early hours prompted a negative response.

But why does sound alter my body’s reactions? "You have an emotional response to sound," explains Prof. Clark. Sound is detected by the ear and sent to the brain, where one region—the amygdala—performs an emotional assessment. This area is part of the body's fight-or-flight response, which has evolved to help us react quickly to potential threats, like a predator crashing through the bushes. 

"So as a result, your heart rate increases, your nervous system kicks in, and you release stress hormones," Prof. Clark further explains. While this response is beneficial in emergencies, prolonged noise exposure can cause damage. 

"If you’re exposed for several years and your body is continuously reacting like that, your risk of developing issues such as heart attacks, high blood pressure, stroke, and type 2 diabetes increases," states Prof. Clark. Alarmingly, this reaction occurs even while we sleep. You might think you adapt to noise; I thought I did when I lived near an airport. But the biology tells a different story.

"You never turn your ears off; when you’re asleep, you’re still listening. So those stress responses, including increased heart rate, continue even during sleep," adds Prof. Clark.

Noise is defined as unwanted sound. Major contributors include transportation—like traffic, trains, and airplanes—as well as the sounds of social gatherings. One person's enjoyable party might be another's intolerable noise.

I met Coco at her fourth-floor flat in the historic Vila de Gràcia area of Barcelona, Spain. Her door was adorned with a bag of freshly picked lemons from a neighbor, her fridge contained a tortilla cooked by another, and she offered me fancy cakes made by a third neighbor who is training in patisserie. From her balcony, one can see the famous Sagrada Familia cathedral, making it easy to understand why Coco loves living there. Unfortunately, the charm comes at a significant cost, and she believes she might have to leave.

"It's extremely noisy; it's 24-hour noise," she tells me. There's a dog park nearby where owners walk their pets, which bark at all hours—2, 3, 4, 5 a.m.—and the courtyard serves as a public space for everything from children's birthday parties to all-day concerts, often ending with fireworks.

She pulls out her phone to play recordings of the loud music that makes her windows vibrate. Her home should be a refuge from work stress, but the noise "brings frustration; I feel like crying." She has been "hospitalized twice with chest pain" and firmly believes that noise is harming her health, stating, "There is a physical change that I feel; it does something to your body, for certain."

In Barcelona, an estimated 300 heart attacks and 30 deaths each year are attributed to traffic noise, according to researcher Dr. Maria Foraster, who has reviewed noise-related evidence for the World Health Organization. Dr. Foraster emphasizes that traffic noise has the most significant impact on health due to its prevalence.

Across Europe, noise is linked to 12,000 premature deaths each year, along with millions of cases of severely disturbed sleep and serious noise annoyance, which can negatively affect mental health. I met Dr. Foraster at a café separated from one of Barcelona's busiest roads, where we continued discussing the pervasive issue of noise pollution and its profound effects on public health.