How our noisy world is seriously damaging our health

We are being surrounded by an invisible killer. It is so pervasive that we barely notice it is shortening our lifespans. This killer is triggering heart disease, type 2 diabetes, and some studies even suggest it is linked to dementia. Its widespread presence makes it a significant threat to public health.

What do you think it might be? The answer is noise—and its impact on the human body goes far beyond just damaging hearing. Professor Charlotte Clark of St. George's, University of London, states: "This is a public health crisis, and we have a huge number of people exposed to noise in their daily lives." The pervasive nature of noise pollution makes it a serious concern.

I have been investigating when noise becomes dangerous, talking to people whose health has been affected by noise, and trying to find ways to overcome the noisy world we live in. I first met Professor Clark in an unusually quiet sound lab. We would observe my body's reaction to noise, and I was fitted with a device that looked like a chunky smartwatch, which would measure my heart rate and skin sweat levels. This detailed approach allowed for a comprehensive analysis of the effects of noise.

Professor Clark explained: "There is solid evidence that traffic noise affects your heart health." The joyful sounds of a playground had a calming effect on my body, while dog barks and a neighbor's party in the early hours of the morning caused negative reactions. Sound is detected by the ears and transmitted to the brain, where the amygdala assesses the sound emotionally. This is part of the body's "fight or flight" response, which is designed to help us react quickly to sounds like a predator moving through the bushes. Understanding this mechanism helps to explain the physiological impact of noise.

Professor Clark told me: "So your heart rate will go up, your nervous system will start to kick in, and you'll release stress hormones." All of this is beneficial in an emergency, but over time, it starts to cause damage. She said: "If you're exposed to noise for years, your body is constantly reacting like this, and that increases your risk of diseases like heart disease, high blood pressure, stroke, and type 2 diabetes." The chronic activation of the stress response contributes to long-term health problems.

This damage can even occur silently while we are sound asleep. You might think you've adapted to the noise. I used to think that when I lived in a house near the airport. But biology tells us a different story. Professor Clark added: "You never turn off your ears; when you're sleeping, you're still listening. So those reactions, like your heart rate going up, are still happening when you're asleep." This highlights the insidious nature of noise pollution, even during rest.

Noise is unwanted sound. Transportation—traffic, trains, and airplanes—is a major source of noise, but so is the sound of us having fun. One person's great party is another person's unbearable noise. I met Coco in a fourth-floor apartment in Barcelona's historic Gràcia neighborhood. The subjective nature of noise makes it a complex issue to address.

Hanging on her door was a bag of freshly picked lemons, a gift from a neighbor, and her refrigerator was stocked with tortillas made by another neighbor, and she also offered me a delicate cake made by a third neighbor who was training to be a pastry chef. From the balcony, you could see the city's famous Sagrada Familia. It's easy to understand why Coco fell in love with living here, but it comes at a huge cost, and she believes she will be forced to leave. The community spirit is overshadowed by the pervasive noise.

She told me: "It's very noisy here... it's 24-hour noise." There's a dog park where owners walk their dogs, and the dogs bark "at 2 a.m., 3 a.m., 4 a.m., 5 a.m.," and the courtyard is a public space used for everything from children's birthday parties to all-day concerts, ending with fireworks. She took out her phone and played a recording of music, so loud that the glass in her windows was vibrating. The relentless noise disrupts her daily life and well-being.

Her home should be a haven from the stresses of work, but the noise "brings frustration, I want to cry." She has been "hospitalized twice for chest pains" and "absolutely" believes that the noise is causing stress, which is damaging her health. She said: "I feel physical changes in my body, it definitely has an impact on your body." The physical and emotional toll of noise pollution is evident in her experience.

According to Dr. Maria Foraster, a noise evidence reviewer for the World Health Organization, in Barcelona, traffic noise alone causes about 300 heart attacks and 30 deaths each year. Noise also causes 12,000 premature deaths each year, as well as millions of cases of severe sleep disturbance and serious noise annoyance, all of which affect mental health. The statistics highlight the significant public health impact of noise pollution.

I met Dr. Foraster at a café separated from one of Barcelona's busiest roads by a small park. My sound meter showed the noise from the distant traffic here was just over 60 decibels. We could easily talk over the noise without raising our voices, but that was already an unhealthy volume. She told me that for heart health, the key number is 53 decibels, and the higher it is, the greater the health risk. Even seemingly moderate levels of noise can have detrimental effects.

Dr. Foraster said: "This 53 means that we need to be in a rather quiet environment." That's just during the day, and at night we need even lower levels. She said: "At night we need quiet." While it's not just about volume, the extent to which the sound is disruptive and the amount of control you have over it all affect our emotional response to noise. The context and characteristics of the noise influence its impact.

Dr. Foraster believes that the health effects of noise are "comparable to the levels of air pollution" but are harder to understand. She said: "We are used to understanding that chemicals affect health and that they are toxic, but to understand that a physical factor like noise affects our health, and not just our hearing, is not so simple." The intangible nature of noise makes it challenging to recognize as a health hazard.

A noisy party might be fun and make life worth living, but for another person, it's unbearable noise. Traffic noise has the greatest impact on health because so many people are exposed to it. But traffic is also the sound of going to work, shopping, and taking children to school. Addressing noise means asking people to live differently—which creates its own problems. Balancing the benefits of activities with the need for noise reduction is a complex task.

Dr. Natalie Mueller of the Barcelona Institute for Global Health took me for a walk in the city center. We started on a busy road—my sound meter showed over 80 decibels—and then we went to a quiet, tree-lined street where the noise dropped to just over 50 decibels. But this street had something different—it used to be a busy road, but now the space has been given over to pedestrians, cafes, and gardens. I could see the shadows of the old crossroads in the shape of the flower beds. Vehicles can still drive slowly here. Urban planning can play a significant role in mitigating noise pollution.

Remember earlier in the lab, we found that some sounds can soothe the body. Dr. Mueller said: "It's not completely quiet, but it's a different perception of sound and noise." My heart rate dropped, and I stopped sweating. The initial plan was to create more than 500 of these areas, called "superblocks"—pedestrian-friendly areas created by combining several city blocks. Prioritizing pedestrian spaces can improve the acoustic environment.

Dr. Mueller predicted that the city's noise would be reduced by 5-10%, which would prevent about "150 premature deaths each year" from noise alone. And that's just the "tip of the iceberg" of health benefits. But only six superblocks have actually been built. The city council declined to comment. The implementation of noise reduction strategies faces challenges and political hurdles.

However, the danger of noise is continuing to grow. Urbanization is bringing more people into noisy cities. Dhaka, Bangladesh, is one of the fastest-growing megacities in the world. This brings more traffic and fills the city with the din of honking horns. Rapid urbanization exacerbates the problem of noise pollution in many cities.

Artist Momina Rahman Roya has earned the title of "lone crusader" for his silent protests that have raised awareness of the city's noise problems. For about 10 minutes each day, he stands at the intersection of several busy roads, holding up a large yellow sign accusing drivers who honk their horns loudly of creating a huge nuisance. Individual actions can bring attention to the issue of noise pollution.

He took on this mission after his daughter was born. He said: "I want to stop all the honking, not just from Dhaka, but from Bangladesh. If you see birds, trees, or rivers, no one makes noise without humans, so humans are responsible for this." He believes that humans have a responsibility to reduce noise pollution.

But the beginnings of political action are also emerging here. Syeda Rizwana Hasan, the Bangladeshi government's environmental advisor and minister, told me she is "very concerned" about the health effects of noise. Action is being taken to crack down on honking to reduce noise levels—through awareness campaigns and stricter enforcement of existing laws. She said: "It's not possible to do it in a year or two, but I think it's possible to ensure that the city becomes less noisy, and when people feel that, they will feel better, and when it's less noisy, I believe their habits will also change." Government intervention is crucial for addressing noise pollution on a larger scale.

Solutions to noise problems can be difficult, complex, and challenging. What I am left with is a new awareness of the need to find some space in our lives to escape the noise, because as Dr. Masrur Abdul Kader of the University of Professionals Bangladesh says, it is "a silent killer and a chronic poison." The urgency of addressing noise pollution is underscored by its long-term health consequences.