But despite this growing body of evidence, little is known about how noise pollution might contribute to heart problems. To shed light on that question, researchers from Johannes Gutenberg University in Germany compiled and analysed findings from dozens of previous studies on noise and various health outcomes.
Based on existing evidence, the new review suggests that noise disrupts the body on the cellular level. Researchers say it induces stress responses and activates the sympathetic “fight or flight” nervous system. This causes a spike in stress hormones, which eventually lead to cardiovascular damage. Noise also is a driving factor in oxidative stress and metabolic abnormalities which contribute to other diseases like diabetes. For people with risk factors for cardiovascular disease, living in a noisy environment could accelerate atherosclerosis.
“The important point is that noise is not just annoying,” lead author Dr. Thomas Munzel, director of the department of internal medicine, said. While his paper focuses largely on cardiovascular and metabolic implications of noise, he points out that there’s growing evidence that chronic noise can cause mental-health diseases (including depression and anxiety), and can impair children’s cognitive development.
One way noise pollution affects heart health is by disrupting sleep. In studies, night time noise has been linked to an increase in blood pressure, even when people didn’t wake up or realise their sleep had been disrupted. ‘You can can close your eyes but not your ears,” Munzel said. ‘Our body will always react with a stress reaction.’
But even chronic noise during the day will have major effects on the body, said Dr. James O’Keefe, a cardiologist at the Mid America Heart Institute, Saint Luke’s Hospital, in Kansas City. ‘When we’re exposed to loud noises, the sympathetic nervous system dominates,” said O’Keefe, who was not involved in the new review. “That can really put your system on alert and makes you jumpy, which can wear down your resilience — just like any other type of physical or mental stress.” O’Keefe said that, as a cardiologist who focuses on prevention, he’s read a lot about the connection between noise pollution and heart health. “But I don’t really think it’s something the average physician or cardiologist is particularly tuned into,” he said.
Munzel said people in urban areas around the world should worry about noise pollution, and that the problem is getting worse as more people are living in large cities. “It is important to note that no one can develop tolerance to noise,” he said, despite what many people believe. In fact, people’s cardiovascular systems actually seem to become more sensitive to noise — and so more easily damaged — over time.
While there’s no volume threshold established for heart-disease risk, Munzel said that chronic exposure to anything over 60 decibels (the level of a typical conversation in an office) has the potential to harm the cardiovascular system. A telephone ringing produces about 80 decibels, a jackhammer 100, and an aircraft at takeoff a 120.
Most background music is between 80 and 90 decibels, well over the threshold at which damage to the cardiovascular system has been observed if below that at which damage to hearing becomes apparent.
“I hope that in future politicians will make laws that protect the people from environmental stressors,” he said. A reduction in overall noise pollution, he said, “will be a factor that can be influenced by politicians only and not by patients and doctors.’
Pipedown, in association with other groups, intends to keep pressing politicians on this vital issue. In the longer run, it is indeed a matter of life and death.