People living in urbans areas might dismiss the sounds of honking horns, thumping jackhammers and screeching breaks as mere annoyances that disturb their peace and quiet. But regular exposure to noise pollution may increase their risk of heart attacks and other cardiovascular diseases.
A recent review in the Journal of the American College of Cardiology offers some insight into how chronic exposure to noise impacts us on a molecular level to increase our risk of cardiovascular conditions.
Turning Up the Volume
Starting at as low as 50 decibels (db) — the sound of light traffic — chronic night-time exposure to noise pollution can start to have negative cardiovascular effects. As the volume gets turned up, the risk increases. A 2015 meta-analysis found that the risk of coronary artery disease increases for every 10 db increase in chronic exposure to transportation noise starting at 50 db.
Chronic nighttime noise that disturbs one’s sleeps may have the most detrimental impact on heart health. One study of 3.6 million people living around London’s Heathrow airport found that those exposed to the highest levels of nighttime aircraft noise had a 29 percent increased risk for stroke hospitalizations. [PULL_QUOTE]
Blood Vessel Stress
“It’s getting on my nerves!” is a common reaction to bothersome noises. And in fact, this response is quite apt. Sound pollution causes stress to our autonomic nervous system, the involuntary part of the nervous system that controls our organs and regulates internal mechanisms such as blood pressure, heart rate, breathing and digestion. When noise disturbances stimulate the sympathetic nervous system (a subset of the autonomic nervous system), the body releases the stress hormones cortisol, adrenaline and noradrenaline. Chronic exposure to these stress hormones damages the inner lining of blood vessels, a condition known as endothelial dysfunction, which is associated with various forms of cardiovascular disease.
Studies in mice who have been exposed to continuous aircraft noise compared to a control group exposed to “white noise” (a constant swoosh) showed an increase in blood pressure, endothelial dysfunction and increased marker of stress. The difference in the mice exposed to white noise versus aircraft noise suggests not all noises are created equally —noise patterns, frequency and exposure time all have impacts on heart health.
Still, while certain types of noise appear to be more harmful than others, most sounds above 50 db still increase a person’s risk of cardiovascular disease. So go ahead: Shut the windows and shush those loud neighbors. It’s for your health.