People who live close to airports could be at greater risk of heart attacks, life-threatening heart arrhythmias and strokes, a study shows.
Those who lived in areas where aircraft noise was higher than recommended were found to have stiffer and thicker heart muscles, which were less efficient at pumping blood around the body. This was especially the case for people exposed to higher aircraft noise at night, according to the study by British researchers.
They said that could be due to disturbed sleep and the fact that people are more likely to be at home at night and exposed to the noise, they said.
Dr Gaby Captur, of the University College London Institute of Cardiovascular Science and consultant cardiologist at the Royal Free Hospital in London, told The National that previous animal experiments have shown that mice exposed to simulated aircraft noise experienced higher blood pressure and the release of stress hormones.
This happens in several ways, she said, including activating the body's fight or flight response, which results in short-term circulatory changes such as a raised blood pressure and heart rate, as well as indirectly, by creating annoyance, stress, and the disturbance of sleep.
"These reactions can lead to long-term health outcomes through chronic stress responses, potentially contributing to conditions like hypertension, cardiovascular diseases, and poor sleep, resulting in next-day fatigue among those living near airports," she added.
The study also builds on a previously known link between high levels of aircraft noise with higher blood pressure and obesity in people – both of which were found to account for a significant portion of the link between noise and differences in heart structure and function in the new study.
“Between a quarter and half of the link was attributed to a higher BMI (body mass index) among participants exposed to higher levels of aircraft noise, while between nine per cent to 36 per cent of the link was attributed to these participants having higher blood pressure (this was among those exposed to daytime aircraft noise only)," said first author Dr Cristian Topriceanu, of the UCL Institute of Cardiovascular Science.
“Other factors that could be triggered by the stress response to aircraft noise include impaired sleep, inflammation, and atherosclerosis (build-up of fats, cholesterol and other substances in our arteries).”
The study is observational, so the researchers could not say with certainty that high levels of aircraft noise caused the differences in heart structure and function.
“However, our findings add to a growing body of evidence that aircraft noise can adversely affect heart health and our health more generally,” said senior author Dr Captur.
“Concerted efforts from government and industry are needed to reduce our exposure to aircraft noise and mitigate its impact on the health of millions of people who live close to airports or under flight paths.”
The study, which was published in the Journal of the American College of Cardiology (JACC), studied detailed heart imaging data from 3,635 people who lived close to four major airports in England – Heathrow, Gatwick, Birmingham and Manchester airports.
Around eight per cent lived in an area with high daytime aircraft noise, defined as more than 50 decibels, while three per cent lived in an area with high noise at night, between 11pm and 7am, at 45 decibels on average. The WHO recommends aircraft noise limits of 45 decibels on average during the day and 40 decibels on average at night.
Heart MRIs were carried out at least three years after the readings of aircraft noise were taken. Comparing the hearts of those who lived in areas with higher aircraft noise with those who lived in lower aircraft noise areas, and taking into account factors like age, sex and lifestyle factors, the researchers found that those who still lived in a higher aircraft noise area had about 10-20 per cent worse heart structure and function than their counterparts in these areas who had moved away.
They then looked at a separate sample of 21,360 people who had undergone detailed scans of their heart, concluding that someone with stiffer and thicker heart muscles, like those who live in high aircraft noise areas, are two to four times more likely to suffer a heart attack, abnormal heart rhythm, or stroke.
“We are concerned that the type of abnormalities we saw with night-time aircraft noise might result in increased risk of heart problems and stroke. Aircraft noise at night has been shown to affect sleep quality and this may be an important factor affecting health,” said Professor Anna Hansell from the University of Leicester.
“The role of noise on heart health is currently under investigation. However, there are many established ways to look after your heart. These include eating a healthy and balanced diet, keeping physically active, maintaining a healthy weight, giving up smoking if you smoke, reducing alcohol consumption, keeping conditions such as high blood pressure and diabetes under control, and taking medication including cholesterol-lowering drugs if prescribed by your doctor.”
