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The work, which is due to be presented at a meeting of the American Heart Association, found that the risk was similar regardless of people's sleeping patterns, and suggest that chronic exposure to loud transportation noise may increase the risk of cardiovascular disease.
“The key finding of our study is that the relationship between noise exposure and cardiovascular disease events, and the number of cardiovascular risk factors developed, was similar among people with and without unhealthy sleep, suggesting that healthy sleep is not protective against adverse heart impacts of noise exposure,” says lead study author Joseph Nguyen, an internal medicine resident physician at Massachusetts General Hospital and a member of the Cardiovascular Imaging Research Center in Boston. “We expected that disordered sleep would influence the relationship between noise exposure and heart disease. It was surprising to find that sleep health appeared to play no role."
Researchers analysed medical records and lifestyle surveys for more than 100,000 adults, and US government transportation noise data—looking at average noise levels above 45-50 decibels, which is comparable to moderate rainfall or typing on a keyboard. “It is important to note that the noise levels in our dataset are a 24-hour average, rather than peak noise levels, which may be much higher. For example, subway stations have an average noise level of about 75 decibels at rest and can be more than 100 decibels when trains are arriving or leaving,” Nguyen says.
The findings, he says, highlight the importance of limiting environmental noise exposure as much as possible. “People with noise exposure should consider strategies to reduce noise levels, such as installing thicker drywall, windows and doors in their home; placing bedrooms in the quietest areas of the house; planting dense trees and vegetation in the yard to absorb noise; and using earplugs during sleep,” he said.
Engineers also have a role to play. On roads, they're testing porous asphalt, which is peppered with tiny air pockets that soak up the sound of tyres on the road. It cuts traffic noise by up to six decibels, and has been implemented widely in the
Netherlands. In Germany and France, rail operators are testing rubber dampers that can be clamped to rails to stop them vibrating as trains pass. In cities, researchers are building knee-high roadside barriers lined with acoustic meta-materials,
shaped to trap certain frequencies. In the skies, jet engines are being
equipped with "chevron" edges that mix exhaust with the surrounding air more smoothly, lowering the roar on take-off.
“This study adds to the growing evidence that shows environmental factors such as air pollution, noise, artificial light, chemical pollutants and climate-related events may be contributing to the significant burden of cardiovascular disease as a leading cause of death worldwide. Creating stronger policies to reduce adverse environmental exposures and building durable infrastructure that emphasizes wellness, will help us tackle these environmental issues and help improve heart health, and create healthier, more sustainable communities for our children and our children’s children,“ said Keith Churchwell, co-author of the American Heart Association joint scientific statement.
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