Silent night? Well, a recent study shows that a night in London, where the noise from traffic reaches levels of more than 60 dB, leads to a 5% risk of getting a stroke among elders.
Other numbers are just as alarming. Researchers from the London School of Hygiene and Tropical Medicine in collaboration with Imperial College London and King’s College London, analyzed the results from a study covering over 8.6 million people during the years 2003-2010. People over 75 years of age, living in areas measuring above the 60 dB level, had a 9% increase in stroke cases, compared to elders living in neighborhoods with less noise. Younger adults suffered a 5% increase in the same type of risks.
A leading cause of stroke is hypertension, which in turn is linked to high blood pressure, where one of the major causes is stress in our day-to-day lives. Being exposed to high levels of traffic noise could certainly lead to higher levels of stress, although the researching team also take into account other factors that could lower the risks for stress and strokes.
Doctor Anna Hansell, co-author from the MRC-PHE Centre for Environment & Health at Imperial College London explains further: “From this type of study, we can’t tell for certain what the risks of noise are to an individual, but these are likely to be small in comparison with known risk factors for circulatory diseases like diet, smoking, lack of exercise, and medical conditions such as raised blood pressure and diabetes. However, our study does raise important questions about the potential health effects of noise in our cities that need further investigation.”
The World Health Organization, WHO, have defined levels above 55 dB from daytime traffic noise, as a point where people are exposed to health risks due to the noise. In London alone, more than 1.6 million people live with this type of stressful levels daily. Individual differences can certainly have an impact that lower or raise the risks, such as having your windows facing away from the noisy street, or the air pollution where you live and how much smoke from cigarettes you are exposed to daily.
The study backs up several other studies which have been linking a bit less serious health problems, such as sleep problems or increased blood pressure, to road traffic noise. However, lead author Doctor Jaana Halonen from the London School of Hygiene and Tropical Medicine, talks about the reasons for taking the results of the new findings as a big warning sign: “Road traffic noise has previously been associated with sleep problems and increased blood pressure, but our study is the first in the UK to show a link with deaths and strokes. This is the largest study of its kind to date, looking at everyone living inside the M25 over a seven-year period. Our findings contribute to the body of evidence suggesting reductions in traffic noise could be beneficial to our health.”
One would think that switching from conventional cars to electric ones would solve this problem of people facing the interrelated increased risk of death entirely. However, it is also well-known that the silent electric cars can create danger in themselves – people just don’t hear them coming around that corner.
This is taken seriously as well, and laws regulating the levels of noise allowed from new, conventional cars, are written at the same time as laws regulating how much noise has to be added to electric cars, just to warn people off in advance that one is closing in on them.
Image: Oran Viriyinci