One of the greatest challenges associated with living close to a highway or in the heart of a town is interruption or lack of sleep due to traffic noise. A new study by the Danish Cancer Society has indicated that beyond being prone to frequent insomnia, people who are exposed to louder sounds of traffic near their homes have a higher risk of heart attack.
The researchers found that for every 10-decibel increase in traffic noise, there was 12 per cent higher risk of heart attack. They also add that they began seeing increases in risk starting at around 40 dB. In the study published in PLOS ONE journal, lead author, Mette Sorensen, and her fellow researchers followed more than 50,000 men and women, ages 50 to 64, living in Copenhagen and Aarhus, two of Denmark’s largest cities.
Each participant reported their lifestyle behaviours like diet and physical activity, as well as the place each lived over a 10-year period. The researchers monitored the participants’ health over the course of the study, comparing it to the geographic location of their homes. The researchers also figured out how much traffic noise each person had been exposed to by analysing traffic patterns around the participants’ homes. During the 10-year study period, 1,600 people had a first attack and the louder the traffic noise near their homes was, the greater the risk they faced. The link between noise and heart attacks held even after the researchers accounted for other factors like air pollution exposure, diet, gender and weight.
“There are a variety of things that could explain the association: stress, for one. People who live in hectic urban centers tend to have more stress than those in quieter locales, and stress is a well-known trigger of heart attack. The noise itself probably does increase stress and the levels of stress hormones like adrenaline. Your blood pressure is probably going up as well,” said Dr. Robert Bonow, a professor of Medicine at the Northwestern Feinberg School of Medicine.
The study also suggests that traffic noise does not have to be deafening to affect your health. Forty decibels, they added, is about as loud as a bird call or the inside of a library and, by comparison, a vacuum cleaner is 70 dB, and a passenger car traveling at 65 miles per hour measures 77 dB from 25 feet away. The researchers recommended that people, who live near traffic prone areas, should sleep in a quieter interior room.
People with longer commutes tend to be less physically active, even after the researchers took into account extenuating factors such as age, race, educational levels and family size. Seventy-six per cent of people who worked within five miles from their homes averaged at least 30 minutes of moderate-to-vigorous exercise per day, compared to just 70 per cent of those whose commute exceeded 30 miles round-trip.