Traffic noise raises risk of blood pressure
POSTED September 12, 2009 - 16:27 | POSTED BY Neharika Sabharwal
Last edited by Harpreet Bhagrath on September 12, 2009 - 20:10
Theo Bodin and a team of researchers from Lund University Hospital, Sweden conducted a study to investigate the change in blood pressure, heart rate, and stress hormone levels resulting from exposure to high levels of traffic noise.
Bodin stated, "Road traffic is the most important source of community noise. Non-auditory physical health effects that are biologically plausible in relation to noise exposure include changes in blood pressure, heart rate, and levels of stress hormones."
A large survey conducted
The team designed a large cross-sectional survey and collected data from 24,238 residents aged 18-80 years from Scania in southern Sweden. The information gathered was related to how close they lived to busy roads, health and lifestyle.
Other factors taken into account were sex, age, alcohol intake, exercise, education, smoking and socioeconomic status.
They then calculated the average road noise over a period of 24-hours, in the areas the subjects lived in.
The researchers observed that a moderate exposure to traffic noise did not affect the blood pressure in most people.
A 10 percent increase in hypertension was noted in people exposed to the traffic din between 45-64 decibels. However, noise exceeding 60 decibels was associated with as much as 45 percent increase in blood pressure.
Effect more pronounced in the young and middle aged than old
The researchers noted that the effect of noise was more significant among the relatively young and middle-aged people, perhaps because hyper-tension is less common in their age group. They concluded that noise leads to stress, which in turn releases hormones that boost blood pressure.
Bodin said, "We found that exposure above 60 decibels was associated with high blood pressure among the relatively young and middle-aged, an important risk factor for cardiovascular diseases such as heart attack and stroke."
The surprise element was that people above 60 years were not much affected by higher levels of noise.
“One explanation for the absence of effect among the elderly could be that the effect of noise may become less important, or harder to detect, relative to other risk factors with increasing age,” said the researchers.
The study was funded by the Swedish Council for Working Life and Social Research. It was published in the online journal Environmental Health, which is owned by a company called BioMed Central.
