Traffic noise bad for your health

New York - Sitting in traffic can get your blood boiling temporarily but living near it might raise your risk of high blood pressure long-term, according to a Swedish study.

Researchers from Lund University Hospital found that among 24 238 Swedish adults aged between 18 and 80, those living near noisier roads were more likely to report having high blood pressure than those living in more peaceful surroundings.

"Road traffic is the most important source of commmunity noise," said research Theo Bodin in a statement.

"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."

Middle-aged adults with the highest traffic-noise exposure - averaging more than 64 decibels which is just louder than an ordinary conversation - were almost twice as likely to report high blood pressure compared to other people.

Of the adults aged 40 to 59, 28% of those with the highest traffic noise exposure said they had high blood pressure compared to 17% living nearer to quieter roads.

A similar pattern was seen among young adults but not among the elderly which the researchers suggested was because older people had multiple risk factors for high blood pressure.

Stressful situation

"The effect of noise may become less important, or harder to detect, relative to other risk factors with increasing age. Alternatively, it could be that noise annoyance varies with age," said Bodin.

He said figures show that 30% of the population of the European Union hears an average traffic noise exceeding 55 decibels around the clock.

The findings, published in the online journal Environmental Health, which involved calculating the average 24-hour traffic noise level in the area were people lived, add to evidence that chronic noise exposure may spell health trouble.

Other studies have found that people living near airports or working in noisy jobs have an increased risk of high blood pressure and heart attack.

The theory is that noise essentially signals to the body that it's in a stressful situation and so chronic exposure may cause long-term increases in stress hormone production, heart rate and blood pressure. Noise can also disrupt sleep.

But the Swedish researchers said the current findings do not prove that nearby traffic caused study participants' high blood pressure but suggest it might have been a factor in some cases.

The researchers did not measure participants' blood pressure but just asked them if they had high blood pressure.

They said more research was needed into how much effect noise has on health.