A Surprising Cause of High Blood Pressure

A new and surprising cause of high blood pressure has been discovered.

People who live within earshot of traffic noise - loud engines running, constant honking horns and the scream of screeching brakes - have an increased risk of high blood pressure according to work that appears in the September 9, 2009 issue of the open access journal Environmental Health.

And since hypertension can exist for years in silence, without a single symptom, it's important to be aware of things around you that might increase your risk.

One of those may be too much time spent near busy, noisy roadways. Noise pollution is one of the most destructive forms of pollution, with more noise out there today than ever before. And fewer ways to escape it.

However, the source of most of the modern barrage of sound is transportation related, the noise of cars, planes and trains.

The team of researchers out of Sweden's Lund University Hospital analyzed data from just over 24,000 public health questionnaires filled out by subjects ranging in age from 18 to 80 years old concerning their living arrangements in Scania, a province in southern Sweden.

The researchers also calculated the average residential exposure to traffic noise by using the common traffic levels, speed limits and the distance from a subject's home to the road.

About 30% of Europeans live in places where the noise from nearby traffic averaged 55 decibels or higher. In the U.S. subways are a major source of excessive noise exposure for an estimated 33 million riders each workday.

This says nothing of the many other sounds, like blaring stereos, construction equipment, screaming sirens and the like that assault our ears each and every day.

According to the research, young and middle-aged subjects in the study who lived near traffic noise above 60 decibels (the sound level of normal conversation) were more likely to have high blood pressure.

In fact, the risk of hypertension went up by more than 25% for those who were exposed to traffic noise at this level. The effect was most apparent for middle-aged adults from 40 to 59 years old. The association with high blood pressure got stronger as the sound level got higher. For sounds above 64 decibels, the risk of hypertension rose by more than 90%.

According to the experts, the likely culprits for the rise in blood pressure from the noise was the stress and disruption to sleep of the traffic sounds from the road.

Interestingly, among 60 to 80 year olds higher decibel levels didn't impact hypertension. Science knows that aging causes gradual hearing loss, especially in the high frequencies. As young people often don't have high blood pressure, it may be that the impact of the traffic noise was more obvious.

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

If you're worried about the levels of noise around you, there are things you can do. If you're looking to get the sound outside your home under control, one of the most natural, earth-friendly suggestions is to plant trees or tall shrubs at the edge of your property. Manmade materials of either renewable wood material or recycled plastic also serve to absorb sound and leave you with some welcome peace and quiet, or at least less noise.

Other options include double glazing the house, ear plugs are night and thicker curtains, as these action may reduce the noise levels in the house, which is seen to be the cause of high blood pressure in those taking part in the study.