This is very very interesting - may explain why I get so aggravated by the gardeners and their goddammed loud leaf blowers that not only make so much noise and keep me from my precious sleep but they also pollute and smell awful!
How noise causes illness
How could exposure to noise have such devastating effects on human health as causing cardiovascular disease?
Key to solving this puzzle is recognising that noise can create a form of chronic stress that keeps our bodies in a state of constant alert. Research published last year by Wolfgang Babisch of Germany's Federal Environmental Agency in Berlin shows that even when you are asleep, your ears, brain and body continue to react to sounds, raising levels of stress hormones such as cortisol, adrenalin and noradrenalin.
This makes evolutionary sense, as all animals need to be alert to threats even when they are asleep, so they can wake up and flee if necessary, says Andy Moorhouse, an acoustics researcher at the University of Salford, UK.
However, if these stress hormones are in constant circulation, they can cause long-term physiological changes that could be life-threatening. The end result can be anything from heart failure and strokes to high blood pressure and immune problems. "All this is happening imperceptibly, and this is the key," says Deepak Prasher of University College London, who collaborated on the WHO study. "Even when you think you're used to noise, these physiological changes are still happening," he says.
What's more, there are a wide range of sources of noise stress. Some are big and obvious, such as constant heavy traffic or aircraft taking off, while others are much more subtle and difficult to define as "pollution", yet can still cause intense anxiety and irritation. In the case of noisy neighbours, for example, stress might be triggered simply by knowing a neighbour is in, even if they are not being noisy at that point. "If you have no control over the noise, that's what creates anger and stress and causes people to tip over the edge," says Val Wheedon, a veteran campaigner against noise pollution in the UK and co-founder of the UK Noise Association. In such disputes, noise serves not only as an irritation, but symbolises perceived lack of consideration in others, priming the body for confrontation, Wheedon adds.
Noise can aggravate stress still further if it disturbs sleep, which can result in constant fatigue and outbursts of aggressiveness and irritability. People exposed to noise during their sleep have been shown to wake up more often and fidget more in their sleep - both indicators of sleep disruption.
There is also mounting evidence that excessive noise disrupts learning and education. As far back as 1975, studies by Arline Bronzaft in New York showed that the reading skills of children in classrooms next to noisy railways lagged three to four months behind those of their peers in quieter classrooms. More recently, Staffan Hygge of the Laboratory of Applied Psychology in Gävle, Sweden, demonstrated that the long-term memory recall of children in part of Munich, Germany, improved by 25 per cent after a nearby airport was closed (Psychological Science, vol 13, p 469). The recall ability of children living near the new airport deteriorated by the same amount once it opened.
