House prices may dictate where you live. But if you're looking near an airport, be warned. Two research papers in the BMJ (one based in the UK and covering people of all ages, and one in the US of over-65s) show a link between exposure to aircraft noise and admission to hospital for heart disease.
The US study found a 3.5% increase among people exposed to higher levels while the UK study showed up to 20% increase in stroke and heart disease. The UK study included 3.6 million people living near Heathrow and defined aircraft noise as being a nuisance at 57 decibels (dB). A normal conversation is 50dB.
The researchers divided the study into neighbourhoods of 300 people and took into account ethnicity (heart disease is more common in South Asian people), social deprivation, lung cancer as a proxy for smoking and in some areas they looked at traffic noise and pollution. They still found an increased risk of stroke and heart disease related to noise. The researchers couldn't separate the effects of night versus daytime noise as areas with the highest noise levels had both.
Rates for stroke were 24% higher in areas with the most noise compared with those with the least, and rates for heart disease were 21% higher. So should you avoid living near an airport – and, if so, isn't living by a motorway just as bad for you?
The solution
The studies show a link only, but do support previous research that found a correlation between rises in blood pressure and exposure to aircraft noise. Noise startles the sympathetic nervous system into releasing adrenaline and noradrenaline that increase blood pressure and heart rate. It raises cortisol, which increases blood sugar levels. The theory is that this repeated stress damages the heart.
Other studies show similar links between road traffic noise and heart disease and stroke. In a Danish study of 57,053 people in Copenhagen, aged between 50 and 64, researchers calculated the noise from traffic (looking at road type, speeds and average amount of traffic) and linked levels to heart attacks that had been recorded in the Danish hospital registry. They found a 10dB higher level of road traffic noise was associated with a 12% higher risk for heart attacks. The study took other risk factors into account such as sex, smoking status and BMI.
The fact that environmental noise has widespread effects is even shown in a study of urban blackbirds that found traffic noise rather than artificial light shifted their dawn chorus to an earlier time. But these studies have limitations and eating healthily, exercising and not smoking will do more for your heart than moving house.
