Aircraft noise raises blood pressure even when one is sleeping

15 February, 2008

High-decibel noise from aircraft is not only jarring to the ears but can raise one's blood pressure (hypertension) even when one is asleep.

In a study conducted by the European Heart Journal and funded by the European Commission (EC), researchers monitored 140 sleeping volunteers in their homes near Heathrow airport in London and three other large airports in Europe.

It was found that the blood pressure of the volunteers went up after being exposed to a noise louder than 35 decibels, irrespective of whether the noise was caused by overhead aircraft, or snoring.

The volunteers' blood pressure was measured remotely at 15-minute intervals.

Noise created by aircraft triggered an average increase in systolic blood pressure of 6.2 mmHg and an average increase in diastolic blood pressure of 7.4 mmHg.

Similar increases in blood pressure were noticed in case of other noise sources, such as road traffic.

The study also found that, the louder the noise, the greater the increase in blood pressure. For every 5-decibel rise in aircraft noise at its loudest point, there was an increase of 0.66 mmHg in systolic blood pressure.

A research conducted on the subject by the same team earlier had shown that people who have been living for at least 5 years under a flight path near an international airport run a greater risk of high blood pressure compared to people living in less noisy enivronments.

Collectively, both studies suggest that living under a flight path almost doubles the risk of hypertension.

The researchers calculated that, for every extra 10 decibels of aircraft noise, the risk of hypertension rose by 14% in both men and women.

However, they admitted that the mechanism by which aircraft elevates blood pressure is still not known. They are planning further studies to look at the theory that the brain reacts to noise by raising levels of the stress hormone cortisol.

Dr Lars Jarup, lead researcher, from Imperial College, London, was quoted by BBC as saying, "We know that noise from air traffic can be a source of irritation, but our research shows that it can also be damaging for people's health – which is particularly significant in light of plans to expand international airports.”

High blood pressure can lead to stroke, heart failure, heart attack and kidney failure. Over a billion adults worldwide are estimated to suffer from the condition.