Aircraft noise raises blood pressure

  • Deborah Condon

The noise from aircraft or traffic can raise a person’s blood pressure at night, even if it does not wake them, the results of a new study indicate.

A team of European researchers monitored 140 volunteers at their homes near London Heathrow Airport and three other major European airports. The volunteers’ blood pressure was measured at 15 minute intervals. This was then analysed in relation to the noise recorded in the volunteers’ bedrooms.

The study found that the participants’ blood pressure increased noticeably after they experienced a ‘noise event’. This was defined as a noise louder than 35 decibels, such as aircraft travelling overhead, traffic passing outside or a partner snoring.

The effect could be seen even if the volunteer remained asleep and so was not consciously disturbed.

Blood pressure is measured using two numbers, e.g. 120/80. The first figure is the systolic blood pressure (the pressure in the arteries when the heart contracts and pushes the blood out into the body). The second figure is the diastolic blood pressure (the pressure in the arteries when the heart is filled with blood as it relaxes between two beats).

According to the World Health Organisation, high blood pressure is defined as 140/90mmHg or more.

The researchers found that aircraft noise events caused an average increase in systolic blood pressure of 6.2mmHg and an average increase in diastolic blood pressure of 7.4mmHg. Similar increases were seen for other noise sources, such as road traffic.

The researchers also found that the increase in blood pressure was related to the loudness of the noise. A greater increase in blood pressure could be seen when the noise level was higher. For example, for every five decibel increase in aircraft noise at its loudest point, there was an increase of 0.66mmHg in systolic blood pressure.

The decibel level, not the origin of the sound, was the key factor in determining the effect that each noise event had on the volunteers’ blood pressure. In other words, there were similar effects regardless of the type of noise, where the ‘loudness’ of the noise was the same.

The research follows recent findings by the same researchers, showing that people who have been living for at least five years near an international airport, under a flight path, have a greater risk of developing high blood pressure, compared to people living in quieter areas.

That study, which was published in the journal Environmental Health Perspectives, showed that an increase in night-time airplane noise of 10 decibels increased the risk of high blood pressure by 14% in both men and women.

“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. Our studies show that night-time aircraft noise can affect your blood pressure instantly and increase the risk of hypertension”, said Dr Lars Jarup of Imperial College London.

He added that measures need to be taken to reduce noise levels from aircraft, particularly at night, ‘in order to protect the health of people living near airports’.

The researchers are continuing their studies to find out whether combined exposure to noise and air pollution increases the risk of heart disease.

Details of these findings are published in the European Heart Journal.

For more information on heart health, see our Heart Disease Clinic at http://www.heart.ie


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