MedWire News: Aircraft and traffic noise increase people's blood pressure levels even when they are asleep, results of a European study show.

"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," said researcher Dr Lars Jarup from Imperial College London in the UK.

Lead researcher Dr Klea Katsouyanni, from the National and Kapodistrian University of Athens in Greece, and colleagues studied 140 volunteers who lived near Heathrow airport in the UK and three other major European airports.

The team analysed the participants' blood pressure levels every 15 minutes while they slept and monitored noise levels in their bedrooms.

The researchers found that the volunteers' blood pressure levels increased noticeably after they experienced a noise greater than 35 decibels, such as aircraft passing overhead, traffic on a road outside their house or a partner snoring.

For example, aircraft noise increased the volunteers' average blood pressure levels by between 6.2 mmHg and 7.4 mmHg.

Further analysis revealed that for every 5 decibel increase in noise, the volunteers' average blood pressure levels increased by 0.66 mmHg.

The effect of noise on the volunteers' blood pressure levels occurred even when they remained asleep and were not consciously disturbed.

The findings follow another study conducted by the same researchers, which showed that people living near international airports have a greater risk of developing high blood pressure than those who live in quieter areas.

Dr Jarup concluded: "Our studies show that night-time aircraft noise can affect your blood pressure instantly and increase the risk of hypertension.

"It is clear to me that measures need to be taken to reduce noise levels from aircraft, in particular during night-time, in order to protect the health of people living near airports."

The research is appears in an advance online publication by the European Heart Journal.