Night-time noise from aircraft, traffic or even snoring can increase a person's blood pressure even if it does not wake them, a study suggests.
Researchers measured the blood pressure of 140 sleeping volunteers in their homes near Heathrow and three other major European airports, remotely every 15 minutes.
Their findings published in the European Heart Journal showed blood pressure increased noticeably after a 'noise event' - a noise louder than 35 decibels - such as aircraft travelling overhead, traffic passing outside or a partner snoring. This effect could be seen even if the volunteer remained asleep and so was not consciously disturbed.
Aircraft noise events caused an average increase in systolic blood pressure of 6.2 mmHg and an average increase in diastolic blood pressure of 7.4 mmHg. The increase in blood pressure was larger if the noise was louder. For example, for every 5dB increase in aircraft noise at its loudest point, there was an increase of 0.66 mmHg in systolic blood pressure.
The research follows a study 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 than a population living in quieter areas.
Dr Lars Jarup, one of the authors of the study from the Department of Epidemiology and Public Health at Imperial College London, said: "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."