The noise of traffic increases the risk of stroke, according to a Danish study published in the European Heart Journal. Mette Sorensen from the Danish Cancer Society and colleagues analyzed data on more than 50 000 people living in urban areas.
For each increase of 10 decibels for residential exposure to traffic noise, the risk of vascular accident (CVA) cerebral increased by 27% in people over 65 (and 14% for people of all ages the young are practically not affected). Above 60 decibels, the risk increased further. Noise is a stressor and disrupts sleep. It promotes the activation of the sympathetic nervous and endocrine systems, causing an increase in blood pressure and heart rate and the release of stress hormones, the researchers noted.
Previous studies had already shown a link between traffic noise and increased blood pressure and heart attacks.
The study did not account the level of pollution, which may be related to noise and is also associated with increased cardiovascular risk.
In October 2009, the World Health Organization (WHO) presented recommendations for health protection against noise pollution at night. It set an exposure limit annual average night not exceeding 40 decibels, equivalent to the noise in a quiet street of a residential neighborhood.