Harmful effects of living near airports, highways on your heart

Are you living near the highway or airport? Beware, you could be suffering from high risk of heart diseases. According to a study, years of exposure to excess noise can severely damage your heart. The study warns that prolonged exposure to excess noise may increase the risk of heart disease and stroke.

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How is excess noise harmful to the heart

Excess noise activates a brain region involved in stress response and promotes blood vessel inflammation, say researchers at Massachusetts General Hospital in the US. They say that people with the highest levels of chronic noise exposure, such as highway and airport noise, showed increased risk of suffering cardiovascular problems such as heart attacks and strokes, regardless of other risk factors.

 "A growing body of research reveals an association between ambient noise and cardiovascular disease, but the physiological mechanisms behind it have remained unclear," said Azar Radfar, a research fellow at the Massachusetts General Hospital in Boston.

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The study on chronic noise exposure

The study provides deeper insight into the biological mechanisms of the interplay between cardiovascular disease and chronic noise exposure, researchers said. "We believe our findings offer an important insight into the biology behind this phenomenon," Radfar said.

• Researchers experimented upon 499 people with average age of 56 years. All participants were free of cardiovascular illness and cancer at the start of the study.
• The researchers studied the link between noise exposure and major cardiovascular events. After an analysis of those who had simultaneous PET and CT scan imaging of their brains and blood vessels, diagnostic validation was done in a subset of 281 subjects.
• Using those images, the scientists assessed the activity of the amygdala an area of the brain involved in stress regulation and emotional responses, among other functions.        
• To capture cardiovascular risk, the researchers examined the participants' medical records based on the initial imaging studies.
• Of the 499 participants, 40 experienced a cardiovascular event (eg heart attack or stroke) in the five years following the initial testing.
• To gauge noise exposure, the researchers used participants' home addresses and derived noise level estimates from the US Department of Transportation.
• People with the highest levels of noise exposure had higher levels of amygdalar activity and more inflammation in their arteries, researchers said.
• These people also had a greater than three-fold risk of suffering a heart attack or a stroke and other major cardiovascular events, compared with people who had lower levels of noise exposure, researchers said.
• That risk remained elevated even after they accounted for other cardiovascular and environmental risk factors, including air pollution, high cholesterol, smoking and diabetes.
• Additional analysis revealed that high levels of amygdalar activity appears to unleash a pathway that fuels cardiac risk by driving blood vessel inflammation, a well-known risk factor for cardiovascular disease.

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(With PTI inputs)