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Bad air has lingering effect on heartbeat

PENN STATE(US)—Breathing combustion-related particles that are in diesel and coal combustion, as well as in oil, gas, and wood combustion used for cooking and heating, places stress on the heart’s regulation capacity for up to six hours, which in turn may contribute to cardiovascular disease.

The body’s ability to properly regulate heartbeat so the heart can pump the appropriate amounts of blood into the circulation system relies on the stability of the heart’s electrical activity, called electrophysiology.

“Air pollution is associated with cardiopulmonary mortality and morbidity, and it is generally accepted that impaired heart electrophysiology is one of the underlying mechanisms,” says Fan He, master’s program graduate at Penn State.

“This impairment is exhibited through fluctuations in the heart rate from beat to beat over an established period of time, known as heart rate variability. It is also exhibited through a longer period for the electric activity to return to the baseline, known as ventricular repolarization.

“The time course, how long it would take from exposure to cardiac response, has not been systematically investigated,” says He.

“We conducted this study to investigate the relationship between particle matter and heart electrophysiology impairment, especially the time course.”

The researchers reported their results in recent issues of the Journal of Exposure Science and Environmental Epidemiology and in Environmental Health Perspectives.

Liao’s team of researchers studied 106 people from central Pennsylvania, mostly in the Harrisburg metropolitan area. Nonsmokers over the age of 45 without severe cardiac problems wore air-quality and heart-rate monitors for 24 hours. The devices recorded data in one-minute intervals.

Results indicate that heart electrophysiology was affected up to six hours after elevated PM2.5 exposure. These adverse effects may trigger the onset of acute cardiac events and over time may result in increased risk of chronic heart disease. PM2.5 refers to particles up to 2.5 micrometers in size.

“Our findings may contribute to further understanding of the pathophysiology of air pollution-related cardiac events, specifically our results indicating elevated PM2.5 exposure is associated with immediate disturbance of cardiac electrical activities within six hours after exposure,” says Duanping Liao, professor of public health sciences.

The National Institute of Environmental Health Sciences funded this study.

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