Ozone Exposure May Increase Risk of Heart Attack

Ozone exposure associated with heart harm

(RxWiki News) Exposure to an excessive amount of ozone may cause harm to the heart that can increase the risk of heart attack, researchers have found in a small study.

At the ground level, ozone is created when pollution from power plants, industry, chemical solvents and cars react with sunlight.

"Set your thermostat slightly higher in summer."

Robert B. Devlin, PhD, the study’s lead author and senior scientist at the U.S. Environmental Protection Agency’s (EPA) National Health and Environmental Effects Research Laboratory, noted that the findings show a plausible explanation for the association between acute ozone exposure and death.

Study participants exposed to ozone were found to have vascular inflammation, nervous system changes related to heart rhythm control and less ability to dissolve blood clots in blood vessels.

During the controlled study, 23 participants between the ages of 19 and 33 were exposed to 0.3 parts per million of ozone for two hours, more than the EPA’s eight hour ozone standard of 0.076 ppm.

The two-hour exposure was roughly equal to to exposure to 0.076 ppm for eight hours. Changes caused by the exposure were reversible in the young and healthy volunteers.

During a period at least two weeks apart, participants were also exposed to clean air. Study volunteers alternated 15-minute periods of rest and stationary cycling during the exposure tests.

Immediately after ozone exposure and the following morning, investigators found that participants had Increased blood levels of interleukin 1beta, a signature marker of inflammation believed to play a key role in heart disease.

They also determined participants experienced a decrease in plasminogen activator inhibitor 1 and plasminogen, which help dissolve blood clots along the walls of arteries, and a heart rhythm change was detected, suggesting altered automatic nervous system control of heart rate.

“People can take steps to reduce their ozone exposure, but a lot of physicians don’t realize this,” Devlin said.

Exposure to ground-level ozone can be reduced by using household and garden chemicals wisely, properly maintaining cars, taking public transportation when feasible, and conserving electricity.

The EPA also suggests limiting outdoor physical activity when Air Quality Index is poor. Ozone often peaks in the mid-afternoon or early evening.

The study, funded by the EPA, was recently published in Circulation, an American Heart Association journal.

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Review Date: 
June 25, 2012