This summer, it’s in your best interest to pay attention to local ozone level alerts. A recent study found that just two hours of exercising during increase ozone levels can cause unfavorable changes in heart function–even in those with no history of heart disease.
The study, recently published in the journal Circulation, asked healthy, young volunteers to participate in two hours of intermittent exercise in a lab while being exposed first to “clean” air, and then to air containing 0.3 parts per million of ozone. While this level is somewhat higher than average ozone levels in most U.S. cities, it is on par with the amount of ozone a person in an average American city would be exposed to if they spent seven to eight hours outside.
Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found. Troposheric, or ground level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). Ground level ozone can be especially bad in urban areas during hot summer months.
Scientists were surprised to find that after just two short hours under the ozone conditions, participants experienced a nearly 99 percent jump in levels of interleukin-8, an marker for inflammation in the blood vessels. They also showed a 42 percent drop in plasminogen levels, which lowers the body’s ability to break up blood clots.
“This study provides a plausible explanation for the link between acute ozone exposure and death,” Robert Devlin, a senior scientist at the U.S. Environmental Protection Agency’s National Health and Environmental Effects Research Laboratory and the study’s lead author, said in a statement.
Before planning a day of outdoor fun or exercise, be sure to check the ozone levels in your area. A complete evaluation of current ozone levels in the U.S. can be found at AirNow.gov.
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