My Healthy Heart BlogsAdvertisementAdapted from a

My Healthy Heart BlogsAdvertisementAdapted from a

My Healthy Heart Blogs


Adapted from a HealthDay news release.

Joggers who run where there is a high concentration of air pollutants may want to take a breather after a new study confirmed that exercising in polluted air can increase risk of heart attack or arrhythmia.

The Scottish study reported that exposure to diesel fumes significantly reduced blood flow in the hearts of men who jog. The study looked at 20 men, all of whom had suffered a heart attack in the past but whose heart disease was stable. All participants were exposed to diluted diesel exhaust or filtered air for one hour both while resting and while riding an exercise bike.

Heart rates increased similarly in both the filtered air and diesel exhaust sessions. But those in the diesel exhaust group had lowered blood flow to the heart. The diesel exhaust also reduced the release of endothelial tissue plasminogen activator, a "clot buster."

The effects of exercising in polluted air may be even more dramatic than reported in these controlled studies where the negative effects of diesel pollutants are compounded by other particles in the air.

Previous research has associated short-term exposure to air pollution to cardiovascular disease and death. One study found that long-term exposure to air pollution increased the risk of death from cardiovascular disease by 76 percent. The dangers appear to be greatest with fine particulate air pollutants.

An earlier study also found that an interaction between the fine particles found in diesel exhaust and the fatty acids in LDL (bad) cholesterol activates the genes that can cause inflammation in blood vessels, speeding up the process of atherosclerosis. Atherosclerosis contributes to hardening of arteries.

Still, researchers and experts advocate exercise as an effective way to prevent heart disease risk. This new information indicates exercisers should try to avoid exercising outdoors at times when air pollution is high.

The study was reported in the New England Journal of Medicine.


New England Journal of Medicine September 13, 2007