The air you breathe every day may be threatening the health of your heart, leading to the formation of plaque that blocks arteries. Researchers have found that when you inhale polluted air, your immune system responds by setting off an inflammatory process that leads to artery blockages threatening the heart. By simply breathing cleaner air, you may be able to lower your risk of this dangerous development.

Scientists at Ohio State University have found that when you are continually exposed to very fine particulate matter in polluted air, your body responds by allowing white blood cells to travel out of bone marrow and enter the bloodstream. Consequently, these white blood cells collect in the circulatory system and fat tissue where they release chemicals leading to inflammation that encourages arterial plaque. Eventually, these blockages can cut off blood flow to the heart.

Artery Problems

Laboratory research at the Mount Sinai School of Medicine and the New York University School of Medicine shows that exposure to polluted air can increase plaque formation by at least 1.5 times. The researchers also found that combining a high fat diet with breathing polluted air presents a special danger to heart health. “This (study)… demonstrates measurable changes in plaque production and artery inflammation following exposure to fine particle matter (in air pollution),” says David A Schwartz, M.D., former director of the National Institute of Environmental Health Sciences.

Immune Response

The cellular activity that leads to cardiovascular disease from polluted air is basically an immune response that has escalated out of control. Under normal circumstances, inflammation is beneficial: It allows the immune system to expel or destroy pathogens and invading microbes that can cause disease. But when pollution causes excessive inflammation that plays no role in healing or protecting the body, this abnormal, heightened immune response can lead to blocked blood vessels as well as weight gain and diabetes.

Interestingly, the actions that lead to cardiovascular problems seem to begin in fluid that lines the lungs. Polluted air changes the molecular structure of this fluid into a form that sets off a cascade of damaging white blood cell activity.

“Our main hypothesis is that particulate matter (from pollution) stimulates inflammation in the lung, and products of that inflammation spill over into the body’s circulation, traveling to fat tissue to promote inflammation and causing vascular dysfunction,” says Sanjay Rajagopalan, M.D., who authored the study.

The protective fluid in the lungs is filled with molecules called phospholipids. The scientists found that when you breathe in polluted air these phospholipids become oxidized, harmfully altering their shape and functions.

“After exposure (to air pollution) there is an increase in oxidized phospholipids in the lung fluid,” says Thomas Kampfrath, another researcher at Ohio State. “… the increase in oxidized phospholipids in turn promotes inflammation.”

Protecting Heart And Lungs

The lesson you need to take away from this research:  Avoid dirty air and be careful not to exercise outside when the air is particularly bad. “We used to think air pollution was problem that primarily affects the lungs. We now know it is also bad for the heart,” warns Robert A. Kloner, M.D., Ph.D., director of research at the Heart Institute of the Good Samaritan Hospital in Los Angeles.