What Causes a Heart Attack?

Everyday occurrences such as drinking coffee and alcohol, physical exertion and even breathing can help spur a heart attack, according to a Belgium study published in the journal The Lancet. The study researchers analyzed data from 36 separate studies of potential triggers for heart attack in people ranging in age from 44 to 72 years old. They then calculated the relative risk posed by each trigger and the population-attributable fraction (PAF)-the proportion of total heart attacks estimated to have been caused by a specific trigger.

Their results found that air pollution due to time spent in traffic triggered 7.4 percent of heart attacks. Other potential triggers included

  • Physical exertion 6.2 percent
  • Alcohol 5 percent
  • Negative emotions 3.9 percent
  • Sexual activity 2.2 percent
  • Cocaine and marijuana use just under one percent

Although only a small number of people in the entire population are exposed to cocaine, as opposed to the hundreds of millions exposed to air pollution on a daily basis, air pollution was estimated to cause more heart attacks across the population.

"Of the triggers for heart attack studied, cocaine is the most likely to trigger an event in an individual, but traffic has the greatest population effect as more people are exposed to the trigger. PAFs give a measure of how much disease would be avoided if the risk was no longer present," wrote the researchers. The World Health Organization (WHO) describes air pollution as "a major environmental risk to health" and estimates that it causes about two million premature deaths worldwide each year.

And while exposure to secondhand smoke was not included in the study, the effects are probably of the same magnitude as air pollution, the authors concluded, citing evidence from British studies showing that bans on smoking in public places have reduced the rate of heart attack by 17 percent.

Reducing Your Risk for Heart Attack

While air pollution may contribute to the development of cardiovascular diseases, a person's relative risk for contracting heart disease due to air pollution is small compared with the impact of established cardiovascular risk factors, such as smoking, obesity, or high blood pressure, according to the American Heart Association.

To stay heart healthy:

  • Eliminate saturated and trans fats from your diet and instead choose monounsaturated fats such as olive oil or canola oil.
  • Choose lowfat protein sources such as lean meat, poultry, and fish; lowfat dairy products; and legumes-beans, peas, and lentils
  • Eat more fresh fruits and vegetables and whole grains
  • Exercise at least 30 minutes a day, most days of the week


Medical News Today. "Air Pollution Can Trigger Heart Attacks To Same Extent As Known Risks Like Physical Exertion, Alcohol And Coffee." February, 24, 2011.

Mayo Clinic. "Heart-Healthy Diet: 8 Steps to Prevent Heart Disease."

American Heart Association. "Air Pollution, Heart Disease and Stroke." April 11, 2011.