Deceptive Headlines about Exercise and Heart Attacks

"You Can Exercise Yourself to Death, Says New Study" was the headline in The New York Post on October 17, 2017. Headlines like that are likely to discourage people from exercising and thus to shorten their lives. The entire article was a disturbing and offensive misinterpretation of a study from the University of Illinois at Chicago of 3,175 people in the CARDIA study (Mayo Clinic Proceedings, Oct. 16, 2017). The study showed that men who spend a lot of time exercising each week have more plaques in their arteries than moderate exercisers, but it did not show that these men suffer more heart attacks. The world's scientific literature shows that heavy exercisers live longer and suffer far fewer heart attacks than people who do not exercise (JAMA Intern Med, 2015;175: 959–967; Circulation, 2007;116(9):1094-1105).

The study showed that white, but not black, men who worked out at least seven hours a week over 25 years were 86 percent more likely to have a buildup of plaques in the arteries leading to their hearts by their fifties. The authors used an X-ray test called "calcium score" to measure plaques in arteries. The U.S. exercise guidelines recommend 150 minutes of moderate activity or 75 minutes of vigorous activity weekly (Physical Activity Guidelines, US Department of Health and Human Services, 2008:683), and the heavy-exercising group in this study exercised three times more than this recommendation. The authors of the new study state that their findings "do not suggest that anyone should stop exercising" and that "this plaque buildup may well be of the more stable kind, and thus less likely to rupture and cause heart attacks, which was not evaluated in this study."

Why the People Who Exercise Extensively May Have More Plaques Plaques form in arteries primarily because of an unhealthful diet. Vigorous and prolonged exercise burns lots of calories so it makes you eat more food. If your exercise program causes you to eat more of the unhealthful foods, you can expect to have more plaques in your arteries. A diet that is high in sweets, refined grains, sugared drinks, juices, red meats, processed meats and fried foods is associated with increased risk for forming plaques and suffering and dying from heart attacks (Journal of the American College of Cardiology, July 2017;70(4)). A heart-attack-preventing diet is high in vegetables, fruits, whole grains, beans, nuts and other seeds.

A heart attack has little to do with the amount or size of plaques in arteries, and a heart artery that is 99 percent blocked does not cause a heart attack. A heart attack is caused by a sudden complete blockage of blood flow to the heart muscle. First a plaque breaks off from the inner lining of an artery leading to the heart. Then that area bleeds and clots. If the clot extends to block all flow of blood through that artery, the heart muscle is deprived completely of oxygen and that part of the heart muscle dies. Exercise does not prevent plaques from forming, but exercise can stabilize plaques so that they are less likely to break off to cause heart attacks. See Exercisers Have More Stable Plaques

• What you eat and genetics cause plaques to form in arteries.

• A heart attack is caused by a plaque breaking off from an artery.

• Exercise stabilizes plaques so they are far less likely to break off to cause a heart attack.

• People who eat lots of plaque-forming foods have more plaques, regardless whether they exercise or not.

• Athletes eat more food than non-exercisers

• Athletes who eat unhealthful foods are likely to have more plaques. 
Caution: Check with your doctor about your exercise program and diet if you have evidence of heart disease: high blood pressure, high blood cholesterol, high triglycerides, high blood sugar or HBA1c, high C-reactive protein (a measure of inflammation), an abnormal EKG, or chest pain, particularly with exercise.

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