IS EXTREME EXERCISE BAD FOR YOUR HEART?
When it comes to exercise, we often encourage ourselves to push it to the limits in order to see the best results in the least amount of time. But is there such a thing as too much exercise, and couldit actually be damaging to your heart?INCREASED CORONARY CALCIUMA study conducted at the St. George’s, University of London, presented at a meeting of the European Society of Cardiology, found that extreme exercise volume or intensity could be associated with increased levels of atherosclerosis in the coronary arteries. Dr. Sanjay Sharman, a British sports cardiologist who is the medical director for the London marathon, oversaw the study.The study involved two groups— one group was made up of 169 competitive endurance athletes over the age of 40 and the other group involved 171 people (also over the age of 40) who were more sedentary but exercised up to 150 minutes per week, which is the amount of exercise per week currently recommended by a U.S. exercise guideline. The competitive endurance athletes were malesand females who had been competing in endurance exercise for more than 10 years and ran more than 35 miles or cycled more than 150 kilometers per week, said Dr. Ahmed Merghani, a cardiologist who led the study. Both groups contained individuals who did not smoke, weren’t diabetic and didn’t have high cholesterol.“What we found is that individuals and athletes who exercise at extreme levels … do have a higher degree of coronary calcium or hardening of their arteries, which is something that’s often seen in coronary artery disease,” said Dr. Merghani. And while certainly exercise is beneficial, it is possible to reach a certain point where you see diminishing returns, he added. “But I have to point out that point is really quite high and it probably doesn’t affect the majority of people who are recreational athletes.”DENSE VERSUS SOFT PLAQUEBut there was also some good news that came out of the study, said Dr. Merghani. There are different types of plaque that can build up in the arteries— hard or soft calcium, or a mixture ofboth. The extreme exercisers in the study had more dense plaque, which is less likely to cause a blockage in the arteries and result in a heart attack or stroke. On the other hand, soft calciumis more vulnerable and more likely to break off. But even so, plaque-free arteries are ideal, he added.But what could be causing the more extreme exercisers to increase their coronary calcium levels? While no one really knows the answer to that, said Dr. Merghani, it could due to rubbing friction on the artery wall, which over time could start to harden. Other factors could be underlying inflammation and/or unbalanced hormones. In fact, the fastest men in the study had higher levels of coronary calcium, and this may be due to hormones, said Dr. Merghani. Females are more protected because of estrogen, which protects the arteries.CAUSE FOR CONCERN?So should extreme exercisers be concerned? Larger studies are required to determine that. “We know for a fact that people who do exercise live longer,” said Dr. Merghani. “My feeling is that if youdo that degree of exercise, and you’re healthy, don’t smoke, keep a good weight, have a good diet— I think you probably would have more benefits regardless of what your calcium shows.”However, if you do exercise to that extreme and have high blood pressure and smoke, among other risk factors, this would of course not be good for our health. “But I think the study as a whole probably does at least prove that exercise is not infinitely beneficial, and I think people think that the more you do, that the more benefits you get,” he said.Dr. Merghani hopes that the study will lead to more interest in this area of research. “We hope to collaborate with others and hope that the study will encourage others to produce largerstudies.”
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