Athlete's Heart Blog

Dr Larry Creswell

Dr. Larry Creswell on athletes and heart health.
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In the News: Why Do Athletes Live Longer?

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I came across an interesting article in the November 30th edition of U.S. News & World report online and thought I’d share it with you here. It’s interesting reading.

There is an abundance of data that indicate beneficial effects of exercise….and one of those benefits may be a longer life-expectancy. But why?

Last week, in the online version of Circulation, an American Heart Association medical journal, a group of investigators in Hamburg, Germany report some novel findings in young and middle-aged track and field athletes in an article, entitled “Physical exercise prevents cellular senescence in circulating leukocytes and in the vessel wall.”

It turns out that endurance athletes have longer telomeres–the DNA at the tips of the chromosomes that protect cells–in their white blood cells compared to non-athletes. The authors speculate that this feature provides, over a lifetime, an anti-aging effect.

It’s also interesting to note that three American scientists shared the Nobel Prize in Medicine this year for their work, over many years, to understand the telomeres and the process of cell death and aging. You can read about this in a report at cnn.com from earlier this week.

Scientists are only beginning to understand the process of aging in humans, but it is nice to know that endurance athlete’s may have a leg up!

In the News: Acute Effects of Marathoning on the Heart

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At last month’s annual scientific meeting of the American Heart Association, investigators from the William Beaumont Hospital in Royal Oak, Michigan, reported on a small study of runners who participated in the 2008 Detroit Marathon.

The abstract for their presentation was published in the Abstract Book for the meeting and their findings are also summarized in this article from ScienceNews online.

There has long been the concern that there is acute (and possible long-lasting) heart damage in amateur runners who participate in marathon events. The study participants underwent blood tests, a cardiac MRI scan, and 24-hour Holter monitoring (tape recording of the ECG) 4 weeks before and then immediately after the marathon. The authors reported that, although there is release of a small amount cardiac enzymes into the bloodstream (indicating potential heart stress) during and immediately after a marathon, there is no evidence of damage per se to the heart. They also confirm the findings of many previous investigators that there is mild to moderate enlargement of the right atrium and right ventricle when they are measured immediately after the marathon. These changes are thought to resolve within 3 to 6 months after the event.

The detailed findings from this study probably won’t appear in medical journal for a year or more, but long-distance runners should take some comfort from this report.

The Athlete’s Cardiac Paradox

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With a nearly unquenchable thirst for healthier living, the ranks of athletes at all levels have grown over the past 20 years. More than 7 million high school athletes, nearly 400,000 college athletes, and countless millions of adult Americans now exercise routinely or take part actively in competitive athletics. The heart-healthy benefits of regular exercise have been widely documented, but we also know that strenuous exercise increases the risk of sudden death due to a variety of cardiac conditions, either known or unknown to the athlete. This is what I’ve been calling the athlete’s cardiac paradox.
There is ample evidence that regular exercise produces a variety of health benefits. As a result, physical activity is strongly recommended by educators, parents, and the medical community. We know, particularly in adults, that regular exercise can: 1) help to maintain a healthy weight; 2) reduce the incidence of type 2 diabetes; 3) have a beneficial effect on the blood pressure; 4) delay or limit the progression of typical coronary artery disease (“hardening of the arteries”); and 5) reduce the chance of having a cardiovascular event such as acute myocardial infarction (AMI), or “heart attack.” And beyond the cardiovascular benefits, there are social and psychological benefits for most individuals who make exercise a part of their daily or weekly routine.
But despite the many clear advantages of exercise, we’ve all heard reports of athletes who have died suddenly, often during exercise or competition. When famous athletes are involved, these stories often garner national news attention. But the problem affects local athletes just the same. For young individuals, the risk of death among athletes may be as much as 2.5 times the risk for non-athletes. For seemingly healthy adults, the reported risk ranges anywhere from 5 to 50 times. Thankfully, the absolute numbers of such deaths is relatively small, though. In the United States, the risk for young athletes is probably in the range of 1 sudden death per 100,000 athletes per year. There have been various estimates for the risk of exercise-related sudden death in adults, with a range of 1 per 20,000 to 82,000 individuals per year. But for adults, this is on top of an additional risk of exercise-related acute myocardial infarction (AMI), or “heart attack.”
For our purposes as we go forward, we should probably divide the athletic population into those under 30 years of age and those older than 30 years of age. This is obviously just an arbitrary cut-off, but it turns out that the cardiac conditions responsible for sudden death are very different for these two groups. For the younger group, hereditary or congenital conditions such as hypertrophic cardiomyopathy (HOCM), coronary artery anomalies, aortic stenosis, aortic dissection (especially with Marfan’s syndrome), arrhythmogenic right ventricular cardiomyopathy, and myocarditis predominate. For the older age group, typical coronary artery disease is the most common cause of sudden death.
As athletes, what should we do?
1. Be aware of the problem. It’s easy for the young athlete to believe he or she is invincible. The young athlete is often the picture of health. But this may not necessarily be true.
2. Take charge of your own (or your child’s) heart health. Nobody will do this for you. It’s important for athletes of all ages to establish a good relationship with a physician—and particularly one who is knowledgeable about the issues of heart disease in athletes. After they leave school, most “healthy” men don’t continue to see a physician. You and your physician should work together to plan how to best screen for any possible cardiovascular disease that you might have. And assuming it’s safe to proceed with your exercise program or training routine, you should work together when any issues arise. Treat symptoms such as chest pain, palpitations, unusual shortness of breath, or light-headedness (or blacking out) seriously. Report these to your physician and work exhaustively to find a cause.
3. Prepare for emergencies. This is particularly true if you’re involved in the leadership of organized exercise programs, training events, or competitions. Be ready for medical emergencies of all sorts, including those arising from cardiovascular problems, and particularly sudden death caused by arrhythmias. It will be helpful to all of us in the long term if cardiovascular events be reported and disseminated to the athletic and medical community. It’s the only way that we can learn.
As physicians, what can we do to help?
1. Become knowledgeable about the problem. I worry that too few primary care physicians are truly knowledgeable about the many issues related to cardiovascular disease in athletes. And I know that cardiologists with a particular interest in this area are few and far between. We should be ready to refer our patients to these specialists, though, when issues arise that we cannot resolve for the athlete.
2. Recommend appropriate exercise programs. There is sufficient information about many cardiac conditions that we can make sound recommendations about continued participation in sports activities for those affected individuals. For some athletes, this will mean a change in the type or intensity of exercise that is safe.
3. Exclude individuals from athletic activities if their cardiac conditions place them at very high risk.
These are some of the issues that we’ll explore in the weeks and months ahead. My friends at Endurance Corner sent me an abstract about atrial arrhythmias in endurance athletes. This is an interesting and common problem and I’ll be back next time to share some info.
Thanks for stopping by. I hope that you’ll stop back often and I hope that you’ll offer your comments, questions, and suggestions. I’m happy to talk about questions that might be on your mind. And I’ll bet that we have a great deal to learn from each other, too.