Exercise helps protect against cardiovascular disease and many other illnesses, but is too much of a good thing risky, and even potentially lethal?
Researchers at the University of B.C. will conduct the first study of its kind in Canada trying for an answer. They’re recruiting 2,000 competitive athletes aged 12 to 35 for a study investigating the prevalence of cardiac abnormalities, which could lead to “Black Swan Events” — sudden cardiac death (SCD).
Undetected, untreated, inherited or acquired cardiac abnormalities can lead to SCD. Although rare in athletes (three in every 100,000, according to some research), they’re high-profile because they’re so unexpected in those in peak physical form.
Research done in Italy suggests that the strain competitive athletes put on their hearts may predispose them to a 2.8 times higher risk of SCD, compared to non-athletes.
There’s evidence that the risk of SCD is increasing, however, possibly because of greater participation in high-intensity competitions like triathlons. The “athletic heart” label is given to the enlarged organs of athletes whose hearts may also be shaped differently. Multiple imaging and other tests are often required to distinguish whether athletic heart re-modelling is true evidence of serious heart disease, or a benign byproduct of training.
Dr. Brett Heilbron, co-director of the Advanced Cardiac Imaging program at St. Paul’s Hospital, said athletes can be tricky cases, and doctors have to be careful not to make an overdiagnosis.
After the Italian study, Italy, Israel and Japan started periodic screening for competitive athletes. The International Olympic Committee (IOC) also requests such tests and may disqualify athletes from competition if their conditions pose a high risk. But Canada has no such requirements and no data yet on which to base recommendations.
In the B.C. study, athletes will get a physical examination by a doctor that will include blood pressure, pulse and heart sound testing. They will also fill out a questionnaire about family history and have an ECG (electrocardiogram). If anomalies or concerns are detected, lead researcher/cardiologist Dr. Saul Isserow or another doctor will do followup tests.
Isserow is the founder/medical director of the non-profit organization Sports Cardiology B.C. He’s also director of cardiology services at UBC Hospital and director of Vancouver General Hospital’s Centre for Cardiovascular Health.
To qualify for the study, athletes cannot have a previous history of cardiac disease and must be involved in an organized sport program that requires frequent, intense training and competition.
At an educational event this week held at the new Fortius Sports and Health Institute in Burnaby, Isserow told coaches and others in attendance about the rationale for the study. He said long-term, excessive exercise may induce adverse changes in the heart. Knowing more about the safe upper limits of intensive training for both competitive and recreational athletes is critically important, he said, noting that information pertinent to Canadian demographics may be more relevant than that coming from other parts of the world.
A study done on 134 high school athletes in Maryland found no life-threatening defects but non-lethal abnormal findings were found in 36 athletes.
“We need a local database so we can establish prevalence (of heart abnormalities) here, to help prevent premature coronary disease and deaths,” Isserow said.
“The last thing I want to do is give the impression that exercise is risky,” Isserow said. “Exercise has many benefits. It is unbelievably good. But we are trying to find out how we can do it in a safe, effective, reasonable manner,” he said.
Dr. Jack Taunton, a sports medicine expert who was chief medical officer at the Vancouver 2010 Olympic Games, said he hopes that the baseline research will expand to include recreational and older athletes.
The screening study is being sponsored through a $100,000 anonymous donation to the VGH and UBC Hospital Foundation. If any problems are detected among participants, medical visits will be covered by the public health care system. Cardiac disorders that may lead to SCD include cardiomyopathy, coronary artery disease, arrhythmias, myocarditis, aortic aneurysm, aortic stenosis, and certain rare, often inherited, syndromes.
Sun Health Issues Reporter