Vigorous exercise not tied to increased risk of adverse events in rare heart condition
Vigorous exercise does not appear to increase the risk of death or life-threatening arrhythmia for people with hypertrophic cardiomyopathy (HCM), according to a study supported by the National Institutes of Health.
HCM is a rare, inherited disorder that causes the heart muscle to become thick and enlarged and affects 1 in 500 people worldwide. It has been associated with sudden cardiac death in young athletes and other young people. However, the study, published in JAMA Cardiology, found that people with the disease who exercise vigorously are no more likely to die or experience severe cardiac events than those who exercised moderately or not at all.
For the study, the researchers recruited 1,660 people who either had HCM or the gene for HCM but had not yet manifested the disease (8% of the total). They ranged from ages 8 to 60 and were recruited from 42 high-volume HCM medical centers in the United States and other countries, including the United Kingdom, Canada, Australia, and New Zealand. About 60% of participants were male. The study excluded people who could not exercise for established medical reasons, such as those awaiting heart transplantation or with severe asthma.
The participants were divided according to self-reported exercise levels based on a physical activity questionnaire used in research studies. About 15% of the participants reported being sedentary, 43% said they did moderate exercise, such as brisk walking, and 42% said they did vigorous exercise, such as running or fast swimming. The researchers then followed the groups for about three years and looked at the occurrence of four main cardiovascular events during that period: sudden deaths, resuscitated sudden cardiac arrests, arrhythmic syncope (which can include fainting or passing out), and appropriate ICD shocks.
To simplify these measurement outcomes, the researchers used a statistical formula that measured a composite of these four events. The researchers found that 77 participants, or 1.5% per year, who reported exercising vigorously died or had severe cardiac events – the same percentage as those who exercised moderately or described themselves as sedentary. The outcome was similar for competitive exercisers (39% of the vigorous group) and for a subgroup of 42 young people who participated in interscholastic competitive sports such as baseball, track, soccer, and basketball.
