Study Finds Intense Exercises Might Not Be The Cause of Cardiac Arrest

According to a study funded by the National Institutes of Health, intense exercise does not seem to raise the chance of passing away or experiencing a life-threatening arrhythmia in persons with hypertrophic cardiomyopathy (HCM). One in 500 persons worldwide suffers from HCM, a rare genetic condition that makes the heart muscle thick and enlarges.

Young athletes and other young people have been connected to sudden cardiac death. The study, which was written up in JAMA Cardiology, discovered that patients with the condition who exercise frequently are no more inclined to pass away or suffer severe heart attacks compared to those who exercise modestly or not at all.  

The National Heart, Lung, and Blood Institute (NHLBI), a division of the National Institutes of Health, provided funding for the observational study, which questions the limitations on activities frequently advised for people with the illness. It is the broadest investigation of the association between HCM and exercise.  

1,660 individuals (8.3% of the total population) with HCM or the HCM gene but no disease symptoms were enrolled in the study. They were drawn from 42 high-volume HCM medical facilities in the .U.S. and abroad, including the UK, Canada, Australia, and New Zealand. Their ages ranged from 8 to 60. Men made up about 60% of the participants. The study did not include people who could not exercise for general medical conditions, such as those who needed a heart transplant or had severe asthma.  

A frequent physical activity questionnaire used in research studies was used to split the individuals into groups based on their self-reported exercise levels. About 15% of the participants claimed to be inactive, 43% claimed to engage in moderate activity, like brisk walking, and 42% claimed to engage in intense exercise, like running or fast swimming.

After nearly three years of monitoring the groups, the researchers looked at the occurrence of four major cardiovascular events such as Sudden fatalities, Resuscitated sudden cardiac arrests, syncope (which can include passing out), Adequate ICD shocks.  

The researchers employed a statistical method that evaluated an amalgam of these four events to make the measurement results more understandable. The researchers discovered that 77 people, or 1.5% each year, who reported engaging in strenuous exercise passed away or experienced severe cardiac problems – the same proportion as those who engaged in moderate exercise or self-described as sedentary.

Similar results were obtained for a subgroup of 42 young people who played competitive interscholastic sports like baseball, track, soccer, and basketball, as well as for competitive exercisers (39% of the active group).  

“This finding is important and provides a measure of comfort that exercise may be safe for persons with HCM,” said Patrice Desvigne-Nickens, M.D., a medical officer in the Heart Failure and Arrhythmias Branch of the NHLBI’s Division of Cardiovascular Sciences. “However, we emphasize that people with the condition shouldn’t exercise before getting their absolute risk of sudden cardiac death assessed by a clinician competent in HCM. Understanding that all HCM patients may be at risk for sudden mortality is crucial. 

A grant from the NHLBI, number 1R01HL125918, helped fund this study. The study’s preliminary findings were previously discussed at an American College of Cardiology meeting in March.