People living with arrhythmogenic cardiomyopathy (ACM), a heritable heart condition that can significantly increase risks for sudden cardiac death, are advised to avoid high-intensity aerobic exercise. However, questions remain about whether higher-intensity strength training, which affects the heart differently from endurance exercise, could be less risky. Now, through the Johns Hopkins Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Registry, investigators conducted one of the first studies to assess the separate effects of strength versus endurance exercise on the heart in ACM and found that strength training was not associated with an increased likelihood for developing a sustained ventricular arrhythmia for people living with or who have genetic risks for the condition. 

The findings published Sept. 10 in JACC: Clinical Electrophysiology. 

“There have been a lot of questions about the safety of strength training for people living with or at risk for arrhythmogenic cardiomyopathy,” says Lili Barouch, M.D., the senior study author and director of the sports cardiology program at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease. “This study opens the door to help researchers further assess this — and supports continued shifts with moving away from blanket recommendations for exercise to support personalized decision-making between physicians and patients.” 

About 1 in every 1,000 to 5,000 people worldwide are estimated to have arrhythmogenic cardiomyopathy. The condition is caused by mutations in certain genes that support the heart’s ability to contract and pump blood throughout the body. The high demands of heart-pumping exercise, like sprinting and cycling, can put extra stress on affected heart cells and cause damage over time or lead to sudden cardiac arrest or death for individuals with the greatest risks. These types of events often occur between a person’s 20s and 40s. 

Physicians have known about the risks of high-intensity aerobic exercise, but they haven’t had data to inform or help patients make decisions about strength training — which doesn’t put the same type of stress on the heart. To better assess links between strength activities and heart problems among people with arrhythmogenic cardiomyopathy, researchers partnered with 355 participants in the Johns Hopkins ARVC registry to inquire about their physical activity levels from childhood (age 10) throughout their enrollment in the study. They then compared the type of exercise they did to incidents of ventricular arrhythmia. 

A ventricular arrhythmia in this study was classified as a person experiencing ventricular tachycardia — or a sustained, rapid heartbeat — lasting more than 30 seconds at 100 beats per minute or higher, a ventricular fibrillation/flutter, sudden cardiac arrest, sudden cardiac death, or use of an implantable cardiac device. About half of participants, 55%, experienced a ventricular arrhythmia. Among those who did, about half occurred when they first enrolled in the study — which often followed a diagnosis or cardiac event. 

Participants, who consisted of U.S. adults, were a median age of 34 when they first joined the study and 44 when the study concluded. Interviews were conducted by phone. To assess the associations with physical activity and increased risks for heart problems, the investigators grouped exercise levels into four categories: endurance, strength training, dual (endurance and strength) or sedentary. Endurance athletes participated in at least four hours of weekly vigorous aerobic activities, such as cycling, swimming or running. Strength athletes participated in at least two hours of weekly strength-based training activities, such as weightlifting, climbing or martial arts. Dual athletes participated in both or mixed endurance and strength activities. The sedentary group included participants who did not meet criteria for the strength or endurance groups. 

Based on this review, endurance athletes were 58% more likely to experience a ventricular arrythmia compared with the sedentary or strength groups. There was no further increased risk for ventricular arrhythmia among dual athletes compared to endurance athletes. There were also no significant increased risks for ventricular arrhythmia for strength athletes compared to the sedentary group. 

More than half (55%) of study participants were dual athletes, followed by those in the sedentary (26%), endurance (12%) and strength (7%) groups. Participants were split almost evenly among men and women, and 70% had an arrhythmic cardiomyopathy diagnosis. 

Overall, participants completed an average of six hours of weekly aerobic exercise before enrolling in the study and about two hours each week a few years later. Similarly, participants completed an average of more than 2.75 hours of weekly strength training activities before enrolling in the study and just under an hour each week a few years later. 

“We know how important physical activity is to many people living with or at risk for arrhythmic cardiomyopathy,” says Cindy James, Ph.D., Sc.M., research director at the Johns Hopkins ARVC Program and Johns Hopkins Center for Inherited Heart Diseases. “This is one of many reasons why research in this area is critical to inform shared medical decisions to support a person’s physical health and their overall well-being.” 

Additional authors include Katia Chiampas, Steven Muller, Evans Osuji, Alan Jacobsen, Lisa Yanek, Richard Cararick, Alessio Gasperetti, Crystal Tichnell, Brittney Murray and Hugh Calkins. 

This research is supported by the Johns Hopkins ARVD/C Program, which has received funding and support from the Leonie-Wild Foundation, the Leyla Erkan Family Fund for ARVD Research, The Hugh Calkins, Marvin H. Weiner, and Jacqueline J. Bernstein Cardiac Arrhythmia Center, the Dr. Francis P. Chiramonte Private Foundation, the Dr. Satish, Rupal, and Robin Shah ARVD Fund at Johns Hopkins, the Bogle Foundation, the Campanella family, the Patrick J. Harrison Family, the Peter French Memorial Foundation and Wilmerding Endowments. 

Calkins discloses consulting for Boston Scientific Corp, Medtronic Inc., Biosense Webster, Pfizer, StrideBio, Rocket and Abbott. He also receives research support from Tenaya Inc. (which supports Crystal Tichnell and Cynthia James), Medtronic, Biosense Webster, Farapulse and Adagio. Carrick receives research funding from the National Institutes of Health (T32HL007227, L30HL165535) and is a recipient of the Semyon and Janna Friedman Fellowship award. James receives research support from Rocket Pharmaceuticals (which supports Crystal Tichnell), Lexeo Therapeutics and ARVADA Therapeutics. 

On the Web

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