Strength Training Not Linked to Ventricular Arrhythmia in ACM

Strength training was not associated with an increased risk of sustained ventricular arrhythmia among people living with or at genetic risk for arrhythmogenic cardiomyopathy (ACM), according to a retrospective review of 355 participants in the Johns Hopkins Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Registry. The study is published in the JACC: Clinical Electrophysiology.¹

“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, MD, the senior study author and director of the sports cardiology program at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease, in a statement.² “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.”

Endurance Exercise Raised Risk; Strength Training Did Not

People with ACM, a heritable condition that can significantly raise the risk of sudden cardiac death, have long been advised to avoid high-intensity aerobic exercise, but data on strength training have been lacking. The new analysis is among the first to separate the cardiac effects of strength-based activity from endurance exercise in this population.

Investigators grouped participants' self-reported activity, gathered through phone interviews covering physical activity from age 10 onward, into 4 categories: endurance (at least 4 hours of weekly vigorous aerobic activity, such as cycling, swimming, or running), strength (at least 2 hours of weekly weight training, climbing, or martial arts), dual (a mix of both), or sedentary (meeting neither threshold). Endurance athletes were 58% more likely to experience a ventricular arrhythmia than those in the sedentary or strength groups. Dual athletes, who trained in both disciplines, carried no additional risk compared with endurance athletes alone, and strength athletes showed no significant increase in arrhythmia risk compared with the sedentary group.

Registry Tracked Activity From Childhood Through Middle Age

The review drew on 355 ARVC registry participants, all US adults, who were interviewed by phone about activity dating back to childhood. A ventricular arrhythmia was defined as sustained ventricular tachycardia lasting more than 30 seconds at 100 beats per minute or higher, ventricular fibrillation or flutter, sudden cardiac arrest or death, or use of an implantable cardiac device. Overall, 55% of participants experienced a ventricular arrhythmia during the study period, and about half of those events occurred at enrollment, often following a diagnosis or cardiac event.

Participants were a median age of 34 when they joined the registry and 44 when the study concluded; 70% had received an ACM diagnosis, and the group was split nearly evenly between men and women. More than half, 55%, were classified as dual athletes, followed by sedentary (26%), endurance (12%), and strength (7%) groups. Weekly activity levels fell over time: participants averaged 6 hours of aerobic exercise a week before enrolling, dropping to about 2 hours a few years later, while strength training fell from more than 2.75 hours weekly to just under 1 hour.

Findings Build on Earlier Evidence Linking Exercise to Arrhythmic Risk

Current guidelines restrict high-intensity aerobic exercise and competitive sports for people with ACM or a pathogenic gene variant, guidance rooted partly in a 2013 Johns Hopkins study finding that high-intensity exercise was associated with earlier disease penetrance and greater arrhythmic risk among carriers of ACM-linked desmosomal mutations.³ That guidance has left strength training's role largely undefined, the study authors noted.¹

“We know how important physical activity is to many people living with or at risk for arrhythmic cardiomyopathy,” said Cynthia James, PhD, ScM, research director of the Johns Hopkins ARVC Program and Johns Hopkins Center for Inherited Heart Diseases, said in a statement.² “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.”

References

1. Chiampas K, Muller SA, Osuji E, et al. Strength-based exercise is not associated with ventricular arrhythmia in arrhythmogenic cardiomyopathy—towards safer exercise options. JACC Clin Electrophysiol. Published online September 10, 2026. doi:10.1016/j.jacep.2026.07.035
2. Strength training not linked to heart problems for people with arrhythmogenic cardiomyopathy. Johns Hopkins Medicine. News release. September 10, 2026. Accessed September 16, 2026. https://www.hopkinsmedicine.org/news/newsroom/news-releases/2026/09/strength-training-not-linked-to-heart-problems-for-people-with-arrhythmogenic-cardiomyopathy
3. James CA, Bhonsale A, Tichnell C, et al. Exercise increases age-related penetrance and arrhythmic risk in arrhythmogenic right ventricular dysplasia/cardiomyopathy-associated desmosomal mutation carriers. J Am Coll Cardiol. 2013;62(14):1290-1297. doi:10.1016/j.jacc.2013.06.033