New Johns Hopkins registry research shows strength training is not associated with increased arrhythmia risk in athletes with arrhythmogenic cardiomyopathy.
On September 10, 2026, researchers using the Johns Hopkins Arrhythmogenic Right Ventricular Cardiomyopathy Registry published new findings in a major clinical journal. The study was published in JACC: Clinical Electrophysiology under the title Strength-Based Exercise is Not Associated with Ventricular Arrhythmia in Arrhythmogenic Cardiomyopathy Towards Safer Exercise Options. A Johns Hopkins team used this registry to examine whether strength-based exercise and endurance exercise were associated with ventricular-arrhythmia risk. They specifically looked at people living with, or genetically at risk for, arrhythmogenic cardiomyopathy.
The primary conclusion of the study challenges the idea that all vigorous activity carries identical risk for this population. Researchers found that participants categorized as endurance athletes were 58 percent more likely to experience a ventricular arrhythmia than those in the sedentary or strength groups. In contrast, strength athletes did not have a statistically significant increase in ventricular-arrhythmia risk compared with the sedentary group. This distinction is vital because it separates two training modalities that are frequently grouped together under the broad label of exercise.
It is important to understand the specific boundaries of this statistical finding. The 58 percent figure is a relative comparison against the sedentary or strength groups. It is not a statement that 58 percent of all endurance athletes developed an arrhythmia. The report did not provide an absolute risk for each group, a confidence interval, a p-value, or a hazard ratio for the 58 percent estimate.
Furthermore, participants who combined endurance and strength training did not have a further statistically significant increase in risk compared with endurance athletes. The study does not establish that shifting from endurance training to strength training will reduce an individual athlete's personal risk. It simply shows that strength-based exercise was not associated with increased ventricular-arrhythmia risk in this registry analysis. The research does not prove that strength training actively prevents arrhythmias.
Cindy James, research director at the Johns Hopkins ARVC Program and Johns Hopkins Center for Inherited Heart Diseases, was identified as a researcher on the study. She emphasized the importance of research that can inform shared medical decisions. These decisions must support the physical health and overall well-being of people living with this condition.
The study observed 355 United States adults over a multi-year period. These participants had a median age of 34 years at enrollment and a median age of 44 years when the study concluded. Seventy percent of the cohort had an arrhythmogenic cardiomyopathy diagnosis, while the remainder were genetically at risk. Researchers reconstructed participants' exercise histories from age 10 through enrollment and divided them into four distinct categories.
To classify these activity histories, the endurance group performed at least four hours of vigorous aerobic activity per week. This vigorous volume included cycling, swimming, or running. The strength group performed at least two hours of strength-based activity per week, including weightlifting, climbing, or martial arts. The dual group included participants who performed both endurance and strength activities, while the sedentary group met neither threshold.
The distribution of participants across these four categories was highly uneven. The dual group represented 55 percent of participants, making it the largest category by a significant margin. The sedentary group accounted for 26 percent of the cohort. The endurance group comprised 12 percent of participants, while the strength group represented just 7 percent.
A ventricular-arrhythmia outcome included sustained ventricular tachycardia lasting more than 30 seconds at 100 beats per minute or higher. The outcome definition also included ventricular fibrillation or flutter, sudden cardiac arrest, sudden cardiac death, or use of an implantable cardiac device. Overall, 55 percent of participants experienced a ventricular arrhythmia during the study period. About half of those events occurred at enrollment, which often followed a diagnosis or cardiac event.
Because the study was observational and based on registry participants, the findings demonstrate associations rather than proving absolute causation. The exposure data relied on recalled activity from age 10 through enrollment and later interviews. This recall method creates potential classification limitations. Additionally, the report did not provide detailed information on specific genotypes, participant selection, or exact event counts for each exercise category.
For ambitious adults over 35, managing physical health means making informed adjustments to long term training habits. This study marks a significant shift for masters endurance athletes who have a diagnosis or a pathogenic genotype. Historically, clinical discussion continues to treat high-intensity endurance exercise as a major concern in established arrhythmogenic cardiomyopathy. Repeated heavy exercise can increase ventricular wall stress and may accelerate disease expression in susceptible people.
A recent clinical review states that exercise advice for people with arrhythmogenic right ventricular cardiomyopathy should be highly individualized. Medical professionals should base this advice on several key factors. These include the patient's phenotype, genotype, and previous ventricular arrhythmia. Specialists must also consider ventricular function, training intensity, exercise duration, and patient values.
The study senior author, Lili Barouch, serves as director of the sports cardiology program at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease. Barouch noted that the study supports moving away from blanket exercise recommendations toward personalized decisions between physicians and patients. For athletes looking to preserve function as they age, strength training for endurance athletes over 35 remains a crucial focus. The findings suggest that vigorous endurance volume and strength-based activity should not automatically be treated as carrying the same risk.
This distinction is especially relevant for older athletes who want to maintain muscle strength and independence. The registry finding did not identify an increased ventricular-arrhythmia association for the strength group compared with the sedentary group. However, the relatively small size of the strength group means this is not universal proof of safety. The broad definition of strength training included weightlifting, climbing, and martial arts, so the data does not confirm that all resistance formats have identical cardiovascular demands.
Masters athletes should treat high-volume vigorous endurance training as a completely separate question from resistance work. The 58 percent higher relative association for the endurance group compared with the sedentary or strength groups is a serious consideration. Combining disciplines does not neutralize this effect, as dual athletes did not have a further increased risk compared with endurance athletes. Their risk remained elevated in line with the endurance category, which highlights the importance of understanding how concurrent training impacts the body when managing a chronic condition.
A clinical review notes that regular low-intensity activity may remain appropriate for selected clinically stable patients after specialist assessment. Exercise restriction alone does not eliminate arrhythmic risk entirely. If you experience exertional chest discomfort or unexplained palpitations, you should seek immediate clinical review. Fainting and declining exercise tolerance are also serious warning signs. You should never use this study to self-prescribe harder training sessions.
A 2026 review reported that exercise-induced ventricular arrhythmias have been described in around 40 percent of patients with confirmed arrhythmogenic cardiomyopathy. This prevalence is particularly notable in those with more extensive biventricular structural involvement. It is crucial to note that this approximately 40 percent figure comes from confirmed clinical cohorts. It should not be treated as the risk for all endurance athletes or genotype-positive adults undergoing routine screening.
For athletes without this condition or a relevant genotype, these findings should not dictate routine training decisions. The study population consisted exclusively of people living with or genetically at risk for the condition. The broader direction of the evidence is toward individualized exercise prescriptions rather than a simple binary distinction between exercise and complete rest. The findings support discussing a sensible strategy for endurance training with chronic health conditions with a specialist to keep you moving safely for years to come.
For masters endurance athletes managing arrhythmogenic cardiomyopathy, this research supports shifting away from extreme aerobic volume toward a personalized mix of moderated endurance and dedicated strength work under specialist guidance.
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