Can intense physical activity cause cardiomyopathy (disease of the heart muscle)?

From the Guidelines

Extreme exercise can potentially contribute to cardiomyopathy, but this typically occurs only in rare cases with excessive, prolonged endurance training, and most exercise is beneficial for heart health. The risk of cardiomyopathy due to exercise is generally low, and the benefits of regular physical activity for cardiovascular health are well-established 1. However, some athletes who engage in extreme endurance activities like ultramarathons or ironman competitions over many years may develop what's called "athlete's heart," which includes structural changes that can resemble cardiomyopathy. These changes include enlarged heart chambers and thickened heart walls. The mechanism involves repeated strain on the heart muscle, leading to inflammation, scarring, and remodeling of heart tissue.

The American College of Cardiology Foundation/American Heart Association guidelines recommend that patients with hypertrophic cardiomyopathy (HCM) not participate in high-intensity exercise due to the increased risk of sudden cardiac death 1. However, more recent studies suggest that moderate-intensity exercise may be safe and beneficial for patients with HCM, improving cardiorespiratory fitness and reducing the risk of cardiovascular mortality 1. The 2020 AHA/ACC guideline for the diagnosis and treatment of patients with HCM recommends at least 150 to 300 minutes of moderate-intensity or 75 to 150 minutes of vigorous-intensity aerobic exercise weekly, and emphasizes the importance of individualized exercise recommendations and supervision for patients with HCM 1.

Key points to consider:

• Most exercise is beneficial for heart health, and the risk of cardiomyopathy due to exercise is generally low
• Extreme endurance activities may increase the risk of cardiomyopathy, but this is rare and typically occurs with excessive, prolonged training
• Moderate-intensity exercise may be safe and beneficial for patients with HCM, improving cardiorespiratory fitness and reducing the risk of cardiovascular mortality
• Individualized exercise recommendations and supervision are important for patients with HCM
• The benefits of regular physical activity for cardiovascular health are well-established, and patients with HCM should aim to meet the recommended guidelines for physical activity 1.

From the Research

Cardiomyopathy and Extreme Exercise

• Extreme exercise can cause cardiomyopathy, as it places a large hemodynamic stress on the heart, resulting in cardiac remodeling that can become maladaptive and heighten the risk of various arrhythmias, influence the rate of coronary atherosclerosis, and alter the risk of sudden cardiac death 2.
• The cardiomyopathies are a heterogeneous group of primary myocardial diseases characterized by a propensity to fatal arrhythmias and are the leading cause of sudden cardiac death in young athletes, with intensive exercise being a potential trigger for fatal arrhythmias 3.
• Hypertrophic cardiomyopathy (HCM) is the most frequently cited cause of exercise-related sudden cardiac death (SCD) in young individuals, and while conservative exercise recommendations have been made, recent studies suggest that mild and moderate exercise is safe and can improve functional capacity and quality of life in individuals with HCM 4.

Risks and Precautions

• High-intensity endurance sports can lead to structural alterations of the heart muscle even in healthy individuals, and individuals who participate in such activities should be aware of the potential risks 5.
• Competitive sports are contraindicated in most forms of hypertrophic cardiomyopathy (HCM), myocarditis, pericarditis, and right ventricular cardiomyopathy/dysplasia, and prescreening is recommended before participating in competitive sports 5.
• Physical exercise in patients with heart disease should be accompanied by regular medical check-ups, and most rehabilitation programs perform physical activity and training schedules according to current guidelines 5.

Treatment and Management

• Beta-blockers have been shown to improve cardiac function in patients with idiopathic dilated cardiomyopathy and other forms of cardiomyopathy, including ischaemic cardiomyopathy 6.
• Treatment of cardiomyopathy should be individualized, and exercise recommendations should be made on a case-by-case basis, taking into account the specific type and severity of the cardiomyopathy, as well as the individual's overall health and medical history 3, 4.