Myocarditis Exercise Recommendations

Myocarditis is an inflammation of the heart muscle and is one of the cardiac conditions associated with sudden death in young athletes. When it occurs, myocarditis often has no symptoms early on, and a young athlete may feel well enough to compete, unaware of the problem. After the diagnosis is made, however, it is necessary for them to significantly restrict their exercise in order to reduce complications, including the risk of sudden death. 

These limitations can be frustrating, especially in cases where the myocarditis is mild and is producing few or no symptoms. Young athletes can be tempted to ignore the restrictions their doctors have placed on them. 

When can a young person with myocarditis ease back into exercise, how much exercise will be doable in the future, and what exercises may or may not be recommended?

Myocarditis Overview

Myocarditis is an inflammatory disease affecting the heart muscle. Myocarditis can be caused by numerous underlying conditions including infections (such as the Coxsackie virus, toxoplasmosis, and Lyme disease), various autoimmune diseases (such as lupus), and reactions to various toxins and drugs (such as to cocaine). In more than a few cases no specific underlying cause can be found, in which case the myocarditis is said to be “idiopathic.”

Symptoms of myocarditis can vary tremendously in patients with myocarditis, depending largely on the degree of inflammation present in the heart and the amount of heart muscle damaged by the inflammation.

When myocarditis is severe and affects a large portion of the heart muscle, it can produce overt cardiomyopathy and heart failure. This is usually accompanied by symptoms which include dyspnea (shortness of breath), fatigue, weakness, and edema (swelling).

On the other hand, myocarditis may affect only small portions of the heart muscle, with only very mild symptoms such as mild weakness or easy fatiguability. Sometimes, the only symptom is chest pain that only occurs during exercise. In some cases of myocarditis, there are no symptoms at all.

Myocarditis may occur as a very acute illness, or it may produce a chronic, smoldering illness.

Diagnosing Myocarditis

There are a number of tests that are used to diagnose myocarditis, including an electrocardiogram (ECG). Again, it's important to note, that some people who experience sudden death due to myocarditis have had only mild symptoms, and therefore, have not had the testing which would reveal the diagnosis.

A Special Note for Young Athletes

s mentioned at the beginning, exercise for young athletes with even mild myocarditis can be dangerous. These are the people who are most prone to sudden death during athletic events. For far too many victims of exercise-induced sudden death, there was no apparent reason to perform heart tests that would give clues that heart inflammation was present.

If you are a parent with a child with mild myocarditis, it is important to make sure your child is as familiar with exercise recommendations as you are. Myocarditis often develops at the same time of life when young people are trying to become independent and make their own decisions. In addition to the risk of death, too much exercise may put a child at risk of permanent heart damage and disability, and it's paramount that these young athletes understand this.

When a diagnosis of myocarditis is made in a young athlete, it is most often strongly recommended that they completely avoid all competitive sports for at least six months, only resuming competition if cardiac tests show complete recovery.

Early Exercise After a Diagnosis

When myocarditis is first diagnosed, exercise is usually curtailed completely until a full understanding of the details of the condition is known. In general, exercise (of any degree) is not recommended until the function of the left ventricle of the heart (the large heart chamber that pumps blood to the rest of the body) is back to normal, and there are no abnormal heart rhythms. Even if there are no arrhythmias, and ventricular function is normal, exercise should not be restarted if there are any signs of persistent inflammation in the heart, or dangerous scar tissue.

Many other factors will need to be considered as well, including the possible cause of the myocarditis, and if it is transient (such as an infection) or a progressive process. Some causes increase the risk of sudden death much more than others.

Easing Into Exercise

As a person's condition improves, and moderate exercise is deemed safe, it can be beneficial to resume exercise. That said, any exercise should only be started under the careful guidance of your cardiologist. For many people, cardiac rehabilitation may be prescribed to make sure this takes place in a controlled setting.

Once a person is cleared to return to exercise, only moderate exercise is usually recommended for several weeks or months. Moderate exercise is enough to see the benefits with regard to inflammation, whereas extreme exercise may not only be risky but may enhance the heart-damaging effects of viral myocarditis.

Competitive Exercise

Competitive exercise should be avoided for at least 6 months (European recommendations, American recommendations are 3 to 6 months), and then only returned to under the guidance of a cardiologist. In many cases athletic competition will have to be delayed for substantially longer than this.

Before returning to competitive activity, athletes should be thoroughly evaluated with an ECG, stress ECG, Holter monitoring, and an echocardiogram. Some cardiologists may recommend a heart MRI, though we aren't certain of the benefit at this time. Athletes that have scarring of their heart may be at greater risk of abnormal rhythms and sudden death, and a return to competition may not be recommended.

Long-Term Outlook

The long-term outlook with regard to exercise recommendations with myocarditis will depend on the cause, as well as any permanent cardiac damage that was sustained by the inflammation. Many viral causes of myocarditis are self-limited but may leave lasting damage which could restrict physical activity in the future.

Good and Bad Exercises

The best type of exercises for those who are recovering from myocarditis will depend on several factors, including any persistent cardiac damage or scarring. A program for exercise should be carefully worked out with your cardiologist, and beginning with cardiac rehabilitation is a way to monitor activity as safely as possible early on when activity is begun.

Bottom Line

Myocarditis is often caused by viral infections which can affect young adult athletes. Unfortunately, those most at risk for sudden death are often those with the mildest disease, as their symptoms have not alerted them to the problem.

Once diagnosed, physical activity is greatly restricted for several months. Prior to returning to activity, a cardiologist will want to see that heart muscle function, particularly left the ventricular function, has been restored, and that no abnormal heart rhythms are present. It's also important to make sure the inflammation of myocarditis has resolved, though there are no simple ways to determine this. Cardiac testing including an ECG, ECG stress test, echocardiogram, Holter monitoring, and other tests may be recommended.

Once you begin exercise again, your progression and the particular exercises recommended need to be tailored to your particular situation and should be carefully discussed with your cardiologist. This should be accompanied by any precautions suggested and information on any symptoms to watch for to determine if the activity is too much.