Myocarditis Exercise Recommendations

And the importance of following activity restrictions

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. 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. 

Young athlete hurdling
Henrik Sorensen / Getty Images

These exercise 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. 

The risk of exercise-induced sudden death is real even with mild cases of myocarditis. It is critical that young athletes restrict their athletic activities until given an "all clear" by their cardiologist.

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

The answers to these questions are specific to each patient, but there are some basic truths that can provide a better idea of what an active life with myocarditis might look like.

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 occurs during exercise. In some cases of myocarditis, there are no symptoms at all.

Myocarditis may occur as a very acute or chronic illness.

Diagnosing Myocarditis

There are a number of tests that are used to diagnose myocarditis, including an electrocardiogram (ECG).

However, in far too many cases of exercise-induced sudden death, there was no apparent reason to perform heart tests (i.e., they did not experience related symptoms), so the heart inflammation was left to persist undetected.

A Special Note for Young Athletes

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.

If you are a parent with a child with mild myocarditis, it is important to make sure your child is as familiar with these exercise recommendations as you are.

Myocarditis often develops at the same time in life when young people are trying to become independent and make their own decisions. It's paramount that young athletes understand the risks of them diverting from their doctor's recommendations, namely:

  • Young athletes with even mild myocarditis are those most prone to sudden death during athletic events.
  • Too much exercise may put a child with myocarditis at risk of permanent heart damage and disability.

Early Exercise After a Diagnosis

When myocarditis is first diagnosed, exercise is usually curtailed completely until there is a full understanding of the details of one's condition.

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 physical activity. That said, any exercise should only be started under the careful guidance of your cardiologist.

Once a person is cleared to return to exercise, they are usually restricted to moderate activities for several weeks or months. Moderate exercise can provide benefits with regard to inflammation without the risks that come with extreme exercise (including enhancement of the heart-damaging effects of viral myocarditis).

For many people, cardiac rehabilitation may be prescribed to make sure one exercises in a controlled setting.

Competitive Exercise

Competitive exercise should be avoided for at least three to six 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 the benefit of this is not certain 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 exercise 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

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. Make sure you are clear not only about what you should and should not do, but what precautions you should take to stay safe and what symptoms may indicate the activity is too much for your heart.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. Shaw N, Phelan D. Myocarditis in the Athlete. Published January 31, 2018.

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