In a recent study published in the journal JAMA Cardiology, German researchers used cardiac MRI to study the hearts of adults who had recently recovered from COVID-19. 60% had myocarditis, or inflammation of the heart muscle, which can have serious or even fatal results with strenuous physical activity. Many physicians now recommend that if you’re diagnosed with the coronavirus, you should refrain from exercise and sports for at least two weeks, and talk to your doctor about heart tests to see if you should wait longer.