Could exercise retrain the heart in long COVID?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age 18 years or older 2. Previously documented SARS-CoV-2 RNA positivity from an oral or nasal swab, as measured by a nucleic acid amplification test, documented positive antigen testing, or positive nucleocapsid antibody. Documentation of the positive test is required. 3. Presence of persistent symptoms, defined as at least one COVID-attributed symptom newly present during acute illness or worse than baseline and reported to still be present for at least 90 days following symptom onset. This will be ascertained using study case report forms. 4. Reduced exercise capacity \<100% predicted or self-reported reduction in exercise capacity compared to pre-COVID. 5. Willing and able to actively participate in cardiac rehabilitation including attending at least 12 in person sessions at UCSF Parnassus (intervention arm only). 6. Agree to participate in the LIINC Study including the cardiovascular substudy if they are not already participating. Exclusion Criteria: 1. Pregnant or intention to become pregnant during study 2. Pre-existing congenital heart disease, heart failure, pulmonary hypertension, heart or lung transplant, or cardiac valve surgery 3. Myocardial infarction, or coronary artery bypass graft surgery, or new diagnosis of heart failure with a reduced ejection fraction \<40% within 90 days prior to enrollment (Class I indications for cardiac rehabilitation) 4. Acute myocarditis diagnosed \<90 days prior 5. Atrial fibrillation, atrial flutter, or other arrhythmias requiring antiarrhythmic therapy 6. Use of beta-blockers, non-dihydropyridine calcium channel blockers or ivabradine 7. Implanted pacemaker or defibrillator 8. Chronic lung disease requiring the use of home oxygen therapy 9. Inability to ride a sitting bicycle for CPET 10. Severe post-exertional malaise or symptom worsening that would preclude participation in cardiac rehabilitation 11. Medical or psychological comorbidities that would prevent safe participation in the trial, in the opinion of the Principal Investigator