Clinical Research Directory

Inclusion Criteria: * Veterans with prior COVID-19, with residual symptoms of long COVID including increased fatigability. * Inclusion limited to age 18 and over Exclusion Criteria: * Blood pressure \<110/60 mmHg, either systolic or diastolic value which may affect participant safety during assessments will be at the discretion of the study physician * Unable to hold warfarin, novel oral anticoagulants (NOACs) or aspirin for 3 days prior to muscle biopsy, or to hold thienopyridine medications for 5 days prior to muscle biopsy * Current use of organic nitrates or phosphodiesterase type 5 (PDE5) inhibitors * Orthopedic or other chronic condition which limits physical activity or functional testing assessments * End-stage disease * Dementia or other reason unable to give informed consent * Anemia (hemoglobin \<11.0 g/dL in men or hemoglobin \<10.0 g/dL in women) * Unstable psychiatric diagnosis * Clinically significant alcohol intake or substance abuse * Chronic use of oral corticosteroids or medications that affect muscle function * Use of anti-bacterial mouthwash or antacids that confound the nitrate/nitrite/NO pathway. * Suicidal ideations * Unwilling to hold Viagra-like drugs (i.e. Viagra, Cialis, Levitra, other phosphodiesterase inhibitors) * Involved in another greater than minimal risk study * Other clinically unstable medical condition as determined by the study physician