Inclusion Criteria:  Subjects must meet the following criteria to be included in the study:  Male or Females between 18 -80 years of age at the time of consent Able to provide informed consent. Prior confirmed COVID-19 diagnosis by standard Real time Polymerase Chain Reaction (RT-PCR) assay or Immunoglobin M/G (IgM/IgG) rapid serological test at least 4 weeks prior to screening visit. Ambulatory patients may be attending COVID long term follow up clinic or discharged from hospital for at least one week. Evidence of new and/or persistent respiratory symptoms at least 4 weeks after the onset of acute COVID-19 infection. This will be determined by history of respiratory symptoms: cough, wheeze, limitation of activities. Able to perform an exercise of moderate activity e.g., walking up a hill or climbing stairs (required to assess Borg RPE) Able to walk unaided for a minimum distance of 10 meters (distance validated for completion of 6-minute walk test)  Exclusion Criteria:  Subjects to whom any of the following applies will be excluded from the study:  Pregnancy or of childbearing age without a highly effective method or at least two forms of effective contraception and/ or abstinence for the duration of study. Highly effective methods of contraception (Contraception with < 1% failure rate) are: hormonal contraceptives (e.g. combined oral contraceptives, patch, vaginal ring, injectables, and implants); intrauterine device (IUD) or intrauterine system (IUS); vasectomy and tubal ligation. Effective methods of contraception may include barrier methods of contraception (e.g., male condom, female condom, cervical cap, diaphragm, contraceptive sponge). Breastfeeding females. Evidence of active thromboembolic disorder - defined by those receiving parenteral anticoagulant or thrombolytic therapy. Pre-existing evidence of unstable angina and myocardial infraction during the previous month, contraindications to the 6MWT. Subject, who in the opinion of the Investigator, is unsuitable to participate.