Inclusion Criteria:  Serological or clinical diagnosis of CoV-2 infection Ability to provide written informed consent.  Inclusion criteria specifically for the impaired exercise capacity group includes an abnormal response on 6 minute walk test including any one of:  Peripheral oxygen desaturation < 85% predicted walk distance Lactate rise> 1.0 from baseline Borg score > 5 for breathlessness or fatigue at end of test  Exclusion Criteria:  < 18 years old. Considered a vulnerable adult Participant unwilling to consent Terminal illness or severe comorbidities affecting attendance or study investigations Pregnancy If the participant is not willing to give their consent for a clinical advisor to contact them if necessary Inability or presence of a contra-indication for exercise testing Chronic oral corticosteroid use (e.g. any maintenance dose of oral steroid, 4 or more course of oral steroid in previous 12 months, but not including prescription of dexamethasone during the acute episode of COVID-19, as long as that has been discontinued).