Exercise capacity following SARS-CoV-2 infection is related to changes in cardiovascular and lung function in military personnel.

BACKGROUND: Since the COVID-19 pandemic, post-COVID syndrome (persistent symptoms/complications lasting >12 weeks) continues to pose medical and economic challenges. In military personnel, where optimal fitness is crucial, prolonged limitations affecting their ability to perform duties has occupational and psychological implications, impacting deployability and retention. Research investigating post-COVID syndrome exercise capacity and cardiopulmonary effects in military personnel is limited. METHODS: UK military personnel were recruited from the Defence Medical Services COVID-19 Recovery Service. Participants were separated into healthy controls without prior SARS-CoV-2 infection (group one), and participants with prolonged symptoms (>12 weeks) after mild-moderate (community-treated) and severe (hospitalised) COVID-19 illness (group 2 and 3, respectively). Participants underwent cardiac magnetic resonance imaging (CMR) and spectroscopy, echocardiography, pulmonary function testing and cardiopulmonary exercise testing (CPET). RESULTS: 113 participants were recruited. When compared in ordered groups (one to three), CPET showed stepwise decreases in peak work, work at VT1 and VO2 max (all p < 0.01). There were stepwise decreases in FVC (p = 0.002), FEV1 (p = 0.005), TLC (p = 0.002), VA (p < 0.001), and DLCO (p < 0.002), and a stepwise increase in A-a gradient (p < 0.001). CMR showed stepwise decreases in LV/RV volumes, stroke volumes and LV mass (LVEDVi/RVEDVi p < 0.001; LVSV p = 0.003; RVSV p = 0.001; LV mass index p = 0.049). CONCLUSION: In an active military population, post-COVID syndrome is linked to subclinical changes in maximal exercise capacity. Alongside disease specific changes, many of these findings share the phenotype of deconditioning following prolonged illness or bedrest. Partitioning of the relative contribution of pathological changes from COVID-19 and deconditioning is challenging in post-COVID syndrome recovery.

Intracardiac shunt assessment using CT coronary angiography.

BACKGROUND: Detection of intracardiac shunts using CT Coronary Angiography (CTCA) is currently based on anatomical demonstration of defects. We assessed a novel technique using a standard CTCA test bolus in detecting shunts independent of anatomical assessment and to provide an estimate of Qp/Qs. METHODS: We retrospectively reviewed 51 CTCAs: twenty-one from patients with known simple left to right intracardiac shunts with contemporaneous functional assessment (using CMR) within 6 months, 20 controls with structurally normal hearts, and 10 patients with shunt repairs. From the dynamic acquisition of a test bolus, we measured mean Hounsfield Units (HU) in various anatomical structures. We created time/density curves from the test bolus data, and calculated disappearance time (DT) from the ascending aorta (deriving a Qp/Qs), peak ascending aortic HU, and mean coefficient of variation of the arterial curves, and compared these with the Qp/Qs from the respective CMR. RESULTS: Patients with intracardiac shunts had significantly higher test bolus derived Qp/Qs compared with both the controls, and the repaired shunt comparator group. There was a very strong agreement between the test bolus derived Qp/Qs, and Qp/Qs as measured by CMR (Intraclass correlation 0.89). Mean bias was 0.032 â€‹± â€‹0.341 (95% limits of agreement -0.64 to 0.70). Interobserver, and intraobserver agreement of the disappearance time was excellent (0.99, 0.99 (reader 1) and 1.00 (reader 2) respectively). CONCLUSION: In this proof-of-concept study, we demonstrate a novel technique to detect, and to estimate severity of left to right intracardiac shunts on routine Cardiac CT.

The Use and Efficacy of FFR-CT: Real-World Multicenter Audit of Clinical Data With Cost Analysis.

BACKGROUND: Fractional flow reserve-computed tomography (FFR-CT) is endorsed by UK and U.S. chest pain guidelines, but its clinical effectiveness and cost benefit in real-world practice are unknown. OBJECTIVES: The purpose of this study was to audit the use of FFR-CT in clinical practice against England's National Institute for Health and Care Excellence guidance and assess its diagnostic accuracy and cost. METHODS: A multicenter audit was undertaken covering the 3 years when FFR-CT was centrally funded in England. For coronary computed tomographic angiograms (CCTAs) submitted for FFR-CT analysis, centers provided data on symptoms, CCTA and FFR-CT findings, and subsequent management. Audit standards included using FFR-CT only in patients with stable chest pain and equivocal stenosis (50%-69%). Diagnostic accuracy was evaluated against invasive FFR, when performed. Follow-up for nonfatal myocardial infarction and all-cause mortality was undertaken. The cost of an FFR-CT strategy was compared to alternative stress imaging pathways using cost analysis modeling. RESULTS: A total of 2,298 CCTAs from 12 centers underwent FFR-CT analysis. Stable chest pain was the main symptom in 77%, and 40% had equivocal stenosis. Positive and negative predictive values of FFR-CT were 49% and 76%, respectively. A total of 46 events (2%) occurred over a mean follow-up period of 17 months; FFR-CT (cutoff: 0.80) was not predictive. The FFR-CT strategy costs £2,102 per patient compared with an average of £1,411 for stress imaging. CONCLUSIONS: In clinical practice, the National Institute for Health and Care Excellence criteria for using FFR-CT were met in three-fourths of patients for symptoms and 40% for stenosis. FFR-CT had a low positive predictive value, making its use potentially more expensive than conventional stress imaging strategies.

Computed tomographic angiography in coronary artery disease.

Coronary computed tomographic angiography (CCTA) is becoming the first-line investigation for establishing the presence of coronary artery disease and, with fractional flow reserve (FFRCT), its haemodynamic significance. In patients without significant epicardial obstruction, its role is either to rule out atherosclerosis or to detect subclinical plaque that should be monitored for plaque progression/regression following prevention therapy and provide risk classification. Ischaemic non-obstructive coronary arteries are also expected to be assessed by non-invasive imaging, including CCTA. In patients with significant epicardial obstruction, CCTA can assist in planning revascularisation by determining the disease complexity, vessel size, lesion length and tissue composition of the atherosclerotic plaque, as well as the best fluoroscopic viewing angle; it may also help in selecting adjunctive percutaneous devices (e.g., rotational atherectomy) and in determining the best landing zone for stents or bypass grafts.

Contemporary cardiovascular computed tomography (CCT) training: Serial surveys of the international CCT community by the Fellow and Resident Leaders of the Society of Cardiovascular Computed Tomography (SCCT) Committee (FiRST) and SCCT Future Leaders Program (FLP).

BACKGROUND: As cardiovascular computed tomography (CCT) practice evolves, the demand for specialists continues to increase. However, CCT training remains variable globally with limited contemporaneous data to understand this heterogeneity. We sought to understand the role of CCT globally and the training available to underpin its use. METHODS: We performed two consecutive surveys of cardiology and radiology physicians, two years apart, utilizing the Society of Cardiovascular Computed Tomography (SCCT) website, weblinks, social media platforms, and meeting handouts to maximize our response rate. We compared United States (US)-based vs. international responses to understand global similarities and differences in practice and training in the surveys. RESULTS: 235 respondents (37% trainees and 63% educators/non-trainees) initiated the first survey with 174 (74%) completing the core survey, with 205 providing their work location (114 US and 91 international). Eighty-four percent (92/110) of educator respondents stated a need for increased training opportunities to meet growing demand. Dedicated training fellowships are heterogenous, with limited access to structural heart imaging training, despite structural scanning being performed within institutions. The lack of a standardized curriculum was identified as the main obstacle to effective CCT learning, particularly in the US, with web-based learning platforms being the most popular option for improving access to CCT training. 148 trainees initiated the second survey with 107 (72%) completing the core components (51% North America, 49% international). Only 68% said they would be able to meet their required CCT education needs via their training program. Obstacles in obtaining CCT training again included a lack of a developed curriculum (51%), a lack of dedicated training time (35%), and a lack of local faculty expertise (31%). There was regional variability in access to CCT training, and, in contrast to the first survey, most (89%) felt 1:1 live review of cases with trained/expert reader was most useful for improving CCT training alongside formal curriculum/live lectures (72%). CONCLUSIONS: There is a need to expand dedicated CCT training globally to meet the demand for complex CCT practice. Access to CCT education (didactic and 1:1 case-based teaching from expert faculty), implementation of recently published global training curricula, and increased teaching resources (web-based) as an adjunct to existing experiential learning opportunities, are all deemed necessary to address current educational shortfalls.

Deep-Learning for Epicardial Adipose Tissue Assessment With Computed Tomography: Implications for Cardiovascular Risk Prediction.

BACKGROUND: Epicardial adipose tissue (EAT) volume is a marker of visceral obesity that can be measured in coronary computed tomography angiograms (CCTA). The clinical value of integrating this measurement in routine CCTA interpretation has not been documented. OBJECTIVES: This study sought to develop a deep-learning network for automated quantification of EAT volume from CCTA, test it in patients who are technically challenging, and validate its prognostic value in routine clinical care. METHODS: The deep-learning network was trained and validated to autosegment EAT volume in 3,720 CCTA scans from the ORFAN (Oxford Risk Factors and Noninvasive Imaging Study) cohort. The model was tested in patients with challenging anatomy and scan artifacts and applied to a longitudinal cohort of 253 patients post-cardiac surgery and 1,558 patients from the SCOT-HEART (Scottish Computed Tomography of the Heart) Trial, to investigate its prognostic value. RESULTS: External validation of the deep-learning network yielded a concordance correlation coefficient of 0.970 for machine vs human. EAT volume was associated with coronary artery disease (odds ratio [OR] per SD increase in EAT volume: 1.13 [95% CI: 1.04-1.30]; P = 0.01), and atrial fibrillation (OR: 1.25 [95% CI: 1.08-1.40]; P = 0.03), after correction for risk factors (including body mass index). EAT volume predicted all-cause mortality (HR per SD: 1.28 [95% CI: 1.10-1.37]; P = 0.02), myocardial infarction (HR: 1.26 [95% CI:1.09-1.38]; P = 0.001), and stroke (HR: 1.20 [95% CI: 1.09-1.38]; P = 0.02) independently of risk factors in SCOT-HEART (5-year follow-up). It also predicted in-hospital (HR: 2.67 [95% CI: 1.26-3.73]; P ≤ 0.01) and long-term post-cardiac surgery atrial fibrillation (7-year follow-up; HR: 2.14 [95% CI: 1.19-2.97]; P ≤ 0.01). CONCLUSIONS: Automated assessment of EAT volume is possible in CCTA, including in patients who are technically challenging; it forms a powerful marker of metabolically unhealthy visceral obesity, which could be used for cardiovascular risk stratification.

Exercise tolerance, fatigue, mental health, and employment status at 5 and 12 months following COVID-19 illness in a physically trained population.

Failure to recover following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may have a profound impact on individuals who participate in high-intensity/volume exercise as part of their occupation/recreation. The aim of this study was to describe the longitudinal cardiopulmonary exercise function, fatigue, and mental health status of military-trained individuals (up to 12-mo postinfection) who feel recovered, and those with persistent symptoms from two acute disease severity groups (hospitalized and community-managed), compared with an age-, sex-, and job role-matched control. Eighty-eight participants underwent cardiopulmonary functional tests at baseline (5 mo following acute illness) and 12 mo; 25 hospitalized with persistent symptoms (hospitalized-symptomatic), 6 hospitalized and recovered (hospitalized-recovered); 28 community-managed with persistent symptoms (community-symptomatic); 12 community-managed, now recovered (community-recovered), and 17 controls. Cardiopulmonary exercise function and mental health status were comparable between the 5 and 12-mo follow-up. At 12 mo, symptoms of fatigue (48% and 46%) and shortness of breath (SoB; 52% and 43%) remain high in hospitalized-symptomatic and community-symptomatic groups, respectively. At 12 mo, COVID-19-exposed participants had a reduced capacity for work at anaerobic threshold and at peak exercise levels of deconditioning persist, with many individuals struggling to return to strenuous activity. The prevalence considered "fully fit" at 12 mo was lowest in symptomatic groups (hospitalized-symptomatic, 4%; hospitalized-recovered, 50%; community-symptomatic, 18%; community-recovered, 82%; control, 82%) and 49% of COVID-19-exposed participants remained medically nondeployable within the British Armed Forces. For hospitalized and symptomatic individuals, cardiopulmonary exercise profiles are consistent with impaired metabolic efficiency and deconditioning at 12 mo postacute illness. The long-term deployability status of COVID-19-exposed military personnel is uncertain.NEW & NOTEWORTHY Subjective exercise limiting symptoms such as fatigue and shortness of breath reduce but remain prevalent in symptomatic groups. At 12 mo, COVID-19-exposed individuals still have a reduced capacity for work at the anaerobic threshold (which best predicts sustainable intensity), despite oxygen uptake comparable to controls. The prevalence of COVID-19-exposed individuals considered "medically non-deployable" remains high at 47%.

National Trends in Coronary Artery Disease Imaging: Associations With Health Care Outcomes and Costs.

BACKGROUND: In 2016, the National Institute for Health and Care Excellence Clinical Guideline Number 95 ("Chest pain of recent onset") (CG95) recommended coronary computed tomography angiography (CCTA) as the first-line test for possible angina. OBJECTIVES: The purpose of this study was to determine the impact of temporal trends in imaging use on outcomes for coronary artery disease (CAD) following the CG95 recommendations. METHODS: Investigations from 2012 to 2018 were extracted from a national database and linked to hospital admission and mortality registries. Growth rates were adjusted for population size, with image modality use, cardiovascular hospital admissions, and mortality compared using Kendall's rank correlation. The impact of CG95 was assessed using an interrupted time-series analysis. RESULTS: A total of 1,909,314 investigations for CAD were performed, with an annualized per capita growth of 4.8%. Costs were £0.35 million/100,000 population/year with an increase of 2.8%/year mirroring inflation (2.5%/year). CG95 was associated with a rise in CCTA (exp[ß]: 1.10; 95% CI: 1.03-1.18), no change in myocardial perfusion imaging, and a potential modest fall (exp[ß]: 0.997; 95% CI: 0.993-1.00]) in invasive coronary angiography. There was an apparent trend between computed tomography angiography growth and invasive catheter angiography reduction across regions (Kendall Tau: -0.19; P = 0.08). CCTA growth was associated with a reduction in cardiovascular mortality (Kendall Tau: -0.21; P = 0.045), and ischemic heart disease deaths (Kendall Tau: -0.22; P = 0.042), with an apparent trend with reduced all-cause mortality (Kendall Tau: -0.19; P = 0.07). CONCLUSIONS: Imaging investigations for CAD are increasing. Greater regional increases in CCTA were associated with fewer hospitalizations for myocardial infarction and a more rapid decline in CAD mortality.

Cardiopulmonary, Functional, Cognitive and Mental Health Outcomes Post-COVID-19, Across the Range of Severity of Acute Illness, in a Physically Active, Working-Age Population.

BACKGROUND: The COVID-19 pandemic has led to significant morbidity and mortality, with the former impacting and limiting individuals requiring high physical fitness, including sportspeople and emergency services. METHODS: Observational cohort study of 4 groups: hospitalised, community illness with on-going symptoms (community-symptomatic), community illness now recovered (community-recovered) and comparison. A total of 113 participants (aged 39 ± 9, 86% male) were recruited: hospitalised (n = 35), community-symptomatic (n = 34), community-recovered (n = 18) and comparison (n = 26), approximately five months following acute illness. Participant outcome measures included cardiopulmonary imaging, submaximal and maximal exercise testing, pulmonary function, cognitive assessment, blood tests and questionnaires on mental health and function. RESULTS: Hospitalised and community-symptomatic groups were older (43 ± 9 and 37 ± 10, P = 0.003), with a higher body mass index (31 ± 4 and 29 ± 4, P < 0.001), and had worse mental health (anxiety, depression and post-traumatic stress), fatigue and quality of life scores. Hospitalised and community-symptomatic participants performed less well on sub-maximal and maximal exercise testing. Hospitalised individuals had impaired ventilatory efficiency (higher VE/V̇CO2 slope, 29.6 ± 5.1, P < 0.001), achieved less work at anaerobic threshold (70 ± 15, P < 0.001) and peak (231 ± 35, P < 0.001), and had a reduced forced vital capacity (4.7 ± 0.9, P = 0.004). Clinically significant abnormal cardiopulmonary imaging findings were present in 6% of hospitalised participants. Community-recovered individuals had no significant differences in outcomes to the comparison group. CONCLUSION: Symptomatically recovered individuals who suffered mild-moderate acute COVID-19 do not differ from an age-, sex- and job-role-matched comparison population five months post-illness. Individuals who were hospitalised or continue to suffer symptoms may require a specific comprehensive assessment prior to return to full physical activity.

Great debates in cardiac computed tomography: OPINION: "Artificial intelligence and the future of cardiovascular CT - Managing expectation and challenging hype".

This manuscript has been written as a follow-up to the "AI/ML great debate" featured at the 2021 Society of Cardiovascular Computed Tomography (SCCT) Annual Scientific Meeting. In debate style, we highlighti the need for expectation management of AI/ML, debunking the hype around current AI techniques, and countering the argument that in its current day format AI/ML is the "silver bullet" for the interpretation of daily clinical CCTA practice.

Exercise ECG for Screening in Military Aircrew.

INTRODUCTION: The exercise electrocardiogram (ExECG), or stress test, is a widely used screening tool in occupational medicine designed to detect occult coronary artery disease, and assess performance capacity and cardiovascular fitness. In some guidelines, it is recommended for high-risk occupations in which occult disease could possibly endanger public safety. In aviation medicine, however, there is an ongoing debate on the use and periodicity of ExECG for screening of aircrew.METHOD: In the German Armed Forces, aircrew applicants and active-duty aircrew undergo screening ExECG. We analyzed 7646 applicant ExECGs (5871 from pilot and 1775 from nonpilot applicants) and 17,131 ExECGs from 3817 active-duty pilots. All were performed at the German Air Force Centre of Aerospace Medicine (GAFCAM) and analyzed for ECG abnormalities, performance capacity, blood pressure, and heart rate response.RESULTS: Only 15/5871 (0.2%) of pilot applicants required further investigation and none were ultimately disqualified for aircrew duties due to their ExECG results. Of the nonpilot applicants, 22/1775 (1.2%) required further diagnostic work-up due to their ExECG findings, with only 1 ultimately disqualified. From active-duty pilots, 84/17,131 (0.5%) ExECGs revealed findings requiring further investigation, with only 2 pilots ultimately disqualified from flying duties.DISCUSSION: The extremely low yield of ExECG findings requiring further evaluation and/or disqualification for aircrew duties suggest its use is questionable and not cost-effective as a screening tool in this cohort. It may be enough to perform ExECG on clinical indication alone.Guettler N, Nicol ED, Sammito S. Exercise ECG for screening in military aircrew. Aerosp Med Hum Perform. 2022; 93(9):666-672.

Altered lung physiology in two cohorts after COVID-19 infection as assessed by computed cardiopulmonography.

The longer-term effects of COVID-19 on lung physiology remain poorly understood. Here, a new technique, computed cardiopulmonography (CCP), was used to study two COVID-19 cohorts (MCOVID and C-MORE-LP) at both ∼6 and ∼12 mo after infection. CCP is comprised of two components. The first is collection of highly precise, highly time-resolved measurements of gas exchange with a purpose-built molecular flow sensor based around laser absorption spectroscopy. The second component is estimation of physiological parameters by fitting a cardiopulmonary model to the data set. The measurement protocol involved 7 min of breathing air followed by 5 min of breathing pure O2. One hundred seventy-eight participants were studied, with 97 returning for a repeat assessment. One hundred twenty-six arterial blood gas samples were drawn from MCOVID participants. For participants who had required intensive care and/or invasive mechanical ventilation, there was a significant increase in anatomical dead space of ∼30 mL and a significant increase in alveolar-to-arterial Po2 gradient of ∼0.9 kPa relative to control participants. Those who had been hospitalized had reductions in functional residual capacity of ∼15%. Irrespectively of COVID-19 severity, participants who had had COVID-19 demonstrated a modest increase in ventilation inhomogeneity, broadly equivalent to that associated with 15 yr of aging. This study illustrates the capability of CCP to study aspects of lung function not so easily addressed through standard clinical lung function tests. However, without measurements before infection, it is not possible to conclude whether the findings relate to the effects of COVID-19 or whether they constitute risk factors for more serious disease.NEW & NOTEWORTHY This study used a novel technique, computed cardiopulmonography, to study the lungs of patients who have had COVID-19. Depending on severity of infection, there were increases in anatomical dead space, reductions in absolute lung volumes, and increases in ventilation inhomogeneity broadly equivalent to those associated with 15 yr of aging. However, without measurements taken before infection, it is unclear whether the changes result from COVID-19 infection or are risk factors for more severe disease.

Comprehensive clinical assessment identifies specific neurocognitive deficits in working-age patients with long-COVID.

INTRODUCTION: There have been more than 425 million COVID-19 infections worldwide. Post-COVID illness has become a common, disabling complication of this infection. Therefore, it presents a significant challenge to global public health and economic activity. METHODS: Comprehensive clinical assessment (symptoms, WHO performance status, cognitive testing, CPET, lung function, high-resolution CT chest, CT pulmonary angiogram and cardiac MRI) of previously well, working-age adults in full-time employment was conducted to identify physical and neurocognitive deficits in those with severe or prolonged COVID-19 illness. RESULTS: 205 consecutive patients, age 39 (IQR30.0-46.7) years, 84% male, were assessed 24 (IQR17.1-34.0) weeks after acute illness. 69% reported ≥3 ongoing symptoms. Shortness of breath (61%), fatigue (54%) and cognitive problems (47%) were the most frequent symptoms, 17% met criteria for anxiety and 24% depression. 67% remained below pre-COVID performance status at 24 weeks. One third of lung function tests were abnormal, (reduced lung volume and transfer factor, and obstructive spirometry). HRCT lung was clinically indicated in <50% of patients, with COVID-associated pathology found in 25% of these. In all but three HRCTs, changes were graded 'mild'. There was an extremely low incidence of pulmonary thromboembolic disease or significant cardiac pathology. A specific, focal cognitive deficit was identified in those with ongoing symptoms of fatigue, poor concentration, poor memory, low mood, and anxiety. This was notably more common in patients managed in the community during their acute illness. CONCLUSION: Despite low rates of residual cardiopulmonary pathology, in this cohort, with low rates of premorbid illness, there is a high burden of symptoms and failure to regain pre-COVID performance 6-months after acute illness. Cognitive assessment identified a specific deficit of the same magnitude as intoxication at the UK drink driving limit or the deterioration expected with 10 years ageing, which appears to contribute significantly to the symptomatology of long-COVID.

The effect of medium-term recovery status after COVID-19 illness on cardiopulmonary exercise capacity in a physically active adult population.

A failure to fully recover following coronavirus disease 2019 (COVID-19) may have a profound impact on high-functioning populations ranging from frontline emergency services to professional or amateur/recreational athletes. The aim of the study is to describe the medium-term cardiopulmonary exercise profiles of individuals with "persistent symptoms" and individuals who feel "recovered" after hospitalization or mild-moderate community infection following COVID-19 to an age, sex, and job-role matched control group. A total of 113 participants underwent cardiopulmonary functional tests at a mean of 159 ± 7 days (∼5 mo) following acute illness; 27 hospitalized with persistent symptoms (hospitalized-symptomatic), 8 hospitalized and now recovered (hospitalized-recovered); 34 community managed with persistent symptoms (community-symptomatic); 18 community managed and now recovered (community-recovered); and 26 controls. Hospitalized groups had the least favorable body composition (body mass, body mass index, and waist circumference) compared with controls. Hospitalized-symptomatic and community-symptomatic individuals had a lower oxygen uptake (V̇o2) at peak exercise (hospitalized-symptomatic, 29.9 ± 5.0 mL/kg/min; community-symptomatic, 34.4 ± 7.2 mL/kg/min; vs. control 43.9 ± 3.1 mL/kg/min, both P < 0.001). Hospitalized-symptomatic individuals had a steeper V̇e/V̇co2 slope (lower ventilatory efficiency) (30.5 ± 5.3 vs. 25.5 ± 2.6, P = 0.003) versus. controls. Hospitalized-recovered had a significantly lower oxygen uptake at peak (32.6 ± 6.6 mL/kg/min vs. 43.9 ± 13.1 mL/kg/min, P = 0.015) compared with controls. No significant differences were reported between community-recovered individuals and controls in any cardiopulmonary parameter. In conclusion, medium-term findings suggest that community-recovered individuals did not differ in cardiopulmonary fitness from physically active healthy controls. This suggests their readiness to return to higher levels of physical activity. However, the hospitalized-recovered group and both groups with persistent symptoms had enduring functional limitations, warranting further monitoring, rehabilitation, and recovery.NEW & NOTEWORTHY At 5 mo postinfection, community-treated individuals who feel recovered have comparable cardiopulmonary exercise profiles to the physically trained and active controls, suggesting a readiness to return to higher intensity/volumes of exercise. However, both symptomatic groups and the hospital-recovered group have persistent functional limitations when compared with active controls, supporting the requirement for ongoing monitoring, rehabilitation, and recovery.