Cardiopulmonary exercise testing in COVID-19 patients at 3 months follow-up

Exercise Capacity and Occupational Competence Sequelae in COVID-19 Survivors: A Longitudinal Study

The Sars-Cov-2 infection disease (COVID-19) causes symptoms during both acute and post-COVID phases. This study assessed exercise capacity and occupational competence of 20 hospitalized COVID-19 patients, at discharge and three months later using the 6-Minute Step Test and Occupational Self-Assessment. Significant differences were found in both exercise capacity and occupational competence scores between discharge and three months later (p < 0.05). However, these measurements were not correlated (p > 0.05). Although patients show improvement after discharge, some symptoms persisted, affecting their exercise, and occupational performance. Further research is needed to explore long-term occupational outcomes of COVID-19 beyond one year.

Effects of a cardiopulmonary telerehabilitation using functional exercises in individuals after COVID-19 hospital discharge: A randomized controlled trial

IntroductionIndividuals with severe coronavirus disease 2019 (COVID-19) may present respiratory and motor complications, requiring rehabilitation programs (RP) for long periods. However, access to cardiopulmonary rehabilitation is poor. Cardiopulmonary telerehabilitation is an alternative for cardiopulmonary dysfunction, improving functional capacity, dyspnea, and quality of life. Moreover, few clinical trials verified the effectiveness of telerehabilitation using functional exercise for post-COVID symptoms. Thus, the present study aimed to verify the effects of cardiopulmonary telerehabilitation using functional and accessible exercises in individuals after COVID-19 hospital discharge.MethodsThis blinded, randomized, and controlled clinical trial and included 67 adult individuals after COVID-19 hospital discharge. Participants were randomized into the groups of telerehabilitation (TG; n = 33) and control (CG; n = 34). TG underwent an individualized exercise program (functional and accessible exercises) supervised by a physical therapist (videoconference), and CG received guidance on general care and self-monitoring of vital signs (videoconference). The primary outcome was performance and physiological responses on the 6-minute step test (6MST). Secondary outcomes were performance on the 2-minute stationary walk test (2MSWT), 30-second chair stand test (30CST), and quality of life using the 36-Item Short Form Health Survey (SF-36) questionnaire physical functioning concept (PF).ResultsFunctional capacity (6MST) improved by 28 ± 17 steps in TG and 15 ± 26 in CG (p = 0.04). For secondary outcomes, performance on 2MSWT increased by 39 ± 6 steps in TG and 10 ± 6 in CG (p = 0.00); 30CST by 3 ± 1 repetitions in TG and 1.5 ± 0.5 in CG (p = 0.05); and PF (SF-36) by 17 ± 4 points in TG and 12 ± 4 in CG (p = 0.00). Also, peak oxygen uptake VO2peak (6MST) improved by 3.8 ± 1 mL min-1 kg-1 in TG and 4.1 ± 1 in CG (p = 0.6), and heart rate demand (6MST) by 11 ± 37% in TG and -4 ± 19% in CG (p = 0.04).ConclusionsCardiopulmonary telerehabilitation using functional exercises improved the exercise and functional capacity assessed using 6MST, 30CST, and 2MSWT and the quality of life of individuals after COVID-19 hospital discharge.

Maximal oxygen uptake, pulmonary function and walking economy are not impaired in patients diagnosed with long COVID

INTRODUCTION

SARS-CoV-2 may result in the development of new symptoms, known as long COVID, a few months after the original infection.

PURPOSE

It is elusive to what extent physical capacity in patients diagnosed with long COVID is impacted.

METHODS

We compared maximal oxygen uptake (V̇O2max), one of the single most important factors for cardiovascular health and mortality, expired lung volumes and air flow, oxygen cost of walking and 6-min-walking-test (6MWT), in 20 patients diagnosed with long COVID (11 males and 9 females; 44 ± 16 years (SD); 26.7 ± 3.8BMI, duration of acute phase 1.7 ± 1.2 weeks, tested 4 ± 3 months after long COVID diagnosis) with 20 healthy age and sex matched controls (11 males and 9 females; 44 ± 16 years; 25.9 ± 4.0BMI).

RESULTS

Long COVID patients had a V̇O2max of 41.4 ± 16.2 mL∙kg-1∙min-1(men) and 38.2 ± 7.5 (women) and this was not different from controls. Similarly, mean spirometry measures in the patient group (VC; FVC; FEV1; FEV1/FVC) were also not different (85-106%) from predicted healthy values. Finally, inclined treadmill (5%, 4 km∙h-1) walking economy was not different between the groups (long COVID: 15.2 ± 1.1 mL∙kg-1∙min-1; controls: 15.2 ± 1.2 mL∙kg-1∙min-1), while the 6MWT revealed a difference (long COVID: 606 ± 118 m; controls: 685 ± 85 m; p = 0.036).

CONCLUSION

V̇O2max, oxygen cost of walking, and spirometry measurements did not appear to be impaired in patients diagnosed with long COVID with a prior mild to moderate SARS-CoV-2 infection. The typical outcomes in these essential factors for health and longevity implies that while long COVID can present with a range of symptoms, caution should be made when attributing these symptoms directly to compromised pulmonary function or V̇O2max.

Global prevalence of post-COVID-19 condition: a systematic review and meta-analysis of prospective evidence

INTRODUCTION

We investigated the prevalence of new or persistent manifestations experienced by COVID-19 survivors at 3 or more months after their initial infection, collectively known as post-COVID-19 condition (PCC).

METHODS

We searched four electronic databases and major grey literature resources for prospective studies, systematic reviews, authoritative reports and population surveys. A random-effects meta-analysis pooled the prevalence data of 22 symptoms and outcomes. The GRADE approach was used to assess the certainty of evidence. PROSPERO CRD42021231476.

RESULTS

Of 20 731 identified references, 194 met our inclusion criteria. These studies followed 483 531 individuals with confirmed COVID-19 diagnosis over periods of up to 2 years. Most focused on adults, nearly two-thirds were conducted in Europe and 63% were of high or moderate quality. The supplementary search identified 17 systematic reviews, five authoritative reports and four population surveys that reported on PCC prevalence. Our analysis revealed that more than half of COVID-19 survivors experienced one or more symptoms more than a year after their initial infection. The most common symptoms were fatiguedyspneamemory, sleep or concentration disturbances; depressionand pain. Limitation in returning to work was the most common outcome. Prevalence tended to be higher among females, individuals hospitalized during their initial infection and those who experienced severe COVID-19 illness.

CONCLUSION

PCC presents a significant health burden, affecting some groups more than others. This information will help inform health care system policies and services for people living with PCC and those caring for them.

Use of cardiopulmonary exercise testing to identify mechanisms of exertional symptoms in children with long COVID

BACKGROUND

Little is known about the mechanisms of exercise intolerance and exertional symptoms in children with long COVID. Through utilization of cardiopulmonary exercise testing (CPET), this study is the first of its kind to evaluate exertional symptoms and attempt to identify potential mechanism of long COVID-19 in children.

OBJECTIVE

To determine if CPET will uncover potential reasons for persistent symptoms of long COVID when there is no indication of cardiopulmonary or upper airway disease.

METHODS

We performed a retrospective chart review study involving children 6-17 years of age with symptoms of long COVID at Phoenix Children''s Hospital from January 1, 2021, to June 1, 2022. Symptoms included but were not limited to exercise intolerance, fatigue, shortness of breath, dyspnea on exertion, and chest pain. We recorded any measurable abnormalities present on CPET after comparing it to established normal reference ranges. Range, median, and SD of data points were calculated and p values were determined using the Mann-Whitney U and Fisher's exact test.

RESULTS

Twenty-three children with exertional symptoms consistent with long COVID were identified. The most frequent symptoms reported during exercise include dyspnea on exertion (35%), followed by chest pain (30%) and dizziness (13%). Nearly half of the children (47%) demonstrated decreased exercise capacity with 30% displaying limitations due to deconditioning, 22% limited by body habitus, and 13% due to bronchospasm. Other contributing factors include ventilation to perfusion mismatch and volitional hyperventilation.

CONCLUSION

Decreased aerobic activity due to multiple factors was found in 47% of children with a history of COVID-19. This study illustrates the importance of ongoing research into this phenomenon to elucidate its mechanism and assist physicians in making decisions regarding referral to specialists for further testing.

Comparative Analysis of Submaximal and Maximal Effort Capacities in Patients Post-COVID-19 and Individuals with Chronic Restrictive Lung Diseases

Whether impairments in submaximal and maximal effort capacities in individuals following acute COVID-19 infection resemble those found in patients with chronic pulmonary disease remains unclear. We aimed to analyze the submaximal and maximal effort capacities of patients after COVID-19 infection and those with alterations in lung mechanics similar to those observed in patients with chronic respiratory diseases. This retrospective cross-sectional observational study paired a group of post-COVID-19 individuals with another group of patients with chronic respiratory disease, using spirometric patterns similar to those observed post-COVID-19. Data from Spirometry, 6 min walk test (6-MWT), and cardiopulmonary exercise test (CPET) variables were compared, and correlations between spirometric variables and 6-WT/CPET were examined. The final sample comprised 20 patients, including 10 post-COVID-19 patients with a restrictive lung disease (RLD) pattern identified using spirometry and 10 patients with RLD. Both groups presented similar patterns of the analyzed variables, with significant correlations observed between forced vital capacity (FVC) the distance and speed achieved during the 6-MWT, and a negative correlation between FVC and V' E max. The degree of restriction in the overall sample influenced the covered distance and speed during the 6-MWT as well as the maximum minute ventilation during maximal effort.

A Systematic Review and Meta-Analysis on Aerobic Fitness Dynamics in Post-COVID-19 Athletes: Implications in the Return-to-Play Performance

Maximal oxygen uptake (V.O2max) assesses athletic performance; however, its values are inconsistent in post-COVID-19 athletes. This study aimed to analyze the dynamics of V.O2max in post-COVID-19 athletes. Observational studies were identified by screening the PubMed database published up to 17 July 2023. The initial electronic search found 320 studies. Of these, 26 employing the cardiopulmonary exercise test (CPET) to assess aerobic fitness were selected. Of the 2625 pooled athletes, 1464 were infected and considered as the post-COVID-19 group, either asymptomatic or symptomatic, while the remaining 1161, who were uninfected or had V.O2max results prior to infection, were defined as the infection-free group. Age and V.O2max were differently distributed between post-COVID-19 athletes and those without infection (p = 0.03 in both). Persistent symptoms athletes had 8 mL/Kg/min lower V.O2max than those without infection (p = 0.04). In addition, post-infected athletes who underwent CPET after 12 weeks showed a significant reduction of 2.9 mL/Kg/min in V.O2max according to the increase in body mass index (BMI). The pooled analysis showed that aerobic fitness was reduced in athletes post-COVID-19. V.O2max was negatively correlated with BMI in those who underwent CPET at 12 weeks, suggesting that symptoms persist beyond 12 weeks, affecting return-to-play.

Comparison of the muscle oxygenation during submaximal and maximal exercise tests in patients post-coronavirus disease 2019 syndrome with pulmonary involvement

INTRODUCTION

Pulmonary involvement is prevalent in patients with coronavirus disease 2019 (COVID-19). Arterial hypoxemia may reduce oxygen transferred to the skeletal muscles, possibly leading to impaired exercise capacity. Oxygen uptake may vary depending on the increased oxygen demand of the muscles during submaximal and maximal exercise.

OBJECTIVE

This study aimed to compare muscle oxygenation during submaximal and maximal exercise tests in patients with post-COVID-19 syndrome with pulmonary involvement.

METHODS

Thirty-nine patients were included. Pulmonary function (spirometry), peripheral muscle strength (dynamometer), quadriceps femoris (QF) muscle oxygenation (Moxy® device), and submaximal exercise capacity (six-minute walk test (6-MWT)) were tested on the first day, maximal exercise capacity (cardiopulmonary exercise test (CPET)) was tested on the second day. Physical activity level was evaluated using an activity monitor worn for five consecutive days. Cardiopulmonary responses and muscle oxygenation were compared during 6-MWT and CPET.

RESULTS

Patients' minimum and recovery muscle oxygen saturation were significantly decreased; maximum total hemoglobin increased, heart rate, blood pressure, breathing frequency, dyspnea, fatigue, and leg fatigue at the end-of-test and recovery increased in CPET compared to 6-MWT (p < .050). Peak oxygen consumption (VO2peak) was 18.15 ± 4.75 ml/min/kg, VO2peak; percent predicted < 80% was measured in 51.28% patients. Six-MWT distance and QF muscle strength were less than 80% predicted in 58.9% and 76.9% patients, respectively.

CONCLUSIONS

In patients with post-COVID-19 syndrome with pulmonary involvement, muscle deoxygenation of QF is greater during maximal exercise than during submaximal exercise. Specifically, patients with lung impairment should be evaluated for deoxygenation and should be taken into consideration during pulmonary rehabilitation.

The Effect of Dietary Supplementation on Physical Performance in Adolescent Male Soccer Players Infected with SARS-CoV-2

BACKGROUND/OBJECTIVES

The impact of the COVID-19 infection on athletes was reported to influence physical health, both decreasing performance and increasing the risk of injuries. This study aimed to assess the physical performance (maximal aerobic power, muscle function, and speed) of a group of male adolescent soccer players before and after COVID-19 infection and to compare the effects of nutrition intervention on physical performance.

METHODS

This study included 99 male soccer players, between 13 and 15 years old, that had mild SARS-CoV-2 infection. Their physical performance was evaluated in three periods (1 month before and 1 and 3 months after the infection). The subjects were divided into two groups, one with rigorous nutrition intervention and one without. Physical performance was evaluated through five tests: hand grip strength, 10 m sprint test, 30 m sprint test, beep test, and bench press.

RESULTS

A total of 20.2% had mild restrictions at spirometry after infection. One month after the infection, four of the five tests (hand grip strength, 10 m sprint test, 30 m sprint test, and beep test) showed statistically significantly (p < 0.005) better results in the nutrition intervention group. The same difference in results in the four tests was maintained 3 months after infection (p < 0.005).

CONCLUSIONS

Nutrition intervention with a strict dietary plan and an increase in daily calories and protein and also vitamin and mineral supplements in young athletes may be effective for faster recovery of physical parameters from COVID-19 infection, and its beneficial effects should be studied further in this infection as well as in other respiratory tract infections.

Functional Recovery of Adults Following Acute COVID-19: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis aimed to investigate the objective, functional recovery of patients more than 3 months after acute coronavirus disease 2019 (COVID-19) infection.

METHODS

Comprehensive database searches of EMBASE, PubMed/MEDLINE, Cochrane COVID-19 Study Register, CINAHL, and Google Scholar in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement were carried out until October 19, 2022. Data were extracted and agreed in duplicate. Data were narratively synthesized, and a series of meta-analyses were performed using the random-effects inverse variance method.

RESULTS

One-hundred six papers covering 20,063 patients, who were either hospitalized or not hospitalized with acute COVID-19 and were followed-up between 3 and 24 months, were included. Percentage predicted 6-minute walk distance at 3 months to <5 months was 84.3% (95% CI = 79.2-89.3; n = 21; I2 = 98.3%) and 92.5% (95% CI = 89.8-95.3; n = 9; I2 = 94.5%) at ≥11 months. Cardiopulmonary exercise testing revealed the percentage predicted peak oxygen consumption rate ($peak\dot{\mathsf{V}}{\mathsf{o}}_{\mathsf{2}}$) at 3 months to <5 months was 77.3% (95% CI = 71.0-83.7; n = 6; I2 = 92.3%) and 95.4% (95% CI = 87.1-103.6; n = 2; I2 = 77.3%) at ≥11 months. Mean handgrip strength was greatest at ≥11 months at 31.16 kg (95% CI = 19.89-42.43; n = 2; I2 = 98.3%) of all time points. All analyses showed marked heterogeneity.

CONCLUSION

Patients have reduced physical function more than 3 months after COVID-19 infection. Better physical function in multiple physical domains is found after a longer recovery time.

IMPACT

Physical function as measured by the 6-minute walk test, hand grip strength, and cardiopulmonary exercise testing is reduced at 3 months after COVID-19 infection and can remain over 11 months of follow-up. This protracted recovery following acute COVID-19 infection supports the need to assess physical function at any clinical follow-up, and further research into rehabilitation programs and intervention for patients who have not recovered.

Analysis of fat oxidation capacity during cardiopulmonary exercise testing indicates long-lasting metabolic disturbance in patients with post-covid-19 syndrome

BACKGROUND & AIMS

Post-COVID-19 Syndrome (PCS) is characterized by symptoms including fatigue, reduced physical performance, dyspnea, cognitive impairment, and psychological distress. The mechanisms underlying the onset and severity of PCS point to mitochondrial dysfunction as significant contributor. This study examined fat oxidation as a function of mitochondrial capacity during exercise.

METHODS

Single-center prospective cohort study during inpatient rehabilitation. Cardiopulmonary exercise testing and assessment of fatigue using questionnaires were performed at admission and discharge. Detailed spirometric breath-by-breath data were used to calculate substrate oxidation rates.

RESULTS

Patients (N = 187; 38 % women; 49.7 ± 11.4 years) were referred to rehabilitation 253.4 ± 130.6 days after infection. Lead symptoms included fatigue/exercise intolerance (79.9 %), shortness of breath (77.0 %), and cognitive dysfunction (55.1 %). Fat oxidation capacity was disturbed in PCS patients overall (AUC: 11.3 [10.7-11.9]) compared to healthy controls (p < 0.0001), with hospitalization during acute infection predicting the level of disturbance (p < 0.0001). Low exercise capacity and high fatigue scores resulted in reduced fat oxidation (both p < 0.0001). In particular, younger males were affected by significantly reduced fat oxidation capacity (sex: p = 0.002; age: p < 0.001). Metabolic disturbance was significantly improved during exercise-based rehabilitation (AUC: 14.9 [14.4-15.4]; p < 0.0001), even for the group of younger impaired males (+44.2 %; p < 0.0001). Carbohydrate oxidation was not impaired.

CONCLUSIONS

PCS-specific restrictions in fat oxidation may indicate persistent mitochondrial dysfunction. Clinical assessment of PCS patients should include detailed breath-by-breath analysis during exercise to identify metabolic alterations especially in the group of younger males identified in this report. Exercise-based rehabilitation results in improved exercise capacity and fat oxidation and thus likely mitochondrial function.

CLINICAL TRIALS

NCT06468722.

Evaluation of myocardial work and exercise capacity in patients recovered from the severe form of COVID-19

Background

The impact of COVID-19 goes beyond its acute form and can lead to the persistence of symptoms and the emergence of systemic disorders, defined as long-term COVID.

Methods

We performed a cross-sectional study that included patients over 18 years of age who recovered from the severe form of COVID-19 at least 60 days after their discharge. Patients and controls were enrolled to undergo transthoracic echocardiography (TTE) using a more sensitive tool, myocardial work, in combination with cardiopulmonary exercise testing (CPET).

Results

A total of 52 patients and 31 controls were enrolled. Significant differences were observed in ejection fraction (LVEF; 62 ± 7 vs. 66 ± 6 %; p = 0.007), global longitudinal strain (LVGLS; -18.7 ± 2.6 vs. -20.4 ± 1.4 %; p = 0.001), myocardial wasted work (GWW; 152 ± 81 vs. 101 ± 54 mmHg; p = 0.003), and myocardial work efficiency (GWE; 93 ± 3 vs. 95 ± 2 %; p = 0.002). We found a significant difference in peak VO2 (24.4 ± 5.4 vs. 33.4 ± 8.8 mL/kg/min; p < 0.001), heart rate (160 ± 14 vs. 176 ± 11 bpm; p < 0.001), ventilation (84.6 ± 22.6 vs. 104.9 ± 27.0 L/min; p < 0.001), OUES% (89 ± 16 vs. 102 ± 22 %; p = 0.002), T ½ (120.3 ± 32 vs. 97.6 ± 27 s; p = 0.002) and HRR at 2 min (-36 ± 11 vs. -43 ± 13 bpm; p = 0.010).

Conclusion

Our findings revealed an increased wasted work, with lower myocardial efficiency, significantly reduced aerobic exercise capacity, and abnormal heart rate response during recovery, which may be related to previously described late symptoms. The reduction in functional capacity during physical exercise is partly associated with a decrease in resting myocardial work efficiency. These findings strongly indicate the need to determine whether these manifestations persist in the long term and their impact on cardiovascular health and quality of life in COVID-19 survivors.

Sex-specific differences of cardiopulmonary fitness and pulmonary function in exercise-based rehabilitation of patients with long-term post-COVID-19 syndrome

BACKGROUND

Post-COVID-19 Syndrome (PCS) entails a spectrum of symptoms, including fatigue, reduced physical performance, dyspnea, cognitive impairment, and psychological distress. Given the effectiveness of exercise-based rehabilitation for PCS, this study examined the efficacy of rehabilitation for PCS patients, focusing on sex-specific differences.

METHODS

Prospective cohort study during inpatient rehabilitation. Cardiopulmonary exercise testing and spirometry were performed at admission and discharge. Questionnaires were used to assess fatigue, health-related quality of life, wellbeing, and workability for up to 6 months.

RESULTS

145 patients (36% female, 47.1 ± 12.7 years; 64% male, 52.0 ± 9.1 years; p = 0.018) were referred to rehabilitation 262.0 ± 128.8 days after infection (female, 285.5 ± 140.6 days; male, 248.8 ± 112.0 days; p = 0.110). Lead symptoms included fatigue/exercise intolerance (81.4%), shortness of breath (74.5%), and cognitive dysfunction (52.4%). Women presented with higher relative baseline exercise capacity (82.0 ± 14.3%) than males (68.8 ± 13.3%, p < 0.001), but showed greater improvement in submaximal workload (p = 0.026). Men exhibited higher values for FEV1, FEV1/VC, PEF, and MEF and lower VC at baseline (p ≤ 0.038), while FEV1/VC improvement more in women (p = 0.027). Higher baseline fatigue and lower wellbeing was detected in women and correlated with impaired pulmonary function (p < 0.05). Disease perception including fatigue, health-related quality of life, wellbeing and workability improved with rehabilitation for up to six-month.

CONCLUSIONS

Rehabilitation improves cardiopulmonary fitness, pulmonary function and disease burden in women and men with long-term PCS. Women with PCS may benefit from intensified respiratory muscle training. Clinical assessment should include cardiopulmonary exercise testing and pulmonary function tests and fatigue assessments for all PCS patients to document limitations and tailor therapeutical strategies.

Effects of aerobic training on cardiopulmonary fitness in patients with long COVID-19: a randomized controlled trial

BACKGROUND

Long COVID-19 is characterized by systemic deterioration of the entire body, leading to significant physical and mental disorders. Exercise training has the potential to improve persistent symptoms and cardiopulmonary functions.

METHOD

This was a single-center, randomized, controlled trial. Twenty-four patients aged 18 to 75 years who had a history of SARS-CoV-2 infection and long COVID symptoms. Patients were randomly allocated in a 1:1 ratio to receive either a 4-week exercise training program or an attention control group. The training group participated in 12 supervised aerobic sessions on a cycling ergometer over 4 weeks. The outcomes were to assess the impact of a 4-week aerobic exercise on the persistent symptoms and cardiopulmonary fitness, the surrogate endpoints of COVID-19 recovery and cardiopulmonary health.

RESULTS

After the 4-week intervention, significant reductions were observed in the total number of symptoms in the training group. Specifically, 67.8% of patients in the training group exhibited reduced or completely resolved symptoms, in comparison to 16.7% in the control group (P = 0.013). After adjusting for gender, significant improvements in the training group were observed for exercise time (Pgroup*time = 0.028), maximum load (Pgroup*time = 0.01), and peak VO2 (Pgroup*time = 0.001), as well as O2 pulse (Pgroup*time = 0.042) and maximum heart rate (Pgroup*time = 0.007). The score of Short Form-12, depression, anxiety, perceived stress, and insomnia did not show significant changes between groups (Pgroup*time > 0.05).

CONCLUSION

A supervised aerobic training program has the potential to alleviate persistent symptoms and improve exercise tolerance in patients with long COVID-19. Further research is necessary to confirm these effects in a large population. This intervention could be easily implemented in non-hospital settings, potentially benefiting a broader range of individuals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT05961462. Registered on July 25, 2023.

Evaluating performance on the Glittre-ADL test in men with long COVID 3 years after a SARS-CoV-2 infection

Background/objective

Many COVID-19 survivors, especially those who have been hospitalized, have been suffering numerous complications that limit their activities of daily living, although changes that persist 3 years after infection are still not known. We aimed to investigate the impact of long COVID on the Glittre-ADL test (TGlittre) 3 years after acute infection in men who needed hospitalization and explore whether the performance on the TGlittre is associated with impairments in lung function, muscle strength, physical function and quality of life (QoL).

Methods

Cross-sectional study with 42 men with long COVID who took the TGlittre. They underwent pulmonary function tests and measurements of handgrip strength and quadriceps strength (QS). Additionally, they also completed the Saint George Respiratory Questionnaire (SGRQ) and Functional Independence Measure (FIM).

Results

The mean age was 52 ± 10.6 years, while the mean time after diagnosis of COVID-19 was 37 ± 3.5 months. The mean TGlittre time was 3.3 (3.1-4.1) min, which was 10% greater than the time expected for normal individuals to complete it. The TGlittre time was correlated significantly with the QS (rs = -0.397, p = 0.009), pulmonary diffusion (rs = - 0.364, p = 0.017), FIM (rs = -0.364, p = 0.017) and the "activity" domain score of the SGRQ (rs = 0.327, p = 0.034).

Conclusion

Functional capacity on exertion as measured by the TGlittre time is normal in most men with long COVID 3 years after hospitalization. However, this improvement in functional capacity does not seem to be reflected in muscle strength or QoL, requiring continued monitoring even after 3 years.

Optimizing cardiopulmonary rehabilitation duration for long COVID patients: an exercise physiology monitoring approach

The presence of prolonged symptoms after COVID infection worsens the workability and quality of life. 200 adults with long COVID syndrome were enrolled after medical, physical, and mental screening, and were divided into two groups based on their performance. The intervention group (n = 100) received supervised rehabilitation at Department of Pulmonology, Semmelweis University with the registration number 160/2021 between 01/APR/2021-31/DEC/2022, while an age-matched control group (n = 100) received a single check-up. To evaluate the long-term effects of the rehabilitation, the intervention group was involved in a 2- and 3-month follow-up, carrying out cardiopulmonary exercise test. Our study contributes understanding long COVID rehabilitation, emphasizing the potential benefits of structured cardiopulmonary rehabilitation in enhancing patient outcomes and well-being. Significant difference was found between intervention group and control group at baseline visit in pulmonary parameters, as forced vital capacity, forced expiratory volume, forced expiratory volume, transfer factor for carbon monoxide, transfer coefficient for carbon monoxide, and oxygen saturation (all p < 0.05). Our follow-up study proved that a 2-week long, patient-centered pulmonary rehabilitation program has a positive long-term effect on people with symptomatic long COVID syndrome. Our data showed significant improvement between two and three months in maximal oxygen consumption (p < 0.05). Multidisciplinary, individualized approach may be a key element of a successful cardiopulmonary rehabilitation in long COVID conditions, which improves workload, quality of life, respiratory function, and status of patients with long COVID syndrome.

Association of pulmonary function test abnormalities and quality-of-life measures after COVID-19 infection

BACKGROUND

Long-COVID is a multisystem disease that can lead to significant impairments in health-related quality of life (HRQoL). Following COVID-19 infection, abnormalities on pulmonary function tests (PFT) are common. The primary aim of this study is to evaluate for any correlation between PFT abnormalities and impairment in HRQoL scores following COVID-19 infection.

METHODS

This is an analysis of a prospective cohort of patients in Louisville, KY who were infected with COVID-19. Data collected included demographics, past medical history, laboratory tests, PFTs, and several HRQoL questionnaires such as the EuroQol 5 Dimension HRQoL questionnaire (EQ-5D-5 L), Generalized Anxiety Disorder 7 (GAD-7), Patient Health Questionnaire (PHQ-9), and Posttraumatic stress disorder checklist for DSM-5 (PCL-5). Descriptive statistics were performed, comparing PFTs (normal vs abnormal) and time since COVID-19 infection (3- vs 6- vs ≥ 12 months).

RESULTS

There were no significant differences in FEV1, FVC, or the percentage of patients with abnormal PFTs over time after COVID-19 infection. Following COVID-19, patients with normal PFTs had worse impairment in mobility HRQoL scores and change in GAD-7 scores over time. There were no differences over time in any of the HRQoL scores among patients with abnormal PFTs.

CONCLUSIONS

Among patients with an abnormal PFT, there was no temporal association with HRQoL scores as measured by EQ-5D-5 L, GAD-7, PHQ-9, and PCL-5. Among patients with a normal PFT, mobility impairment and anxiety may be associated with COVID-19 infection. Following COVID-19 infection, impairment in HRQoL scores is not completely explained by the presence of abnormalities on spirometry.

Determinants of cardiorespiratory fitness measured by cardiopulmonary exercise testing in COVID-19 survivors: a systematic review with meta-analysis and meta‑regression

BACKGROUND

The relationship between cardiorespiratory fitness and its possible determinants in post-COVID-19 survivors has not been systematically assessed.

OBJECTIVES

To identify and summarize studies comparing cardiorespiratory fitness measured by cardiopulmonary exercise testing in COVID-19 survivors versus non-COVID-19 controls, as well as to determine the influence of potential moderating factors.

METHODS

We conducted a systematic search of MEDLINE/PubMed, Cochrane Library, EMBASE, Google Scholar, and SciELO since their inceptions until June 2022. Mean differences (MD), standard mean differences (SMD), and 95% confidence intervals (CI) were calculated. Subgroup and meta-regression analyses were used to evaluate potential moderating factors.

RESULTS

48 studies (3372 participants, mean age 42 years, and with a mean testing time of 4 months post-COVID-19) were included, comprising a total of 1823 COVID-19 survivors and 1549 non-COVID-19 controls. After data pooling, VO2 peak (SMD=1.0 95% CI: 0.5, 1.5; 17 studies; N = 1273) was impaired in COVID-19 survivors. In 15 studies that reported VO2 peak values in mL/min/kg, non-COVID-19 controls had higher peak VO2 values than COVID-19 survivors (MD=6.2, 95% CI: 3.5, 8.8; N = 905; I2=84%). In addition, VO2 peak was associated with age, time post-COVID-19, disease severity, presence of dyspnea, and reduced exercise capacity.

CONCLUSION

This systematic review provides evidence that cardiorespiratory fitness may be impaired in COVID-19 survivors, especially for those with severe disease, presence of dyspnea, and reduced exercise capacity. Furthermore, the degree of reduction of VO2 peak is inversely associated with age and time post-COVID.

Insights from Chilean NCDs Hospitalization Data during COVID-19

The COVID-19 pandemic has affected the lifestyles of people of all ages, conditions and occupations. Social distance, remote working, changes in diet and a lack of physical activity have directly and indirectly affected many aspects of mental and physical health, particularly in patients with many comorbidities and non-communicable diseases (NCDs). In our paper, we analyzed COVID-19 hospitalized and non-hospitalized cases according to comorbidities to assess the average monthly percentage change (AMPC) and monthly percentage change (MPC) using open access data from the Chilean Ministry of Science, Technology, Knowledge and Innovation. As expected, the infection mainly affected patients with comorbidities, including cardiovascular risk factors. The hospitalized cases with obesity and chronic lung disease increased throughout the period of June 2020-August 2021 (AMPC = ↑20.8 and ↑19.4%, respectively, p < 0.05), as did all the non-hospitalized cases with comorbidities throughout the period (AMPC = ↑15.6 to ↑30.3 [p < 0.05]). The increases in hospitalizations and non-hospitalizations with comorbidities may be associated with physical inactivity. A healthy lifestyle with regular physical activity may have had a protective effect on the COVID-19 severity and related events in the post-pandemic period, especially for the NCD population.

Long-term reduced functional capacity and quality of life in hospitalized COVID-19 patients

Background

Persistent symptoms and exercise intolerance have been reported after COVID-19, even months after the acute disease. Although, the long-term impact on exercise capacity and health-related quality of life (HRQoL) is still unclear.

Research question

To assess the long-term functional capacity and HRQoL in patients hospitalized due to COVID-19.

Study design and methods

This is a prospective cohort study, conducted at two centers in Brazil, that included post-discharge COVID-19 patients and paired controls. The cohort was paired by age, sex, body mass index and comorbidities, using propensity score matching in a 1:3 ratio. Patients were eligible if signs or symptoms suggestive of COVID-19 and pulmonary involvement on chest computed tomography. All patients underwent cardiopulmonary exercise testing (CPET) and a HRQoL questionnaire (SF-36) 6 months after the COVID-19. The main outcome was the percentage of predicted peak oxygen consumption (ppVO2). Secondary outcomes included other CPET measures and HRQoL.

Results

The study sample comprised 47 post-discharge COVID-19 patients and 141 healthy controls. The mean age of COVID-19 patients was 54 ± 14 years, with 19 (40%) females, and a mean body mass index of 31 kg/m2 (SD, 6). The median follow-up was 7 months (IQR, 6.5-8.0) after hospital discharge. PpVO2 in COVID-19 patients was lower than in controls (83% vs. 95%, p = 0.002) with an effect size of 0.38 ([95%CI], 0.04-0.70). Mean peak VO2 (22 vs. 25 mL/kg/min, p = 0.04) and OUES (2,122 vs. 2,380, p = 0.027) were also reduced in the COVID-19 patients in comparison to controls. Dysfunctional breathing (DB) was present in 51%. HRQoL was significantly reduced in post COVID patients and positively correlated to peak exercise capacity.

Interpretation

Hospitalized COVID-19 patients presented, 7 months after discharge, with a reduction in functional capacity and HRQoL when compared to historical controls. HRQoL were reduced and correlated with the reduced peak VO2 in our population.

Cardiopulmonary testing in long COVID-19 versus non-COVID-19 patients with undifferentiated Dyspnea on exertion

BACKGROUND

Dyspnea and fatigue are characteristics of long SARS-CoV-2 (COVID)-19. Cardiopulmonary exercise testing (CPET) can be used to better evaluate such patients.

RESEARCH QUESTION

How significantly and by what mechanisms is exercise capacity impaired in patients with long COVID who are coming to a specialized clinic for evaluation?

STUDY DESIGN AND METHODS

We performed a cohort study using the Mayo Clinic exercise testing database. Subjects included consecutive long COVID patients without prior history of heart or lung disease sent from the Post-COVID Care Clinic for CPET. They were compared to a historical group of non-COVID patients with undifferentiated dyspnea also without known cardiac or pulmonary disease. Statistical comparisons were performed by t-test or Pearson's chi2 test controlling for age, sex, and beta blocker use where appropriate.

RESULTS

We found 77 patients with long COVID and 766 control patients. Long COVID patients were younger (47 ± 15 vs 50 ± 10 years, P < .01) and more likely female (70% vs 58%, P < .01). The most prominent difference on CPETs was lower percent predicted peak V̇O2 (73 ± 18 vs 85 ± 23%, p < .0001). Autonomic abnormalities (resting tachycardia, CNS changes, low systolic blood pressure) were seen during CPET more commonly in long COVID patients (34 vs 23%, P < .04), while mild pulmonary abnormalities (mild desaturation, limited breathing reserve, elevated V̇E/V̇CO2) during CPET were similar (19% in both groups) with only 1 long COVID patient showing severe impairment.

INTERPRETATION

We identified severe exercise limitation among long COVID patients. Young women may be at higher risk for these complications. Though mild pulmonary and autonomic impairment were common in long COVID patients, marked limitations were uncommon. We hope our observations help to untangle the physiologic abnormalities responsible for the symptomatology of long COVID.

Rehabilitation Improves Persistent Symptoms of COVID-19: A Nonrandomized, Controlled, Open Study in Brazil

OBJECTIVE

This study aimed to investigate the effects of an 8-wk face-to-face rehabilitation program on subjects with persistent symptoms of COVID-19 compared with a remote monitoring group.

DESIGN

This is clinical, nonrandomized, controlled, and open study. The face-to-face supervised rehabilitation lasted eight consecutive weeks, twice a week. The remote monitoring group received health guidance. The allocation was carried out by preference because of the emergency period without vaccination during the pandemic. Fatigue, dyspnea (Pulmonary Functional Status and Dyspnea Questionnaire), and exercise capacity (Incremental Shuttle Walk Test) were the primary outcome measures. Lung function, functional status (Post-COVID-19 Functional Status), symptoms of anxiety and depression (Hospital Anxiety and Depression Scale), attention (d2-R), memory (Rey's Auditory-Verbal Learning Test), handgrip strength, and knee extensor strength were secondary outcome measures.

RESULTS

Thirty-seven subjects (24.3% hospitalized) completed the baseline and final assessment, rehabilitation ( n = 22, 40.8 [SD, 10.0] yrs, 54.5% female), or remote guidance ( n = 15, 45.4 [SD, 10.5] yrs, 40% female). Both groups showed improved fatigue and exercise capacity. Exercise rehabilitation improved dyspnea, anxiety, attention, and short-term memory.

CONCLUSIONS

Rehabilitation is essential for dyspnea in subjects with persistent symptoms of COVID-19 while fatigue naturally reverses.

Functional rehabilitation based on therapeutic exercise training in patients with postacute COVID syndrome (RECOVER)

INTRODUCTION AND OBJECTIVES

Postacute COVID syndrome (PACS) is common after acute SARS-CoV-2 infection. One of the most frequent and disabling symptoms is exercise intolerance (EI). Recent evidence suggests that EI in PACS has a peripheral (metabolic-neuromuscular) origin, suggesting that exercise training may be an effective treatment. The aim of this study was to assess the role a therapeutic physical exercise program (TPEP) in PACS with EI.

METHODS

This single-center, open-label, randomized clinical trial compared an exercise training program (intervention group) with regular physical activity recommendations (control group) in patients with PACS and EI. The intervention group underwent an 8-week TPEP. The primary endpoint was improvement in functional capacity, assessed as the change in peak VO2.

RESULTS

We included 50 participants with PACS (73% women, mean age 47±7.1 years). The intervention group showed a 15% improvement in peak VO2 (peak VO2 pre- and postintervention: 25.5±7.7mL/kg/min and 29.3±4.7 mL/kg/min; P <.001) and a 13.2% improvement in predicted values (92.1±14.3% and 108.4±13.4%; P <.001). No significant changes in VO2 values were observed in the control group. Unlike the control group, the intervention group also showed improvements in all secondary outcomes: quality of life scales, muscle power, maximum inspiratory power, metabolic flexibility, and body fat percentage.

CONCLUSIONS

The program improved functional capacity in patients with PACS and EI.

Cardiopulmonary exercise testing in younger patients with persistent dyspnea following acute, outpatient COVID-19 infection

Studies using cardiopulmonary exercise testing (CPET) to evaluate persistent dyspnea following infection with COVID-19 have focused on older patients with co-morbid diseases who are post-hospitalization. Less attention has been given to younger patients with post-COVID-19 dyspnea treated as outpatients for their acute infection. We sought to determine causes of persistent dyspnea in younger patients recovering from acute COVID-19 infection that did not require hospitalization. We collected data on all post-COVID-19 patients who underwent CPET in our clinic in the calendar year 2021. Data on cardiac function and respiratory response were abstracted, and diagnoses were assigned using established criteria. CPET data on 45 patients (238.3 ± 124 days post-test positivity) with a median age of 27.0 (22.0-40.0) were available for analysis. All but two (95.6%) were active-duty service members. The group showed substantial loss of aerobic capacity-average VO2 peak (L/min) was 84.2 ± 23% predicted and 25 (55.2%) were below the threshold for normal. Spirometry, diffusion capacity, high-resolution computed tomography, and echocardiogram were largely normal and were not correlated with VO2 peak. The two most common contributors to dyspnea and exercise limitation following comprehensive evaluation were deconditioning and dysfunctional breathing (DB). Younger active-duty military patients with persistent dyspnea following outpatient COVID-19 infection show a substantial reduction in aerobic capacity that is not driven by structural cardiopulmonary disease. Deconditioning and DB breathing are common contributors to their exercise limitation. The chronicity and severity of symptoms accompanied by DB could be consistent with an underlying myopathy in some patients, a disorder that cannot be differentiated from deconditioning using non-invasive CPET.

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.

Hospital and intensive care unit stay associated with body mass index affect cardiorespiratory fitness in patients with COVID-19

BACKGROUND

The effects of coronavirus disease 2019 (COVID-19) on the cardiorespiratory fitness of hospitalized and obese patients are of utmost relevance. This study aimed to analyze how hospital and intensive care unit (ICU) stay together with body mass index affect cardiorespiratory fitness in patients with COVID-19.

METHODS

251 participants (males, n = 118; females, n = 133) were assigned to four groups: non-hospitalized COVID-19 patients (n = 65, age: 45.3 years), hospitalized COVID-19 patients (n = 63, age: 57.6 years), COVID-19 patients admitted to the ICU (n = 61, age: 56.9 years), and control group (n = 62, age: 49.8 years). An incremental cardiopulmonary exercise test was performed between 3 and 6 weeks after medical discharge from hospital.

RESULTS

Higher peak oxygen uptake (VO2peak), ventilatory efficiency and power output were found in ICU patients with normal weight (NW) than in overweight (OW) (Mean difference: 0.1 L·min-1, -5.5, 29.0 W, respectively) and obese (OB) ICU patients (Mean difference: 0.1 L·min-1, -5.0, 26.2 W, respectively) (p < .05). In NW, OW and OB participants, higher VO2peak and power output were observed in control group compared with non-hospitalized (Mean difference: NW: 0.2 L·min-1, 83.3 W; OW: 0.2 L·min-1, 60.0 W; OB: 0.2 L·min-1, 70.9 W, respectively), hospitalized (Mean difference: NW: 0.2 L·min-1, 72.9 W; OW: 0.1 L·min-1, 58.3 W; OB: 0.2 L•min-1, 91.1 W, respectively) and ICU patients (Mean difference: NW: 0.1 L·min-1, 70.9 W; OW: 0.2 L·min-1, 91.1 W; OB: 0.3 L·min-1; 65.0 W, respectively) (p < .05).

CONCLUSIONS

The degree of severity of COVID-19, especially identified by hospitalization and ICU stay, together with obesity and overweight were key factors in reducing cardiorespiratory fitness in patients with COVID-19.

Effects of a telerehabilitation program and detraining on cardiorespiratory fitness in patients with post-COVID-19 sequelae: A randomized controlled trial

BACKGROUND

This study aimed to evaluate the effects of a 15-week telerehabilitation program and a detraining period on cardiorespiratory fitness and mechanical efficiency in patients with post-COVID-19 sequelae.

METHODS

131 patients with post-COVID-19 sequelae were randomly assigned to one of two groups: patients who carried out the supervised telerehabilitation program (TRG, n = 66) and a control group (CG, n = 65). An incremental cardiopulmonary exercise testing (CPET) was performed on cycle ergometer to compare cardioventilatory responses between experimental groups.

RESULTS

A significant increase in the CPET duration, peak power output, and mechanical efficiency was observed in TRG compared to CG after the telerehabilitation program (p ≤ 0.001). A significant increase in the CPET duration, peak power output, and mechanical efficiency was verified at 3 months compared to the pretest and after detraining in TRG (p < 0.001). A significant increase in peak oxygen uptake (V̇O2peak ) was identified after the intervention and in the detraining period compared to the pretest in both experimental groups (p < 0.001). A higher ventilatory efficiency was observed after the telerehabilitation program (p = 0.021) than in pretest only in TRG.

CONCLUSIONS

A 15-week supervised home telerehabilitation program improved exercise capacity, power output, and mechanical efficiency in TRG compared to a CG. The telerehabilitation program was not more effective in improving V̇O2peak than the activities of the CG. However, ventilatory efficiency was improved only after the telerehabilitation program. The reported results after the detraining period highlight the need to maintain the rehabilitation program over time.

A Pulmonary Telerehabilitation Program Improves Exercise Capacity and Quality of Life in Young Females Post-COVID-19 Patients

OBJECTIVE

To examine the impact of telerehabilitation training on exercise capacity, lung function, and health-related quality of life (HRQOL) in comparison to no rehabilitation for post-COVID-19 symptoms in adult females.

METHODS

A randomized controlled trial of 48 females after mild to moderate COVID-19 survival were equally and randomly assigned to one of two groups: intervention group or control group. Three sessions per week for 6 weeks of a telerehabilitation program provided via a smartphone to the intervention group. Spirometry was used to quantify lung function, a 6-minute walk test (6MWT) measured in meters to measure exercise capacity, and the Short Form Health Survey-36 was used to assess HRQOL.

RESULTS

After treatment, there was no statistically significant difference in forced vital capacity (FVC) or forced expiratory volume in 1 second (FEV1) between groups (p>0.05), but the 6MWT of the intervention group increased significantly more than that of the control group (p=0.001). The percent of change in 6MWT for the intervention group and control group was 14.22% and 4.21%, respectively. After therapy, the intervention group's HRQOL significantly improved when compared to the control group's (p=0.001).

CONCLUSION

This study showed that a telerehabilitation programs improved exercise capacity and HRQOL in young females post-COVID-19 compared to no rehabilitation.

Exercise ventilatory response after COVID-19: comparison between ambulatory and hospitalized patients

Inefficient ventilatory response during cardiopulmonary exercise testing (CPET) has been suggested as a cause of post-COVID-19 dyspnea. It has been described in hospitalized patients (HOSP) with lung parenchymal sequelae but also after mild infection in ambulatory patients (AMBU). We hypothesize that AMBU and HOSP have different ventilatory responses to exercise, due to different etiologies. We analyzed CPET realized between July 2020 and May 2022 of patients with persisting respiratory symptoms 3 mo after COVID-19. Chest computed tomography (CT) scan, pulmonary function tests, quality of life, and respiratory questionnaires were collected. CPET data were specifically explored as a function of ventilation (V̇e) and time. Seventy-nine consecutive patients were included (42 AMBU and 37 HOSP, median: 54 [44-60] yr old, 57% female). Patients were hospitalized for a median of 20 [8-34] days, with pneumonia (41%) or acute respiratory distress syndrome (ARDS; 30%). Among HOSP, 12(32%) patients had abnormal values for spirometry and 18(51%) for carbon monoxide diffusing capacity (P < 0.001). CPET showed no differences between AMBU and HOSP in peak absolute O2 uptake (V̇o2) (1.59 [1.22-2.11] mL·min-1; P = 0.65). Tidal volume (VT) as a function of V̇e, was lower in AMBU than in HOSP (P < 0.01) toward the end of exercise. The slope of the V̇e-CO2 production was higher than normal in both groups (30.9 [26.1-34.3]; P = 0.96). In conclusion, the severity of COVID-19 did not influence the exercise capacity, but AMBU demonstrated a less efficient ventilatory response to exercise as compared with HOSP. CPET with exploration of data as a function of V̇e and throughout the exercise better unveil ventilatory inefficiency.NEW & NOTEWORTHY We evaluated the exercise ventilatory response in patients with persisting dyspnea after severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. We found that despite similar peak power and peak absolute O2 uptake, tidal volume as a function of ventilation was lower in ambulatory than in hospitalized patients toward the end of exercise, reflecting ventilatory inefficiency. We call for evaluation of minute ventilation with the exploration of data throughout the exercise and not only peak data to better unveil ventilatory inefficiency.

Does COVID-19 impair V̇o2peak in patients with cardiorespiratory disease? Insight from cardiopulmonary responses to maximal exercise pre- and post-illness

Reduced exercise capacity has been suggested as a cardinal sequela of COVID-19. However, only cross-sectional approaches that either do not consider individuals with concomitant cardiorespiratory disease or account for exercise capacity before infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) support this assumption. Is reduced exercise capacity a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease? We retrospectively reviewed cardiopulmonary exercise testing (CPET) data collected across three hospitals between October 2018 and March 2022. Forty-two patients who completed a CPET before and after COVID-19 and 25 patients who performed two separate CPETs but did not contract COVID-19 (CTL) were included. Within each patient, the same test protocol was performed at the first and second CPETs. The time between CPETs was similar between the groups (COVID-19 489 ± 534 vs. CTL 534 ± 257 days, P = 0.662). The COVID-19 group performed the CPETs 312 ± 232 days before and 176 ± 110 days after infection. Exercise time, peak heart rate, peak systolic pressure, oxygen uptake (V̇o2) at anaerobic threshold, peak ventilation, and ventilatory efficiency were not different between the CPETs in both groups. Peak V̇o2 was reduced from before to after SARS-CoV-2 infection. However, the change in V̇o2peak from the first to the second CPET was not different between COVID-19 vs. CTL. Accounting for V̇o2peak before COVID-19 and including a group of control patients, we find limited evidence for reduced exercise capacity as a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease.NEW & NOTEWORTHY There is accumulating evidence that reduced exercise capacity is, or can be, an outcome following COVID-19. However, evidence to date relies upon cross-sectional approaches that either do not consider patients with concomitant cardiorespiratory disease or account for pre-infection exercise capacity data. Accounting for V̇o2peak before COVID-19 and including a group of control patients, we find limited evidence for reduced exercise capacity as a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease.

Patients with persistent symptoms after COVID-19 attending a multidisciplinary evaluation: Characteristics, medical conclusions, and satisfaction

OBJECTIVE

Among patients attending a multidisciplinary day-hospital program for persistent symptoms after COVID-19, we aimed i) to describe their characteristics ii) to present the medical conclusions (diagnoses and recommendations) and iii) to assess the patients' satisfaction and its correlates.

METHODS

For this retrospective chart review study, frequent symptoms were systematically assessed. Standardized questionnaires explored fatigue (Pichot scale), physical activity (Ricci & Gagnon scale), health-related quality of life (Short-Form Health Survey), anxiety and depressive symptoms (Hospital Anxiety and Depression scale) and associated psychological burden (Somatic-Symptom-Disorder B criteria Scale). Medical record conclusions were collected and a satisfaction survey was performed at 3-months follow-up.

RESULTS

Among 286 consecutive patients (median age: 44 years; 70% women), the most frequent symptoms were fatigue (86%), breathlessness (65%), joint/muscular pain (61%) and cognitive dysfunction (58%), with a median duration of 429 days (Inter-quartile range (IqR): 216-624). Questionnaires revealed low levels of physical activity and quality of life, and high levels of fatigue, anxiety, depression, and psychological burden, with 32% and 23% meeting the diagnostic criteria for a depressive or anxiety disorder, respectively. Positive arguments for a functional somatic disorder were found in 76% of patients, including 96% with no abnormal clinical or test findings that may explain the symptoms. Physical activity rehabilitation was recommended for 91% of patients. Patients' median satisfaction was 8/10 (IqR: 6-9).

CONCLUSION

Most patients attending this program presented with long-lasting symptoms and severe quality of life impairment, received a diagnosis of functional somatic disorder, and reported high levels of satisfaction regarding the program.

Medical Rehabilitation of Patients with Post-COVID-19 Syndrome-A Comparison of Aerobic Interval and Continuous Training

INTRODUCTION

Post-COVID-19 syndrome (PCS) is a multisystemic disorder marked by impaired physical performance as one lead symptom. Since it has been suggested that endurance training as part of medical rehabilitation may be effective in improving physical performance capacity in PCS, this study aimed to compare different modes of aerobic endurance training.

METHODS

A total of 110 PCS patients (49.3 ± 11.8 years; 38% women; time after infection = 260.2 ± 127.5 days) underwent detailed clinical screening including symptom-limited cardiopulmonary exercise testing at admission and after 4-6 weeks of inpatient medical rehabilitation. Questionnaires were used to assess disease perception. Patients performed controlled isocaloric cycle ergometer training (3-5 sessions/week; 18 min) as either continuous training (CT) at 50% of maximal workload or as interval training (IT; load = 60%, relief = 30%). Outcomes of PCS patients were compared to coronary artery disease patients (CAD; n = 96) to evaluate overall training effectiveness.

RESULTS

Training participation was comparable between the groups, with no indication of training-specific exercise-induced fatigue. Overall, PCS patients improved significantly by a mean of 6.8 ± 12.1% for W at VT1; 3.1 ± 10.0% for VO2 at VT1; 5.5 ± 14.7% for O2 pulse at VT1; 7.5 ± 15.0% for W at VO2peak; 2.7 ± 11.0% for VO2peak and 4.6 ± 12.4% for O2 pulse at VO2peak (all p < 0.05) with no significant differences between groups (p > 0.05). Both groups showed reduced levels of fatigue, anxiety, and depression as well as improved quality of life and wellbeing (all p < 0.05). Compared to guideline-based cardiac rehabilitation, PCS patients showed a similar improvement in workload and oxygen uptake compared to CAD patients.

CONCLUSION

PCS patients benefit from aerobic endurance training performed as moderate continuous or interval training as part of a medical rehabilitation program in terms of improved physical exercise capacity and disease perception. The results for PCS patients are comparable to the guideline-based rehabilitation of CAD patients.

Post-COVID-19 syndrome: Physical capacity, fatigue and quality of life

PURPOSE

Post-Covid-19 syndrome is defined as the persistence of symptoms beyond 3 months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The most common symptoms include reduced exercise tolerance and capacity, fatigue, neurocognitive problems, muscle pain and dyspnea. The aim of our work was to investigate exercise capacity and markers of subjective wellbeing and their independent relation to post-COVID-19 syndrome.

PATIENTS AND METHODS

We examined a total of 69 patients with post-COVID-19 syndrome (23 male/46 female; age 46±12 years; BMI 28.9±6.6 kg/m2) with fatigue and a score ≥22 in the Fatigue Assessment Scale (FAS). We assessed exercise capacity on a cycle ergometer, a 6-minute walk test, the extent of fatigue (FAS), markers of health-related quality of life (SF-36 questionnaire) and mental health (HADS).

RESULTS

On average the Fatigue Assessment Scale was 35.0±7.4 points. Compared with normative values the VO2max/kg was reduced by 8.6±5.8 ml/min/kg (27.7%), the 6MWT by 71±96 m (11.9%), the health-related quality of life physical component score by 15.0±9.0 points (29.9%) and the mental component score by 10.6±12.8 points (20.6%). Subdivided into mild fatigue (FAS score 22-34) and severe fatigue (FAS score ≥35), patients with severe fatigue showed a significant reduction of the 6-minute walk test by 64±165 m (p<0.01) and the health-related quality of life physical component score by 5.8±17.2 points (p = 0.01). In multiple regression analysis age (β = -0.24, p = 0.02), sex (β = 0.22, p = 0.03), mental (β = -0.51, p<0.01) and physical (β = -0.44, p<0.01) health-related quality of life and by trend the 6-minute walk test (β = -0.22, p = 0.07) were associated with the FAS.

CONCLUSION

Patients with post-COVID-19 syndrome show reduced maximal and submaximal physical performance as well as limitations in quality of life, particularly pronounced in the physical components. These results are essentially influenced by the severity of fatigue and implicating the need for targeted treatments.

SARS-CoV-2 post-acute sequelae in previously hospitalised patients: systematic literature review and meta-analysis

BACKGROUND

Many individuals hospitalised with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection experience post-acute sequelae of SARS-CoV-2 infection (PASC), sometimes referred to as "long COVID". Our objective was to conduct a systematic literature review and meta-analysis to identify PASC-associated symptoms in previously hospitalised patients and determine the frequency and temporal nature of PASC.

METHODS

Searches of MEDLINE, Embase, Cochrane Library (2019-2021), World Health Organization International Clinical Trials Registry Platform and reference lists were performed from November to December 2021. Articles were assessed by two reviewers against eligibility criteria and a risk of bias tool. Symptom data were synthesised by random effects meta-analyses.

RESULTS

Of 6942 records, 52 studies with at least 100 patients were analysed; ∼70% were Europe-based studies. Most data were from the first wave of the pandemic. PASC symptoms were analysed from 28 days after hospital discharge. At 1-4 months post-acute SARS-CoV-2 infection, the most frequent individual symptoms were fatigue (29.3% (95% CI 20.1-40.6%)) and dyspnoea (19.6% (95% CI 12.8-28.7%)). Many patients experienced at least one symptom at 4-8 months (73.1% (95% CI 44.2-90.3%)) and 8-12 months (75.0% (95% CI 56.4-87.4%)).

CONCLUSIONS

A wide spectrum of persistent PASC-associated symptoms were reported over the 1-year follow-up period in a significant proportion of participants. Further research is needed to better define PASC duration and determine whether factors such as disease severity, vaccination and treatments have an impact on PASC.

Physical Activity in Long COVID: A Comparative Study of Exercise Rehabilitation Benefits in Patients with Long COVID, Coronary Artery Disease and Fibromyalgia

Exercise in long COVID is poorly studied. Nevertheless, exerciserehabilitation could improve cardiorespiratory, muscular and autonomic functions. We aimed to investigate improvement in physical and autonomic performances of long COVID patients (n = 38) after a 4-week exercise rehabilitation program (3 sessions/week) compared to two control groups composed of coronary artery disease (n = 38) and fibromyalgia patients (n = 38), two populations for whom exercise benefits are well known. Efficacy of exercise training was assessed by a cardiopulmonary exercise test, a handgrip force test, and a supine heart rate variability recording at rest before and after the rehabilitation program. Cardiorespiratory and muscular parameters were enhanced after exercise rehabilitation in the three groups (p < 0.001). No significant difference was observed for the autonomic variables. Through this comparative study with control groups, we confirm and reinforce the interest of caring for long COVID patients without post-exertional symptom exacerbation by exercise rehabilitation of both strength and endurance training, by personalizing the program to the patient and symptoms.

Systematic Review of the Prevalence of Long COVID

Background

Long COVID occurs in those infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) whose symptoms persist or develop beyond the acute phase. We conducted a systematic review to determine the prevalence of persistent symptoms, functional disability, or pathological changes in adults or children at least 12 weeks postinfection.

Methods

We searched key registers and databases from January 1, 2020 to November 2, 2021, limited to publications in English and studies with at least 100 participants. Studies in which all participants were critically ill were excluded. Long COVID was extracted as prevalence of at least 1 symptom or pathology, or prevalence of the most common symptom or pathology, at 12 weeks or later. Heterogeneity was quantified in absolute terms and as a proportion of total variation and explored across predefined subgroups (PROSPERO ID CRD42020218351).

Results

One hundred twenty studies in 130 publications were included. Length of follow-up varied between 12 weeks and 12 months. Few studies had low risk of bias. All complete and subgroup analyses except 1 had I² ≥90%, with prevalence of persistent symptoms range of 0%-93% (pooled estimate [PE], 42.1%; 95% prediction interval [PI], 6.8% to 87.9%). Studies using routine healthcare records tended to report lower prevalence (PE, 13.6%; PI, 1.2% to 68%) of persistent symptoms/pathology than self-report (PE, 43.9%; PI, 8.2% to 87.2%). However, studies systematically investigating pathology in all participants at follow up tended to report the highest estimates of all 3 (PE, 51.7%; PI, 12.3% to 89.1%). Studies of hospitalized cases had generally higher estimates than community-based studies.

Conclusions

The way in which Long COVID is defined and measured affects prevalence estimation. Given the widespread nature of SARS-CoV-2 infection globally, the burden of chronic illness is likely to be substantial even using the most conservative estimates.

How fit are military hyperbaric personnel after an asymptomatic or mild symptomatic COVID-19 infection? A retrospective study

INTRODUCTION

In the diving community there is a special need to know if asymptomatic or mild COVID-19 disease impacts the cardiopulmonary functioning of individuals with occupational exposure to extreme environments. To date, no controlled studies have been conducted comparing COVID-19-infected hyperbaric employees and non-COVID-19-infected peers in a military setting.

METHODS

Between June 2020 and June 2021, healthy, hyperbaric, military personnel aged between 18 and 54 years old, who had recovered from asymptomatic or subclinical COVID-19 disease at least one month earlier, were analysed. Non-COVID-infected peers with medical assessments during the same period were used as the control group. Somatometry, spirometry, VO₂ max, and DLCO were measured for each group.

RESULTS

No clinically relevant differences in somatometry, lung function tests, and exercise testing were found between the COVID-19 group and the controls. However, the percentage of individuals with a decrease in estimated VO2-max of 10% or more was significantly greater in the COVID group than in the control group (24 vs. 7.8%, P = 0.004).

CONCLUSIONS

After asymptomatic or mild symptomatic COVID-19 infections, military hyperbaric employees are as fit as those who had not encountered COVID-19. As this research was based on a military population, it cannot be extrapolated to a nonmilitary population. Further studies in nonmilitary populations are necessary to determine the medical relevance of the present findings.

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

Corrigendum to "The prevalence and long-term health effects of long Covid among hospitalised and non-hospitalised populations: a systematic review and meta-analysis"

[This corrects the article DOI: 10.1016/j.eclinm.2022.101762.].

Changes in cardiopulmonary exercise capacity and limitations 3-12 months after COVID-19

RATIONALE

To describe cardiopulmonary function during exercise 12 months after hospital discharge for coronavirus disease 2019 (COVID-19), assess the change from 3 to 12 months, and compare the results with matched controls without COVID-19.

METHODS

In this prospective, longitudinal, multicentre cohort study, hospitalised COVID-19 patients were examined using a cardiopulmonary exercise test (CPET) 3 and 12 months after discharge. At 3 months, 180 performed a successful CPET, and 177 did so at 12 months (mean age 59.3 years, 85 females). The COVID-19 patients were compared with controls without COVID-19 matched for age, sex, body mass index and comorbidity. Main outcome was peak oxygen uptake (V'_{O2  peak}).

RESULTS

Exercise intolerance (V'_{O2  peak} <80% predicted) was observed in 23% of patients at 12 months, related to circulatory (28%), ventilatory (17%) and other limitations including deconditioning and dysfunctional breathing (55%). Estimated mean difference between 3 and 12 months showed significant increases in V'_{O2  peak} % pred (5.0 percentage points (pp), 95% CI 3.1-6.9 pp; p<0.001), V'_{O2  peak}·kg^-1 % pred (3.4 pp, 95% CI 1.6-5.1 pp; p<0.001) and oxygen pulse % pred (4.6 pp, 95% CI 2.5-6.8 pp; p<0.001). V'_{O2  peak} was 2440 mL·min^-1 in COVID-19 patients compared to 2972 mL·min^-1 in matched controls.

CONCLUSIONS

1 year after hospital discharge for COVID-19, the majority (77%), had normal exercise capacity. Only every fourth had exercise intolerance and in these circulatory limiting factors were more common than ventilator factors. Deconditioning was common. V'_{O2  peak} and oxygen pulse improved significantly from 3 months.

Expert guidance on the management and challenges of long-COVID syndrome: a systematic review

INTRODUCTION

Long-COVID is a condition characterized by the permanence of symptoms beyond 4 weeks after an initial infection. It affects 1 out of 5 people and is loosely related to the severity of acute infection and pathological mechanisms, which are yet to be understood.

AREAS COVERED

This article looks at currently available and under-studied therapies for long-COVID syndrome. It particularly gives focus to ongoing trials and reviews the underlying mechanisms. A comprehensive literature search was performed on PubMed and clincaltrial.gov of clinical trials concerning the management of long-COVID syndrome.

EXPERT OPINION

'Long-COVID' syndrome is a new emergency characterized by several symptoms such as fatigue, dyspnea, cognitive and attention disorders, sleep disorders, post-traumatic stress disorder, muscle pain, and concentration problems. Despite the many guidelines available to date, there are no established treatments of long-COVID. Pharmacological research is studying known drugs that act on the reduction or modulation of systemic inflammation, or innovative drugs used in similar pathologies. Rehabilitation now seems to be the safest treatment to offer, whereas we will have to wait for the pharmacological research trials in progress as well as plan new trials based on a better understanding of the pathogenic mechanisms.

Cardiopulmonary Exercise Testing in Post-COVID-19 Patients: Where Does Exercise Intolerance Come From?

BACKGROUND

Post-COVID-19 exercise intolerance is poorly understood. Cardiopulmonary exercise testing (CPET) can identify the underlying exercise limitations.

OBJECTIVES

To evaluate the source and magnitude of exercise intolerance in post-COVID-19 subjects.

METHODS

Cohort study assessing subjects with different COVID-19 illness severities and a control group selected by propensity score matching. In a selected sample with CPET prior to viral infection, before and after comparisons were performed. Level of significance was 5% in the entire analysis.

RESULTS

One hundred forty-four subjects with COVID-19 were assessed (median age: 43.0 years, 57% male), with different illness severities (60% mild, 21% moderate, 19% severe). CPET was performed 11.5 (7.0, 21.2) weeks after disease onset, with exercise limitations being attributed to the peripheral muscle (92%), and the pulmonary (6%), and cardiovascular (2%) systems. Lower median percent-predicted peak oxygen uptake was observed in the severe subgroup (72.2%) as compared to the controls (91.6%). Oxygen uptake differed among illness severities and controls at peak and ventilatory thresholds. Conversely, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse were similar. Subgroup analysis of 42 subjects with prior CPET revealed significant reduction in only peak treadmill speed in the mild subgroup and in oxygen uptake at peak and ventilatory thresholds in the moderate/severe subgroup. By contrast, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse did not change significantly.

CONCLUSIONS

Peripheral muscle fatigue was the most common exercise limitation etiology in post-COVID-19 patients regardless of the illness severity. Data suggest that treatment should emphasize comprehensive rehabilitation programs, including aerobic and muscle strengthening components.

After the Storm: Regeneration, Repair, and Reestablishment of Homeostasis Between the Alveolar Epithelium and Innate Immune System Following Viral Lung Injury

The mammalian lung has an enormous environmental-epithelial interface that is optimized to accomplish the principal function of the respiratory system, gas exchange. One consequence of evolving such a large surface area is that the lung epithelium is continuously exposed to toxins, irritants, and pathogens. Maintaining homeostasis in this environment requires a delicate balance of cellular signaling between the epithelium and innate immune system. Following injury, the epithelium can be either fully regenerated in form and function or repaired by forming dysplastic scar tissue. In this review, we describe the major mechanisms of damage, regeneration, and repair within the alveolar niche where gas exchange occurs. With a focus on viral infection, we summarize recent work that has established how epithelial proliferation is arrested during infection and how the innate immune system guides its reconstitution during recovery. The consequences of these processes going awry are also considered, with an emphasis on how this will impact postpandemic pulmonary biology and medicine.

Evaluation of long-term sequelae by cardiopulmonary exercise testing 12 months after hospitalization for severe COVID-19

BACKGROUND

Cardiopulmonary exercise testing (CPET) is an important clinical tool that provides a global assessment of the respiratory, circulatory and metabolic responses to exercise which are not adequately reflected through the measurement of individual organ system function at rest. In the context of critical COVID-19, CPET is an ideal approach for assessing long term sequelae.

METHODS

In this prospective single-center study, we performed CPET 12 months after symptom onset in 60 patients that had required intensive care unit treatment for a severe COVID-19 infection. Lung function at rest and chest computed tomography (CT) scan were also performed.

RESULTS

Twelve months after severe COVID-19 pneumonia, dyspnea was the most frequently reported symptom although only a minority of patients had impaired respiratory function at rest. Mild ground-glass opacities, reticulations and bronchiectasis were the most common CT scan abnormalities. The majority of the patients (80%) had a peak O₂ uptake (V'O₂) considered within normal limits (median peak predicted O₂ uptake (V'O₂) of 98% [87.2-106.3]). Length of ICU stay remained an independent predictor of V'O₂. More than half of the patients with a normal peak predicted V'O₂ showed ventilatory inefficiency during exercise with an abnormal increase of physiological dead space ventilation (VD/Vt) (median VD/VT of 0.27 [0.21-0.32] at anaerobic threshold (AT) and 0.29 [0.25-0.34] at peak) and a widened median peak alveolar-arterial gradient for O₂ (35.2 mmHg [31.2-44.8]. Peak PetCO₂ was significantly lower in subjects with an abnormal increase of VD/Vt (p = 0.001). Impairments were more pronounced in patients with dyspnea. Peak VD/Vt values were positively correlated with peak D-Dimer plasma concentrations from blood samples collected during ICU stay (r² = 0.12; p = 0.02) and to predicted diffusion capacity of the lung for carbon monoxide (D_LCO) (r² =  - 0.15; p = 0.01).

CONCLUSIONS

Twelve months after severe COVID-19 pneumonia, most of the patients had a peak V'O₂ considered within normal limits but showed ventilatory inefficiency during exercise with increased dead space ventilation that was more pronounced in patients with persistent dyspnea.

TRIAL REGISTRATION

NCT04519320 (19/08/2020).

Low Cardiorespiratory Fitness Post-COVID-19: A Narrative Review

Patients recovering from COVID-19 often report symptoms of exhaustion, fatigue and dyspnoea and present with exercise intolerance persisting for months post-infection. Numerous studies investigated these sequelae and their possible underlying mechanisms using cardiopulmonary exercise testing. We aimed to provide an in-depth discussion as well as an overview of the contribution of selected organ systems to exercise intolerance based on the Wasserman gears. The gears represent the pulmonary system, cardiovascular system, and periphery/musculature and mitochondria. Thirty-two studies that examined adult patients post-COVID-19 via cardiopulmonary exercise testing were included. In 22 of 26 studies reporting cardiorespiratory fitness (herein defined as peak oxygen uptake-VO2peak), VO2peak was < 90% of predicted value in patients. VO2peak was notably below normal even in the long-term. Given the available evidence, the contribution of respiratory function to low VO2peak seems to be only minor except for lung diffusion capacity. The prevalence of low lung diffusion capacity was high in the included studies. The cardiovascular system might contribute to low VO2peak via subnormal cardiac output due to chronotropic incompetence and reduced stroke volume, especially in the first months post-infection. Chronotropic incompetence was similarly present in the moderate- and long-term follow-up. However, contrary findings exist. Peripheral factors such as muscle mass, strength and perfusion, mitochondrial function, or arteriovenous oxygen difference may also contribute to low VO2peak. More data are required, however. The findings of this review do not support deconditioning as the primary mechanism of low VO2peak post-COVID-19. Post-COVID-19 sequelae are multifaceted and require individual diagnosis and treatment.

Long COVID: mechanisms, risk factors and recovery

NEW FINDINGS

What is the topic of this review? The emerging condition of long COVID, its epidemiology, pathophysiological impacts on patients of different backgrounds, physiological mechanisms emerging as explanations of the condition, and treatment strategies being trialled. The review leads from a Physiological Society online conference on this topic. What advances does it highlight? Progress in understanding the pathophysiology and cellular mechanisms underlying Long COVID and potential therapeutic and management strategies.

ABSTRACT

Long COVID, the prolonged illness and fatigue suffered by a small proportion of those infected with SARS-CoV-2, is placing an increasing burden on individuals and society. A Physiological Society virtual meeting in February 2022 brought clinicians and researchers together to discuss the current understanding of long COVID mechanisms, risk factors and recovery. This review highlights the themes arising from that meeting. It considers the nature of long COVID, exploring its links with other post-viral illnesses such as myalgic encephalomyelitis/chronic fatigue syndrome, and highlights how long COVID research can help us better support those suffering from all post-viral syndromes. Long COVID research started particularly swiftly in populations routinely monitoring their physical performance - namely the military and elite athletes. The review highlights how the high degree of diagnosis, intervention and monitoring of success in these active populations can suggest management strategies for the wider population. We then consider how a key component of performance monitoring in active populations, cardiopulmonary exercise training, has revealed long COVID-related changes in physiology - including alterations in peripheral muscle function, ventilatory inefficiency and autonomic dysfunction. The nature and impact of dysautonomia are further discussed in relation to postural orthostatic tachycardia syndrome, fatigue and treatment strategies that aim to combat sympathetic overactivation by stimulating the vagus nerve. We then interrogate the mechanisms that underlie long COVID symptoms, with a focus on impaired oxygen delivery due to micro-clotting and disruption of cellular energy metabolism, before considering treatment strategies that indirectly or directly tackle these mechanisms. These include remote inspiratory muscle training and integrated care pathways that combine rehabilitation and drug interventions with research into long COVID healthcare access across different populations. Overall, this review showcases how physiological research reveals the changes that occur in long COVID and how different therapeutic strategies are being developed and tested to combat this condition.

Effects of continuous aerobic training associated with resistance training on maximal and submaximal exercise tolerance, fatigue, and quality of life of patients post-COVID-19

BACKGROUND AND PURPOSE

Dyspnea, fatigue, and reduced exercise tolerance are common in post-COVID-19 patients. In these patients, rehabilitation can improve functional capacity, reduce deconditioning after a prolonged stay in the intensive care unit, and facilitate the return to work. Thus, the present study verified the effects of cardiopulmonary rehabilitation consisting of continuous aerobic and resistance training of moderate-intensity on pulmonary function, respiratory muscle strength, maximum and submaximal tolerance to exercise, fatigue, and quality of life in post-COVID-19 patients.

METHODS

Quasi-experimental study with a protocol of 12 sessions of an outpatient intervention. Adults over 18 years of age (N = 26) with a diagnosis of COVID-19 and hospital discharge at least 15 days before the first evaluation were included. Participants performed moderate-intensity continuous aerobic and resistance training twice a week. Maximal and submaximal exercise tolerance, lung function, respiratory muscle strength, fatigue and quality of life were evaluated before and after the intervention protocol.

RESULTS

Cardiopulmonary rehabilitation improved maximal exercise tolerance, with 18.62% increase in peak oxygen consumption (VO2peak) and 29.05% in time to reach VO2 peak. VE/VCO2 slope reduced 5.21% after intervention. We also observed increased submaximal exercise tolerance (increase of 70.57 m in the 6-min walk test, p = 0.001), improved quality of life, and reduced perceived fatigue after intervention.

DISCUSSION

Patients recovered from COVID-19 can develop persistent dysfunctions in almost all organ systems and present different signs and symptoms. The complexity and variability of the damage caused by this disease can make it difficult to target rehabilitation programs, making it necessary to establish specific protocols. In this work, cardiopulmonary rehabilitation improved lung function, respiratory muscle strength, maximal and submaximal exercise tolerance, fatigue and quality of life. Continuous aerobic and resistance training of moderate intensity proved to be effective in the recovery of post-COVID-19 patients.

Post-Acute Sequelae of COVID-19: The Potential Role of Exercise Therapy in Treating Patients and Athletes Returning to Play

Post-acute sequelae of coronavirus disease 19 (COVID-19) (PASC) describe a wide range of symptoms and signs involving multiple organ systems occurring after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, representing a growing health problem also in the world of sport and the athletic population. Patients with PASC have new, returning, or persisting symptoms four or more weeks after the infection. Among the most frequent symptoms, patients complain of fatigue, dyspnea, exercise intolerance, and reduced functional capacity that interfere with everyday life activity. The role of exercise programs in PASC patients will be identified, and upcoming studies will establish the magnitude of their benefits. However, the benefits of exercise to counteract these symptoms are well known, and an improvement in cardiopulmonary fitness, functional status, deconditioning, and quality of life can be obtained in these patients, as demonstrated in similar settings. Based on this background, this review aims to summarise the current evidence about the PASC syndrome and the benefit of exercise in these patients and to provide a practical guide for the exercise prescription in PASC patients to help them to resume their functional status, exercise tolerance, prior activity levels, and quality of life, also considering the athletic population and their return to play and sports competitions.

Effect of a home-based inspiratory muscle training programme on functional capacity in postdischarged patients with long COVID: the InsCOVID trial

BACKGROUND

Fatigue and exercise intolerance are the most common symptoms in patients with long COVID.

AIMS

This study aimed to evaluate whether a home-based inspiratory muscle training (IMT) programme improves maximal functional capacity in patients' long COVID after a previous admission due to SARS-CoV-2 pneumonia.

METHODS

This study was a single-centre, blinded assessor, randomised controlled trial. Twenty-six patients with long COVID and a previous admission due to SARS-CoV-2 pneumonia were randomly assigned to receive either a 12-week IMT or usual care alone (NCT05279430). The physiotherapist and participants were not blinded. Patients allocated to the IMT arm were instructed to train at home twice daily using a threshold inspiratory muscle trainer and to maintain diaphragmatic breathing during the training session. The usual care arm received no intervention.The primary endpoint was the change in peak oxygen consumption (peakVO2). Secondary endpoints were changes in quality of life (QoL), ventilatory efficiency and chronotropic response during exercise (evaluated by chronotropic index-CI_x- formula). We used linear mixed regression analysis for evaluating changes in primary and secondary endpoints.

RESULTS

The mean age of the sample and time to first visit after discharge were 50.4±12.2 years and 362±105 days, respectively. A total of 11 (42.3%) were female. At baseline, the mean of peakVO₂, ventilatory efficiency and CIx were 18.9±5 mL/kg/min, 29.4±5.2 and 0.64±0.19, respectively. The IMT arm improved their peakVO₂ significantly compared with usual care (+Δ 4.46 mL/kg/min, 95% CI 3.10 to 5.81; p<0.001). Similar positive findings were found when evaluating changes for CI_x and some QoL dimensions. We did not find significant changes in ventilatory efficiency.

CONCLUSION

In long COVID patients with a previous admission due to SARS-CoV-2 pneumonia, IMT was associated with marked improvement in exercise capacity and QoL.

TRIAL REGISTRATION NUMBER

NCT05279430.