Ventilation dynamics using a portable device coupled to the six-minute walk test in people with long-COVID syndrome: a preliminary study.

OBJECTIVE: To investigated the dynamic ventilatory responses and their influence on functional exercise capacity in patients with long-COVID-19 syndrome (LCS). RESULTS: Sixteen LCS patients were subjected to resting lung function (spirometry and respiratory oscillometry-RO) and cardiopulmonary performance to exercise (Spiropalm®-equipped six-minute walk test-6MWT and cardiopulmonary exercise test-CPX). At rest, spirometry showed a normal, restrictive and obstructive pattern in 87.5%, 6.25% and 6.25% of participants, respectively. At rest, RO showed increased resonance frequency, increased integrated low-frequency reactance and increased difference between resistance at 4-20 Hz (R4-R20) in 43.7%, 50%, and 31.2% of participants, respectively. The median of six-minute walking distance (DTC6) was 434 (386-478) m, which corresponds to a value of 83% (78-97%) of predicted. Dynamic hyperinflation (DH) and reduced breathing reserve (BR) were detected in 62.5% and 12.5% of participants, respectively. At CPX, the median peak oxygen uptake (VO2peak) was 19 (14-37) ml/kg/min. There was a significant correlation of 6MWD with both R4-R20 (rs=-0.499, P = 0.039) and VO2peak (rs=0.628, P = 0.009). Our results indicate that DH and low BR are contributors to poor exercise performance, which is associated with peripheral airway disease. These are promising results considering that they were achieved with simple, portable ventilatory and metabolic systems.

Clinical and economic outcomes of pharmacological stress tests in patients with a history of COVID-19.

BACKGROUND: Despite millions of COVID-19 cases in the United States, it remains unknown whether a history of COVID-19 infection impacts the safety of pharmacologic myocardial perfusion imaging stress testing (pharmacologic MPI). HYPOTHESIS: The aim of this study was to assess if a prior COVID-19 infection was associated with a higher risk of complications during and following pharmacologic MPI testing. METHODS: This retrospective cohort analysis included 179 803 adults (≥18 years) from the PharMetrics® Plus claims database who underwent pharmacologic MPI between March 1, 2020 and February 28, 2021. Patients with a history of COVID-19 infection (COVID-19 group) were compared with propensity-score matched no-COVID-19 history group for reversal agent use, 30-day resource use, and post-MPI cardiac events/procedures. RESULTS: The most commonly used stress agent was regadenoson (91.7%). The COVID-19 group (n = 6372; 3.5%) had slightly higher: reversal agent use (difference 1.13% [95% confidence interval [CI]: 0.33, 1.92]), all-cause costs (difference USD $128 [95% CI: $73-$181]), and office visits (81.5% vs. 77.0%) than the no-COVID-19 group. Prior COVID-19 infection did not appear to impact subsequent cardiac events/procedures. CONCLUSIONS: COVID-19 history was associated with slightly higher reversal agent use, all-cause costs, and office visits after pharmacologic MPI; however, the differences were not clinically meaningful. Concerns for use of stress agents in patients with prior COVID-19 do not appear to be warranted.

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 (DLCO) (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).

Cardiopulmonary Exercise Testing Distinguishes between Post-COVID-19 as a Dysfunctional Syndrome and Organ Pathologies.

(1) Background: Dyspnea is one of the most frequent symptoms among post-COVID-19 patients. Cardiopulmonary exercise testing (CPET) is key to a differential diagnosis of dyspnea. This study aimed to describe and classify patterns of cardiopulmonary dysfunction in post-COVID-19 patients, using CPET. (2) Methods: A total of 143 symptomatic post-COVID-19 patients were included in the study. All patients underwent CPET, including oxygen consumption, slope of minute ventilation to CO2 production, and capillary blood gas testing, and were evaluated for signs of limitation by two experienced examiners. In total, 120 patients reached a satisfactory level of exertion and were included in further analyses. (3) Results: Using CPET, cardiovascular diseases such as venous thromboembolism or ischemic and nonischemic heart disease were identified as either cardiac (4.2%) or pulmonary vascular (5.8%) limitations. Some patients also exhibited dysfunctional states, such as deconditioning (15.8%) or pulmonary mechanical limitation (9.2%), mostly resulting from dysfunctional breathing patterns. Most (65%) patients showed no signs of limitation. (4) Conclusions: CPET can identify patients with distinct limitation patterns, and potentially guide further therapy and rehabilitation. Dysfunctional breathing and deconditioning are crucial factors for the evaluation of post-COVID-19 patients, as they can differentiate these dysfunctional syndromes from organic diseases. This highlights the importance of dynamic (as opposed to static) investigations in the post-COVID-19 context.

Functional limitations 12 months after SARS-CoV-2 infection correlate with initial disease severity: An observational study of cardiopulmonary exercise capacity testing in COVID-19 convalescents.

BACKGROUND: Cardiopulmonary Exercise Testing (CPET) provides a comprehensive assessment of pulmonary, cardiovascular and musculosceletal function. Reduced CPET performance could be an indicator for chronic morbidity after COVID-19. METHODS: Patients ≥18 years with confirmed PCR positive SARS-CoV-2 infection were offered to participate in a prospective observational study of clinical course and outcomes of COVID-19. 54 patients completed CPET, questionnaires on respiratory quality of life and performed pulmonary function tests 12 months after SARS-CoV-2 infection. RESULTS: At 12 months after SARS-CoV-2 infection, 46.3% of participants had a peak performance and 33.3% a peak oxygen uptake of <80% of the predicted values, respectively. Further impairments were observed in diffusion capacity and ventilatory efficiency. Functional limitations were particularly pronounced in patients after invasive mechanical ventilation and extracorporeal membrane oxygenation treatment. Ventilatory capacity was reduced <80% of predicted values in 55.6% of participants, independent from initial clinical severity. Patient reported dyspnea and respiratory quality of life after COVID-19 correlated with CPET performance and parameters of gas exchange. Risk factors for reduced CPET performance 12 months after COVID-19 were prior intensive care treatment (OR 5.58, p = 0.004), SGRQ outcome >25 points (OR 3.48, p = 0.03) and reduced DLCO (OR 3.01, p = 0.054). CONCLUSIONS: Functional limitations causing chronic morbidity in COVID-19 survivors persist over 12 months after SARS-CoV-2 infection. These limitations were particularly seen in parameters of overall performance and gas exchange resulting from muscular deconditioning and lung parenchymal changes. Patient reported reduced respiratory quality of life was a risk factor for adverse CPET performance.

Oxygen uptake kinetics and chronotropic responses to exercise are impaired in survivors of severe COVID-19.

The post-acute phase of coronavirus disease 2019 (COVID-19) is often marked by several persistent symptoms and exertional intolerance, which compromise survivors' exercise capacity. This was a cross-sectional study aiming to investigate the impact of COVID-19 on oxygen uptake (V̇o2) kinetics and cardiopulmonary function in survivors of severe COVID-19 about 3-6 mo after intensive care unit (ICU) hospitalization. Thirty-five COVID-19 survivors previously admitted to ICU (5 ± 1 mo after hospital discharge) and 18 controls matched for sex, age, comorbidities, and physical activity level with no prior history of SARS-CoV-2 infection were recruited. Subjects were submitted to a maximum-graded cardiopulmonary exercise test (CPX) with an initial 3-min period of a constant, moderate-intensity walk (i.e., below ventilatory threshold, VT). V̇o2 kinetics was remarkably impaired in COVID-19 survivors as evidenced at the on-transient by an 85% (P = 0.008) and 28% (P = 0.001) greater oxygen deficit and mean response time (MRT), respectively. Furthermore, COVID-19 survivors showed an 11% longer (P = 0.046) half-time of recovery of V̇o2 (T1/2V̇o2) at the off-transient. CPX also revealed cardiopulmonary impairments following COVID-19. Peak oxygen uptake (V̇o2peak), percent-predicted V̇o2peak, and V̇o2 at the ventilatory threshold (V̇o2VT) were reduced by 17%, 17%, and 12% in COVID-19 survivors, respectively (all P < 0.05). None of the ventilatory parameters differed between groups (all P > 0.05). In addition, COVID-19 survivors also presented with blunted chronotropic responses (i.e., chronotropic index, maximum heart rate, and heart rate recovery; all P < 0.05). These findings suggest that COVID-19 negatively affects central (chronotropic) and peripheral (metabolic) factors that impair the rate at which V̇o2 is adjusted to changes in energy demands.NEW & NOTEWORTHY Our findings provide novel data regarding the impact of COVID-19 on submaximal and maximal cardiopulmonary responses to exercise. We showed that V̇o2 kinetics is significantly impaired at both the onset (on-transient) and the recovery phase (off-transient) of exercise in these patients. Furthermore, our results suggest that survivors of severe COVID-19 may have a higher metabolic demand at a walking pace. These findings may partly explain the exertional intolerance frequently observed following COVID-19.

The Evaluation of Functional Abilities Using the Modified Fullerton Functional Fitness Test Is a Valuable Accessory in Diagnosing Men with Heart Failure.

The assessment of functional abilities reflects the ability to perform everyday life activities that require specific endurance and physical fitness. The Fullerton functional fitness test (FFFT) seems to be the most appropriate for assessing physical fitness in heart failure (HF) patients. The study group consisted of 30 consecutive patients hospitalized for the routine assessment of HF with a reduced ejection fraction (HFrEF). They formed the study group, and 24 healthy subjects formed the control group. Each patient underwent a cardiopulmonary exercise test (CPET), transthoracic echocardiography and FFFT modified by adding the measurement of the handgrip force of the dominant limb with the digital dynamometer. The HF patients had significantly lower peak oxygen uptake (peakVO2), maximal minute ventilation, and higher ventilatory equivalent (VE/VCO2). The concentrations of B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) were significantly higher in the study group. The results of all the FFFT items were significantly worse in the study group. FFFT parameters, together with the assessment of the strength of the handgrip, strongly correlated with the results of standard tests in HF. FFFT is an effective and safe tool for the functional evaluation of patients with HFrEF. Simple muscle strength measurement with a hand-held dynamometer can become a convenient and practical indicator of muscle strength in HF patients.

COVID-19 and physical activity in sedentary individuals: differences in metabolic, cardiovascular, and respiratory responses during aerobic exercise performed with and without a surgical face masks.

BACKGROUND: The Coronavirus-19 (COVID-19) impairs metabolic, cardiovascular, and pulmonary functions in human metabolism, and wearing face masks is recommended for the prevention of contracting or exposing others to cardio-respiratory infections. Since the effect of wearing a surgical face mask (SFM) on cardiopulmonary exercise capacity has not been systematically reported we aimed to determine the effects of wearing SFM during an incremental walking test on metabolic, cardiovascular, and pulmonary gas exchange responses in sedentary individuals. METHODS: The evaluations were performed using a repeated measures study design. Seven sedentary males (age: 40 years, height: 178 cm, weight: 88 kg, BMI: 28 kg/m2, VO2max: 32.7±3.9 mL/kg/min) and 7 sedentary female participants (age: 34 years, height: 169 cm, weight: 62 kg, BMI: 22 kg/m2, VO2max: 32.1±6.8 mL/kg/min) volunteered to participate in the current study. Anthropometric parameters were measured using a Bioelectrical impedance analysis prior to each testing session. The measures of lung function assessed by spirometry, breathing pattern, maximal exercise capacity with-and-without mask were measured with a breath-by-breath automated exercise metabolic system during incremental Bruce protocol on a treadmill with two consecutive sessions with 48-h intervals. Blood pressure values (systolic and diastolic pressure) of the individuals were taken and recorded within 1 minute at the end of every ten minutes, without speed changes. RESULTS: VO2, VCO2, and VE were significantly lower during exercise performed with SFM (P<0.001). Heart rate, systolic and diastolic blood pressure were also found significantly higher during exercise performed with SFM (P<0.01). CONCLUSIONS: Wearing a SFM during incremental walking predispose a decrease in oxygen delivery while increasing pulmonary ventilation in sedentary individuals. Thus, it could be speculated that surgical face masks have a negative impact on oxygen delivery during exercise which results in decreased exercise performance due to the restricted ventilatory conditions.

Impact of mild COVID-19 on balance function in young adults, a prospective observational study.

Balance is of essential importance in human life. The aim of the study is to examine the incidence of balance impairments in young adults who have recovered from mild COVID-19. The study involved 100 subjects, divided into two groups: the study group (50 individuals) comprised subjects who had recovered from mild COVID-19, and the control group (50 individuals) consisted of healthy subjects matched for gender and age. Balance was assessed using a force platform and clinical tests such as: timed up and go test, 15-s step test, sit-to-stand test and 6-min walk test. The assessment on the platform showed greater balance impairments in the trials with eyes closed; more specifically, compared to the controls, in trials with double-leg support the subjects from the study group acquired significantly higher scores in X average (lateral coordinates) (p < 0.05), Path length, V average (average Centre of Foot Pressure Velocity) (p < 0.05) and Area circular (p < 0.01), with even more significant results in trials with single-leg support in X average (p < 0.001), Y average (anterior-posterior coordinates) (p < 0.001) and Path length (p = 0.004). Higher scores in the timed up and go test were found in the study group (p = 0.013). The control group had higher scores in the remaining tests. The current findings show that mild COVID-19 may lead to balance impairments in young adults. Statistically significant differences in balance were found between the subjects in the study group and the healthy controls. Further studies in this area should take into account more age groups, and patients recovered from severe COVID-19, and should investigate long-term consequences of COVID-19 reflected by balance problems.

Consequences of the SARS-CoV-2 Infection on Anaerobic Performances in Young Elite Soccer Players.

The COVID-19 pandemic required local confinement measures reducing sport practice with possible consequences on the athletes' performances. Furthermore, anaerobic detraining was underestimated and poorly known in adolescents. This article aimed to assess the effects of SARS-CoV-2 infection and 1-month COVID-19 confinement on jump testing in young elite soccer players despite a 1-month multimodal training program followed by a 1-month soccer retraining period. Thirty-one elite soccer players aged 14 were included; 16 were infected by the SARS-CoV-2 and compared with 15 non-infected elite soccer players before and after 1 month of COVID-19 confinement, and after 1 month of a soccer retraining period. Squat jumps (SJ), countermovement jumps with (CMJs) and without arm swinging (CMJ) and multiple consecutive jumps (stiffness) were used to explore the anaerobic performances. Analysis of variance for repeated measures was used to compare the positive and negative SARS-CoV-2 groups, taking into account the confinement period (low training) and the retraining soccer period. The jump tests were not altered in the positive SARS-CoV-2 group compared to the negative SARS-CoV-2 group after confinement (SJ: 31.6 ± 5.6 vs. 32.7 ± 3.7; CMJ: 34.1 ± 6.9 vs. 34.2 ± 2.6; CMJs: 38.6 ± 6.8 vs. 40.3 ± 3.9; stiffness: 28.5 ± 4.3 vs. 29.1 ± 3.7) and at 1 month of this period (SJ: 33.8 ± 5.5 vs. 36.2 ± 4.6; CMJ: 34.7 ± 5.5 vs. 36.4 ± 3.5; CMJs: 40.4 ± 6.7 vs. 42.7 ± 5.5; stiffness: 32.6 ± 4.7 vs. 34.0 ± 4.3). The SARS-CoV-2 infection had no consequence on anaerobic performances assessed by jump tests in adolescent soccer players. The adolescents' growth could explain the absence of alteration of jump performances during the COVID-19 confinement. These results can be useful to manage the recovery of the anaerobic fitness after SARS-CoV-2 infection occurring in adolescent athletes.

Effects of a healthy lifestyle intervention and COVID-19-adjusted training curriculum on firefighter recruits.

There are knowledge gaps regarding healthy lifestyle (HLS) interventions in fire academy settings and also concerning the impacts of the pandemic on training. We enrolled fire recruits from two fire academies (A and B) in New England in early 2019 as the historical control group, and recruits from academies in New England (B) and Florida (C), respectively, during the pandemic as the intervention group. The three academies have similar training environments and curricula. The exposures of interest were a combination of (1) an HLS intervention and (2) impacts of the pandemic on training curricula and environs (i.e. social distancing, masking, reduced class size, etc.). We examined the health/fitness changes throughout training. The follow-up rate was 78%, leaving 92 recruits in the historical control group and 55 in the intervention group. The results show an HLS intervention improved the effects of fire academy training on recruits healthy behaviors (MEDI-lifestyle score, 0.5 ± 1.4 vs. - 0.3 ± 1.7), systolic blood pressure (- 7.2 ± 10.0 vs. 2.9 ± 12.9 mmHg), and mental health (Beck Depression score, - 0.45 ± 1.14 vs. - 0.01 ± 1.05) (all P < 0.05). The associations remained significant after multivariable adjustments. Moreover, a 1-point MEDI-lifestyle increment during academy training is associated with about 2% decrement in blood pressures over time, after multivariable adjustments (P < 0.05). Nonetheless, the impacts of pandemic restrictions on academy procedures compromised physical fitness training, namely in percent body fat, push-ups, and pull-ups.

Estimated Oxygen Consumption with the Abbreviated Method and Its Association with Vaccination and PCR Tests for COVID-19 from Socio-Demographic, Anthropometric, Lifestyle, and Morbidity Outcomes in Chilean Adults.

COVID-19 causes cardiovascular and lung problems that can be aggravated by confinement, but the practice of physical activity (PA) could lessen these effects. The objective of this study was to evaluate the association of maximum oxygen consumption (V˙O2max) with vaccination and PCR tests in apparently healthy Chilean adults. An observational and cross-sectional study was performed, in which 557 people from south-central Chile participated, who answered an online questionnaire on the control of COVID-19, demographic data, lifestyles, and diagnosis of non-communicable diseases. V˙O2max was estimated with an abbreviated method. With respect to the unvaccinated, those who received the first (OR:0.52 [CI:0.29;0.95], p = 0.019) and second vaccine (OR:0.33 [CI:0.18;0.59], p = 0.0001) were less likely to have an increased V˙O2max. The first vaccine was inversely associated with V˙O2max (mL/kg/min) (ß:-1.68 [CI:-3.06; -0.3], p = 0.017), adjusted for BMI (ß:-1.37 [CI:-2.71; -0.03], p = 0.044) and by demographic variables (ß:-1.82 [CI:-3.18; -0.46], p = 0.009); similarly occur for the second vaccine (ß: between -2.54 and -3.44, p < 0.001) on models with and without adjustment. Having taken a PCR test was not significantly associated with V˙O2max (mL/kg/min). It is concluded that vaccination significantly decreased V˙O2max, although it did not indicate cause and effect. There is little evidence of this interaction, although the results suggest an association, since V˙ O2max could prevent and attenuate the contagion symptoms and effects.

Feasibility, efficacy and safety of exercise stress echocardiography during the COVID-19 pandemic.

OBJECTIVE: To assess the feasibility, efficacy and safety of performing exercise stress echocardiography (ESE) for the assessment of myocardial ischaemia during the COVID-19 pandemic. METHODS AND RESULTS: Baseline data were collected prospectively on 740 consecutive patients (mean age 61.4 years, 56.8% males), referred for a stress echocardiogram (SE), who underwent ESE between July 2020 (immediate post lockdown) and January 2021 according to national safety guidelines, in addition to patients wearing masks during ESE. Retrospective analysis was performed on follow-up data for outcomes. Propensity score matching was used to compare workload achieved during ESE pre-COVID-19, in 768 consecutive patients who underwent ESE between May 2014 and May 2015. Of the 725 (97.9%) diagnostic tests obtained, 69 (9.3%) demonstrated significant inducible ischaemia (≥3 segments) with no serious adverse events. Of the 61 patients who underwent coronary angiography, 51 (83%) demonstrated flow-limiting coronary artery disease. During a mean follow-up period of 4.6 months, one first-cardiac event was recorded.Compliance with mask-wearing throughout ESE was seen in 98.7% of patients. Of the 17 healthcare professionals performing ESE, none contracted COVID-19 during this period. SE service performance increased to 96.8% of prepandemic levels (100%) from 26.6% at the start of July 2020 to the end of December 2020.Propensity-matched data showed no significant difference in exercise workload between patients undergoing ESE during and prepandemic. CONCLUSION: Performing ESE during the COVID-19 pandemic, with safety measures in place, is feasible, efficacious and safe. It impacted on the time patients were waiting to undergo a diagnostic test and yielded appropriate outcomes.Service evaluation authorisation of research capability numberSE20/059.

Ongoing Exercise Intolerance Following COVID-19: A Magnetic Resonance-Augmented Cardiopulmonary Exercise Test Study.

Background Ongoing exercise intolerance of unclear cause following COVID-19 infection is well recognized but poorly understood. We investigated exercise capacity in patients previously hospitalized with COVID-19 with and without self-reported exercise intolerance using magnetic resonance-augmented cardiopulmonary exercise testing. Methods and Results Sixty subjects were enrolled in this single-center prospective observational case-control study, split into 3 equally sized groups: 2 groups of age-, sex-, and comorbidity-matched previously hospitalized patients following COVID-19 without clearly identifiable postviral complications and with either self-reported reduced (COVIDreduced) or fully recovered (COVIDnormal) exercise capacity; a group of age- and sex-matched healthy controls. The COVIDreducedgroup had the lowest peak workload (79W [Interquartile range (IQR), 65-100] versus controls 104W [IQR, 86-148]; P=0.01) and shortest exercise duration (13.3±2.8 minutes versus controls 16.6±3.5 minutes; P=0.008), with no differences in these parameters between COVIDnormal patients and controls. The COVIDreduced group had: (1) the lowest peak indexed oxygen uptake (14.9 mL/minper kg [IQR, 13.1-16.2]) versus controls (22.3 mL/min per kg [IQR, 16.9-27.6]; P=0.003) and COVIDnormal patients (19.1 mL/min per kg [IQR, 15.4-23.7]; P=0.04); (2) the lowest peak indexed cardiac output (4.7±1.2 L/min per m2) versus controls (6.0±1.2 L/min per m2; P=0.004) and COVIDnormal patients (5.7±1.5 L/min per m2; P=0.02), associated with lower indexed stroke volume (SVi:COVIDreduced 39±10 mL/min per m2 versus COVIDnormal 43±7 mL/min per m2 versus controls 48±10 mL/min per m2; P=0.02). There were no differences in peak tissue oxygen extraction or biventricular ejection fractions between groups. There were no associations between COVID-19 illness severity and peak magnetic resonance-augmented cardiopulmonary exercise testing metrics. Peak indexed oxygen uptake, indexed cardiac output, and indexed stroke volume all correlated with duration from discharge to magnetic resonance-augmented cardiopulmonary exercise testing (P<0.05). Conclusions Magnetic resonance-augmented cardiopulmonary exercise testing suggests failure to augment stroke volume as a potential mechanism of exercise intolerance in previously hospitalized patients with COVID-19. This is unrelated to disease severity and, reassuringly, improves with time from acute illness.

Laminar flow ventilation system to prevent airborne infection during exercise in the COVID-19 crisis: A single-center observational study.

Particulate generation occurs during exercise-induced exhalation, and research on this topic is scarce. Moreover, infection-control measures are inadequately implemented to avoid particulate generation. A laminar airflow ventilation system (LFVS) was developed to remove respiratory droplets released during treadmill exercise. This study aimed to investigate the relationship between the number of aerosols during training on a treadmill and exercise intensity and to elucidate the effect of the LFVS on aerosol removal during anaerobic exercise. In this single-center observational study, the exercise tests were performed on a treadmill at Running Science Lab in Japan on 20 healthy subjects (age: 29±12 years, men: 80%). The subjects had a broad spectrum of aerobic capacities and fitness levels, including athletes, and had no comorbidities. All of them received no medication. The exercise intensity was increased by 1-km/h increments until the heart rate reached 85% of the expected maximum rate and then maintained for 10 min. The first 10 subjects were analyzed to examine whether exercise increased the concentration of airborne particulates in the exhaled air. For the remaining 10 subjects, the LFVS was activated during constant-load exercise to compare the number of respiratory droplets before and after LFVS use. During exercise, a steady amount of particulates before the lactate threshold (LT) was followed by a significant and gradual increase in respiratory droplets after the LT, particularly during anaerobic exercise. Furthermore, respiratory droplets ≥0.3 µm significantly decreased after using LFVS (2120800±759700 vs. 560 ± 170, p<0.001). The amount of respiratory droplets significantly increased after LT. The LFVS enabled a significant decrease in respiratory droplets during anaerobic exercise in healthy subjects. This study's findings will aid in exercising safely during this pandemic.

Comparison of Ratings of Perceived Exertion and Target Heart Rate-Based Exercise Prescription in Cardiac Rehabilitation: A RANDOMIZED CONTROLLED PILOT STUDY.

PURPOSE: Although ratings of perceived exertion (RPE) are widely used to guide exercise intensity in cardiac rehabilitation (CR), it is unclear whether target heart rate ranges (THRRs) can be implemented in CR programs that predominantly use RPE and what impact this has on changes in exercise capacity. METHODS: We conducted a three-group pilot randomized control trial (#NCT03925493) comparing RPE of 3-4 on the 10-point modified Borg scale, 60-80% of heart rate reserve (HRR) with heart rate (HR) monitored by telemetry, or 60-80% of HRR with a personal HR monitor (HRM) for high-fidelity adherence to THRR. Primary outcomes were protocol fidelity and feasibility. Secondary outcomes included exercise HR, RPE, and changes in functional exercise capacity. RESULTS: Of 48 participants randomized, four patients dropped out, 20 stopped prematurely (COVID-19 pandemic), and 24 completed the protocol. Adherence to THRR was high regardless of HRM, and patients attended a median (IQR) of 33 (23, 36) sessions with no difference between groups. After randomization, HR increased by 1 ± 6, 6 ± 5, and 10 ± 9 bpm ( P = .02); RPE (average score 3.0 ± 0.05) was unchanged, and functional exercise capacity increased by 1.0 ± 1.0, 1.9 ± 1.5, 2.0 ± 1.3 workload METs (effect size between groups, ηp2 = 0.11, P = .20) for the RPE, THRR, and THRR + HRM groups, respectively. CONCLUSIONS: We successfully implemented THRR in an all-RPE CR program without needing an HRM. Patients randomized to THRR had higher exercise HR but similar RPE ratings. The THRR may be preferable to RPE in CR populations for cardiorespiratory fitness gains, but this needs confirmation in an adequately powered trial.

Identification of factors impairing exercise capacity after severe COVID-19 pulmonary infection: a 3-month follow-up of prospective COVulnerability cohort.

BACKGROUND: Patient hospitalized for coronavirus disease 2019 (COVID-19) pulmonary infection can have sequelae such as impaired exercise capacity. We aimed to determine the frequency of long-term exercise capacity limitation in survivors of severe COVID-19 pulmonary infection and the factors associated with this limitation. METHODS: Patients with severe COVID-19 pulmonary infection were enrolled 3 months after hospital discharge in COVulnerability, a prospective cohort. They underwent cardiopulmonary exercise testing, pulmonary function test, echocardiography, and skeletal muscle mass evaluation. RESULTS: Among 105 patients included, 35% had a reduced exercise capacity (VO2peak < 80% of predicted). Compared to patients with a normal exercise capacity, patients with reduced exercise capacity were more often men (89.2% vs. 67.6%, p = 0.015), with diabetes (45.9% vs. 17.6%, p = 0.002) and renal dysfunction (21.6% vs. 17.6%, p = 0.006), but did not differ in terms of initial acute disease severity. An altered exercise capacity was associated with an impaired respiratory function as assessed by a decrease in forced vital capacity (p < 0.0001), FEV1 (p < 0.0001), total lung capacity (p < 0.0001) and DLCO (p = 0.015). Moreover, we uncovered a decrease of muscular mass index and grip test in the reduced exercise capacity group (p = 0.001 and p = 0.047 respectively), whilst 38.9% of patients with low exercise capacity had a sarcopenia, compared to 10.9% in those with normal exercise capacity (p = 0.001). Myocardial function was normal with similar systolic and diastolic parameters between groups whilst reduced exercise capacity was associated with a slightly shorter pulmonary acceleration time, despite no pulmonary hypertension. CONCLUSION: Three months after a severe COVID-19 pulmonary infection, more than one third of patients had an impairment of exercise capacity which was associated with a reduced pulmonary function, a reduced skeletal muscle mass and function but without any significant impairment in cardiac function.

Persistent Exertional Intolerance After COVID-19: Insights From Invasive Cardiopulmonary Exercise Testing.

BACKGROUND: Some patients with COVID-19 who have recovered from the acute infection after experiencing only mild symptoms continue to exhibit persistent exertional limitation that often is unexplained by conventional investigative studies. RESEARCH QUESTION: What is the pathophysiologic mechanism of exercise intolerance that underlies the post-COVID-19 long-haul syndrome in patients without cardiopulmonary disease? STUDY DESIGN AND METHODS: This study examined the systemic and pulmonary hemodynamics, ventilation, and gas exchange in 10 patients who recovered from COVID-19 and were without cardiopulmonary disease during invasive cardiopulmonary exercise testing (iCPET) and compared the results with those from 10 age- and sex-matched control participants. These data then were used to define potential reasons for exertional limitation in the cohort of patients who had recovered from COVID-19. RESULTS: The patients who had recovered from COVID-19 exhibited markedly reduced peak exercise aerobic capacity (oxygen consumption [VO2]) compared with control participants (70 ± 11% predicted vs 131 ± 45% predicted; P < .0001). This reduction in peak VO2 was associated with impaired systemic oxygen extraction (ie, narrow arterial-mixed venous oxygen content difference to arterial oxygen content ratio) compared with control participants (0.49 ± 0.1 vs 0.78 ± 0.1; P < .0001), despite a preserved peak cardiac index (7.8 ± 3.1 L/min vs 8.4±2.3 L/min; P > .05). Additionally, patients who had recovered from COVID-19 demonstrated greater ventilatory inefficiency (ie, abnormal ventilatory efficiency [VE/VCO2] slope: 35 ± 5 vs 27 ± 5; P = .01) compared with control participants without an increase in dead space ventilation. INTERPRETATION: Patients who have recovered from COVID-19 without cardiopulmonary disease demonstrate a marked reduction in peak VO2 from a peripheral rather than a central cardiac limit, along with an exaggerated hyperventilatory response during exercise.

Maximal exercise outcomes with a face mask: the effects of gender and age differences on cardiorespiratory responses.

BACKGROUND: Surgical masks have become an important accessory of physical activity in daily life due to the COVID-19 pandemic. AIMS: To determine the effects of the surgical mask on respiratory gas exchange parameters, dyspnoea, and hemodynamic responses during maximal exercise in different age groups and gender. METHODS: Twenty-six healthy participants between 18 and 65 years (mean 37.35 ± 15.99) performed a maximal exercise test twice randomly, with and without a mask. To determine the respiratory gas exchange parameters (peak oxygen consumption (VO2peak), minute ventilation (VE), energy expenditure (EE), respiratory rate), and hemodynamic responses, each participant underwent a maximal exercise test with Bruce protocol on the treadmill. The modified Borg scale (MBS) was used to determine the dyspnoea before and after exercise test. RESULTS: Test duration (min), metabolic equivalents (MET), VO2peak ml/kg/min, respiratory rate, and peak heart rate (HRpeak) of young participants after exercise test with and without a mask were higher than in middle-aged participants (p < 0.01). There was no significant difference between males and females in test duration, VO2peak ml/kg/min, VO2peak ml/min, MET, VE l/min, respiratory rate, MBS, and EE in masked tests (p > 0.05). CONCLUSION: The surgical mask use affected the maximal exercise capacity of middle-aged participants more than young participants. Although males performed better than females in tests without masks, the decrease in exercise capacity with mask use was greater than in females. Advanced age and male gender may be factors that need more attention during exercise with mask use. TRIAL REGISTRATION NUMBER AND DATE: NCT04498546-02/17/2021.

Usefulness of physical function sub-item of SF-36 survey to predict exercise intolerance in patients with heart failure.

BACKGROUND: Exercise intolerance is widely known to be a major cardinal symptom in patients with heart failure (HF), but due to the recent coronavirus disease 2019 epidemic, it is still difficult to directly measure exercise tolerance in many hospitals and facilities. The 36-Item Short-Form Health Survey physical functioning (SF-36PF) pertain to lower extremity functioning and walking. The purpose of this study was to investigate whether SF-36PF is a useful predictor of exercise intolerance and to provide its optimal cut-off value for patients with HF. METHODS AND RESULTS: SF-36PF and 6-min walking distance (6MWD) were evaluated in 372 consecutive patients with HF. Exercise intolerance was defined at 6MWD cut-offs of 200, 300, and 400 m. The addition of SF-36PF to the pre-existing determinants of exercise tolerance significantly improved the area under the curve scores (0.85 vs. 0.89, P = 0.011 for 6MWD <200 m; 0.90 vs. 0.93, P = 0.001 for 6MWD <300 m; 0.88 vs. 0.90, P = 0.021 for 6MWD <400 m) for the predictive effect on exercise intolerance. The cut-off values of SF-36PF for predicting exercise intolerance defined by 6MWD <200, 300, and 400 m were 45, 50, and 70, respectively. CONCLUSIONS: SF-36PF is a useful tool as an alternative index to predict exercise intolerance in patients with HF.