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RATIONALE: Diaphragm thickness is increased in cystic fibrosis (CF), but it shows a marked variability between patients. The variable response of the diaphragm to loading may reflect the combined and opposite effects of training by the respiratory disease and systemic inflammation. OBJECTIVES: To assess the impact of systemic inflammation on diaphragm and limb muscle strength and bulk in adult patients with CF. METHODS: In 38 stable patients with CF and 20 matched control subjects, we measured fat-free mass (FFM), inspiratory muscle strength, diaphragm thickness, quadriceps and biceps strength and cross-sectional area, and circulating levels of leukocytes, C-reactive protein, IL-6, IL-8, IL-17, tumor necrosis factor-alpha, tumor necrosis factor-alpha soluble receptors, and immunoglobulin G. MEASUREMENTS AND MAIN RESULTS: Patients had increases in several inflammatory markers that correlated with the severity of lung disease and nutritional depletion. Compared with control subjects, patients with CF had increased diaphragm thickness and inspiratory muscle strength and showed a trend toward a reduction in limb muscle strength and bulk. Multiple regression analyses identified FFM and airway resistance as independent predictors of diaphragm thickness, but systemic inflammation had no (or only a minor) predictive effect on FFM, inspiratory muscle strength, diaphragm thickness, and limb muscle strength and bulk. CONCLUSIONS: In patients with CF, the intensity of systemic inflammation does not account significantly for the variance of FFM and diaphragm or limb muscle strength and bulk. Training of the diaphragm in CF occurs despite the presence of systemic inflammation. [ABSTRACT FROM AUTHOR]

PURPOSE: High altitude exposure has consistently been reported to decrease forced vital capacity (FVC), but the mechanisms accounting for this observation remain incompletely understood. We investigated the possible contribution of a hypoxia-related decrease in respiratory muscle strength. METHODS: Maximal inspiratory and expiratory pressures (MIP and MEP), sniff nasal inspiratory pressure (SNIP), FVC, peak expiratory flow rate (PEF), and forced expiratory volume in 1 s (FEV1) were measured in 15 healthy subjects before and after 1, 6, and 12 h of exposure to an equivalent altitude of 4267 m in a hypobaric chamber. RESULTS: Hypoxia was associated with a progressive decrease in FVC (5.59 +/- 0.24 to 5.24 +/- 0.26 L, mean +/- SEM, P < 0.001), MIP (130 +/- 10 to 114 +/- 8 cm H2O, P < 0.01), MEP (201 +/- 12 to 171 +/- 11 cm H2O, P < 0.001), and SNIP (125 +/- 7 to 98 +/- 7 cm H2O, P < 0.001). MIP, MEP, and SNIP were strongly correlated to FVC (r ranging from 0.77 to 0.92). FEV1 didn't change, and PEF increased less than predicted by the reduction in air density (11-20% of sea-level value compared with 32% predicted). CONCLUSION: We conclude that a decrease in respiratory muscle strength may contribute to the decrease in FVC observed at high altitude. [ABSTRACT FROM AUTHOR]

Patients with cardiac disease exhibit exaggerated sympathoexcitation, pressor, and ventilatory responses to muscle metaboreflex activation (MMA). However, the effects of cardiac rehabilitation (CR) and especially resistance training (RT) modalities on MMA are not well known. This study investigated how CR impacts MMA in such patients, specifically examining the effects of two different resistance training (RT) protocols following 12 weeks of CR. In addition to endurance exercises, 32 patients were randomized into either a 3/7 RT modality (comprising 5 sets of 3-7 repetitions) or a control (CTRL) modality (involving 3 sets of 9 repetitions), with distinct inter-set rest intervals (15 s for 3/7 and 60 s for CTRL). MMA, gauged by blood pressure (BP) and ventilatory (Ve) responses during a handgrip exercise at 40% effort and subsequent post-exercise circulatory occlusion, demonstrated CR's significant impact. Systolic BP, initially at + 28 ± 23% pre-CR, improved to + 11 ± 15% post-CR (P = .011 time effect; P = .131 group effect). Diastolic BP showed a similar trend, from + 27 ± 23% to + 13 ± 15% (P = .099 time effect; P = .087 group effect). Ve, initially at + 60 ± 39%, reduced to + 14 ± 19% post-CR (P < .001 time effect; P = .142 group effect). Critical parameters-maximal oxygen consumption, lean mass, hand grip, and quadriceps strength-exhibited parallel increases in both 3/7 and CTRL groups (P < .05 time effect; P > .3 group effect). Ultimately, CR demonstrated comparable improvements in MMA across both RT modalities, indicating its positive influence on cardiovascular responses and physical performance in individuals with cardiac conditions., Competing Interests: Declarations Conflict of interest No conflicts of interest, financial or otherwise, are declared by the authors., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Occupational exposure to charcoal smoke and dust is a threat to workers' respiratory systems., Research Question: What is the prevalence of COPD in charcoal workers compared with that of farmers in rural areas of Democratic Republic of Congo (DRC)?, Study Design and Methods: This cross-sectional, comparative, and multisite study was performed in the charcoal-producing provinces of southwestern DRC. We randomly included charcoal workers and compared them with farmers (age range, 18-70 years). Air quality indexes, anthropometric features, physical activity, sociodemographic characteristics, and related medical events data were recorded. A lung function questionnaire was used to assess respiratory symptoms and spirometry was performed. COPD was defined as the presence of respiratory symptoms for > 3 months with an FEV 1 to FVC ratio less than the lower limit of normal. The prevalence of COPD was calculated, and logistic regression was used to identify COPD-associated factors., Results: We included 485 participants between August 2020 and July 2021. Charcoal producers (CPs; n = 229) were compared with farmers (n = 118), and charcoal saleswomen (n = 72) were compared with vegetable saleswomen (n = 66). Respective groups were similar in age, job seniority, height, and weight. The air was more polluted at charcoal workplaces. The prevalence of COPD was higher in CPs than in farmers (39.7% vs 14.4%; P < .0001) and higher in charcoal saleswomens compared with vegetable saleswomen (40.3% vs 13.6%; P < .0001). Being a charcoal worker was associated independently with COPD in the CP and farmers groups (adjusted OR, 3.54; 95% CI, 1.94-6.46) and in the saleswomen group (adjusted OR, 7.85; 95% CI, 2.85-21.5), where it was also associated independently with young age (adjusted OR, 0.85; 95% CI, 0.80-0.93) and monthly income (adjusted OR, 0.88; 95% CI, 0.83-0.96)., Interpretation: In rural areas of DRC, producing or selling charcoal is associated with a higher risk of COPD., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

The 3/7 resistance training (RT) method involves performing sets with increasing numbers of repetitions, and shorter rest periods than the 3x9 method. Therefore, it could induce more metabolic stress in people with heart failure with reduced ejection fraction (HFrEF) or coronary artery disease (CAD). This randomized cross-over study tested this hypothesis. Eleven individuals with HFrEF and thirteen with CAD performed high-intensity interval training (HIIT) for 30 min, followed by 3x9 or 3/7 RT according to group allocation. pH, HCO 3- , lactate, and growth hormone were measured at baseline, after HIIT, and after RT. pH and HCO 3- decreased, and lactate increased after both RT methods. In the CAD group, lactate increased more (6.99 ± 2.37 vs. 9.20 ± 3.57 mmol/L, p = 0.025), pH tended to decrease more (7.29 ± 0.06 vs. 7.33 ± 0.04, p = 0.060), and HCO 3- decreased more (18.6 ± 3.1 vs. 21.1 ± 2.5 mmol/L, p = 0.004) after 3/7 than 3x9 RT. In the HFrEF group, lactate, pH, and HCO 3- concentrations did not differ between RT methods (all p > 0.248). RT did not increase growth hormone in either patient group. In conclusion, the 3/7 RT method induced more metabolic stress than the 3x9 method in people with CAD but not HFrEF.

Purpose: The purpose of this study was to determine and compare the effectiveness of three different resistance training (RT) methods for cardiac rehabilitation., Methods: Individuals with heart failure with reduced ejection fraction (HFrEF, n = 23) or coronary artery disease (CAD, n = 22) and healthy controls (CTRL, n = 29) participated in this randomized crossover trial of RT exercises at 70% of the one-maximal repetition on a leg extension machine. Peak heart rate (HR) and blood pressure (BP) were measured noninvasively. The three RT methods were five sets of increasing repetitions from three to seven (RISE), of decreasing repetitions from seven to three (DROP), and three sets of nine repetitions (USUAL). Interset rest intervals were 15 sec for RISE and DROP and 60 sec for USUAL., Results: Peak HR differed on average by <4 bpm between methods in the HFrEF and CAD groups ( P < .02). Rises in systolic BP (SBP) in the HFrEF group were comparable across methods. In the CAD group, mean SBP at peak exercise increased more in RISE and DROP than in USUAL ( P < .001), but the increase was ≤10 mm Hg. In the CTRL group, SBP was higher for DROP than for USUAL (152 ± 22 vs 144 ± 24 mm Hg, respectively; P < .01). Peak cardiac output and perceived exertion did not differ between methods., Conclusions: The RISE, DROP, and USUAL RT methods induced a similar perception of effort and similar increases in peak HR and BP. The RISE and DROP methods appear more efficient as they allow a comparable training volume in a shorter time than the USUAL method., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

The interaction between oral and/or mental cognitive tasks and postural control and mobility remains unclear. The aim of this study was to analyse the influence of speech production and cognitive load levels on static balance and timed up and go (TUG) during dual-task activities. Thirty healthy young subjects (25 ± 4 years old, 17 women) participated in this study. A control situation and two different cognitive arithmetic tasks were tested: counting backward in increments of 3 and 7 under oral (O) and mental (M) conditions during static balance and the TUG. We evaluated the dual-task cost (DTC) and the effect of speech production (SP) and the level of cognitive load (CL) on these variables. There was a significant increase in the centre of pressure oscillation velocity in static balance when the dual task was performed orally compared to the control situation The DTC was more pronounced for the O than for the M. The SP, but not the CL, had a significant effect on oscillation velocity. There was an increase in TUG associated with the cognitive load, but the mental or oral aspect did not seem to have an influence. Mobility is more affected by SP when the cognitive task is complex. This may be particularly important for the choice of the test and understanding postural control disorders.

Background: Risk stratification is central to the management of pulmonary arterial hypertension (PAH). For this purpose, multiparametric tools have been developed, including the ESC/ERS risk score and its simplified versions derived from large database analysis such as the COMPERA and the French Pulmonary Hypertension Network (FPHN) registries. However, the distinction between high and intermediate-risk profiles may be difficult as the latter lacks granularity. In addition, neither COMPERA or FPHN strategies included imaging-derived markers. We thus aimed at investigating whether surrogate echocardiographic markers of right ventricular (RV) to pulmonary artery (PA) coupling could improve risk stratification in patients at intermediate-risk., Material and Methods: A single-center retrospective analysis including 102 patients with a diagnosis of PAH was performed. COMPERA and FPHN strategies were applied to stratify clinical risk. The univariate linear regression was used to test the influence of the echo-derived parameters qualifying the right heart (right ventricle basal diameter, right atrial area, and pressure, tricuspid regurgitation velocity, tricuspid annular plane systolic excursion -TAPSE-). Among these, the TAPSE and tricuspid regurgitation velocity ratio (TAPSE/TRV) as well as the TAPSE and systolic pulmonary artery pressure ratio (TAPSE/sPAP) were considered as surrogate of RV-PA coupling., Results: TAPSE/TRV and TAPSE/sPAP resulted the more powerful markers of prognosis. Once added to COMPERA, TAPSE/TRV or TAPSE/sPAP significantly dichotomized intermediate-risk group in intermediate-to-low-risk (TAPSE/TRV≥3.74 mm∙nm/s)-1 or TAPSE/sPAP≥0.24 mm/mmHg) and in intermediate-to-high-risk subgroups (TAPSE/TRV<3.74 mm∙(m/s)-1 or TAPSE/sPAP<0.24 mm/mmHg). In the same way, TAPSE/TRV or TAPSE/sPAP was able to select patients at lower risk among those with 2, 1, and 0 low-risk criteria of both invasive and non-invasive FPHN registries., Conclusions: Our results suggest that adopting functional-hemodynamic echo-derived parameters may provide a more accurate risk stratification in patients with PAH. In particular, TAPSE/TRV or TAPSE/sPAP improved risk stratification in patients at intermediate-risk, that otherwise would have remained less characterized., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Patients undergoing weight loss surgery do not improve their aerobic capacity or peak oxygen uptake (VO2peak) after bariatric surgery and some still complain about asthenia and/or breathlessness. We investigated the hypothesis that a post-surgery muscular limitation could impact the ventilatory response to exercise by evaluating the post-surgery changes in muscle mass, strength, and muscular aerobic capacity, measured by the first ventilatory threshold (VT)., Methods: Thirteen patients with obesity were referred to our university exercise laboratory before and 6 months after bariatric surgery and were matched by sex, age, and height to healthy subjects with normal weight. All subjects underwent a clinical examination, blood sampling, and body composition assessment by dual-energy X-ray absorptiometry, respiratory and limb muscle strength assessments, and cardiopulmonary exercise testing on a cyclo-ergometer., Results: Bariatric surgery resulted in a loss of 34% fat mass, 43% visceral adipose tissue, and 12% lean mass (LM) (p < 0.001). Absolute handgrip, quadriceps, or respiratory muscle strength remained unaffected, while quadriceps/handgrip strength relative to LM increased (p < 0.05). Absolute VO2peak or VO2peak/LM did not improve and the first VT was decreased after surgery (1.4 ± 0.3 vs. 1.1 ± 0.4 L min-1, p < 0.05) and correlated to the exercising LM (LM legs) (R = 0.84, p < 0.001)., Conclusions: Although bariatric surgery has numerous beneficial effects, absolute VO2peak does not improve and the weight loss-induced LM reduction is associated to an altered muscular aerobic capacity, as reflected by an early VT triggering early exercise hyperventilation., (© 2021 The Author(s). Published by S. Karger AG, Basel.)

Introduction: Patients with chronic obstructive pulmonary disease (COPD) may demonstrate cognitive function and balance deterioration. These two phenomena are often realized simultaneously during daily living activities, where the risk of falling may be increased due to possible postural disturbance when focusing on a cognitive task during motion. Despite the high rate of falls in COPD, there is currently a lack of affordable clinical instruments to quantify the interaction between cognitive tasks and static balance in these patients. Therefore, this study aims to assess the balance perturbation induced by cognitive tasks using a new cost-effective protocol which can easily be implemented in clinical settings., Method: A total of 21 COPD patients (Age: 64 ± 8 yrs, Forced Expiratory Volume in one second = 41 ± 17%, Women: 7) and 21 matched healthy controls participated in the study. They performed two cognitive tasks (counting backward by 3s and naming animals) with eyes open and with eyes closed. Each trial lasted 60 s, with balance-related parameters recorded and quantified using a Wii Balance Board. A three-way ANOVA (cognitive task, eyes action, and health status) for balance-related parameters derived from the center of pressure displacement was performed., Results: COPD, vision, and cognitive tasks altered the balance; no interaction between conditions was observed. There was no correlation between cognitive ability, respiratory function, and the balance-related parameters., Conclusion: Compared to healthy controls, the COPD patients had impaired balance. Cognitive tasks altered postural control in both COPD and controls, where this alteration was more pronounced with eyes closed., (© 2020 John Wiley & Sons Ltd.)

Background: Pulmonary capillary stress failure is potentially involved in exercise-induced hypoxemia (ie, a significant fall in hemoglobin oxygen saturation [Spo 2 ]) during sea level exercise in endurance-trained athletes. It is unknown whether there are specific properties of pulmonary vascular function in athletes exhibiting oxygen desaturation., Methods: Ten endurance-trained athletes with exercise-induced hypoxemia (EIH), nine endurance-trained athletes with no exercise-induced hypoxemia (NEIH), and 10 untrained control subjects underwent an incremental exercise stress echocardiography coupled with lung diffusion capacity for carbon monoxide (Dlco) and lung diffusion capacity for nitric oxide (Dlno) testing. Functional adaptation of the pulmonary circulation was evaluated with measurements of mean pulmonary arterial pressure (mPAP), pulmonary capillary pressure, pulmonary vascular resistance (PVR), cardiac output (Qc), and pulmonary vascular distensibility (alpha) mathematically determined from the curvilinearity of the multi-point mPAP/Qc relation., Results: EIH athletes exhibited a lower exercise-induced PVR decrease compared with the untrained and NEIH groups (P < .001). EIH athletes showed higher maximal mPAP compared with NEIH athletes (45.4 ± 0.9 mm Hg vs 41.6 ± 0.9 mm Hg, respectively; P = .003); there was no difference between the NEIH and untrained subjects. Alpha was lower in the EIH group compared with the NEIH group (P < .05). Maximal mPAP, Pcap, and alpha were correlated with the fall of Spo 2 during exercise (P < .01, P < .01, and P < .05). Dlno and Dlco increased with exercise in all groups, with no differences between groups. Dlno/Qc was correlated to the exercise-induced Spo 2 changes (P < .05)., Conclusions: EIH athletes exhibit higher maximal pulmonary vascular pressures, lower vascular distensibility, or exercise-induced changes in PVR compared with NEIH subjects, in keeping with pulmonary capillary stress failure or intrapulmonary shunting hypotheses., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

The relationship between cognitive function and breath-holding time is in need of further investigation. We aim to determine whether cognitive mobile games (CMG) are sensitive enough to assess the link between cognition and breath-holding time in non-trained subjects. Thirty-one healthy subjects participated in this study. A set of 3 short CMG: Must Sort (response control), Rush Back (attention, working memory) and True Color (mental flexibility, inhibition) was used. Apneic time was recorded in three different conditions: Total Lung Capacity (TLC): 88 ± 35 s, Functional Residual Capacity (FRC): 49 ± 17 s, and Residual Volume (RV): 32 ± 14 s. In males, breath-holding time at RV was correlated with True Color (r = 0.48) and Rush Back (r = 0.65) and at TLC with True Color (r = 0.45). In women, breath-holding time at TLC and FRC was inversely correlated with Must Sort (r = -0.59 and r = -0.49 respectively). Males and females appeared to differ in their use of cognitive resources during different breath-holding conditions., Competing Interests: Declaration of Competing Interest None of the authors declare competing financial interests., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: With more than 15,000 implanted patients worldwide and a survival rate of 80% at 1-year and 59% at 5-years, left ventricular assist device (LVAD) implantation has become an interesting strategy in the management of heart failure patients who are resistant to other kinds of treatment. There are limited data in the literature on the change over time of exercise capacity in LVAD patients, as well as limited knowledge about the beneficial effects that rehabilitation might have on these patients. Therefore, the aim of our study was to evaluate the evolution of exercise capacity on a cohort of patients implanted with the same device (HeartWare © ) and to analyse the potential impact of rehabilitation., Methods: Sixty-two patients implanted with a LVAD between June 2011 and June 2015 were screened. Exercise capacity was evaluated by cardiopulmonary exercise testing at 6 weeks, 6 and 12 months after implantation., Results: We have observed significant differences in the exercise capacity and evolution between the trained and non-trained patients. Some of the trained patients nearly normalised their exercise capacity at the end of the rehabilitation programme., Conclusions: Exercise capacity of patient implanted with a HeartWare © LVAD increased in the early period after implantation. Rehabilitation allowed implanted patients to have a significantly better evolution compared to non-rehabilitated patients.

Purpose: There has been suggestion that a greater "pulmonary vascular reserve" defined by a low pulmonary vascular resistance (PVR) and a high lung diffusing capacity (DL) allow for a superior aerobic exercise capacity. How pulmonary vascular reserve might affect exercise capacity at moderate altitude is not known., Methods: Thirty-eight healthy subjects underwent an exercise stress echocardiography of the pulmonary circulation, combined with measurements of DL for nitric oxide (NO) and carbon monoxide (CO) and a cardiopulmonary exercise test at sea level and at an altitude of 2250 m., Results: At rest, moderate altitude decreased arterial oxygen content (CaO2) from 19.1 ± 1.6 to 18.4 ± 1.7 mL·dL, P < 0.001, and slightly increased PVR, DLNO, and DLCO. Exercise at moderate altitude was associated with decreases in maximum O2 uptake (V˙O2max), from 51 ± 9 to 43 ± 8 mL·kg⋅min, P < 0.001, and CaO2 to 16.5 ± 1.7 mL·dL, P < 0.001, but no different cardiac output, PVR, and pulmonary vascular distensibility. DLNO was inversely correlated to the ventilatory equivalent of CO2 (V˙E/V˙CO2) at sea level and at moderate altitude. Independent determinants of V˙O2max as determined by a multivariable analysis were the slope of mean pulmonary artery pressure-cardiac output relationship, resting stroke volume, and resting DLNO at sea level as well as at moderate altitude. The magnitude of the decrease in V˙O2max at moderate altitude was independently predicted by more pronounced exercise-induced decrease in CaO2 at moderate altitude., Conclusion: Aerobic exercise capacity is similarly modulated by pulmonary vascular reserve at moderate altitude and at sea level. Decreased aerobic exercise capacity at moderate altitude is mainly explained by exercise-induced decrease in arterial oxygenation.

Background: Excessive exercise-induced hyperventilation and high prevalence of exercise oscillatory breathing (EOB) are present in patients with post-capillary pulmonary hypertension (PH) complicating left heart disease (LHD). Patients with pre-capillary PH have even higher hyperventilation but no EOB. We sought to determine the impact of a pre-capillary component of PH on ventilatory response to exercise in patients with PH and left heart disease., Methods: We retrospectively compared patients with idiopathic or heritable pulmonary arterial hypertension (PAH, n = 29), isolated post-capillary PH (IpcPH, n = 29), and combined post- and pre-capillary PH (CpcPH, n = 12). Diastolic pressure gradient (DPG = diastolic pulmonary artery pressure - pulmonary wedge pressure) was used to distinguish IpcPH (DPG <7 mm Hg) from CpcPH (DPG ≥7 mm Hg)., Results: Pulmonary vascular resistance (PVR) was higher in PAH, intermediate in CpcPH, and low in IpcPH. All patients with CpcPH but 1 had PVR >3 Wood unit. Exercise-induced hyperventilation (high minute ventilation over carbon dioxide production, low end-tidal carbon dioxide) was marked in PAH, intermediate in CpcPH, and low in IpcPH (p < 0.001) and correlated with DPG and PVR. Prevalence of EOB decreased from IpcPH to CpcPH to PAH (p < 0.001)., Conclusions: Patients with CpcPH may have worse hemodynamics than patients with IpcPH and distinct alterations of ventilatory control, consistent with more exercise-induced hyperventilation and less EOB. This might be explained at least in part by the presence and extent of pulmonary vascular disease., (Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

There has been revival of interest in exercise testing of the pulmonary circulation for the diagnosis of pulmonary vascular disease, but there still is uncertainty about body position and the most relevant measurements. Doppler echocardiography pulmonary hemodynamic measurements were performed at progressively increased workloads in 26 healthy adult volunteers in supine, semirecumbent, and upright positions that were randomly assigned at 24-h intervals. Mean pulmonary artery pressure (mPAP) was estimated from the maximum tricuspid regurgitation jet velocity. Cardiac output was calculated from the left ventricular outflow velocity-time integral. Pulmonary vascular distensibility α-index, the percent change of vessel diameter per millimeter mercury of mPAP, was calculated from multipoint mPAP-cardiac output plots. Body position did not affect maximum oxygen uptake (Vo 2max ), maximum respiratory exchange ratio, ventilatory equivalent for carbon dioxide, or slope of mPAP-cardiac output relationships, which was on average of 1.5 ± 0.4 mmHg·l -1 ·min -1 Maximum mPAP, cardiac output, and total pulmonary vascular resistance were, respectively, 34 ± 4 mmHg, 18 ± 3 l/min, and 1.9 ± 0.3 Wood units. However, the semirecumbent position was associated with a 10% decrease in maximum workload. Furthermore, cardiac output-workload or cardiac output-Vo 2 relationships were nonlinear and variable. These results suggest that body position does not affect maximum exercise testing of the pulmonary circulation when results are expressed as mPAP-cardiac output or maximum total pulmonary vascular resistance. Maximum workload is decreased in semirecumbent compared with upright exercise. Workload or Vo 2 cannot reliably be used as surrogates for cardiac output., (Copyright © 2016 the American Physiological Society.)

Background: Patients with pulmonary arterial hypertension (PAH) and with heart failure (HF) have increased ventilatory responses to exercise in proportion to disease severity. Exercise-associated oscillatory ventilation (EOV) predicts poor outcome in HF. Whether EOV occurs in PAH is unknown., Methods: We analyzed the initial cardiopulmonary exercise tests (CPETs) and right heart catheterization data of 109 patients with PAH and in 107 patients with HF consecutively referred to our center., Results: The PAH patients were aged 54±16 years and their NYHA functional class was 2.8±0.5. The HF patients were aged 53±13 years and NYHA 2.4±0.6. Hemodynamic data were obtained in only 36 of them. The patients with PAH compared to those with HF had a lower peak VO2 (13±5 vs 17±5 mL/kg/min, p<0.001) and a higher ventilatory equivalent for CO2 (VE/VCO2) slope (55±21 vs 34±7, p<0.001). Mean pulmonary artery pressure was higher (50±10 vs 29±11 mmHg) and wedge pressure lower (10±3 vs 19±5 mmHg) in PAH patients, but cardiac output was not different (4.0±1.3 vs 4.2±1.2L/min). EOV was present in 22 patients (21%) with HF and in no patient with PAH., Conclusions: Patients with PAH compared to HF with slightly better functional class have a lower aerobic exercise capacity and higher ventilatory responses, but no EOV. An increase in pulmonary artery wedge pressure rather than a low cardiac output may be necessary condition of EOV in HF., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Sex and age affect the pulmonary circulation. Whether there may be racial differences in pulmonary vascular function is unknown. Thirty white European Caucasian subjects (15 women) and age and body-size matched 30 black sub-Saharan African subjects (15 women) underwent a cardiopulmonary exercise test and exercise stress echocardiography with measurements of pulmonary artery pressure (PAP) and cardiac output (CO). A pulmonary vascular distensibility coefficient α was mathematically determined from the natural curvilinearity of multipoint mean PAP (mPAP)-CO plots. Maximum oxygen uptake (V̇o2max) and workload were higher in the whites, while maximum respiratory exchange ratio and ventilatory equivalents for CO2 were the same. Pulmonary hemodynamics were not different at rest. Exercise was associated with a higher maximum total pulmonary vascular resistance, steeper mPAP-CO relationships, and lower α-coefficients in the blacks. These differences were entirely driven by higher slopes of mPAP-CO relationships (2.5 ± 0.7 vs. 1.4 ± 0.7 mmHg·l(-1)·min; P < 0.001) and lower α-coefficients (0.85 ± 0.33 vs. 1.35 ± 0.51%/mmHg; P < 0.01) in black men compared with white men. There were no differences in any of the hemodynamic variables between black and white women. In men only, the slopes of mPAP-CO relationships were inversely correlated to V̇o2max (P < 0.01). Thus the pulmonary circulation is intrinsically less distensible in black sub-Saharan African men compared with white Caucasian Europeans men, and this is associated with a lower exercise capacity. This study did not identify racial differences in pulmonary vascular function in women., (Copyright © 2015 the American Physiological Society.)

Background: The distance walked in 6 minutes (6MWD) has been reported to be linearly related to peak oxygen uptake (VO2) in cardiac diseases and in lung diseases. In these patients, the VO2 during a 6-min walk test (walkVO2) has been found to be nearly equivalent to peakVO2, but with a lower respiratory exchange ratio (RER). Whether these observations translate to the less functionally impaired patients or healthy control subjects is not exactly known., Methods: Thirty-two healthy control subjects and 15 chronic heart failure (CHF) patients performed a 6-min walk test and a maximal cardiopulmonary exercise test (CPET) both with measurements of gas exchange., Results: The 6MWD and peakVO2 were linearly correlated, but with an increased slope appearing above 532 m. In CHF patients, walkVO2 was similar to peakVO2, but with lower heart rate and ventilation than measured at peak exercise. In healthy control subjects, VO2, ventilation and heart rate were lower during the 6-min walk than at maximal exercise but higher than at the anaerobic threshold. The RER during the 6-min walk remained <1 in both groups., Conclusions: Above 500 m, 6MWD becomes less sensitive to any increase in peakVO2. Furthermore, CHF patients and healthy control subjects exercise respectively at maximal and high VO2, but below the anaerobic threshold (as assessed by a CPET) during the 6-min walk test., (© The European Society of Cardiology 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Purpose: The 6 minutes walk test (6MWT) is often shown to be the best predictor of mortality in pulmonary hypertension (PH) probably because it challenges the failing heart to deliver adequate cardiac output. We hypothesised that the 6MWT elicits maximal cardiac output as measured during a maximal cardiopulmonary exercise testing (CPET)., Methods: 18 patients with chronic thromboembolic pulmonary hypertension (n = 12) or pulmonary arterial hypertension (n = 6) and 10 healthy subjects performed a 6MWT and CPET with measurements of cardiac output (non invasive rebreathing device) before and directly after exercise. Heart rate was measured during 6MWT with a cardiofrequence meter., Results: Cardiac output and heart rate measured at the end of the 6MWT were linearly related to 6MW distance (mean±SD: 490±87 m). Patients with a high NT-pro-BNP achieve a maximum cardiac output during the 6MWT, while in normal subjects and in patients with a low-normal NT-proBNP, cardiac output at the end of a 6MWT was lower than achieved at maximum exercise during a CPET. In both cases, heart rate is the major determinant of exercise-induced increase in cardiac output. However, stroke volume increased during CPET in healthy subjects, not in PH patients., Conclusion: Maximal cardiac output is elicited by 6MWT in PH patients with failing right ventricle. Cardiac output increase is dependent on chronotropic response in patients with PH.