Phillips DB; School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
Darko CA; James MD; Vincent SG; McCartney AM; Sreibers LK; Domnik NJ;Neder JA; O’Donnell DE;

Respiratory physiology & neurobiology [Respir Physiol Neurobiol] 2025 Apr 18, pp. 104434.
Date of Electronic Publication: 2025 Apr 18.

The neurophysiological mechanisms of exertional dyspnea in advanced pregnancy remain incompletely understood. This short case report describes the neurophysiological and sensory responses during standardized cardiopulmonary exercise testing (CPET) in one healthy adult female at three timepoints: a) 3 months pre-pregnancy, b) 35 weeks pregnant (third trimester [T3]), and, c) 1 year post-partum.
At rest and during exercise, detailed measurements of neurophysiological, gas-exchange and sensory parameters were completed. Compared to both pre-pregnancy and post-partum, ventilatory requirements, electrical activation of the diaphragm (EMGdi, index of inspiratory neural drive) and esophageal pressure swings were higher in T3 throughout exercise. Moreover, at a given work rate, perceived dyspnea was greater in T3 compared with pre-pregnancy and post-partum and increased in close association with heightened EMGdi throughout exercise. At peak exercise in T3, dyspnea/ventilation and EMGdi/ventilation ratios were greater, compared with pre-pregnancy and post-partum. Compared with pre-pregnancy, EMGdi and perceived dyspnea were greater post-partum near the limits of exercise tolerance, secondary to earlier onset of respiratory compensation-mediated increases in ventilation. In the current case, advanced pregnancy was associated with markedly elevated ratings of dyspnea and lower exercise capacity during a standardized clinical CPET. At submaximal intensities, the heightened dyspnea reflected the awareness of pregnancy-induced increases in ventilatory requirements, inspiratory neural drive, and respiratory muscle effort. At the limits of tolerance, heightened dyspnea and inspiratory neural drive reflected a complex combination of increase ventilatory requirements and mechanical constraints on tidal volume expansion. Compared with pre-pregnancy, residual activity-related dyspnea 1-year post-partum appears to reflect physical deconditioning.

Mamillo, Keti; Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, USA
Frantz, Robert P; Anderson, Jason H; Allison, Thomas G;

JACC. Case reports,2025 Apr 02

Reverse Potts shunt (rPS) is a surgical procedure that creates an anastomosis between the left pulmonary artery and descending aorta to decompress the right ventricle in suprasystemic pulmonary arterial hypertension (PAH). In this paper, we introduce a unique procedure combining cardiopulmonary exercise testing with forehead and popliteal oximetry to evaluate the efficacy of the rPS. Our study involved tests on 4 patients with PAH who had the shunt in place. We found that the level of oxygen saturation in the popliteal artery decreased during exercise and correlated with the rPS efficacy and the overall clinical outcome. In conclusion, we demonstrate a simple, noninvasive technique for evaluating patency and function of rPS in patients with suprasystemic PAH.

Baccelli, Andrea; Guy’s and St Thomas’ NHS Foundation Trust, London, UK.
Rinaldo, Rocco F; Haji, Gulammehdi; Davies, Rachel J;

The European respiratory journal,2025 Apr 10

• Background: Current guidelines recommend a four-strata model based on World Health Organization functional class (WHO-FC), 6-min walk distance (6MWD), and serum levels of brain natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP) for risk stratification in patients with pulmonary arterial hypertension (PAH) during follow-up. We explored the relevance of using cardiopulmonary exercise testing (CPET) as the exercise parameter in place of 6MWD at first reassessment after treatment initiation in PAH.
• Methods: Incident treatment-naïve patients with idiopathic, heritable, drug/toxins-induced, and connective tissue disease-associated PAH between 2010 and 2022 were analysed. Correlations between CPET and haemodynamic and right ventricular (RV) function parameters were explored and those which were significant were carried forward to assess association with survival. Independent predictors were used to derive a four-strata CPET score.
• Results: 262 patients were included. CPET parameters showed better correlations with haemodynamics and RV function than 6MWD. The CPET score included peak oxygen uptake (peak VO ₂ ), the slope relating ventilation to carbon dioxide production (VE/VCO ₂ slope), and peak oxygen pulse. The four-strata model based on WHO-FC, BNP, and CPET score predicted survival at the time of the first re-evaluation, with better accuracy than the model including 6MWD (c-index 0.81 versus 0.71). The CPET score on its own also performed well (c-index 0.82) with a greater spread between categories. Treatment-associated changes in peak VO ₂ and oxygen pulse predicted survival, while changes in 6MWD did not.
• Conclusions: A simplified four-strata CPET score either alone or included with BNP and WHO-FC accurately predicts survival at follow-up in PAH.

Knox-Brown, Ben; Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
Harding, Chris; Chowdhury, Shabana; Pritchard, Andrew; et al;

BMJ open respiratory research,2025 Apr 15

• Introduction: The impact of cycling at different cadences on cardiopulmonary exercise test (CPET) measurements is poorly understood. We aimed to investigate whether higher cadences of pedalling led to meaningful changes in physiological endpoints.
• Methods: Study participants were recruited from healthy staff members working within three NHS trusts across England. At baseline, all participants completed a CPET at 60 rpm and then subsequently completed CPETs at cadences of 70, 80 and 90 rpm, allocated in a random order. To evaluate the mean differences in CPET measurements across the cadences, we used a one-way repeated measures analysis of variance. We then performed post hoc pairwise comparisons with Tukey correction to account for multiple testing.
• Results: Data collection took place between the 19 September 2023 and 9 April 2024. 25 participants had complete data at each cadence. 48% (12 of 25) were female, with a median (IQR) age of 30 years (27-41). There was no significant difference in peak V̇O ₂ across the cadences. Maximum achieved work rate was significantly different across the cadences (p=<0.001). The highest wattage was achieved at 60 rpm (221.2 watts±71.4) and lowest at 90 rpm (210.4 watts, ±77.2). End exercise ventilation increased with increasing cadence (p=0.013), with a mean of 97.6 L/min (±28.3) at 60 prm and 107.0 L/min (±33.9) at 90 prm. Breathing reserve decreased with increasing cadence (p=0.009), with a mean of 45.6 L/min (±28.8) at 60 rpm and 35.1 L/min (±23.5) at 90 rpm. There were minimal differences in other CPET parameters.
• Conclusion: In a healthy population, higher cycling cadences increased ventilatory demand and reduced maximum work rate. This could have implications for CPETs in the clinical setting, where physiological responses to higher cadences may be more exaggerated.
• Competing Interests: Competing interests: KPS reports consultation fees from ndd medical technologies outside of the published work. All other authors declare no conflict of interest.

Rodrigues, Sara;
Verardino, Renata Gomes Sanches; Costa-Hong, Valéria; Jordao, Camila Paixao; et al;

Open heart,2025 Apr 02

• Objective: In this randomised two-period crossover trial, the objective was to compare acute changes in arterial distensibility between high-intensity interval physical exercise (HIIPE) and moderate-intensity continuous physical exercise (MICPE) sessions in subjects with elevated blood pressure (BP).
• Methods and Analysis: Participants underwent either MICPE-HIIPE or HIIPE-MICPE sequences with intensity based on cardiopulmonary exercise testing. The main outcome measures included arterial stiffness (by pulse wave velocity (PWV)) at baseline, until 30 min and 24 hours after each physical exercise session. Other measures include office BP, 24-hour ambulatory blood pressure monitoring (ABPM) and applanation tonometry.
• Results: The study involved 29 subjects with elevated BP (76% female, 48±7 years, body mass index=28.3±4.3 kg/m², systolic BP=126±9 mm Hg and diastolic BP=84±4 mm Hg). They presented lower PWV 24 hours after MICPE compared with baseline and to 24-hour HIIPE ((-0.83 (-1.29;-0.37) p=0.001) and (-0.98 (-1.84;-0.12), p=0.021), respectively). Despite no differences in office BP, aortic systolic BP was lower after HIIPE compared with baseline and to 24-hour MICPE (113±19; 118±10 and 117±10 mm Hg; p=0.013).
• Conclusion: In subjects with elevated BP, arterial distensibility is greater 24 hours after MICPE, while aortic systolic BP is lower after HIIPE. The particularities of each method and each exercise intensity can provide specific mechanisms of vascular response to exercise and detect vascular damage early in these subjects.

Scoubeau, Corentin; Faculty of Human Motor Sciences, Université Libre de Bruxelles, Brussels, Belgium.
Carpentier, Julie; Baudry, Stéphane; Faoro, Vitalie; et al;

Physiological reports,2025 Apr

This study investigated body composition, cardiorespiratory, and neuromuscular adaptations induced by three high intensity trainings easy to fit into daily routine. Thirty-seven adults participated in one of the following 8-week interventions: vigorous intensity continuous training (VICT; 28 min at 70% of peak oxygen uptake [VO ₂ peak]), long interval high intensity interval training (LI-HIIT; 6 × 2 min at 85% VO ₂ peak), or short interval HIIT (SI-HIIT; 12 × 30 s at 125% maximal power output). Heart rate (HR) and rating of perceived exertion (RPE) were measured during sessions. Pre- and post-intervention assessments included fat and lean mass, cardiopulmonary exercise testing, knee extensors maximal isometric torque, voluntary activation, and endurance during a submaximal contraction. Compared to SI-HIIT and VICT, LI-HIIT sessions were characterized by a shorter duration, a similar time spent above 90% HR _max , but a higher RPE (p < 0.05). VO ₂ peak and muscle endurance increased respectively by 14% and 12%, while knee extensors torque, voluntary activation, and lean mass increased to a lesser extent (1%-3%) after the interventions (ANOVA time-effect, all p < 0.05). There was no significant difference between the modalities (intervention × time interaction, all p > 0.05). In conclusion, comparable body composition, cardiorespiratory, and neuromuscular adaptations were induced by the three high intensity training protocols, while RPE was higher during LI-HIIT sessions.

Willixhofer, Robin; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
Mapelli, Massimo; Baracchini, Nikita; Campana, Nicola; et al;

Heart (British Cardiac Society),2025 Apr 16

• Background: Cardiopulmonary exercise testing (CPET) is essential for assessing patients with hypertrophic cardiomyopathy (HCM), but the role of pulmonary function testing (PFT) in refining patient stratification remains underexplored. This study investigates the relationship between PFT and CPET parameters in patients with HCM.
• Methods: In this prospective two-centre study, 102 clinically stable patients with HCM underwent PFT and CPET. Spearman’s correlation and multiple linear regression were used to assess relationships between PFT (forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV _₁ )) and CPET variables, adjusting for confounders.
• Results: Patients exhibited preserved lung function (mean FVC: 90.7%; FEV ₁ : 92.5%). Strong correlations were observed between PFT and CPET metrics, including peak VO _₂ (FVC: r=0.649, p<0.001; FEV _₁ : r=0.691, p<0.001) and peak ventilation (FVC: r=0.682, p<0.001; FEV _₁ : r=0.688, p<0.001). Regression analysis confirmed independent associations between PFT and CPET performance (all p<0.001).
• Conclusion: PFT metrics strongly correlate with CPET parameters in HCM, suggesting that PFT could complement CPET for a more comprehensive assessment of exercise capacity and patient stratification.

Collins, Sophie É; Research Institute of the McGill University Health Centre,  Québec, Canada.
Phillips, Devin B;Stickland, Michael K

Autonomic neuroscience : basic & clinical,2025 Apr 05

• Rationale: Chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) are characterized by exaggerated carotid chemoreceptor (CC) sensitivity and exercise intolerance. We tested the hypothesis that participants with elevated CC sensitivity would have the greatest improvement in exercise tolerance with CC inhibition, secondary to increased vascular conductance, and lower ventilatory requirements, dyspnea and leg discomfort.
• Methods: Data from healthy controls, and patients with CHF or COPD were included in this secondary analysis of results from 2 randomized placebo-controlled double-blind crossover trials. Assessments included pulmonary function, incremental cardiopulmonary exercise test, and basal CC sensitivity assessment. High CC sensitivity was defined as either a stepwise hypoxic ventilatory response (HVR) or transient HVR greater than one SD above the mean in healthy controls. Participants received 2 μg/kg/min dopamine or placebo infusions (randomized) during 2 separate constant work-rate exercise tests to examine exercise endurance time (EET) and cardiopulmonary responses.
• Results: Among 33 adults, 17 were categorized to normal HVR (11 controls/3 COPD/3 CHF), and 16 to high HVR (1 control/7 COPD/8 CHF). Participants with high HVR experienced significant dopamine-induced improvements in EET (p _interaction  = 0.011), and reduced leg discomfort at the 4-min isotime (p _interaction  = 0.024). Those with improved vascular conductance and leg discomfort had the greatest improvements in EET (p = 0.042 and p = 0.021, respectively).
• Conclusions: CC inhibition with dopamine in participants with high HVR was associated with improvement in EET. These findings suggest that high HVR is related to exercise limitation, and that improvement in EET is associated with a CC-mediated increase in vascular conductance and leg discomfort.

National Italian Olympic Committee (CONI), Institute of Sport and Science Medicine, Rome, Italy.
Squeo, Maria Rosaria; Menichini, Ilaria; Morviducci, Matteo; Spinelli, Alessandro; et al;

Physiological reports,2025 Apr

Ventilatory efficiency during cardiopulmonary exercise testing (CPET) is obtained by relating minute ventilation (V’ _E ) to CO ₂ output (V’CO ₂ ). Limited information is available regarding exercise ventilatory efficiency in young elite athletes. We assessed ventilatory efficiency in elite athletes; evaluating the influence of sex and/or ESC sport categories; evaluating the agreement between the V’ _E /V’CO ₂ slope and nadir in measuring ventilatory efficiency; evaluating differences between subgroups of athletes stratified by ventilatory efficiency. A cohort of 443 elite athletes prospectively underwent CPET. The slope (s ₁ ) and the intercept of the linear region of the V’ _E /V’CO ₂ relationship, the V’ _E /V’CO ₂ value at the lactate threshold and the V’ _E /V’CO ₂ nadir were used to assess ventilatory efficiency. Male athletes and endurance athletes, both males and females, had higher exercise ventilatory efficiency (p < 0.001). A strong positive correlation was observed between V’ _E /V’CO ₂ s ₁ and nadir (p < 0.001). Of note, both high (V’ _E /V’CO ₂ s ₁ < 24) and very high (V’ _E /V’CO ₂ s ₁ < 22) levels of ventilatory efficiency were associated with greater exercise tolerance (i.e., peak oxygen uptake, maximal power; p < 0.001). The results of our study emphasize the need to include the measurement of ventilatory efficiency in the evaluation of elite athletes, potentially refining their training strategies.

Lv H; Institute of Cardiovascular Diseases of PLA,  (Third Military Medical University), Chongqing, P.R. China.
Liu Z; Sun M; Yu S; Hu M; Bian S; Ye X;Wang K; Dong H; Yang B; Zhou C; Huang L; Yang J;

IScience [iScience] 2025 Feb 27; Vol. 28 (3), pp. 112112.
Date of Electronic Publication: 2025 Feb 27 (Print Publication: 2025).

The dynamic characteristics of cardiorespiratory fitness during high-altitude acclimatization and deacclimatization are not well elucidated, and whether ubiquinol exerts beneficial effects on cardiorespiratory fitness remains debated. In this trial, 41 volunteers were randomized to receive oral ubiquinol or placebo administration, 14 days before departure to highlands. All individuals were carried to 3900 m by air and then returned to 300 m after 7 days. Cardiopulmonary exercise testing was performed at baseline, on the third day after arrival in the highlands, and on the seventh day after return. This trial revealed the dynamic characteristics of cardiorespiratory fitness during the entire high-altitude acclimatization and deacclimatization process. The short-term journey to the highlands did not significantly affect cardiorespiratory fitness or physical performance capacity after the return. Cardiovascular and respiratory recoveries were desynchronized after returning from the highlands. Ubiquinol supplementation maintained the physical performance capacity in the highlands and facilitated acclimatization to hypoxia