E. F. Signini, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil.
R. M. de Abreu, A. Castro, A. M. Santos, G. A. M. Galdino, S. C. G. Moura, et al.

F. Yang, Air Force Health Care Center for Special Services, Hangzhou, China.
W. Tan, Y. Tian, Q. Wu, X. Feng, G. Hu, et al

Physiol Rep 2026 Vol. 14 Issue 8 Pages e70864

To evaluate altitude-stratified differences in static lung function, aerobic capacity, and exercise physiology under standardized normoxic conditions, and identify multiple predictors of peak oxygen uptake (VO₂) reduction among asymptomatic men after prolonged residence at varying altitudes. We conducted a cross-sectional study of 103 asymptomatic men stratified by residential altitude: low (<2500 m; n = 35), high (2500-3500 m; n = 32), and very high (>3500 m; n = 36). All underwent spirometry, fasting blood tests, and symptom-limited cardiopulmonary exercise testing (CPET) in normoxia. Multiple linear regression identified independent predictors of peak VO₂/kg. Very high-altitude residents had significantly lower peak VO₂/kg (-13.4 mL·min^-1·kg^-1 vs. low altitude, p < 0.001), reduced oxygen pulse, and impaired small-airway function (MMEF, FEF₇₅; p < 0.05), despite preserved ventilatory efficiency (VE/VCO₂ slope, p = 0.782). Hemoglobin was elevated at higher altitudes; triglycerides were higher only above 3500 m. Age (β = -0.285), regular exercise (≥3 sessions/week; β = +3.648), and very high-altitude residence (β = -13.370) independently predicted peak VO₂/kg (all p < 0.001; R² = 0.739). Residence above 3500 m causes persistent cardiopulmonary impairment driven by circulatory limitations and smoking, despite preserved ventilatory efficiency. Normoxic assessment identifies regular exercise (≥3 sessions/week) as a key countermeasure against altitude-induced deconditioning. Prioritizing smoking cessation and mandatory exercise programs is therefore recommended for long-term health in high-altitude personnel.

C. P. O’Halloran, Department of Pediatrics, Northwestern University, Chicago, IL, USA.
T. Alsaied, A. P. Wang, K. Ward, C. Laternser, M. D. Files, et al.

J Cardiovasc Magn Reson 2026 Vol. 28 Issue 1 Pages 102729

Background: The synthetic extracardiac (EC) Fontan conduit may become inadequate as patients grow, potentially limiting cardiovascular capacity.

Objective: To evaluate the relationship between EC-Fontan conduit cross-sectional area (CSA), indexed to body surface area (BSA), and exercise performance.

Methods: A cross-sectional analysis of data from the Fontan Outcomes Registry using Clinical Examinations (FORCE) registry was performed. Patients with EC-Fontan anatomy who underwent cardiovascular magnetic resonance imaging (CMR) and cardiopulmonary exercise testing (CPET) within 1 year of each other were analyzed. Median length-averaged and minimum Fontan CSAs were measured using three-dimensional (3D) segmentation and indexed to BSA. The primary outcome was percent predicted peak VO₂ (ppVO₂) on maximal effort CPET. Multivariable linear regression models assessed associations between Fontan CSA/BSA and ppVO₂, adjusting for known predictors of ppVO₂ in Fontan patients.

Results: Of the 493 patients with an EC Fontan and with time-matched CMR and EST, 324 had technically adequate 3D imaging for Fontan conduit measurements and an appropriately documented maximal effort excercise stress test (EST). CMRs occurred at median age of 15 years old and median time of 11 years after Fontan surgery. The median length-averaged and minimum Fontan CSA were 268 mm² (IQR 227-309mm²) and 229 mm² (IQR 194-273mm²), respectively. After adjusting for known predictors of ppVO2 in Fontan patients, both minimum and length-averaged Fontan CSA/BSA were positively associated with ppVO2, such that each mm²/m² increase in minimum CSA/BSA was associated with a 0.08% increase in ppVO2 (p<0.001) or each mm²/m² increase length-averaged CSA/BSA was associated with a 0.07% increase in ppVO2 (p<0.001). Fontan CSA/BSA was not significantly associated with cardiac function measures at rest, including ejection fraction and cardiac output.

Conclusion: Smaller EC-Fontan CSA/BSA is independently associated with reduced exercise capacity after controlling for other known predictors of exercise performance.

N. Lopes Cardoso, Universidade Federal do Rio Grande do Norte, Natal, Brazil.
I. P. Santos, L. Mendes, R. Torres-Castro, J. Vilaro, E. Gimeno-Santos, et al.

Expert Rev Respir Med 2026 Pages 1-11

Introduction: Pulmonary hypertension (PH) is characterized by exertional dyspnea and reduced exercise capacity. This study aims to synthesize current evidence to guide more effective exercise-based interventions.

Methods: This overview included systematic reviews (SRs) of randomized controlled trials in adults with PH that performed an exercise intervention as exercise training (ET), inspiratory muscle training (IMT) or combined training (CT). The main outcome was exercise capacity measured (e.g. six-minute walk test (6MWT) or cardiopulmonary exercise test (CPET). The searches were conducted in seven databases. Two independent reviewers conducted the analysis, with a third resolving disagreements. Methodological quality and certainty of evidence were assessed using AMSTAR-2 and GRADE, along with overlap analysis.

Results: A total of 14 SRs were included, categorized into ET, IMT, and CT. All three interventions demonstrated improvements in functional capacity, with increases in 6MWT distance of >48.5 m (ET), 39.1 m (IMT), and 49.5 m (CT). VO₂peak improved in ET and CT groups by >2.07 and >3.0 mL/kg/min, respectively. Only one study performed IMT, with gains. Overall, methodological quality was rated as critically low, with significant overlap across studies.

Conclusion: These findings suggest a clinically significant benefit of exercise-based interventions, with a slight superiority of CT

Jain B, All India Institute of Medical Sciences, New Delhi, INDIA
Chakrawarty A, Chatterjee P, Dey AB, Khan M

Cureus. 2026 Apr 26;18(4):e107740. doi: 10.7759/cureus.107740. eCollection 2026 Apr.

Background Frailty, intrinsic capacity (IC), and cardiorespiratory fitness each reflect physiological reserve in aging, yet integrated data combining standardized cardiopulmonary exercise testing (CPET) with the World Health Organization (WHO) Integrated Care for Older People (ICOPE) framework and the Fried phenotype are scarce, particularly in South Asian older adults, where the burden of chronic disease may accelerate functional decline.
Methods This cross-sectional study included 130 healthcare-seeking adults aged ≥65 years attending a tertiary geriatric outpatient clinic in India. Frailty was assessed using the Fried phenotype, intrinsic capacity using the World Health Organization Integrated Care for Older People framework across five domains, and cardiorespiratory fitness using CPET to determine maximal oxygen uptake (VO₂max). Associations between IC, frailty, and VO₂max were examined using univariate and multivariable linear regression analyses.
Results Frailty prevalence was 73.1% (95/130 participants). Frail participants demonstrated significantly lower skeletal muscle mass, poorer functional performance, and reduced cardiorespiratory fitness compared with non-frail individuals. Higher IC impairment scores were associated with older age, poorer anthropometric measures, reduced physical performance, and lower absolute VO₂max (all p < 0.05). In univariate analyses, several variables, including age, skeletal muscle mass, handgrip strength, gait speed, physical activity, and IC domains, were associated with VO₂max. In a prespecified multivariable regression model adjusting for age, sex, and frailty status, IC total score remained independently associated with lower absolute VO₂max (β ≈ -31 mL/min per point, p ≈ 0.03). Frailty demonstrated a borderline association but did not retain statistical significance after adjustment.
Conclusions Impairment of intrinsic capacity was independently associated with lower cardiorespiratory fitness in older adults, independent of age, sex, and frailty status. These cross-sectional findings are hypothesis-generating, and prospective studies are required to determine whether intrinsic capacity precedes decline in aerobic fitness and frailty. Integrating intrinsic capacity assessment with objective measures of aerobic fitness may improve early identification of vulnerable older adults and inform preventive geriatric care strategies.

Guerra E; Carlo Poma Hospital, Mantova, Italy.
Segreti A; Carpenito M; Ciancio M; Guarino L; Ricciardi D; Fossati C; Suma S; Gaibazzi N;
Rosiello R; Lettieri C; Papalia R; Pigozzi F; Boriani G; Grigioni F

Echocardiography. 43(5):e70505, 2026 May.

PURPOSE: This study investigated standard and advanced echocardiographic
parameters in endurance athletes with different training profiles, and
their association with exercise performance.

METHODS: Consecutive endurance athletes undergoing cardiological
screening or orthopedic evaluation for knee injuries at Campus Bio-Medico
University Hospital underwent advanced echocardiography and
cardiopulmonary exercise testing. Athletes were categorized into three
groups: (1) Long-Distance (marathon and ultramarathon runners, n = 30);
(2) Mid-Distance (middle-distance runners, n = 27); and (3) Detrained (>=
6 months training interruption, n = 31).

RESULTS: Left ventricular ejection fraction did not differ among groups.
The Long-Distance group had the highest stroke volume index, followed by
the Mid-Distance and Detrained groups (p <0.001). Long-Distance athletes
showed lower left ventricular global longitudinal strain (p = 0.003) and
left atrial reservoir strain (p = 0.003) compared to the other groups,
with no differences in right ventricular free wall strain. Myocardial work
analysis showed higher work index and constructive work, and lower wasted
work, leading to greater global work efficiency in the Long-Distance group
(p <0.001). In multivariable linear regression analysis, stroke volume
index (beta = 1.02, p < 0.001) and global work efficiency (beta = 1.00, p
= 0.001) were independently associated with Peak VO2, whereas global
longitudinal strain was not.

CONCLUSION: Advanced echocardiography provides additional insights into
the athlete’s heart. Myocardial work indices reflect training-related
cardiac adaptations, and left atrial reservoir strain is influenced by
training status. These findings, together with the association of stroke
volume index and global work efficiency with Peak VO2, support the
integration of advanced echocardiographic parameters into athlete
evaluation and monitoring.

Martinez-Otero S; Department of Anaesthesia and ICU, Hospital Clinic de Barcelona, Spain.
Gimenez-Mila M; Arguis MJ; Regueiro A; Rodriguez-Arias
JJ; Sanz de la Garza M; Berenguel A; Gadella A; Kenneally LF;
Martinez-Palli G

PLoS ONE [Electronic Resource]. 21(5):e0348568, 2026.

INTRODUCTION: Transcatheter Aortic Valve Implantation (TAVI) has emerged
as a less invasive alternative to surgical aortic valve replacement,
especially for high-risk patients. While TAVI is expected to improve
symptoms and functional status, clinical recovery is often heterogeneous,
and subjective assessments may not fully capture the degree of
improvement. To our knowledge, the changes in functional capacity
following TAVI have not been well explored using cardiopulmonary exercise
testing (CPET). The study aims to characterise mid-term changes in
exercise tolerance after TAVI and identify clinical and functional
predictors of improvement in exercise capacity and complications after
TAVI.

METHODS AND ANALYSIS: A total of 161 patients with severe aortic stenosis
scheduled for TAVI will be prospectively enrolled across three expert
centres. Each will undergo clinical assessment and incremental CPET within
two weeks before and four to six weeks after the procedure. The primary
outcome is a change in VO2 peak and VO2 at the anaerobic threshold.
Secondary outcomes include exploratory associations between baseline
characteristics and observed changes in functional capacity, quality of
life and complications.

ETHICS AND DISSEMINATION: The bioethics committee of the Hospital Clinic
de Barcelona, Spain, approved this protocol (HCB/2024/0782). All the
participating centres obtained local approval prior to patient
recruitment. The findings will be published in a peer-reviewed journal and
submitted to relevant conferences.

Janssens K; St. Vincent’s Institute of Medical Research, Fitzroy, Australia.
Howden EJ; Mitchell AM; Wright L; Climie RE; Parr EB;
Haykowsky MJ; La Gerche A; Foulkes SJ

American Journal of Physiology – Heart & Circulatory Physiology.
330(6):H1841-H1852, 2026 Jun 01.

During exercise, vascular resistance, the ratio of arterial pressure to
blood flow [i.e., cardiac output (CO)], is an important component of the
hemodynamic response determining peak oxygen uptake (Vo2peak). However,
how systolic blood pressure (SBP) responses reflect this pressure-flow
relationship, and their association with Vo2peak remain incompletely
understood. We performed cardiopulmonary exercise testing in 135 females
(51 +/- 8 yr) across a broad fitness spectrum to evaluate Vo2peak and SBP
responses. SBP responses were stratified by maximal SBP (SBPmax <190 mmHg
or >=190 mmHg) and workload-indexed SBP (SBP/W-slope; low vs. high based
on sex- and age-specific median values). Peak CO (COpeak) was quantified
from exercise cardiac magnetic resonance imaging. SBPmax >=190 mmHg
occurred in 74 participants (55%), high SBP/W-slope in 41 (30%), and 26
(19%) had both. A high SBP/W-slope was associated with lower Vo2peak (1.7
+/- 0.4 vs. 2.1 +/- 0.6 L/min; P < 0.001) and COpeak (12.8 +/- 2.3 vs.
15.7 +/- 3.5 L/min; P < 0.001) and higher total peripheral resistance
(TPRpeak; 11.2 +/- 2.3 vs. 9.0 +/- 2.0 mmHg.min/L; P < 0.001). In
contrast, a low SBP/W-slope despite SBPmax >=190 mmHg had the highest
Vo2peak and COpeak and larger reductions in TPR compared with high
SBP/W-slope groups. SBPmax >=190 mmHg in isolation was associated with
higher Vo2peak and COpeak, although it also identified females with low
fitness and COpeak. Thus, SBP/W-slope provides a framework for
interpreting SBP relative to flow, with higher slopes indicating an
unfavorable pressure-flow profile characterized by higher vascular
resistance, lower COpeak, and reduced Vo2peak. In contrast, SBPmax
reflects both flow and resistance. Incorporating SBP/W-slope may therefore
improve identification of females with impaired pressure-flow regulation.
NEW & NOTEWORTHY In females, a higher workload-indexed systolic blood
pressure (SBP/W)-slope during exercise was associated with greater
peripheral vascular resistance, lower cardiac output, and lower
cardiorespiratory fitness, irrespective of maximal systolic blood pressure
(SBPmax). In contrast, an exaggerated SBPmax alone reflected differing
contributions of increased flow (i.e., cardiac output) or increased
vascular resistance across individuals. Evaluating the SBP/W-slope
provides a more physiologically informed interpretation of exercise blood
pressure and may improve identification of females with impaired
pressure-flow regulation and reduced cardiovascular reserve.

Mielniczuk M; National Research Institute, Warsaw, Poland.
Krzesinski P; Uzieblo-Zyczkowska B; Kwiatkowski P; Kowal J;
Dziuk M; Wlochacz A; Maciorowska M; Malinowski M; Banak M; Surmacz E;
Gielerak G

Cardiology Journal. 33:e00226055, 2026.

BACKGROUND: Chronic total occlusion (CTO) is a common finding on coronary
angiograms of patients diagnosed with coronary artery disease, with an
incidence ranging from 15 to 25%. Despite its high incidence, this type of
coronary lesion is rarely treated with percutaneous coronary intervention.
The key to success appears to be appropriate qualification for
revascularization. Asymptomatic patients should be assessed for inducible
ischemia within the occluded vessel territory to detect patients with a
high ischemic burden, defined as inducible ischemia involving > 10% of the
myocardium. Single-photon emission computed tomography (SPECT) is a
well-established method of myocardial perfusion assessment; however, it is
not widely available, especially in less developed regions. The aim of the
study was to evaluate CTO patients to identify clinical parameters that
could predict the presence of relevant inducible ischemia measured by
SPECT.

METHODS: The study included 50 patients with a single-vessel CTO and
without any other significant coronary artery stenosis. Patients underwent
clinical examination, laboratory tests, echocardiography, 6-minute walk
test, cardiopulmonary exercise testing, exercise impedance cardiography,
and SPECT.

RESULTS: The only parameters associated with a high ischemic burden were
CTO location (in the left anterior descending artery and circumflex
artery) and one echocardiographic parameter: myocardial lateral wall
longitudinal strain.

CONCLUSIONS: Given the high incidence of CTO, there is an increasing need
to define non-invasive markers that could predict the presence of a high
ischemic burden and good clinical outcome after revascularization.
Echocardiographic longitudinal strains are worth further research in terms
of their utility in predicting inducible ischemia.