Del Vecchio L; Southern Cross University, Lismore, Australia
Climstein M

Journal of Sports Medicine & Physical Fitness. 66(2):223-231, 2026 Feb

BACKGROUND: The oxygen uptake efficiency slope (OUES) is a submaximal,
effort-independent index derived from cardiopulmonary exercise testing
that reflects aerobic fitness. Although OUES has shown strong correlations
with maximal oxygen uptake (VO2max) in clinical populations, its validity
and relationship with habitual physical activity in healthy middle-aged
adults remain underexplored. This study aimed to evaluate OUES as a marker
of aerobic fitness and examine its association with self-reported physical
activity in this demographic.

METHODS: Twenty-one middle-aged adults (14 women, seven men; mean age
63.3+/-3.8 years) without known cardiopulmonary disease were recruited.
Participants completed the Sports Medicine Australia pre-exercise
screening questionnaire, including weekly physical activity reporting.
Each participant underwent a graded treadmill test (Bruce protocol) to
submaximal effort, with oxygen uptake (VO2) and ventilation (VE) measured
continuously using a validated portable metabolic system. OUES was
calculated from the linear regression of VO2 against the log10VE). VO2max
was estimated via a resting seismocardiography device (VentriJect
Seismofit R). Pearson’s correlations and one-way ANOVA were used to
evaluate relationships between variables and tertile-based fitness groups.
An independent-samples t-test compared OUES values by sex.

RESULTS: Mean peak VO2 was 25.2+/-4.1 mL/kg/min; mean OUES was
1629.6+/-522.0 mL/min per log L/min. OUES showed a moderate but
non-significant correlation with estimated VO2max (r=0.415, P=0.069) and
no meaningful association with self-reported physical activity (r=-0.012,
P=0.960). One-way ANOVA showed significant differences in VO2max across
VentriJect VO2 tertiles (P<0.001, eta2=0.65), but not in OUES (P=0.162).
Males had significantly higher OUES values than females (2171+/-391 vs.
1366+/-282; P<0.001), with a large effect size (Cohen’s d=2.50).

CONCLUSIONS: OUES can be reliably obtained using a brief treadmill
protocol and portable metabolic equipment in middle-aged adults. While not
associated with self-reported activity, OUES showed moderate correlations
with VO2max and differentiated higher-fitness individuals, especially by
sex. These findings support OUES as a valid submaximal marker of
cardiorespiratory fitness and underscore the importance of objective
fitness measures alongside self-report tools in health and exercise
settings.

Vecchiato M; University Hospital of Padova,  Padova, Italy
Neunhaeuserer D; Zanardo E; Quinto G; Battista F; Aghi A;
Palermi S; Babuin L; Tessari C; Guazzi M; Gasperetti A; Ermolao A

Clinical Research in Cardiology. 115(3):412-423, 2026 Mar.

BACKGROUND AND AIMS: Transient increases (overshoot) in respiratory gas
analyses have been observed during exercise recovery, but their clinical
significance is not clearly understood. An overshoot phenomenon of the
respiratory exchange ratio (RER) is commonly observed during recovery from
maximal cardiopulmonary exercise testing (CPET), but it has been found
reduced in patients with heart failure with reduced ejection fraction
(HFrEF). The aim of the study was to analyze the clinical significance of
these RER recovery parameters and to understand if these may improve the
risk stratification of patients with HFrEF.

METHODS: This cross-sectional study includes HFrEF patients who underwent
functional evaluation with maximal CPET for the heart transplant checklist
at our Sports and Exercise Medicine Division. RER recovery parameters,
including RER overshoot as the percentual increase of RER during recovery
(RER mag), have been evaluated after CPET with assessment of hard clinical
long-term endpoints (MACEs/deaths and transplant/LVAD-free survival).

RESULTS: A total of 190 patients with HFrEF and 103 controls were
included (54.6 +/- 11.9 years; 73% male). RER recovery parameters were
significantly lower in patients with HFrEF compared to healthy subjects
(RER mag 24.8 +/- 14.5% vs 31.4 +/- 13.0%), and they showed significant
correlations with prognostically relevant CPET parameters. Thirty-three
patients with HFrEF did not present a RER overshoot, showing worse
cardiorespiratory fitness and efficiency when compared with those patients
who showed a detectable overshoot (VO2 peak: 11.0 +/- 3.1 vs 15.9 +/- 5.1
ml/kg/min; VE/VCO2 slope: 41.5 +/- 8.7 vs 32.9 +/- 7.9; DELTAPETCO2: 2.75
+/- 1.83 vs 4.45 +/- 2.69 mmHg, respectively). The presence of RER
overshoot was associated with a lower risk of cardiovascular events and
longer transplant-free survival.

CONCLUSION: RER overshoot represents a meaningful cardiorespiratory index
to monitor during exercise gas exchange evaluation; it is an easily
detectable parameter that could support clinicians to comprehensively
interpreting patients’ functional impairment and prognosis. CPET recovery
analyses should be implemented in the clinical decision-making of advanced
HF.

Kouroukli E; Aristotle University of Thessaloniki, Thessaloniki, Greece.
Sarafidis K; Tsanakas J; Hatziagorou E

Pediatric Pulmonology. 61(2):e71492, 2026 Feb.

BACKGROUND: Bronchopulmonary dysplasia is one of the most common
complications of preterm birth and has lifelong repercussions in
respiratory health.

OBJECTIVE: To examine lung function and exercise capacity and assess
potential differences in exertional respiratory pattern and ventilatory
and gas exchange responses in school-aged children with a history of
prematurity and/or BPD.

METHODS: Prospective observational study including children and
adolescents born preterm, with and without BPD, and healthy term-born
controls without a known history of asthma. Participants performed
spirometry and cardiopulmonary exercise testing.

RESULTS: Eighty-two children aged 6-18 years (mean: 11.9 years, SD: 3.1)
were enrolled and examined in three groups: preterm-born with BPD
(gestational age < 32 weeks), preterm-born without BPD (GA < 37 weeks),
and term-born controls (GA >= 37 weeks). FVC, FEV1, FEF25% -75%, and
FEV1/FVC were normal and comparable among the three groups. VO2peak% was
reduced in the BPD group and was significantly lower than the control
group (mean difference: -14.4, CI: -28 to -0.7, adjusted p = 0.04), but
the difference was not significant when adjusting for height. The BPD
group had the highest mean VE/VCO2 adjusted for height (32.7), followed by
the preterm (30.3) and the control group (29.5), and the difference
between the BPD and control group was statistically significant (p =
0.015). Moreover, BPD status was significantly associated with increased
VE/VCO2 (beta = +3.2, CI: 1-5.4, p = 0.005). The rest of the CPET
parameters were within normal limits and comparable among groups.

CONCLUSIONS: Children with BPD have normal lung function but reduced
exercise capacity and decreased ventilatory efficiency during exercise.

Ekstrom M;  Respiratory Medicine, Lund University, Lund, Sweden.
Li PZ; Bourbeau J; Tan WC; Jensen D

Chest. 169(2):449-461, 2026 Feb.

BACKGROUND: Breathlessness on exertion is a common, distressing, and
limiting symptom that can be quantified on incremental cardiopulmonary
exercise testing (CPET) using normative reference equations.

RESEARCH QUESTION: Is the breathlessness abnormality best uncovered and
assessed at symptom limitation (peak exercise) compared with submaximal
exercise intensities?

STUDY DESIGN AND METHODS: This was an analysis of people >= 40 years of
age undergoing symptom-limited incremental cycle CPET in the Canadian
Cohort Obstructive Lung Disease (CanCOLD) study. Each Borg 0-10 category
ratio scale breathlessness intensity rating during CPET was converted to
its probability of being normal, in relation to power output, rate of
oxygen uptake, and minute ventilation using normative reference equations.
Abnormally high exertional breathlessness (abnormal breathlessness) was
defined as a probability of being normal < 0.05.

RESULTS: Of 1,161 participants (42% female), abnormally high
breathlessness was present in 22%, 23%, and 16% in relation to rate of
oxygen uptake and minute ventilation at peak exercise. Among those with
abnormal breathlessness at peak exercise, 55% to 60% had normal
breathlessness across all submaximal exercise intensities. Among those
with normal breathlessness at peak exercise, 93% to 97% were normal across
all serial breathlessness ratings throughout the CPET (interclass
correlation coefficients, 0.93-0.95). Findings were similar in people with
or without chronic airflow limitation, and in people who did or did not
reach maximal exertion at the end (symptom limitation) of the CPET.

INTERPRETATION: The results of this study suggest that abnormal
breathlessness is uncovered and should be assessed at peak exercise during
symptom-limited incremental CPET. These findings inform symptom assessment
in research and clinical practice.

Mallepally A; School of Medicine, Richmond, Virginia, USA.
Dandamudi K; Kaye MG; Zavar T; Parsons B; Krishnamurthy S;
Patel H; Arena R; Canada JM; Trankle CR

Physiological Reports. 14(3):e70770, 2026 Feb.

The Metabolic Exercise test data combined with Cardiac and Kidney Indexes
(MECKI) score has demonstrated prognostic utility in European and Asian
cohorts with heart failure with reduced ejection fraction (HFrEF). We
sought to evaluate its performance in an American cohort. We
retrospectively identified patients who underwent cardiopulmonary exercise
testing (CPX) at our institution in 2022-2024 with data to calculate the
MECKI and CPX Risk scores. The primary endpoint was a composite of death,
heart failure admission, heart transplantation, or ventricular assist
device. Survival analysis was assessed via Kaplan-Meier curves and
log-rank test, with ROC curves for comparison. Overall, 803 patients met
criteria, with 451 (56%) female, 228 (28%) Black race, and median body
mass index 29.4 (25.0-34.2) kg/m2. Pre-existing HFrEF was present in 187
(23%) patients. 719 (90%), 41 (5%), and 43 (5%) patients achieved MECKI
scores <10%, 10%-20%, and >=20%, respectively, with stepwise increases in
2-year risk of primary endpoints (log-rank chi2 = 196.0, p < 0.001). ROC
curves demonstrated better performance of MECKI scores compared to CPX
Risk scores. Events were similarly predicted in patients with HFrEF, with
similar performances between the two scores. In conclusion, in a mixed
American cohort the MECKI score demonstrated robust performance in
predicting event-free survival.

Griffith GJ; Northwestern University, Chicago, IL.
Thomsen B; Xie Z; Zhang A; Davis Z; McKee KE; Corcos DM

Medicine & Science in Sports & Exercise. 58(3):484-492, 2026 Mar 01.

BACKGROUND: Parkinson’s disease (PD) is a neurodegenerative nervous system
condition causing motor and nonmotor symptoms. Endurance training is
commonly prescribed in people with PD for possible slowing of disease
progression. Since people with PD exhibit lower cardiorespiratory fitness,
it is important to understand peak aerobic capacity (VO 2peak ) in people
with PD. VO 2peak prediction equations may be used when cardiopulmonary
exercise testing (CPET) is unavailable; however, exercise-based
PD-specific prediction equations are lacking. The purpose of the study was
to develop a PD-specific VO 2peak prediction equation and to compare this
equation to published VO 2peak prediction equations.

METHODS: This study included N = 127 never-medicated individuals with PD,
aged 40-80 yr, Hoehn and Yahr stages 1-2, within 5 yr of diagnosis, and
exercising <=3 d/wk, who completed a treadmill CPET. Linear regression
analyses were performed to generate the VO 2peak equation from a
validation subsample, which was applied to a cross-validation subsample.
The equation was compared with two published equations for healthy adults.

RESULTS: The PD-specific VO 2peak equation was: VO 2peak (mL/kg/min) =
12.466 + 0.149 x (treadmill speed [m/min]) + 85.7 x (treadmill grade [%,
as a decimal]) – 2.383 x (sex [0 = male, 1 = female]) – 0.135 x (age
[years]). There was no difference between estimated and measured VO 2peak
in the cross-validation subsample. Our equation successfully predicted VO
2peak in early PD, whereas VO 2peak was over- and underestimated in people
with PD by the American College of Sports Medicine and Foster equations,
respectively.

CONCLUSIONS: Clinicians can estimate VO 2peak in individuals with PD to
identify those for whom endurance exercise training should be a major
health priority, develop an exercise prescription, and assess changes in
VO 2peak over time.

Novak P;  Brigham and Women’s Hospital, Boston, Massachusetts, USA
Systrom DM; Witte A; Marciano SP; Felsenstein D; Milunsky JM;
Milunsky A; Krier J; Fishman MC

PLoS ONE [Electronic Resource]. 21(1):e0341278, 2026.

INTRODUCTION: Long COVID and myalgic encephalomyelitis/chronic fatigue
syndrome (ME/CFS) are relatively common and disabling multisystem
disorders that share overlapping features, including post-infectious onset
and similar clinical manifestations such as brain fog, fatigue, muscle
pain, and dysautonomia with orthostatic intolerance. These similarities
suggest that Long COVID and ME/CFS may share common pathophysiological
mechanisms, though the underlying mechanisms remain poorly understood,
partly due to the difficulty in quantifying many of the symptoms.

MATERIALS AND METHODS: This retrospective study evaluated Long COVID and
pre-COVID ME/CFS patients who completed autonomic testing between 2018 and
2023 at the Brigham and Women’s Faulkner Hospital Autonomic Laboratory.
The evaluations included autonomic tests (Valsalva maneuver, deep
breathing, tilt-table test, and sudomotor function) with capnography and
transcranial Doppler monitoring of cerebral blood flow velocity (CBFv) in
the middle cerebral artery, neuropathic assessment through skin biopsies
for small fiber neuropathy (SFN), invasive cardiopulmonary exercise
testing (ICPET), and laboratory analyses covering metabolic, inflammatory,
autoimmune, and hormonal profiles.

RESULTS: A total of 143 Long COVID and 170 ME/CFS patients were analyzed
and compared to 73 healthy controls and 290 patients with hypermobile
Ehlers-Danlos syndrome (hEDS). Tests revealed extensive similarities
between Long COVID and ME/CFS, including reduced orthostatic CBFv (92%/88%
in Long COVID/ME/CFS), mild-to-moderate widespread autonomic failure
(95%/89%), presence of SFN (67%/53%), postural tachycardia syndrome (POTS)
(22%/19%), neurogenic orthostatic hypotension (15%/15%) and preload
failure (96%/92%, assessed in 25/66 Long COVID/ME/CFS). Patients with hEDS
exhibited more severe peripheral neurodegeneration compared to the other
groups. Laboratory tests did not distinguish between the conditions.

CONCLUSION: Both Long COVID and ME/CFS demonstrate dysregulation in
cerebrovascular blood flow, autonomic reflexes, and small fiber
neuropathy, suggesting that these conditions may share a common underlying
pathophysiology. However, differing distributions of findings in patients
with hEDS raise the question of whether these conditions represent
distinct but overlapping syndromes or reflect a shared underlying pathway.
Further research is required to clarify the relationship between these
conditions and the potential underlying pathophysiological mechanisms.

Suzuki T; Department of Cardiology, Yokohama City University Graduate School of Medicine.
Iwahashi N; Abe T; Komura N; Abe M; Konishi M; Otsuka F; SuganoT; Ishigami T; Hibi K

Circulation Journal. 90(2):228-231, 2026 Jan 23.
VI 1

BACKGROUND: Passive leg lifting (PLL) may serve as a simple alternative to
simulate exercise stress.

METHODS AND RESULTS: We evaluated 33 patients with PH who underwent
PLL-RHC and exercise right heart catheterization (RHC); 25 patients were
classified as having PLL-induced PH (LIPH), demonstrating significant
increases in mean pulmonary arterial pressure (mPAP) and mPAP-cardiac
output slopes. Strong correlations were observed between PLL-RHC and
exercise RHC measurements.

CONCLUSIONS: PLL-RHC may represent a simple method for detecting EIPH.

Sato T; Department of Physical Therapy, Fukushima Medical University, Fukushima City, Japan.
Sagawa S; Kataoka D; Igarashi M; Ishibashi R; Endo Y; Tsubaki A; Tamiya H; Morishita S

Advances in Experimental Medicine & Biology. 1498:271-275, 2026.
VI 1

PURPOSE: We aimed to clarify the compensatory changes in oxygenation in
non-active versus active muscles during incremental exercise.

METHODS: Fifteen male volunteers (age, 21.1 +/- 0.5 years) underwent
cardiopulmonary exercise testing (CPET) using a cycle ergometer ramp
protocol, while maintaining the left upper extremity in a drooping
position. We continuously recorded oxygenated hemoglobin (O2Hb),
deoxygenated hemoglobin (HHb), total hemoglobin (THb), and tissue oxygen
saturation (StO2) in the left vastus lateralis (active muscle) and triceps
brachii (non-active muscle), as well as cardiopulmonary parameters, during
the test.

RESULTS: There were significant interactions between time and muscles for
all changes in O2Hb (p < 0.001), HHb (p < 0.001), THb (p < 0.001), and
StO2 (p < 0.001). In the non-active muscle, O2Hb and StO2 remained higher
than at rest until the 40% point of the test, unlike in the active muscle.
HHb increased from the 80% point in the non-active muscle, but it
increased immediately after the start of the test in the active muscle.
THb showed no significant change in the non-active muscle, but it
continued to increase immediately after the start of the test in the
active muscle.

CONCLUSION: During CPET, O2Hb and StO2 in the non-active muscle remained
higher in the low- to moderate-intensity phases than in the rest phase and
decreased in the high-intensity phase, unlike in the active muscle.