Incremental Cardiopulmonary Exercise Testing Research Articles

Nebulized fentanyl does not improve exercise capacity or dyspnoea in fibrosing interstitial lung disease.

Exercise intolerance and exertional dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD) and are associated with worse prognosis and quality of life. Activation of pulmonary vagal afferents influences the ventilatory pattern and contributes to the sensation of dyspnoea. We tested the hypothesis that nebulized fentanyl, which might attenuate aberrant pulmonary afferent activity in FILD, reduces ventilation and dyspnoea while extending exercise endurance time (EET). In this randomized, single-blind, placebo-controlled study, eight FILD patients (two males, 71±6years of age) performed incremental cardiopulmonary cycle exercise tests following nebulization of either fentanyl citrate (100 µg) or 0.9% saline. Previous work indicated that this dose was unlikely to produce central effects. Comparisons between treatment conditions at rest were undertaken using Student's paired t-test, and exercise data were evaluated with two-way ANOVA with repeated measures. Dyspnoea was assessed using the Borg dyspnoea scale. Resting respiratory variables were not different following treatment with fentanyl and saline; however, resting heart rate was lower following fentanyl (P=0.002) and remained lower throughout exercise compared with placebo (P=0.008). Fentanyl did not increase EET (placebo 334±117s vs. fentanyl 348±126s, P=0.250) although overall minute ventilation was reduced slightly (mean difference: -0.97 L/min, P=0.022). There were no differences in ratings of dyspnoea intensity or unpleasantness between the conditions either at rest or at end-exercise. Nebulized fentanyl did not improve EET or exercise dyspnoea but did decrease minute ventilation during exercise, although the extent of this reduction appears clinically insignificant. These findings suggest that nebulized fentanyl is unlikely to offer significant benefits for enhancing exercise capacity in FILD.

Pulmonary vascular structure and function are related to exercise capacity in health and COPD

Although it is generally accepted that aerobic exercise training does not change lung structure or function, some work suggests that greater pulmonary vascular structure and function is associated with higher exercise capacity (VO2peak). Is there a cross-sectional association between the pulmonary vasculature and VO2peak? We hypothesized that those with higher computed tomography (CT) blood vessel volumes, and pulmonary diffusing capacity for carbon monoxide (DLCO) would have higher VO2peak, independent of airflow limitation. Participants from the CanCOLD study were categorized as: never-smokers with normal spirometry (n=263); ever-smokers with normal spirometry (n=407); and chronic obstructive pulmonary disease (COPD): individuals with spirometric airflow obstruction (n=334). Total vessel volume (TVV), the volume for all vessels with a cross-sectional area ≤5 mm2 (BV5), and between 5-10 mm2 (BV5-10) were generated from CT scans and used as indices of pulmonary vascular structure. DLCO was used as an index of pulmonary microvascular function. VO2peak was evaluated via incremental cardiopulmonary exercise testing. General linear regression models revealed that even after controlling for FEV1, emphysema severity and body morphology, DLCO, TVV, BV5 and BV5-10, were independently associated with VO2peak. Interaction effects were observed between COPD and TVV, BV5, and BV5-10 indicating a weaker association between pulmonary vascular volumes and VO2peak in COPD. Our results suggest that pulmonary vascular structure and DLCO is independently associated with VO2peak, regardless of severity of airflow limitation and emphysema, suggesting that these associations are not limited to COPD.

Effects of sildenafil on gas exchange, ventilatory, and sensory responses to exercise in subjects with mild-to-moderate COPD: a randomized cross-over trial

Excess exercise ventilation (high ventilation (V̇E)/carbon dioxide output (V̇CO2)) contributes significantly to dyspnea and exercise intolerance since the earlier stages of chronic obstructive pulmonary disease (COPD). A selective pulmonary vasodilator (inhaled nitric oxide) has shown to increase exercise tolerance secondary to lower V̇E/V̇CO2 and dyspnea in patients with early COPD. We aimed to assess whether a clinically more practical option - oral sildenafil - would be associated with similar beneficial effects. In a randomized, placebo-controlled study, twenty-four patients with mild-to-moderate COPD completed, on different days, two incremental cardiopulmonary exercise tests (CPET) one hour after sildenafil or placebo. Eleven healthy participants performed a CPET in a non-interventional visit for comparative purposes with patients when receiving placebo. Patients (FEV1= 69.4 ± 13.5% predicted) showed higher ventilatory demands (V̇E/V̇CO2), worse pulmonary gas exchange, and higher dyspnea during exercise compared to controls (FEV1= 98.3 ±11.6% predicted). Contrary to our expectations, however, sildenafil (50mg; N= 15) did not change exertional V̇E/V̇CO2, dead space/tidal volume ratio, operating lung volumes, dyspnea, or exercise tolerance compared to placebo (P>0.05). Due to the lack of significant beneficial effects, nine additional patients were trialed with a higher dose (100mg). Similarly, active intervention was not associated with positive physiological or sensory effects. In conclusion, acute oral sildenafil (50 or 100mg) failed to improve gas exchange efficiency or excess exercise ventilation in patients with predominantly moderate COPD. The current study does not endorse a therapeutic role for sildenafil to mitigate exertional dyspnea in this specific patient subpopulation.Clinical trial registry: https://ensaiosclinicos.gov.br/rg/RBR-4qhkf4Web of Science Researcher ID: O-7665-2019

The Effects of Diabetes on Gas Transfer Capacity, Lung Volumes, Muscle Strength, and Cardio-pulmonary Responses During Exercise.

Diabetes is a risk factor for the development of vascular disease, chronic kidney disease, retinopathy, and neuropathy. Diabetes is a co-morbid condition commonly present in patients with respiratory disorders but the extent to which it influences ventilatory capacity, gas exchange, and functional capacity is not well known. Research question Does the presence of diabetes contribute to impairment in spirometry, gas transfer, and exercise capacity? Retrospective analysis of all subjects who performed incremental cardio-pulmonary exercise testing (CPET) between 1988 and 2012 at McMaster University Medical Centre. The impact of diabetes on physiological outcomes and maximum power output (MPO) was assessed using stepwise multiple additive linear regression models including age, height, weight, sex, muscle strength, and previous myocardial infarct as co-variates, and was also stratified based on BMI categories. 40,776 subjects were included in the analysis; 1938 (5%, 66% male) had diabetes. Diabetics were older (59 vs. 53 years), heavier (88.3 vs.78.0 kg), and had a higher BMI (31 vs. 27kg/m2). The presence of diabetes was independently associated with a reduction in FEV1 (-130ml), FVC (-220ml), DLCO (-1.52ml/min/mmHg), and VA (-340ml) but not KCO. Patients with diabetes achieved a lower % predicted MPO[diabetic subjects 70% predicted (670 kpm/min ± 95% CI 284) vs. 80% in non-diabetics (786 kpm/min ± 342), p < 0.001]. With the exception of KCO, these differences persisted across BMI categories and after adjusting for MI. The presence of diabetes is independently associated with weaker muscles, lower ventilatory and gas transfer capacity and translates to a lower exercise capacity. These differences are independent of age, height, weight, sex, and previous MI.

How to evaluate exertional breathlessness using normative reference equations in research

Purpose of review Breathlessness is a common, distressing and limiting symptom in people with advanced disease, but is challenging to assess as the symptom intensity depends on the level of exertion (symptom stimulus) during the assessment. This review outlines how to use recently developed normative reference equations to evaluate breathlessness responses, accounting for level of exertion, for valid assessment in symptom research. Recent findings Published normative reference equations are freely available to predict the breathlessness intensity response (on a 0–10 Borg scale) among healthy people after a 6-minute walking test (6MWT) or an incremental cycle cardiopulmonary exercise test (iCPET). The predicted normal values account for individual characteristics (including age, sex, height, and body mass) and level of exertion (walk distance for 6MWT; power output, oxygen uptake, or minute ventilation at any point during the iCPET). The equations can be used to (1) construct a matched healthy control dataset for a study; (2) determine how abnormal an individual’s exertional breathlessness is compared with healthy controls; (3) identify abnormal exertional breathlessness (rating &gt; upper limit of normal); and (4) validly compare exertional breathlessness levels across individuals and groups. Summary Methods for standardized and valid assessment of exertional breathlessness have emerged for improved symptoms research.

Cardiovascular risk and its influencing factors during exercise in apparently healthy Chinese adult population

BackgroundThere are few studies on the safety of sub-maximal exercise testing of aerobic exercise in apparently healthy Chinese populations. The purpose of this study was to explore the frequency of exercise electrocardiography (ECG) abnormalities and the corresponding exercise intensities, as well as the associated influencing factors, during a symptom-limited stepwise incremental cardiopulmonary exercise test (CPET) in an apparently healthy Chinese population.MethodsA cross-sectional study was done in four communities, one urban and one rural in the North (Beijing) and in the South (Hezhou, Guangxi) of China from 1 January 2017 to 31 December 2018, respectively. Total of 1642 participants was recruited, 918 were eligible and completed demographic indicators, routine blood indicators, physical activity status, symptom-limited CPET and exercise ECG were included in the analysis.ResultsOf the exercise ECG outcomes, 10 (1.1%) were positive and occurred at exercise intensities ≥ 62.50% heart rate reserve (HRR); 44 (4.8%) were equivocal and 864 (94.1%) were normal. Individuals with Cardiovascular Disease Risk Factor (CVDRF) = 3–4 were 2.6 times more likely to have a equivocal and abnormal exercise ECG than those with CVDRF = 0–2. Exercise ECGs of individuals with CVDRF = 5–7 were 5.4 times more likely to be positive and abnormal than exercise ECGs of individuals with CVDRF = 0–2.ConclusionsThe exercise intensity of 62.5% HRR can be used as a safe upper limit for safe participation in exercise in apparently healthy Chinese population; the greater the number of CVDRFs, the greater the likelihood of cardiovascular risk during exercise.

Exceptional exercise capacity in a late bloomer octogenarian triathlete.

Maximal oxygen uptake (V̇O<inf>2max</inf>) gradually declines across the lifespan. However, little is known about the octogenarians. This is a knowledge gap given that individuals living >80 years old is the fastest expanding age-group world-wide. The increase in the elderly population has generated greater awareness in healthy ageing including psychosocial, physical, and cognitive domains, all of which benefit from engagement in physical activity or sport. In the present article are reported characteristics of an octogenarian man (GM), starting training for triathlon when he was 75 years old. GM performed an incremental Cardiopulmonary Treadmill-Running Exercise Test (CPX). A competitive 5-day consecutive triathlon event (sprint distance on days 1, 3, 4, 5 and Olympic distance on day 2) was monitored using an advanced smartwatch. Between 2021 and 2022, he trained for 10-to-12 hours/week, and participated in 59 and 39 competitions, respectively. The CPX showed a V̇O<inf>2max</inf> of 39.8 mL·min-1·kg-1, the 3rd highest value ever described in the literature among octogenarians and corresponding to the ≈60th percentile of 40-to-49-year-old men. During the 5-day triathlon (overall 12:15 h:min), 88% of time was spent at 77-95% of maximum heart rate (i.e., vigorous exercise intensity). In addition, GM was the 2022 Triathlon Olympic distance World Champion. The remarkably high V̇O<inf>2max</inf> and performance described herein were associated with exceptionally high exercise volume and intensity during training and competition, up to more than four times the recommended physical activity by current guidelines. These results further support the benefits of endurance exercise among octogenarians.

Cardiopulmonary Response to Acute Exercise before Hemodialysis: A Pilot Study.

Disparities in physical fitness between immediately before dialysis (pre-D) and the day following dialysis (non-D) have not been investigated despite potential adverse factors such as fluid status, uremia, and electrolyte levels in the pre-dialysis period. The effect of acute exercise immediately before hemodialysis (HD) on HD-related hypotension remains unclear. We hypothesized that cardiopulmonary performance and muscular strength would be inferior in the immediate pre-D period compared to those non-D. Twenty patients receiving chronic HD treatments underwent symptom-limited incremental cardiopulmonary exercise testing (CPET) and isokinetic testing both 1-2 h prior to dialysis (pre-D) and non-D. This investigation was a sub-study of a clinical trial assessing the efficacy of a pre-D exercise training program. Blood pressure profiles during HD post-CPET and pre-D exercise training were compared with those during usual HD sessions. No adverse events were observed during the 80 exercise tests. Prior to dialysis, the nadir of the ventilatory equivalent of CO2 was slightly elevated, the resting heart rate was lower, and the peak systolic blood pressure was higher than those non-D. Contrary to our hypothesis, peak <inline-formula><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover accent="true"><mml:mi mathvariant="normal">V</mml:mi><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math></inline-formula> and quadriceps peak torque showed no differences. Blood pressure profiles during HD post-exercise were similar to those during sessions without prior exercise, except for a lower resting systolic blood pressure at the beginning of HD. Cardiopulmonary response and muscular strength in the 1-2 h prior to HD were comparable with those on the day following HD, with only minor clinically insignificant differences. Acute exercise prior to HD did not affect the magnitude of hypotension during HD. This study suggests a potential alternative timing for exercise training or testing in patients undergoing chronic HD.

Differences in Exercise Capacity, Ventilatory Efficiency, and Gas Exchange between Patients with Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension Residing at High Altitude.

Cardiopulmonary exercise testing (CPET) assesses exercise capacity and causes of exercise limitation in patients with pulmonary hypertension (PH). At altitude, changes occur in the ventilatory pattern and a decrease in arterial oxygen pressure in healthy; these changes are increased in patients with cardiopulmonary disease. Our objective was to compare the response to exercise and gas exchange between patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) residing at the altitude of Bogotá (2640 m). All patients performed an incremental CPET with measurement of oxygen consumption ( ), dead space (VD/VT), ventilatory equivalents (VE/ ), and alveolar-arterial oxygen gradient ( ). test and one-way analysis of variance were used for comparisons between PAH and CTEPH. We included 53 patients, 29 with PAH, 24 with CTEPH, and 102 controls as a reference of the normal response to exercise at altitude. CTEPH patients had a higher New York Health Association (NYHA) functional class than PAH (p = 0.037). There were no differences between patients with PAH and CTEPH in hemodynamics and % of predicted (67.8 18.7 vs. 66.0 19.8, p 0.05), but those with CTEPH had higher dyspnea, VD/VT (0.36 0.09 vs. 0.23 0.9, p 0.001), VE/ (45.8 7.1 vs. 39.3 5.6, p 0.001), and (19.9 7.6 vs. 13.5 7.6, p 0.001) than PAH patients. At altitude, patients with PH present severe alterations in gas exchange during exercise. There were no differences in exercise capacity between PAH and CTEPH, but patients with CTEPH had more dyspnea and greater alterations in gas exchange during exercise. CPET made it possible to identify alterations related to the pathophysiology of CTEPH that could explain the functional class and dyspnea in these patients.

Telerehabilitation improves cardiorespiratory and muscular fitness and body composition in older people with post-COVID-19 syndrome.

The effects of post-coronavirus disease 2019 (COVID-19) syndrome on the cardiorespiratory and muscular fitness in older people are of utmost relevance. This study aimed to evaluate the effects of a 12-week telerehabilitation programme on cardiorespiratory and muscular fitness and body composition in older patients with post-COVID-19 syndrome. One hundred twenty older patients with post-COVID-19 syndrome were randomly assigned to one of two groups: patients who carried out the telerehabilitation programme (n=60; age: 65.0±5.2; female: 14.2%) and a control group (n=60; age: 64.3±5.0; female: 24.5%). An incremental cardiopulmonary exercise testing, isokinetic strength test, and bioelectrical impedance analysis were performed to compare cardiorespiratory and muscle strength responses and body composition between telerehabilitation and control groups. A significant increase in the cardiopulmonary exercise testing duration was found in the telerehabilitation group compared to the control group (mean difference=88.9s, P=0.001). Peak oxygen uptake increased in the telerehabilitation group (mean difference=3.0mL·kg-1·min-1, P<0.001) and control group (mean difference=1.9mL·kg-1·min-1, P<0.001). Power output in cycle ergometer (mean difference=25.9 watts, P<0.001), fat free mass (mean difference=2.1kg, P=0.004), soft lean mass (mean difference=2.1kg, P=0.003), and skeletal muscle mass (mean difference=1.4kg, P=0.003) only increased in the telerehabilitation group. A significant increase in the power output was observed in the telerehabilitation group compared with the control group in both lower limbs after isokinetic strength test of the leg extension at a speed of 60° (right: mean difference=18.7 watts, P=0.012; left: mean difference=15.3 watts, P=0.010). The peak torque of right leg extension increased only in the telerehabilitation group after isokinetic strength test at a speed of 60° (mean difference=13.1N·m, P<0.001). A significant increase in the power output was observed in the telerehabilitation group compared with the control group in the left leg extension after isokinetic strength test at a speed of 180° (mean difference=30.2 watts, P=0.003). The telerehabilitation programme improved cardiorespiratory and muscular fitness, and body composition in older patients with post-COVID-19 syndrome to a greater extent than a control group. The telerehabilitation programmes may be an alternative to improve the sequelae of post-COVID-19 syndrome in older patients.

The cardiovascular implications for exercise intolerance and dyspnoea in electronic cigarette users

Background: Electronic cigarettes (EC) have been proposed as a safe alternative to tobacco smoking, however, several studies have shown adverse health effects of EC. The chronic implications of EC on cardiorespiratory response and exertional dyspnoea are unknown. Aim: To examine the chronic effects of electronic cigarettes (EC) and tobacco cigarettes (TC) on resting vascular function, inflammatory markers, cardiorespiratory responses during exercise and exertional dyspnoea. Methodology: Three groups of young adults (16 each) with normal spirometry (EC users, TC smokers, and never-smokers [NS]) consented to participate in this study following institutional ethics approval. Participants performed spirometry and an incremental cardiopulmonary exercise test (CPET) 20W/2mins on an electronically braked cycle ergometer with blood lactate (BLa) measurements. Flow-mediated dilation (FMD%) of the brachial artery was assessed using Doppler ultrasonography. Venous blood samples were collected to assess inflammatory biomarkers associated with vascular function. Results: EC and TC groups had a lower peak work rate compared to NS controls (184 ± 30; 185 ± 35 vs. 228 ± 44 W, respectively; P &lt; 0.05). During submaximal exercise, EC and TC groups displayed higher ventilation (VE), higher ratings of dyspnoea and more intense leg fatigue compared to NS controls (e.g. 140 W, VE: 62 ± 10; 64 ± 12 vs. 54 ± 7 L/min, Dyspnoea: 5.0 ± 1.9; 6.1 ± 1.9 vs. 3.4 ± 1.7 Borg units, 6.1 ± 2.05; 7.0 ± 1.9 vs. 4.1 ± 2.1 Borg units, respectively; all P &lt; 0.05). The TC group displayed lower ventilatory efficiency (higher V̇E/V̇CO2) and higher blood lactate compared to NS during submaximal exercise (e.g. 140 W, V̇E/V̇CO2: 31.8 ± 5.6 vs. 28.2 ± 2.41, Blood lactate: 6.5 ± 2.4 vs. 4.3 ± 2.5 mmol/L, respectively; P &lt; 0.05 for both). Like the TC group, the EC group showed a trend for lower ventilatory efficiency and higher BLa during submaximal exercise, but they did not reach statistically significant differences compared to NS controls (P = 0.07 for both). FMD was significantly lower in EC and TC groups compared with NS controls (5.4 ± 2.4; 4.6 ± 2.9 vs. 7.9 ± 3.4%, respectively; P &lt; 0.05) and that was associated with elevated Thrombospondin-1 levels. Conclusion: EC and TC impair vascular function and cardiorespiratory responses to exercise and exertional dyspnoea similarly. EC has a detrimental impact on vascular function and exercise capacity and should not be recommended as a ‘healthier’ alternative to TC.

Revisiting the peak breathing reserve &amp;lt; 15% criterion to indicate ventilatory limitation to treadmill incremental cardiopulmonary exercise testing in men and women aged 20 to 80 years

Revisiting the peak breathing reserve &amp;lt; 15% criterion to indicate ventilatory limitation to treadmill incremental cardiopulmonary exercise testing in men and women aged 20 to 80 years

Mechanisms and consequences of excess exercise ventilation in fibrosing interstitial lung disease

The causes and consequences of excess exercise ventilation (EEV) in patients with fibrosing interstitial lung disease (f-ILD) were explored. Twenty-eight adults with f-ILD and 13 controls performed an incremental cardiopulmonary exercise test. EEV was defined as ventilation-carbon dioxide output (⩒E-⩒CO2) slope ≥36 L/L. Patients showed lower pulmonary function and exercise capacity compared to controls. Lower DLCO was related to higher ⩒E-⩒CO2 slope in patients (P<0.05). 13/28 patients (46.4%) showed EEV, reporting higher dyspnea scores (P=0.033). Patients with EEV showed a higher dead space (VD)/tidal volume (VT) ratio while O2 saturation dropped to a greater extent during exercise compared to those without EEV. Higher breathing frequency and VT/inspiratory capacity ratio were observed during exercise in the former group (P<0.05). An exaggerated ventilatory response to exercise in patients with f-ILD is associated with a blunted decrease in the wasted ventilation in the physiological dead space and greater hypoxemia, prompting higher inspiratory constraints and breathlessness.

Confirming the attainment of maximal oxygen uptake within special and clinical groups: A systematic review and meta-analysis of cardiopulmonary exercise test and verification phase protocols.

A plateau in oxygen uptake ([Formula: see text]) during an incremental cardiopulmonary exercise test (CPET) to volitional exhaustion appears less likely to occur in special and clinical populations. Secondary maximal oxygen uptake ([Formula: see text]) criteria have been shown to commonly underestimate the actual [Formula: see text]. The verification phase protocol might determine the occurrence of 'true' [Formula: see text] in these populations. The primary aim of the current study was to systematically review and provide a meta-analysis on the suitability of the verification phase for confirming 'true' [Formula: see text] in special and clinical groups. Secondary aims were to explore the applicability of the verification phase according to specific participant characteristics and investigate which test protocols and procedures minimise the differences between the highest [Formula: see text] values attained in the CPET and verification phase. Electronic databases (PubMed, Web of Science, SPORTDiscus, Scopus, and EMBASE) were searched using specific search strategies and relevant data were extracted from primary studies. Studies meeting inclusion criteria were systematically reviewed. Meta-analysis techniques were applied to quantify weighted mean differences (standard deviations) in peak [Formula: see text] from a CPET and a verification phase within study groups using random-effects models. Subgroup analyses investigated the differences in [Formula: see text] according to individual characteristics and test protocols. The methodological quality of the included primary studies was assessed using a modified Downs and Black checklist to obtain a level of evidence. Participant-level [Formula: see text] data were analysed according to the threshold criteria reported by the studies or the inherent measurement error of the metabolic analysers and displayed as Bland-Altman plots. Forty-three studies were included in the systematic review, whilst 30 presented quantitative information for meta-analysis. Within the 30 studies, the highest mean [Formula: see text] values attained in the CPET and verification phase protocols were similar (mean difference = -0.00 [95% confidence intervals, CI = -0.03 to 0.03] L·min-1, p = 0.87; level of evidence, LoE: strong). The specific clinical groups with sufficient primary studies to be meta-analysed showed a similar [Formula: see text] between the CPET and verification phase (p > 0.05, LoE: limited to strong). Across all 30 studies, [Formula: see text] was not affected by differences in test protocols (p > 0.05; LoE: moderate to strong). Only 23 (53.5%) of the 43 reviewed studies reported how many participants achieved a lower, equal, or higher [Formula: see text] value in the verification phase versus the CPET or reported or supplied participant-level [Formula: see text] data for this information to be obtained. The percentage of participants that achieved a lower, equal, or higher [Formula: see text] value in the verification phase was highly variable across studies (e.g. the percentage that achieved a higher [Formula: see text] in the verification phase ranged from 0% to 88.9%). Group-level verification phase data appear useful for confirming a specific CPET protocol likely elicited [Formula: see text], or a reproducible [Formula: see text], for a given special or clinical group. Participant-level data might be useful for confirming whether specific participants have likely elicited [Formula: see text], or a reproducible [Formula: see text], however, more research reporting participant-level data is required before evidence-based guidelines can be given. PROSPERO (CRD42021247658) https://www.crd.york.ac.uk/prospero.

Is digit ratio (2D:4D) a biomarker for lactate? Evidence from a cardiopulmonary test on professional male footballers

BackgroundLactate accumulation is associated with vigorous exercise, cardiovascular disease and a number of cancers. Digit ratio (2D:4D) has also been linked to oxygen metabolism, myocardial infarction and various cancers. Such similarities suggest the possibility that 2D:4D is a biomarker of lactate. Here, we consider the relationship between 2D:4D and lactate during an incremental cardiopulmonary exercise test. MethodThe participants were male professional football players. The treadmill test began at a speed of 8 km/h when the first lactate measurement was taken. The speed was increased by 2 km/h every 3.15 min, with measurements at 10, 12, 14 and 16 km/h. ResultsThere were 72 Caucasian and 7 Black participants, results are reported for the most numerous group. Lactate levels increased with running speed and were not correlated with age, body size or body composition. Median splits of digit ratios (right, left and right-left 2D:4D [Dr-l]) were calculated. In comparison to the Low ratio group, the High ratio group showed higher lactate levels across speeds. Effect sizes varied from very large to huge (right 2D:4D), large (left 2D:4D) and medium (Dr-l). At the individual level, positive correlations between digit ratios and lactate at the five different speeds varied from large (right 2D:4D), medium (left 2D:4D) and small (Dr-l). ConclusionThere were large positive associations between right 2D:4D and lactate at all running speeds. We discuss our findings in relation to oxygen metabolism and suggest that 2D:4D may be a biomarker for lactate in the wider context of the latter's importance in health and disease.

Aerobic capacity and mitochondrial function in bipolar disorder: a longitudinal study during acute phases and after clinical remission.

Aerobic capacity has shown to predict physical and mental health-related quality of life in bipolar disorder (BD). However, the correlation between exercise respiratory capacity and mitochondrial function remains understudied. We aimed to assess longitudinally intra-individual differences in these factors during mood episodes and remission in BD. This study included eight BD patients admitted to an acute psychiatric unit. Incremental cardiopulmonary exercise test (CPET) was conducted during acute episodes (T0), followed by constant work rate cycle ergometry (CWRCE) to evaluate endurance time, oxygen uptake at peak exercise (VO2peak) and at the anaerobic threshold. The second test was repeated during remission (T1). Mitochondrial respiration rates were assessed at T0 and T1 in peripheral blood mononuclear cells. Endurance time, VO2peak, and anaerobic threshold oxygen consumption showed no significant variations between T0 and T1. Basal oxygen consumption at T1 tended to inversely correlate with maximal mitochondrial respiratory capacity (r=-0.690, p=0.058), and VO2peak during exercise at T1 inversely correlated with basal and minimum mitochondrial respiration (r=-0.810, p=0.015; r=-0.786, p=0.021, respectively). Our preliminary data showed that lower basal oxygen consumption may be linked to greater mitochondrial respiratory capacity, and maximum oxygen uptake during the exercise task was associated with lower basal mitochondrial respiration, suggesting that lower oxygen requirements could be associated with greater mitochondrial capacity. These findings should be replicated in larger samples stratified for manic and depressive states.

Defective exercise-related expiratory muscle recruitment in patients with PHOX2B mutations: A clue to neural determinants of the congenital central hypoventilation syndrome

Introduction and objectivesThe human congenital central hypoventilation syndrome (CCHS) is caused by mutations in the PHOX2B (paired-like homeobox 2B) gene. Genetically engineered PHOX2B rodents exhibit defective development of the brainstem retrotrapezoid nucleus (RTN), a carbon dioxide sensitive structure that critically controls expiratory muscle recruitment. This has been linked to a blunted exercise ventilatory response. Whether this can be extrapolated to human CCHS is unknown and represents the objective of this study. Materials and methodsThirteen adult CCHS patients and 13 healthy participants performed an incremental symptom-limited cycle cardiopulmonary exercise test. Responses were analyzed using guideline approaches (ventilation V'E, tidal volume VT, breathing frequency, oxygen consumption, carbon dioxide production) complemented by a breathing pattern analysis (i.e. expiratory and inspiratory reserve volume, ERV and IRV). ResultsA ventilatory response occurred in both study groups, as follows: V'E and VT increased in CCHS patients until 40 W and then decreased, which was not observed in the healthy participants (p<0.001). In the latter, exercise-related ERV and IRV decreases attested to concomitant expiratory and inspiratory recruitment. In the CCHS patients, inspiratory recruitment occurred but there was no evidence of expiratory recruitment (absence of any ERV decrease, p<0.001). ConclusionsAssuming a similar organization of respiratory rhythmogenesis in humans and rodents, the lack of exercise-related expiratory recruitment observed in our CCHS patients is compatible with a PHOX2B-related defect of a neural structure that would be analogous to the rodents' RTN. Provided corroboration, ERV recruitment could serve as a physiological outcome in studies aiming at correcting breathing control in CCHS.

Perioperative Exercise Testing in Pregnant and Non-Pregnant Women of Reproductive Age: A Systematic Review.

Women have classically been excluded from the development of normal data and reference ranges, with pregnant women experiencing further neglect. The incidence of Caesarean section in pregnant women, and of general operative management in young women (both pregnant and non-pregnant), necessitates the formal development of healthy baseline data in these cohorts to optimise their perioperative management. This systematic review assesses the representation of young women in existing reference ranges for several functional exercise tests in common use to facilitate functional assessment in this cohort. Existing reference range data for the exercise tests the Six Minute Walk Test (6MWT), the Incremental Shuttle Walk Test (ISWT) and Cardiopulmonary Exercise Testing (CPET) in young women of reproductive age were assessed using the MEDLINE (Ovid) database, last searched December 2023. Results were comparatively tabulated but not statistically analysed given underlying variances in data. The role of exercise testing in the perioperative period as an assessment tool, as well as its safety during pregnancy, was evaluated using 65 studies which met inclusion criteria. There is a significant lack of baseline data regarding these tests in this population, especially amongst the pregnant cohort, which limits the application of exercise testing clinically.

Hospital and intensive care unit stay associated with body mass index affect cardiorespiratory fitness in patients with COVID-19.

The effects of coronavirus disease 2019 (COVID-19) on the cardiorespiratory fitness of hospitalized and obese patients are of utmost relevance. This study aimed to analyze how hospital and intensive care unit (ICU) stay together with body mass index affect cardiorespiratory fitness in patients with COVID-19. 251 participants (males, n = 118; females, n = 133) were assigned to four groups: non-hospitalized COVID-19 patients (n = 65, age: 45.3years), hospitalized COVID-19 patients (n = 63, age: 57.6years), COVID-19 patients admitted to the ICU (n = 61, age: 56.9years), and control group (n = 62, age: 49.8years). An incremental cardiopulmonary exercise test was performed between 3 and 6weeks after medical discharge from hospital. Higher peak oxygen uptake (VO2peak), ventilatory efficiency and power output were found in ICU patients with normal weight (NW) than in overweight (OW) (Mean difference: 0.1L·min-1, -5.5, 29.0W, respectively) and obese (OB) ICU patients (Mean difference: 0.1L·min-1, -5.0, 26.2W, respectively) (p < .05). In NW, OW and OB participants, higher VO2peak and power output were observed in control group compared with non-hospitalized (Mean difference: NW: 0.2L·min-1, 83.3W; OW: 0.2L·min-1, 60.0W; OB: 0.2L·min-1, 70.9W, respectively), hospitalized (Mean difference: NW: 0.2L·min-1, 72.9W; OW: 0.1L·min-1, 58.3W; OB: 0.2L•min-1, 91.1W, respectively) and ICU patients (Mean difference: NW: 0.1L·min-1, 70.9W; OW: 0.2L·min-1, 91.1W; OB: 0.3L·min-1; 65.0W, respectively) (p < .05). The degree of severity of COVID-19, especially identified by hospitalization and ICU stay, together with obesity and overweight were key factors in reducing cardiorespiratory fitness in patients with COVID-19.

Cardiorespiratory fitness as a mediator between body fat rate and executive function in college students.

To examine whether body fat rate (BF%) is associated with cardiorespiratory fitness (CRF) and whether cardiorespiratory fitness (CRF) mediates the association between BF% and Executive function (EF) in young adults. In this cross-sectional study, 226 college students were recruited from an university. Flanker, 2-back, and odder and shifting tasks were used to assess EF. The incremental cardiopulmonary exercise tests were performed, and maximal oxygen consumption was recorded during test. The body composition measuring instrument was used to evaluate the participants' BF%. The BF% of college students was negatively correlated with each EF, BF% was negatively correlated with CRF, and CRF was negatively correlated with EF (P< 0.001). Structural equation modeling (SEM) and simultaneous analysis of several groups were used to construct mediator model. The CRF of college students plays a partial mediating role between BF% and EF, and the mediating effect accounts for 48.8% of the total effect value. Sex has no moderate effect on the relationship between BF%, CRF, and EF. College students with high BF% can improve their CRF by strengthening physical exercise, thereby indirectly improving their EF. Therefore, college students who have a higher body fat percentage should be compensated for engaging in physical exercise in order to enhance their CRF and mitigate the detrimental effects of obesity and overweight on EF.