Oxygen Uptake Research Articles

Effects of Cannabidiol Ingestion on Thermoregulatory and Inflammatory Responses to Treadmill Exercise in the Heat in Recreationally Active Males.

Exertional heat stress can induce systemic endotoxin exposure and a pro-inflammatory cascade, likely impairing thermoregulation. Cannabidiol (CBD) is protective in pre-clinical models of tissue ischaemia and inflammation. Therefore, this study examined the effects of CBD ingestion on exercise-induced thermoregulatory and inflammatory responses. In a randomised, double-blinded study, thirteen active males (age 25 ± 5 y; peak oxygen uptake [V̇O2peak] 50.4 ± 3.2 mL/kg/min) ingested 298 mg CBD or placebo 105 minutes before 1 h treadmill exercise (60-65% V̇O2peak) in 32 °C and 50% relative humidity. Core temperature, skin temperature, heart rate, subjective outcomes and sweat loss were assessed during/after exercise. Plasma osmolality, plasma volume changes and plasma markers of intestinal damage (I-FABP), monocyte activation (CD14) and inflammatory cytokine responses (IL-6, IL-8 and TNF-α) were assessed at baseline, pre-exercise, 20- and 90-min post-exercise. Core temperature (∆ 1.69 ± 0.48 °C [CBD] and 1.79 ± 0.53 °C [Placebo]) and I-FABP increased during exercise, with no differences between conditions (p > 0.050). Mean (95% CI) CD14 was 1776 (463 to 3090) pg/mL greater 90 min post-exercise in placebo (p = 0.049). Median (interquartile range) peak IL-6 concentration was -0.8 (-1.1, -0.3) pg/mL less in CBD (p = 0.050), whilst the between-conditions difference in IL-6 area under curve was -113 (-172, 27) pg/mL·270 min (p = 0.054). CBD did not affect thermoregulation during exertional heat stress but appeared to elicit minor immunosuppressive effects, reducing CD14 and IL-6 responses, warranting investigation in humans under more severe heat strain and other pro-inflammatory scenarios.

The Effect of Low-Intensity Interval Exercise with Blood Flow Restriction on Plasma Cardiac Troponin: A Cross-Design Trial.

Low-intensity training with blood flow restriction (BFR) training could induce endurance adaptations, its impact on myocardial markers is still unclear compared to training without BFR. Consequently, the influence of low-intensity interval exercise with and without BFR and high-intensity interval exercise (HIIE) on cardiac troponin was determined in this study. Twelve physically active males between 18 and 26 years volunteered as participants. The participants completed 3 exercise tests in random order, which included 40% VO2max low-intensity cycling without BFR (group L), 40% VO2max low-intensity cycling with BFR set at 60% limb occlusion pressure (LOP) (group B), and 80% VO2max high-intensity cycling without BFR (group H). Participant muscle oxygen, blood flow, oxygen uptake, heart rate (HR), perceived exertion (RPE) rating, and pain levels were determined before and after exercise, after cuff inflation, and pre- and post-each exercise. Moreover, before each protocol, immediately after the exercises, and 3-4 hours after each exercise, elbow vein blood samples were collected to evaluate lactate (LA) and high-sensitivity cardiac troponin T (cTnT). Increased LA was recorded after exercise by the individuals in group H, which was more significant than in group B. Moreover, group B documented a more significant LA increment than group L (P < .05). The peak cTnT of groups B and H after exercise was significantly higher (P < .05). Furthermore, the increase was more significant than the values recorded by group L (P < .05). The present study demonstrated that low-intensity interval exercise combined with BFR could cause cTnT elevations compared to training without BFR. The increase was similar to HIIE protocols.

Exercise as a modality to improve heart transplantation-related functional impairments: An article review.

Heart transplantation (HT), the treatment choice of advanced heart failure patients, is proven effective in increasing the survival and functional status of the recipients. However, compared to normal controls, functional status is lower in HT recipients. Exercise given in cardiac rehabilitation has been shown to improve exercise capacity as measured with peak oxygen uptake (VO2 peak) and muscle strength after completion of the program and cessation of exercise results in loss of exercise benefits. Several factors related to cardiac denervation and the use of immunosuppressive agents in HT recipients result in functional impairments including cardiovascular, pulmonary, exercise capacity, psychological, and quality of life (QoL) problems. High-intensity interval training (HIIT) is the most common type of exercise used in HT recipients and given as a hospital-based program. Improvement of functional impairments was found to have occurred due to primarily musculoskeletal adaptations through improvement of muscle structure and aerobic capacity and cardiovascular adaptations. In general, exercise given after transplantation improved VO2 peak significantly and improvement was better in the HIIT group compared to moderate intensity continuous training or no-exercise groups. Improvement of QoL was ascribed to improvement of exercise capacity, symptoms, pulmonary function, physical capacity improvement, anxiety, and depression.

Kinematical Effects of a Mandibular Advancement Occlusal Splint on Running until Exhaustion at Severe Intensity

The effects of occlusal splints on sport performance have already been studied, although their biomechanical impacts are often overlooked. We investigated the kinematical changes during running until exhaustion at severe intensity while wearing a mandibular advancement occlusal splint. Twelve trained runners completed (i) an incremental protocol on a track to determine their velocity corresponding to maximal oxygen uptake and (ii) two trials of square wave transition exercises at their velocity corresponding to maximal oxygen until exhaustion, wearing two occlusal splints (without and with mandibular advancement). Running kinematics were compared within laps performed during the square wave transition exercises and between splint conditions. The mandibular advancement occlusal splint increased the running distance covered (~1663 ± 402 vs. 1540 ± 397 m, p = 0.03), along with a noticeable lap effect in decreasing stride frequency (p = 0.04) and increasing stride length (p = 0.03) and duty factor (p &lt; 0.001). No spatiotemporal differences were observed between splints, except for improved balance foot contact times in the mandibular advancement condition. An increased knee flexion angle at initial contact (p = 0.017) was noted along laps in the non-advancement condition, despite the fact that no differences between splints were found. Running patterns mainly shifted within laps rather than between conditions, indicating that a mandibular advancement occlusal splint had a trivial kinematical effect.

Mediative role of body mass index in cardiorespiratory fitness-associated vascular remodeling in youth.

Data on fitness-associated arterial remodeling in children is limited. We assessed the relation between cardiorespiratory fitness (CRF) and intima-media thickness (IMT), diameter, IMT:diameter-ratio (IDR), and tensile stress of the common carotid artery (CCA) in 697 healthy German schoolchildren. Further, we explored how body mass index (BMI) may influence these associations. We measured the vascular parameters with a high-resolution ultrasound device. We determined CRF using the FITNESSGRAM® PACER test and calculated each child's allometrically scaled peak oxygen uptake capacity (VO2peak). VO2peak, reflecting CRF, showed positive direct effects on IMT (girls: p < 0.001; boys: p = 0.02) and diameter in girls (p < 0.001). Considering BMI as a mediator, higher CRF was indirectly linked to decreases in IMT (girls: p = 0.04; boys: p = 0.02) and diameter (both p < 0.001), reflecting a competitive mediation. CRF indirectly mitigated the BMI-associated decrease in IDR (both p < 0.001) and increase in tensile stress (both p < 0.001) without affecting any of these parameters directly. CRF appears to be linked to uniform arterial remodeling with balanced hemodynamics and to further alleviate BMI-associated, potentially adverse vascular alterations, highlighting its significant role in cardiovascular health in youth. Data on CRF-associated arterial remodeling in youth is limited. Higher VO2peak, reflecting higher CRF, was positively associated with IMT in girls and boys and diameter in girls. These direct effects were counteracted by the indirect BMI-mediated effect of CRF on IMT and diameter, reflecting a competitive mediation. A higher CRF indirectly mitigated the BMI-associated decrease in IDR and increase in tensile stress without directly affecting any of these parameters. Our findings indicate homogenous remodeling and balanced hemodynamics with increasing CRF-and opposite effects with increasing BMI.

Chest wall muscle area, ventilatory efficiency and exercise capacity in systemic sclerosis.

To investigate the potential contribution of chest wall muscle area (CWMA) to the ventilatory efficiency and exercise capacity in patients with Systemic Sclerosis (SSc) without interstitial lung disease (ILD). Forty-four consecutive SSc patients [F = 37, median age 53.5years (IQR 43.5-58)] were examined using chest high-resolution computed tomography (HRCT), pulmonary function tests and cardiopulmonary exercise testing (CPET). The CWMA was evaluated at the level of the ninth thoracic vertebra on CT images by two independent evaluators blinded to the patient information. CPET parameters analyzed were maximum oxygen uptake (VO2 max) and VO2 at anaerobic threshold (VO2@AT); minute ventilation (VE); maximum tidal volume (VT). A statistically significant positive correlation was found between CWMA and maximum workload (r = 0.470, p < 0.01), VO2 max ml/min (r = 0.380, p < 0.01), VO2@AT (r = 0.343, p < 0.05), VE (r = 0.308, p < 0.05), VT (r = 0.410, p < 0.01) and VO2/heart rate (r = 0.399, p < 0.01). In multiple regression analysis, VO2 max (ml/min) was significantly associated with CWMA [β coefficient = 5.226 (95% CI 2.824, 7.628); p < 0.001], diffusing capacity for carbon monoxide (DLco) [β coefficient = 6.749 (95% CI 1.460, 12.039); p < 0.05] and body mass index (BMI) [β coefficient = 41.481 (95% CI 8.802, 74.161); p < 0.05]. In multiple regression analysis, maximum workload was significantly associated with CWMA [β coefficient = 0.490 (95% CI 0.289, 0.691); p < 0.001], DLco [β coefficient = 0.645 (95% CI 0.202, 1.088); p < 0.01] and BMI [β coefficient = 3.747 (95% CI 1.013, 6.842); p < 0.01]. In SSc-patients without ILD, CWMA represents an important variable in exercise capacity and can be evaluated by the mediastinal window available in the HRCT images required for lung disease staging.

High-Intensity Exercise Training Impact on Cardiorespiratory Fitness, Gait Ability, and Balance in Stroke Survivors: A Systematic Review and Meta-Analysis

Stroke survivors commonly face challenges such as reduced physical activity and cardiorespiratory fitness (CRF) as well as balance and gait impairments, exacerbating their disability. While high-intensity exercise interventions have demonstrated some potential, their effects on these items remain uncertain. Therefore, our study aimed to investigate the impact of high-intensity training protocols on CRF, gait ability, and balance in stroke survivor populations. Two independent investigators systematically searched five databases for relevant RCTs following the PICO model. Through a systematic review of 25 RCTs published up to 31 May 2023, including adult first-stroke survivors, comparing high-intensity exercise training versus low-to-mild or no exercises, we evaluated outcomes such as the Six-Minute Walking Test (6 MWT), peak oxygen uptake (VO2peak), Ten-Meter Walk Test (10 MWT), Berg Balance Scale (BBS), and Timed Up and Go test (TUG). The protocol was registered in PROSPERO (registration number CRD42023456773). Meta-analyses indicated significant enhancements in CRF, as measured by 6 MWT and VO2peak, following high-intensity exercise interventions. However, no significant differences were observed in BBS, 10 MWT, and TUG. Our findings underscore the potential of high-intensity exercise interventions in ameliorating CRF among stroke survivors, although further research involving standardized protocols and long-term follow-ups is imperative to optimize rehabilitation outcomes.

Confirmatory Study on Prediction of Maximal Oxygen Uptake by Ensemble Learning Algorithm

Objective: The prediction model of maximal oxygen uptake (VO2max) was established by different ensemble learning methods. Compared with multiple linear regression, a common prediction method of VO2max, the effectiveness of the ensemble learning model is verified, and screen out the optimal VO2max prediction model. Methods: A total of 84 male college students, were recruited, informed of the purpose and procedure of the experiment, and passed the PAR-Q questionnaire screening. Cardiopulmonary Exercise Test (CPET), lung function, body composition test, VO2max, minute ventilation volume (VE), tidal volume (Vt), weight, and other related indicators. After the correlation analysis of the experimental results, a VO2max multiple linear regression model and an ensemble learning prediction model are computed. Results: The indicators that finally enter the multiple linear regression equation include: weight, Vt, VE. The regression equation is: VO2max (ml/kg/min) = 52.455+0.005×VT (ml/min) + 0.111×VE (L/min)-0.441×weight (kg), and the regression coefficient test results is extremely significant (P&lt;0.01). The VO2max prediction model is computed by using the ensemble learning algorithm and among the five prediction models, it is found that Weighted average (R^2=0.7715) has the best effect, and higher than multiple regression model, there is no significant difference between the actual value and the predicted value VO2max (P&gt;0.05). Conclusion: In the case of a small sample size, the weighted average model predicts VO2max the most accurately, compared with multiple regression models, the ensemble learning model can include more basic indicators, the evaluation of VO2max in the body is more comprehensive, and the prediction results are more accurate.

The impact of an exercise and sport intervention on cognitive function and pain among forcibly displaced individuals at risk for PTSD: a secondary analysis of the SALEEM randomized controlled trial

BackgroundIn response to the global scope of forced displacement, international organizations highlight the need of scalable solutions to support individuals’ health and integration into host societies. Exposure to high mental and physical stress perceived before, during, and after displacement can impair functional capabilities, essential for adapting to a new environment. This secondary analysis examined the impact of an exercise and sport intervention on cognitive function and pain severity among individuals living in a refugee camp in Greece.MethodsWe implemented a randomized controlled trial involving n = 142 (52.8% women) forcibly displaced individuals from Southwest Asia and Sub-Saharan Africa. Participants were randomly assigned to a waitlist or a 10-week co-designed exercise and sport intervention with a 1:1 allocation rate between groups and sexes. Assessments at baseline and follow-up included the Flanker task, the Oddball paradigm, pain severity via visual analog scales, and the Åstrand-Rhyming indirect test of maximal oxygen uptake. We analyzed the intervention effects using structural equation modeling.ResultsOur findings did not indicate a direct intervention effect on cognitive function or pain (p ≥ .332). However, the intervention group significantly improved cardiorespiratory fitness, ß = .17, p = .010, which was associated with faster reaction times in cognitive tasks, ß = − .22, p = .004. Moreover, there was some evidence that adherence might be linked to reduced pain severity, ß = − .14, p = .065.ConclusionsExercise and sport did not directly impact cognitive function and pain severity among a sociodemographically diverse sample living in a refugee camp, suggesting the need for complementary measures. Nevertheless, our results indicate that improvements in cardiorespiratory fitness benefit aspects of attention.Trial registrationThe study was approved by the local ethics committee of the University of Thessaly (no. 39) and registered prospectively on February 8, 2021 at the ISRCTN registry (no. 16291983).

Middle cerebral artery blood velocity and end-tidal carbon dioxide responses to moderate intensity cycling in children, adolescents and adults.

This study investigated the middle cerebral artery blood velocity (MCAv) response to constant work-rate moderate-intensity cycling exercise in 21 children (9.3±0.8 years), 17 adolescents (12.3±0.4 years) and 20 young adults (23.6±2.4 years). Participants completed an incremental ramp test to exhaustion on a cycle ergometer, to determine maximal oxygen uptake and gas exchange threshold (GET), before completing three 6-minute transitions at a moderate-intensity (90% GET), on separate visits. On each visit, bilateral MCAv was measured by transcranial Doppler ultrasonography and breath-by-breath end-tidal carbon dioxide (PETCO2) via a metabolic cart. Data were ensemble-averaged for each participant and analysed using a mono-exponential model. Absolute MCAv was significantly higher throughout exercise in children and adolescents, compared to adults (P<0.001). Children had a significantly lower relative increase in MCAv from baseline (~12%) compared to adolescents (~20%) and adults (~18%, P<0.040). All adolescents and adults had a mono-exponential rise in MCAv and PETCO2, but this was observed in only eight children. Children and adolescents had a significantly faster MCAv time constant (τ , 12±6 and 14±8 s, respectively) compared to adults (27±9 s, P<0.001). MCAv τ was positively associated with faster PETCO2 τ in adolescents (r=0.70, P=0.002) but not children (r=-0.20, P=0.640).Time- and amplitude-based response parameters of MCAv kinetics were significantly associated with PETCO2 kinetics in adults (r=0.50 to 0.74, P≤0.025), but not in children (r=-0.19 to -0.48, P>0.227). These findings suggest that the transition from childhood to adulthood impacts the MCAv response to exercise, and the relationships between PETCO2 and MCAv kinetics during exercise.

The effects of spinal stabilization exercises on functional exercise capacity in individuals with transtibial amputation: A randomized trial.

Optimization of mobility activities with spinal stabilization exercises and reducing spinal loads in individuals with transtibial amputation are recommended by researchers; however, the effect of spinal stabilization exercises on functional exercise capacity has not been investigated. This study aims to investigate the effect of spinal stabilisation exercises on functional exercise capacity in individuals with transtibial amputation. Randomized controlled trial with concealed allocation, assessor blinding. Eighteen individuals with transtibial amputation were included. Conventional physiotherapy program was applied to individuals in control group, and spinal stabilization exercise training was applied to individuals in intervention group together with conventional physiotherapy program for 8 weeks. The primary outcome was maximal oxygen uptake during 6-Minute Stepper Test. The secondary outcomes were maximal energy expenditure, step count and fatigue during 6-Minute Stepper Test, perceived mobility level with prosthesis, and stabilization strength of deep spinal muscles. In the within-group comparisons, the change in the functional exercise capacity, step count, and stabilization strength of deep spinal muscles were found to be statistically significant in both groups. In the between-group comparison, the changes in the functional exercise capacity, perceived mobility level, and stabilization strength of deep spinal muscles were found to be significant in favor of the group in which spinal stabilization exercises were applied. Along with improvement in proximal control of movement, improvements were observed in some parameters that are indicative of physical capacity. Considering the described developments, exercise programs focused on spinal stabilization in individuals with amputation are becoming a serious alternative in clinical practice.

Childhood Physical Fitness as a Predictor of Cognition and Mental Health in Adolescence: The PANIC Study.

Cognitive and mental health problems are highly prevalent in adolescence. While higher levels of physical fitness may mitigate these problems, there is a lack of long-term follow-up studies on the associations of physical fitness from childhood with cognition and mental health in adolescence. We investigated the associations of physical fitness from childhood to adolescence over an 8-year follow-up with cognition and mental health in adolescence. The participants were 241 adolescents (112 girls), who were 6-9years at baseline and 15-17years at 8-year follow-up. Average and change scores for cardiorespiratory fitness (maximal power output [Wmax]; peak oxygen uptake [VO2peak]), motor fitness (10 × 5-m shuttle run), and muscular fitness (standing long jump; hand grip strength) were calculated. Global cognition score was computed from six individual cognitive tasks, and perceived stress and depressive symptoms were assessed at the 8-year follow-up. The data were analysed using linear regression models adjusted for age, sex, and parental education. Average motor fitness was positively associated with global cognition score (standardised regression coefficient [β] - 0.164, 95% confidence interval [CI] - 0.318 to - 0.010) and inversely with perceived stress (β = 0.182, 95% CI 0.032-0.333) and depressive symptoms (β = 0.181, 95% CI 0.028-0.333). Average cardiorespiratory fitness was inversely associated with perceived stress (Wmax: β = - 0.166, 95% CI - 0.296 to - 0.036; VO2peak: β = - 0.149, 95% CI - 0.295 to - 0.002) and depressive symptoms (Wmax: β = - 0.276, 95% CI - 0.405 to - 0.147; VO2peak: β = - 0.247, 95% CI - 0.393 to - 0.102). A larger increase in cardiorespiratory fitness was associated with lower perceived stress (Wmax: β = - 0.158, 95%CI - 0.312 to - 0.003; VO2peak: β = - 0.220, 95%CI - 0.395 to - 0.044) and depressive symptoms (Wmax: β = - 0.216, 95% CI - 0.371 to - 0.061; VO2peak: β = - 0.257, 95%CI - 0.433 to - 0.080). Higher levels of motor fitness in childhood and adolescence were associated with better cognition in adolescence. Higher levels of and larger increases in cardiorespiratory fitness from childhood to adolescence were associated with better mental health in adolescence.

Quantitatively predicting effects of exercise on pharmacokinetics of drugs using a physiologically based pharmacokinetic model.

Exercise significantly alters human physiological functions, such as increasing cardiac output and muscle blood flow, decreasing glomerular filtration rate (GFR) and liver blood flow, thereby, altering absorption, distribution, metabolism and excretion of drugs. In this study, we aimed to establish a database of human physiological parameters during exercise and to construct equations for the relationship between changes in each physiological parameter and exercise intensity, including cardiac output, organ blood flow (e.g. muscle blood flow and kidney blood flow), oxygen uptake, plasma pH and GFR, etc. The polynomial equation was used for illustrating the relationship between the physiological parameters (P) and heart rate (HR), which served as an index of exercise intensity. Pharmacokinetics of midazolam, quinidine, digoxin and lidocaine during exercise were predicted by a whole body physiologically based pharmacokinetic (WB-PBPK) model and the developed database of physiological parameters following administration to 100 virtual subjects. The WB-PBPK model simulation results showed that most of the observed plasma drug concentrations fell within 5th-95th percentiles of the simulations, and the estimated peak concentrations and area under the curve of drugs were also within 0.5-2.0 folds of observations. Sensitivity analysis showed that exercise intensity, exercise duration, medication time and alterations in physiological parameters significantly affected drug pharmacokinetics, and the net effect depending on drug characteristics and exercise conditions. In conclusion, pharmacokinetics of drugs during exercise could be quantitatively predicted using the developed WB-PBPK model and database of physiological parameters. Significance Statement This study simulated real-time changes of human physiological parameters during exercise in the WB-PBPK model and comprehensively investigated pharmacokinetic changes during exercise following oral and intravenous administration. Furthermore, the factors affecting pharmacokinetics during exercise were also revealed.

Gut Dysbiosis in Patients With Fontan Circulation.

The process underlying Fontan pathophysiology is multifactorial and may include gut dysbiosis (GD). We investigated the presence of GD and elucidated its correlation with Fontan pathophysiology. Gut microbiomes of 155 consecutive patients with Fontan pathophysiology and 44 healthy individuals were analyzed using 16S rRNA sequencing of bacterial DNA extracted from fecal samples. GD was evaluated on the basis of α and ß diversities of the gut microbiome and was compared with natural log-transformed C-reactive protein, hemodynamics, von Willebrand factor antigen (a bacterial translocation marker), Mac-2 binding protein glycosylation isomer (a liver fibrosis indicator), peak oxygen uptake, and heart failure hospitalization. Patients with Fontan exhibited GD in terms of α and ß diversities as compared with controls (P<0.01). Reduced α diversity was associated with a failed hemodynamic phenotype, hypoxia, high natural log-transformed C-reactive protein levels, and elevated von Willebrand factor antigen and Mac-2 binding protein glycosylation isomer levels (P<0.05-0.01). In addition to elevated von Willebrand factor antigen and hypoxia, decreased α diversity was independently correlated with a high natural log-transformed C-reactive protein level (P<0.05), which was associated with liver imaging abnormalities and a heightened risk of heart failure hospitalization (P<0.01 for both). Patients with Fontan pathophysiology exhibited GD compared with healthy individuals, and GD was linked to failed hemodynamics and systemic inflammation with a poor prognosis. Therefore, GD may play a pivotal role in a failing Fontan status, including Fontan-associated liver disease, through GD-associated systemic inflammation.

E-Selectin and Asymmetric Dimethylarginine Levels in Adult Cyanotic Congenital Heart Disease: Their Relation to Biochemical Parameters, Vascular Function, and Clinical Status.

Background and Aim: Patients with cyanosis secondary to congenital heart disease (CHD) are characterized by erythrocytosis and increased blood viscosity, which contribute to endothelial dysfunction, increased arterial stiffness, and impaired vascular function, which may affect the final clinical presentation. Asymmetric dimethylarginine (ADMA) and e-selectin (e-sel) are valuable biomarkers for endothelial and vascular dysfunction. Their concentration levels in blood serum have the potential to be an accessible tool that reflects the severity of the disease. We aimed to assess e-sel and ADMA levels and their relationship with the clinical status and endothelial and vascular function. Methods: A cross-sectional study, including 36 adult CHD cyanotic patients [(17 males) (42.3 ± 16.3 years)] with an arterial blood oxygen saturation less than 92% and 20 healthy controls [(10 males) (38.2 ± 8.5 years)], was performed. All the patients underwent a clinical examination, blood testing, and cardiopulmonary tests. Their endothelial function was assessed using the intima media thickness and flow-mediated dilatation. Vascular function, using applanation tonometry methods, was determined using the aortic systolic pressure, aortic pulse pressure, augmentation pressure, augmentation index, pulse pressure amplification, and pulse wave velocity. Results: The concentrations of e-sel and ADMA were significantly higher in the patients with CHD. The E-sel levels correlated positively with red blood cells, hemoglobin concentration, hematocrit, and augmentation pressure; they correlated negatively with blood oxygen saturation, the forced expiratory one-second volume, forced vital capacity, and oxygen uptake. The ADMA levels were found to correlate only with age. Conclusions: The E-sel level, unlike ADMA concentration, reflects the severity of erythrocytosis and hypoxia and, thus, the physical status of patients with cyanotic CHD.

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.

Human–exoskeleton interaction portrait

Human–robot physical interaction contains crucial information for optimizing user experience, enhancing robot performance, and objectively assessing user adaptation. This study introduces a new method to evaluate human–robot interaction and co-adaptation in lower limb exoskeletons by analyzing muscle activity and interaction torque as a two-dimensional random variable. We introduce the interaction portrait (IP), which visualizes this variable’s distribution in polar coordinates. We applied IP to compare a recently developed hybrid torque controller (HTC) based on kinematic state feedback and a novel adaptive model-based torque controller (AMTC) with online learning, proposed herein, against a time-based controller (TBC) during treadmill walking at varying speeds. Compared to TBC, both HTC and AMTC significantly lower users’ normalized oxygen uptake, suggesting enhanced user-exoskeleton coordination. IP analysis reveals that this improvement stems from two distinct co-adaptation strategies, unidentifiable by traditional muscle activity or interaction torque analyses alone. HTC encourages users to yield control to the exoskeleton, decreasing overall muscular effort but increasing interaction torque, as the exoskeleton compensates for user dynamics. Conversely, AMTC promotes user engagement through increased muscular effort and reduces interaction torques, aligning it more closely with rehabilitation and gait training applications. IP phase evolution provides insight into each user’s interaction strategy formation, showcasing IP analysis’s potential in comparing and designing novel controllers to optimize human–robot interaction in wearable robots.

Aficamten and Cardiopulmonary Exercise Test Performance: A Substudy of the SEQUOIA-HCM Randomized Clinical Trial.

Impaired exercise capacity is a cardinal manifestation of obstructive hypertrophic cardiomyopathy (HCM). The Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic Obstructive HCM (SEQUOIA-HCM) is a pivotal study characterizing the treatment effect of aficamten, a next-in-class cardiac myosin inhibitor, on a comprehensive set of exercise performance and clinical measures. To evaluate the effect of aficamten on exercise performance using cardiopulmonary exercise testing with a novel integrated measure of maximal and submaximal exercise performance and evaluate other exercise measures and clinical correlates. This was a prespecified analysis from SEQUOIA-HCM, a double-blind, placebo-controlled, randomized clinical trial. Patients were recruited from 101 sites in 14 countries (North America, Europe, Israel, and China). Individuals with symptomatic obstructive HCM with objective exertional intolerance (peak oxygen uptake [pVO2] ≤90% predicted) were included in the analysis. Data were analyzed from January to March 2024. Randomized 1:1 to aficamten (5-20 mg daily) or matching placebo for 24 weeks. The primary outcome was change from baseline to week 24 in integrated exercise performance, defined as the 2-component z score of pVO2 and ventilatory efficiency throughout exercise (minute ventilation [VE]/carbon dioxide output [VCO2] slope). Response rates for achieving clinically meaningful thresholds for change in pVO2 and correlations with clinical measures of treatment effect (health status, echocardiographic/cardiac biomarkers) were also assessed. Among 282 randomized patients (mean [SD] age, 59.1 [12.9] years; 115 female [40.8%], 167 male [59.2%]), 263 (93.3%) had core laboratory-validated exercise testing at baseline and week 24. Integrated composite exercise performance improved in the aficamten group (mean [SD] z score, 0.17 [0.51]) from baseline to week 24, whereas the placebo group deteriorated (mean [SD] z score, -0.19 [0.45]), yielding a placebo-corrected improvement of 0.35 (95% CI, 0.25-0.46; P <.001). Further, aficamten treatment demonstrated significant improvements in total workload, circulatory power, exercise duration, heart rate reserve, peak heart rate, ventilatory efficiency, ventilatory power, and anaerobic threshold (all P <.001). In the aficamten group, large improvements (≥3.0 mL/kg per minute) in pVO2 were more common than large reductions (32% and 2%, respectively) compared with placebo (16% and 11%, respectively). Improvements in both components of the primary outcome, pVO2 and VE/VCO2 slope throughout exercise, were significantly correlated with improvements in symptom burden and hemodynamics (all P <.05). This prespecified analysis of the SEQUOIA-HCM randomized clinical trial found that aficamten treatment improved a broad range of exercise performance measures. These findings offer valuable insight into the therapeutic effects of aficamten. ClinicalTrials.gov Identifier: NCT05186818.

Observational study of the effects of maximal oxygen uptake on cognitive function and performance during prolonged military exercise

IntroductionMilitary operations place high demands on many cognitive functions, and stressful events characterise the military work environment. The study aimed to examine the relationship between cardiorespiratory fitness, stress response, cognitive...

The effects of percutaneous branch pulmonary artery interventions in biventricular congenital heart disease: study protocol for a randomized controlled Dutch multicenter interventional trial

BackgroundBranch pulmonary artery (PA) stenosis is one of the most common indications for percutaneous interventions in patients with transposition of the great arteries (TGA), tetralogy of Fallot (ToF), and truncus arteriosus (TA). However, the effects of percutaneous branch PA interventions on exercise capacity remains largely unknown. In addition, there is no consensus about the optimal timing of the intervention for asymptomatic patients according to international guidelines. This trial aims to identify the effects of percutaneous interventions for branch PA stenosis on exercise capacity in patients with TGA, ToF, and TA. In addition, it aims to assess the effects on RV function and to define early markers for RV adaptation and RV dysfunction to improve timing of these interventions.MethodsThis is a randomized multicenter interventional trial. TGA, ToF, and TA patients ≥ 8 years with a class IIa indication for percutaneous branch PA intervention according to international guidelines are eligible to participate. Patients will be randomized into the intervention group or the control group (conservative management for 6 months). All patients will undergo transthoracic echocardiography, cardiac magnetic resonance (CMR) imaging, and cardiopulmonary exercise testing at baseline, 6 months, and 2–4 years follow-up. Quality of life (QoL) questionnaires will be obtained at baseline, 2 weeks post intervention or a similar range for the control group, and 6 months follow-up. The primary outcome is exercise capacity expressed as maximum oxygen uptake (peak VO2 as percentage of predicted). A total of 56 patients (intervention group n = 28, control group n = 28) is required to demonstrate a 14% increase in maximum oxygen uptake (peak VO2 as percentage of predicted) in the interventional group compared to the control group (power 80%, overall type 1 error controlled at 5%). Secondary outcomes include various parameters for RV systolic function, RV functionality, RV remodeling, procedural success, complications, lung perfusion, and QoL.DiscussionThis trial will investigate the effects of percutaneous branch PA interventions on exercise capacity in patients with TGA, ToF, and TA and will identify early markers for RV adaptation and RV dysfunction to improve timing of the interventions.Trial registrationClinicalTrials.gov NCT05809310. Registered on March 15, 2023.