Symptom-limited Exercise Test Research Articles

Prediction of central Augmentation Index in healthy adults.

Central Augmentation Index (AIx) is a surrogate marker of large artery stiffness that may provide valuable insight to cardiovascular health. The aim of this study was to evaluate the relationship between AIx and components of physical fitness. One hundred eighty-five healthy men and women (aged 20-79 years) underwent non-invasive assessment of arterial wave reflection to determine AIx, which was corrected to a heart rate of 75 beats per minute (AI×75). Body composition was evaluated using dual energy X-ray absorptiometry (DXA) and aerobic capacity (VO<inf>2max</inf>) was derived from expired gas analysis during a symptom limited exercise test on a treadmill. A multiple linear regression revealed age and VO<inf>2max</inf> as significant predictors of AI×75 [AI×75=32.055 + (0.252×age) - (0.722×VO<inf>2max</inf>)]. Upon removal of VO<inf>2max</inf> from regression analysis, resting heart rate (RHR) and % body fat (BF%) were revealed to be significant predictors of AI×75: AI×75=-61.316 + (0.481×age) + (0.565×BF%) + (0.56×RHR). Our findings demonstrate that central Augmentation Index can be reliably predicted in healthy adults who undergo a maximal exercise or body composition assessment. These prediction equations may be applied in non-medical settings to assist in creating comprehensive health and fitness profiles for healthy clientele.

Early detection of cardiac dysfunction using shear wave imaging: insights into reduced cardiorespiratory fitness in childhood cancer survivors

Abstract Background Diastolic dysfunction is thought to be the earliest cardiotoxic sequel after cancer therapy among childhood cancer survivors. Despite many survivors do exhibit reduced cardiorespiratory fitness (CRF) potentially due to cardiotoxicity, current echocardiographic parameters fail to detect hidden diastolic dysfunction early after therapy (1). High frame rate (HFR) shear wave imaging (SWI) is a novel tool that could give insights about myocardial stiffness, which is a key determining factor of diastolic function. Purpose We aimed at testing the ability of SWI to detect early alterations in myocardial stiffness among childhood cancer survivors and its relation with the reduced CRF. Methods Fifty childhood cancer survivors (mean 20 ±3 years) who received chemo-and/or- radiotherapy (mean time after treatment: 4 ±3 years) and thirty-two matched healthy volunteers (HV) were recruited. Conventional as well as HFR echocardiographic images (ca. 1200 frames/second) were acquired at rest using a modified commercial echocardiography machine. All participants underwent an incremental, symptom-limited cardiopulmonary exercise test on a treadmill measuring peak oxygen consumption (VO2 peak). HFR data were analysed offline. An anatomical M mode was drawn along the ventricular septum, and tissue Doppler acceleration maps were extracted to measure SW velocities after mitral valve closure (MVC) (Figure 1). Results Among cancer survivors, left ventricular ejection fraction (LVEF) and global longitudinal strain were significantly lower compared to HV (56 % ±4 vs 59 % ±4, and 17.6 % ±1.6 vs 19.1 % ±1.2, respectively; p &amp;lt;0.001). However, both LVEF and GLS were within the normal range and none of them correlated with the peak VO2 (Figure 2A&amp;B). None of the echocardiographic diastolic parameters (e.g. mitral E, E/e’, left atrial volume or TR jet velocity) showed significant difference between both groups (P &amp;gt; 0.05). The mean SW velocities were significantly higher in cancer survivors compared to HV (3.9 ±0.6 m/s vs 3.2 ±0.3 m/s respectively; p &amp;lt;0.001). Interestingly, SW velocities among cancer survivors showed moderate significant negative correlation with the VO2 peak (r= -0.590, p &amp;lt;0.001) indicating increasing myocardial stiffness as the cardiorespiratory fitness declined (Figure 2C). Conclusions Our data indicate that myocardial stiffness in cancer survivors is significantly increased. We hypothesize that this increased stiffness may at least in part explain the significantly reduced cardiorespiratory fitness in this population. Echocardiographic shear wave elastography appears as a promising non-invasive tool for early detection of diastolic dysfunction in follow-up of childhood cancer survivors.Figure 1.Figure 2.

Impact of cardiac rehabilitation exercise frequency on exercise capacity in patients with coronary artery disease: a retrospective study

ABSTRACT Cardiac rehabilitation (CR) significantly improves cardiovascular outcomes in patients with coronary artery disease (CAD). International guidelines vary in the minimum recommended frequency of supervised exercise from 1 to 3 sessions per week. This is the first study in the Middle East and North African regions assessing the impact of 2 versus 3 days/week of supervised exercise on peak exercise capacity in patients with CAD. Single-center retrospective cohort study involving 362 patients enrolled in the only CR center in the State of Qatar. Only high-quality data was included by strict evaluation of compliance to the exercise intervention. Fifty patients who underwent a symptom-limited exercise test before and after CR were included (31 patients on 2 days/week, 19 on 3 days/week). No significant differences were observed in baseline characteristics between groups. Exercise intervention differed significantly between groups in exercise training frequency (2 days/week: 1.97 ± 0.2 vs. 3 days/week: 2.7 ± 0.3; p < 0.00). Peak exercise capacity as peak metabolic equivalents of task (MET) significantly increased in both groups (2 days/week: Pre 8.3 ± 2.4 vs. Post 9.4 ± 2.9, p-value 0.00; 3 days/week: Pre 7.4 ± 1.6 vs. Post 8.4 ± 2.0, p-value 0.00). No significant difference was observed between groups for change in Peak Exercise Capacity (2 days/week 1.1 ± 1.1 vs. 3 days/week 1.0 ± 0.9, p = 0.87). When the total number of exercise sessions is equal, supervised exercise frequencies of 2 and 3 days/week may significantly and equally improve peak exercise capacity in patients with CAD.

Effect of aortic valve replacement on myocardial perfusion and exercise capacity in patients with severe aortic stenosis

Aortic valve replacement (AVR) leads to reverse cardiac remodeling in patients with aortic stenosis (AS). The aim of this secondary pooled analysis was to assess the degree and determinants of changes in myocardial perfusion post AVR, and its link with exercise capacity, in patients with severe AS. A total of 68 patients underwent same-day echocardiography and cardiac magnetic resonance imaging with adenosine stress pre and 6–12 months post-AVR. Of these, 50 had matched perfusion data available (age 67 ± 8 years, 86% male, aortic valve peak velocity 4.38 ± 0.63 m/s, aortic valve area index 0.45 ± 0.13cm2/m2). A subgroup of 34 patients underwent a symptom-limited cardiopulmonary exercise test (CPET) to assess maximal exercise capacity (peak VO2). Baseline and post-AVR parameters were compared and linear regression was used to determine associations between baseline variables and change in myocardial perfusion and exercise capacity. Following AVR, stress myocardial blood flow (MBF) increased from 1.56 ± 0.52 mL/min/g to 1.80 ± 0.62 mL/min/g (p < 0.001), with a corresponding 15% increase in myocardial perfusion reserve (MPR) (2.04 ± 0.57 to 2.34 ± 0.68; p = 0.004). Increasing severity of AS, presence of late gadolinium enhancement, lower baseline stress MBF and MPR were associated with a greater improvement in MPR post-AVR. On multivariable analysis low baseline MPR was independently associated with increased MPR post-AVR. There was no significant change in peak VO2 post-AVR, but a significant increase in exercise duration. Change in MPR was associated with change in peak VO2 post AVR (r = 0.346, p = 0.045). Those with the most impaired stress MBF and MPR at baseline demonstrate the greatest improvements in these parameters following AVR and the magnitude of change in MPR correlated with improvement in peak VO2, the gold standard measure of aerobic exercise capacity.

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.

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.

Effect of Supplemental Oxygen on Physiological Responses to Exercise in Fibrotic Interstitial Lung Disease.

We studied the effect of O2 supplementation on physiological response to exercise in patients with moderate to severe interstitial lung disease (ILD). 13 patients (age 66 ± 10 yrs., 7 males) with ILD (TLC 71 ± 22% predicted, carbon monoxide diffusion capacity (DLCO) 44 ± 16% predicted) and 13 healthy individuals (age 50 ± 17 yrs., 7 males) were tested. ILD patients performed symptom-limited cardiopulmonary exercise tests and constant work-rate tests (CWRTs) at 80% of the work-rate (WR) at the gas exchange threshold (GET). Tests breathing room air (RA, 21% O2) were compared to tests performed breathing 30% O2. Oxygen-uptake (V̇O2) kinetics were calculated from the CWRT results. In the ILD group, peak WR, peak V̇O2 and V̇O2 at the GET improved significantly when breathing 30% O2 compared to RA (mean ± SD 66 ± 23 vs 75 ± 26 watts, 15 ± 2 vs 17 ± 4 ml/kg/min and 854 ± 232 vs 932 ± 245 ml/min; p = 0.004, p = 0.001 and p = 0.01, respectively). O2 saturation (SPO2%) at peak exercise was higher with 30% O2 (97 ± 4% vs 88 ± 9%, p = 0.002). The time constant (tau) of V̇O2 kinetics was faster in ILD patients while breathing 30% O2 (41 ± 10 sec) compared to RA (52 ± 14 sec, p = 0.003). There was a negative linear relation between tau and SPO2% with RA (r = -0.76, p = 0.006) and while breathing 30% O2 (r = -0.68, p = 0.02). Using a clinically applicable level of O2 supplementation (30%) improved maximal, aerobic exercise capacity and V̇O2 kinetics in ILD patients, likely due to increased blood O2 content subsequently increasing the O2 delivery to the working muscles.

Remission from depression is associated with improved quality of life and preserved exercise capacity in adults with congenital heart disease.

Improved long-term survival has widened the treatment goals for adults with congenital heart disease (ACHD) by addressing parameters that impact mental well-being and exercise capacity. Depression, a frequent co-morbidity in ACHD, is linked to both. Whether successful treatment of depression also affects cardiac parameters is a matter of debate. This prospective, cross-sectional, longitudinal study included N = 150 ACHD (mean age 35.2 ± 11.3 years, 57% male) at baseline (t0) and N = 114 at follow-up (mean follow-up: 4.8 ± 0.6 years; t1). Patients were interviewed using a structured clinical interview, and severity of depression was assessed using the Montgomery-Asperg Depression Scale (MADRS). Additional testing was performed using self-rating questionnaires concerning depression, anxiety and quality of life (QoL). Exercise capacity (VO2max) was assessed by symptom limited exercise testing. Of N = 33 patients diagnosed with depression at t0, N = 18 patients remitted and N = 15 were non-remitters. Remitters displayed significantly decreased anxiety (P = 0.013), improved global QoL (P = 0.002), and preserved VO2max (P = 0.958) at t1 compared to t0. This was associated with favourable health behaviour at t1 and stable body-mass-index. Contrarily, non-remitters reported further increased anxiety (P = 0.021) and no significant improvement in QoL (P = 0.405). VO2max declined significantly (P = 0.006) and body-mass-index increased (P = 0.004). Never-depressed patients showed no significant changes in anxiety (P = 0.415) or QoL (P = 0.211). VO2max decreased significantly (P < 0.001). In ACHD, remission from depression is associated with better physical functioning, mental health, and QoL. The assessment and treatment of depression in ACHD emerges as an important clinical goal that should be included in a comprehensive multimodal treatment plan.

Exercise pulmonary hypertension in patients with systemic sclerosis based on updated guidelines

Recent European guidelines have introduced the concept of exercise pulmonary hypertension (ex-PH). However, the clinical characteristics of ex-PH in systemic sclerosis (SSc) remains unknown. We aimed to investigate the characteristics of exercise pulmonary hypertension (ex-PH) in patients with systemic sclerosis (SSc), which are unknown. We retrospectively examined 77 patients with SSc who underwent symptom-limited exercise testing using a cycle ergometer with right heart catheterization at our hospital. Nineteen patients with postcapillary PH were excluded. Fifty-eight patients (median age, 63 years; 55 women) were divided into the overt-PH (n = 18, mean pulmonary arterial pressure [PAP] > 20 mmHg and pulmonary vascular resistance > 2 Wood units at rest), ex-PH (n = 19, mean PAP/cardiac output slope > 3), and non-PH (n = 21) groups. Exercise tolerance and echocardiography results were compared among the groups. Peak oxygen consumption was high in the non-PH group, intermediate in the ex-PH group, and low in the overt-PH group (14.5 vs. 13.0 vs. 12.5 mL/kg/min, p = 0.043), and the minute ventilation/peak carbon dioxide production slope was also intermediate in the ex-PH group (32.2 vs. 32.4 vs. 43.0, p = 0.003). The tricuspid annular plane systolic excursion/systolic PAP ratio decreased from non-PH to ex-PH to overt-PH (0.73 vs. 0.69 vs. 0.55 mm/mmHg, p = 0.018). In patients with SSc, exercise PH may represent an intermediate condition between not having PH and overt PH, according to the new guidelines.

Effect of exercise based cardiac rehabilitation on LV systolic function &amp; exercise stress parameters in patients with ischemic cardiomyopathy post anterior STEMI

Background: Cardiovascular diseases are a leading cause of death worldwide. Multiple meta-analysis have demonstrated the benefit of exercise based cardiac rehabilitation. However, the effect of exercise training on left ventricular (LV) systolic function in patients with ischemic cardiomyopathy has been controversial in the literature. Objective: To study the effect of exercise-based cardiac rehabilitation (EBCR) on left ventricular (LV) systolic function and exercise stress parameters (METs achieved, HR recovery and HR reserve) in post anterior STEMI patients with ischemic cardiomyopathy (EF≤45%). Patients and methods: The study included 50 patients with ischemic cardiomyopathy (Post anterior STEMI successfully treated by 1ry PCI) referred for cardiac rehabilitation unit at Ain Shams University Hospitals. The patients were subjected to 3 months of formal exercise based cardiac rehabilitation. Before the CR program, they were subjected to a symptom-limited exercise test (modified Bruce protocol) to exclude any remaining ischemia and calculate enrolment HR reserve, baseline heart rate recovery in 1st minute and 2nd minute (HRR1 and HRR2). Another symptom-limited exercise test was done post CR program to assess the forementioned exercise parameters after completion of the program. Echocardiography was done at baseline and after completion of the CR program for assessment of LV systolic function by ejection fraction (assessed by 2D Simpson’s method) and peak longitudinal strain of the left ventricle (measured using speckle tracking echocardiography). Results: Exercise-based cardiac rehabilitation was associated with significant improvement in LV systolic function as reflected by significant improvement in Global longitudinal strain (GLS) (P-value = 0.0001) in patients with ischemic heart failure. CR was also associated with improvement in the functional capacity as reflected by the improvement in METs as well as in the HRR and HR reserve (P-value = 0.0001). However, there was no significant change regarding EF before and after cardiac rehabilitation (P-value= 0.4582).

Changes in left atrial function following two regimens of combined exercise training in patients with ischemic cardiomyopathy: a pilot study.

Left atrial dysfunction has shown to play a prognostic role in patients with ischemic cardiomyopathy (ICM) and is becoming a therapeutic target for pharmacological and non-pharmacological interventions. The effects of exercise training on the atrial function in patients with ICM have been poorly investigated. In the present study, we assessed the effects of a 12-week combined training (CT) program on the left atrial function in patients with ICM. We enlisted a total of 45 clinically stable patients and randomly assigned them to one of the following three groups: 15 to a supervised CT with low-frequency sessions (twice per week) (CTLF); 15 to a supervised CT with high-frequency sessions (thrice per week) (CTHF); and 15 to a control group following contemporary preventive exercise guidelines at home. At baseline and 12 weeks, all patients underwent a symptom-limited exercise test and echocardiography. The training included aerobic continuous exercise and resistance exercise. The analysis of variance (ANOVA) was used to compare within- and inter-group changes. At 12 weeks, the CTLF and CTHF groups showed a similar increase in the duration of the ergometric test compared with the control (ANOVA p < 0.001). The peak atrial longitudinal strain significantly increased in the CTHF group, while it was unchanged in the CTLF and control groups (ANOVA p = 0.003). The peak atrial contraction strain presented a significant improvement in the CTHF group compared with the CTLF and control groups. The left ventricular global longitudinal strain significantly increased in both the CTHF and the CTLF groups compared with the control group (ANOVA p = 0.017). The systolic blood pressure decreased in the CTHF and CTLF groups, while it was unchanged in the control group. There were no side effects causing the discontinuation of the training. We demonstrated that a CT program effectively improved atrial function in patients with ICM in a dose-effect manner. This result can help with programming exercise training in this population.

Neurophysiological Mechanisms of Exertional Dyspnea in Patient’s Post-Pulmonary Embolism: The Effect of Inhaled Nitric Oxide

Following pulmonary embolism (PE), up to a third of patients develop persistent activity-related dyspnea, even in those without chronic thromboembolic pulmonary hypertension (CTEPH). It has been shown that heightened exertional dyspnea in patients post-PE (without CTEPH) is linked to greater inspiratory neural drive (IND) during exercise. The heightened IND, in turn, is secondary to increased physiological dead space (VD/VT) and greater ventilatory requirements for CO2 (VE/VCO2). The reasons for the increased VD/VT and VE/VCO2 are unclear, although pulmonary microvascular dysfunction and the corresponding capillary hypoperfusion is a potential mechanism. Thus, the current study tested the hypothesis that inhaled nitric oxide (iNO), a selective pulmonary vasodilator, would lower exertional IND and dyspnea, and improve exercise endurance in patients post-PE. In turn, the reduced IND and dyspnea would be linked to reductions in VD/VT and VE/VCO2. In this randomized, double-blind, placebo-controlled crossover study, 14 clinically stable patients with chronic activity related dyspnea post-PE (without evidence of PH) completed symptom-limited constant work rate cycle exercise tests while breathing iNO (40 ppm) or placebo (21% O2), on separate days. IND (assessed by diaphragm electromyography), VD/VT and VE/VCO2 (expired and arterialized blood gas), and dyspnea intensity (modified Borg 0-10 scale) were compared throughout exercise. At rest, right-ventricular systolic pressure (RVSP) with placebo or iNO was estimated by echocardiography. At the highest individual standardized exercise time (5.8±2.0 min), iNO decreased VD/VT (0.22±0.09 vs 0.27±0.07, p=0.02), VE/VCO2 (33.0±3.5 vs 34.5±3.8 units, p=0.04), IND (48.8±10.3 vs 57.6±11.8 %, p=0.02) and dyspnea intensity (3.0±1.0 vs 4.0±1.4 Borg units, p&lt;0.01), compared with placebo. Throughout exercise, estimated alveolar ventilation, O2 saturation, O2 pulse and operating lung volumes were unaffected by iNO (all p&gt;0.05). iNO increased exercise endurance time (8.1±3.5 vs 6.5±2.3 min, p&lt;0.001), compared with placebo. iNO reduced resting RVSP by 2.5±2.0 mmHg. iNO decreased exertional IND and dyspnea, and improved exercise endurance in patients with post-PE. The reduced IND, in turn, may be linked to decreased VD/VT and VE/VCO2, reflecting improved ventilation/perfusion. These data provide preliminary evidence of a partially reversible pulmonary vasculopathy, that contributes to dyspnea and exercise limitation in symptomatic patients post-PE. Queen’s University Spear Endowment Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Exercise limitation in hypertrophic cardiomyopathy: combined stress echocardiography and cardiopulmonary exercise test.

The study aims to investigate exercise-limiting factors in hypertrophic cardiomyopathy (HCM) using combined stress echocardiography and cardiopulmonary exercise test. A symptom-limited ramp bicycle exercise test was performed in the semi-supine position on a tilting dedicated ergometer. Echocardiographic images were obtained concurrently with gas exchange measurements along predefined stages of exercise. Oxygen extraction was calculated using the Fick equation at each activity level. Thirty-six HCM patients (mean age 67±6years, 72% men, 18 obstructive HCM) were compared with age and sex-matched 29 controls. At rest, compared with controls, E/E' ratio (6.26±2.3 vs. 14±2.5, P<0.001) and systolic pulmonary artery pressures (SPAP) (22.6±3.4 vs. 34±6.2mmHg, P=0.023) were increased. Along with the stages of exercise (unloaded; anaerobic threshold; peak), diastolic function worsened (E/e' 8.9±2.6 vs. 13.8±3.6 P=0.011; 9.4±2.3 vs. 18.6±3.3 P=0.001; 8.7±1.9 vs. 21.5±4, P<0.001), SPAP increased (23±2.7 vs. 33±4.4, P=0.013; 26±3.2 vs. 40±2.9, P<0.001; 26±3.5 vs. 45±7mmHg, P<0.001), and oxygen consumption (6.6±1.7 vs. 6.8±1.6, P=0.86; 18.1±2.2 vs. 14.6±1.5, P=0.008; 20.3±3 vs. 15.1±2.1mL/kg/min, P=0.01) was reduced. Oxygen pulse was blunted (6.3±1.8 vs. 6.2±1.9, P=0.79; 10±2.1 vs. 8.8±1.6, P=0.063; 12.2±2 vs. 8.2±2.3mL/beat, P=0.002) due to an insufficient increase in both stroke volume (92.3±17 vs. 77.3±14.5 P=0.021; 101±19.1 vs. 87.3±15.7 P=0.06; 96.5±12.2 vs. 83.6±16.1mL, P=0.034) and oxygen extraction (0.07±0.03 vs. 0.07±0.02, P=0.47; 0.13±0.02 vs. 0.10±0.03, P=0.013; 0.13±0.03 vs. 0.11±0.03, P=0.03). Diastolic dysfunction, elevated SPAP, and the presence of atrial fibrillation were associated with reduced exercise capacity. Both central and peripheral cardiovascular limitations are involved in exercise intolerance in HCM. Diastolic dysfunction seems to be the main driver for this limitation.

Novel wireless laser doppler flowmeter-based investigation of earlobe vascular dynamics in cardiopulmonary exercise testing.

[Purpose] A new wireless laser Doppler blood flowmeter has facilitated easier, more stable measurement of skin perfusion during exercise. However, earlobe blood flow during the cardiopulmonary exercise test remains unascertained. This study aimed to clarify the characteristics of earlobe blood flow during incremental exercise load in healthy individuals. [Participants and Methods] Among 25 healthy males (age 23.6 ± 2.5 years), cycle ergometer-based symptom-limited cardiopulmonary exercise test, after 4 minutes of rest, was conducted with a 4-minute 20W warm-up and a continuous 2W-increase in the work rate every 6 seconds; earlobe blood flow was measured using a wireless laser Doppler blood flowmeter. [Results] Compared with that at rest, earlobe blood flow increased significantly from 50% of exercise peak intensity to a maximum of 1.7 times, but decreased immediately after exercise. The earlobe blood flow %change did not significantly correlate with hemodynamic parameters and its inflection point 36.4% Loadpeak was significantly lower than the anaerobic metabolic threshold 58.1% Loadpeak. [Conclusion] In healthy participants, earlobe blood flow during cardiopulmonary exercise test increased gradually with low-intensity exercise from approximately 1.5 times the resting rate and approached the anaerobic metabolic threshold with a maximum of 1.7 times the resting earlobe blood flow, but decreased quickly after exercise.

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.

Does Smartphone Addiction Impair Maximal Exercise Capacity in Young Adults?

Purpose: Smartphone addiction may reduce the time allocated for physical activity participation. However, it is not known if there is a direct association between smartphone addiction and reduced exercise capacity. Our aim was to investigate whether smartphone addiction impairs maximal exercise capacity, as well as analyzing its influence on the perceived benefits of exercise and physical activity habits in young adults.&#x0D; Material and Method: Forty-six volunteers were evaluated by a symptom-limited incremental exercise test. Smartphone addiction of volunteers was evaluated using Smartphone Addiction Scale- Short Form. Physical activity participation and perceived benefits of physical activity participation were evaluated using International Physical Activity Questionnaire- Short Form and Exercise Benefits/Barriers Scale, respectively.&#x0D; Results: Prevalence of smartphone addiction was 65% in young adults. No significant association was detected between smartphone addiction and any of maximal exercise capacity metrics including test duration, maximum workload achieved in watts or maximum heart rate (p&gt;0.05). Smartphone addiction did not correlate to physical activity participation either (p&gt;0.05). Univariate linear regression revealed Exercise Benefits/Barriers Scale score was able to explain 41% of variance in exercise test duration and 37% of variance in maximal workload (p

Novel wireless laser doppler flowmeter-based investigation of earlobe vascular dynamics in cardiopulmonary exercise testing.

[Purpose] A new wireless laser Doppler blood flowmeter has facilitated easier, more stable measurement of skin perfusion during exercise. However, earlobe blood flow during the cardiopulmonary exercise test remains unascertained. This study aimed to clarify the characteristics of earlobe blood flow during incremental exercise load in healthy individuals. [Participants and Methods] Among 25 healthy males (age 23.6 ± 2.5 years), cycle ergometer-based symptom-limited cardiopulmonary exercise test, after 4 minutes of rest, was conducted with a 4-minute 20W warm-up and a continuous 2W-increase in the work rate every 6 seconds; earlobe blood flow was measured using a wireless laser Doppler blood flowmeter. [Results] Compared with that at rest, earlobe blood flow increased significantly from 50% of exercise peak intensity to a maximum of 1.7 times, but decreased immediately after exercise. The earlobe blood flow %change did not significantly correlate with hemodynamic parameters and its inflection point 36.4% Loadpeak was significantly lower than the anaerobic metabolic threshold 58.1% Loadpeak. [Conclusion] In healthy participants, earlobe blood flow during cardiopulmonary exercise test increased gradually with low-intensity exercise from approximately 1.5 times the resting rate and approached the anaerobic metabolic threshold with a maximum of 1.7 times the resting earlobe blood flow, but decreased quickly after exercise.

FEASIBILITY OF AEROBIC FITNESS TESTING IN AMNESTIC MILD COGNITIVE IMPAIRMENT FROM THE ACT TRIAL

Abstract Aerobic fitness has been postulated as a physiological mechanism of action for aerobic exercise to modify Alzheimer’s disease, but it has not been adequately studied in older adults with (MCI). The purpose of this study is to evaluate the feasibility of a gold-standard, laboratory-based, symptom-limited cycle-ergometer exercise testing (GXT) in older adults with amnestic mild cognitive impairment (aMCI) to assess peak oxygen consumption (VO2max [ml/kg/min]) using baseline data from the ACT Trial. The test was categorized as a submax, near-max, and max test based on if 0, 1, and ≥2 of the American College of Sports Medicine criteria was met: &amp;gt;90% of age-predicted maximum heart rate, plateau in VO2Peak, respiratory exchange ratio &amp;gt;1.10, and rating of perceived exertion &amp;gt;17. VO2max was predicted as 3.5*maximal metabolic equivalents (METs). Among 146 enrolled participants (73.8±5.7 years old with 16.9±2.9 years of education, 51.4% men, and 91.8% Caucasian), 145 completed GXTs. Sixteen GXTs (11.0%) were submax (VO2Peak 13.5±4.4), 53 (36.6%) were near-max (VO2Peak 16.5±4.1), and 76 (52.4%) were max (VO2Peak 18.4±5.1). Predicted VO2max were 21.6±6.8, 28.7±26.3, and 30.0±20.5 from submax, near-max, and max tests, respectively. Among max GXTs, VO2max was 19.5±4.9 in men (n=37) and 17.4±5.1 in women (n=39). In conclusion, GXTs was feasible for ~52% of the participants. METs-based prediction overly inflates VO2max estimates, in comparison to VO2max obtained from max GXTs. VO2max levels are substantially lower in older adults with aMCI than peers (23.1±6.3 in men and 21.1±3.4 in women), suggesting aerobic exercise as an important intervention for this population.

Cardiorespiratory Fitness in Patients With Early-Stage Breast Cancer and Radiation Therapy-Related Fatigue: A Prospective Pilot Study

Purpose/ObjectivesFatigue is among the most common but one of the most poorly understood radiotherapy-associated toxicities. This prospective study sought to investigate whether cardiorespiratory fitness, an integrative measure of whole-body cardiopulmonary function, is associated with patient-reported fatigue among women with early-stage breast cancer undergoing radiotherapy. Materials/MethodsPatients with stage Tis-T2N0M0 breast cancer and an ECOG performance status of 0-1 who were undergoing breast radiotherapy performed a symptom-limited cardiopulmonary exercise test (CPET) on a motorized treadmill to assess cardiorespiratory fitness (VO2peak). Fatigue was assessed by the FACIT Fatigue Scale. Both assessments were performed during or immediately after radiotherapy completion. All patients were treated with an opposed tangent technique to a dose of 4240 cGy in 16 fractions with or without a lumpectomy bed boost. Patients receiving cytotoxic chemotherapy were excluded. Pearson's correlation coefficients and univariate linear regression were used to assess associations between VO2peak, fatigue, and patient characteristics. ResultsTwenty-eight patients (median age 52 years, range 31-71) completed both CPET and FACIT assessments. Median VO2peak was 25.1 mL O2.kg−1.min−1 (range 16.7-41.7). The majority of subjects (78.6%) displayed a VO2peak less than their age-predicted VO2peak. Both age and BMI were significantly associated with VO2peak levels. Median fatigue score was 41.5 (range 10-52), with lower values indicating more fatigue. VO2peak was not associated with FACIT score (p=0.20). ConclusionsOverall, VO2peak was not a significant predictor of radiotherapy-related fatigue. Most breast cancer patients had marked impairments in cardiorespiratory fitness as determined by VO2peak. Larger prospective studies are needed to further investigate this novel finding, and to evaluate the effects of interventions aimed at improving cardiorespiratory fitness and their ability to potentially prevent fatigue.

Medical Rehabilitation of Patients with Post-COVID-19 Syndrome-A Comparison of Aerobic Interval and Continuous Training.

Post-COVID-19 syndrome (PCS) is a multisystemic disorder marked by impaired physical performance as one lead symptom. Since it has been suggested that endurance training as part of medical rehabilitation may be effective in improving physical performance capacity in PCS, this study aimed to compare different modes of aerobic endurance training. A total of 110 PCS patients (49.3 ± 11.8 years; 38% women; time after infection = 260.2 ± 127.5 days) underwent detailed clinical screening including symptom-limited cardiopulmonary exercise testing at admission and after 4-6 weeks of inpatient medical rehabilitation. Questionnaires were used to assess disease perception. Patients performed controlled isocaloric cycle ergometer training (3-5 sessions/week; 18 min) as either continuous training (CT) at 50% of maximal workload or as interval training (IT; load = 60%, relief = 30%). Outcomes of PCS patients were compared to coronary artery disease patients (CAD; n = 96) to evaluate overall training effectiveness. Training participation was comparable between the groups, with no indication of training-specific exercise-induced fatigue. Overall, PCS patients improved significantly by a mean of 6.8 ± 12.1% for W at VT1; 3.1 ± 10.0% for VO2 at VT1; 5.5 ± 14.7% for O2 pulse at VT1; 7.5 ± 15.0% for W at VO2peak; 2.7 ± 11.0% for VO2peak and 4.6 ± 12.4% for O2 pulse at VO2peak (all p < 0.05) with no significant differences between groups (p > 0.05). Both groups showed reduced levels of fatigue, anxiety, and depression as well as improved quality of life and wellbeing (all p < 0.05). Compared to guideline-based cardiac rehabilitation, PCS patients showed a similar improvement in workload and oxygen uptake compared to CAD patients. PCS patients benefit from aerobic endurance training performed as moderate continuous or interval training as part of a medical rehabilitation program in terms of improved physical exercise capacity and disease perception. The results for PCS patients are comparable to the guideline-based rehabilitation of CAD patients.