Dead Space Breathing in Patients with Malignancies: Determination by Cardiopulmonary Exercise Testing

Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives: In this retrospective pilot study, we evaluated patients with hematologic and solid malignancies by CPET to determine the primary source of their dyspnea. Methods: Subjects were exercised on a cycle ergometer with increasing workloads. Minute ventilation, heart rate, breathing reserve, oxygen uptake (V’O2), O2-pulse, ventilatory equivalents for carbon dioxide and oxygen (V’E/V’CO2 and V’E/V’O2, respectively) were measured at baseline and peak exercise. The slope and intercept for V’E/V’CO2 was computed for all subjects. Peak V’O2 4% predicted indicated a circulatory or ventilatory limitation. Results: Complete clinical and physiological data were available for 36 patients (M/F 20/16);32 (89%) exhibited ventilatory or circulatory limitation as shown by a reduced peak V’O2 and 10 subjects with normal physiologic data. The largest cohort comprised the pulmonary vascular group (n = 18) whose mean ± SD peak V’O2 was 61% ± 17% predicted. There were close associations between V’O2 and spirometric values. Peak V’E/V’O2 and V’E/V’CO2 were highest in the circulatory and ventilatory cohorts, consistent with increase in dead space breathing. The intercept of the V’E-V’CO2 relationship was lowest in patients with cardiovascular impairment. Conclusion: Dyspneic patients with malignancies exhibit dead space breathing, many exhibiting a circulatory source for exercise limitation with a prominent pulmonary vascular component. Potential factors include effects of chemo- and radiation therapy on cardiac function and pulmonary vascular endothelium.

Health Evaluation for Hypertensive Population Using Exercise Testing and Health-related Quality of Life Questionnaire

Objectives This study aims to assess the impacts of hypertension on health-related quality of life (HRQOL), as well as cardiovascular functional status (CVFS). Methods An instrument was presented based on WHOQOL-BREF and SP-16 questionnaire and exercise testing. 57 normotensive and 76 hypertensive subjects aged 35-65 year-old participated the health survey using this instrument. Based on the exercise testing results of the two groups, a discriminate function was established and used to investigate cardiovascular risk factors for hypertensive population. Results The results showed that persons with hypertension rated significantly lower scores on physical health (i.e. limitation in performing daily activities and problems with work or mobility) than did normotensives (P < 0.01). The discriminant score obtained from the exercise testing results was capable of reflecting the impacts of hypertension on CVFS. Conclusions The method presented in this paper provides a more powerful tool to estimate the effects of health interventions and medical therapy for hypertensive population than just self-rated HRQOL questionnaire.

Increases in the incremental exercise mean response time across the steady state domain:Implications for exercise testing&prescription

We hypothesized that slowed oxygen uptake(VO_(2))kinetics for exercise transitions to higher power outputs(PO)within the steady state(SS)domain would increase the mean response time(MRT)with increasing exercise intensity during incremental exercise.Fourteen highly trained cyclists(mean±standard deviation[SD]);age(39±6)years[yr];and VO_(2) peak=(61±9)mL/kg/min performed a maximal,ramp incremental cycling test and on separate days,four 6-min bouts of cycling at 30%,45%,65%&75% of their incremental peak PO(Wpeak).SS trial data were used to calculate the MRT and verified by mono-exponential and linear curve fitting.When the ramp protocol attained the value from SS,the PO,in Watts(W),was converted to time(min)based on the ramp function W to quantify the incremental MRT(iMRT).Slope analyses for the VO_(2) responses of the SS versus incremental exercise data below the gas exchange threshold(GET)revealed a significant difference(p=0.003;[0.437±0.08]vs.[0.382±0.05]L·min^(-1)).There was a significant difference between the 45%Wpeak steady state VO_(2)(ss VO_(2))([3.08±0.30]L·min^(-1),respectively),and 30% Wpeak ss VO_(2)(2.26±0.24)(p<0.0001;[3.61±0.80]vs.[2.20±0.39]L·min^(-1))and between the iMRT for 45% and 30% Wpeak ss VO_(2) values([50.58±36.85]s vs.[32.20±43.28]s).These data indicate there is no single iMRT,which is consistent with slowed VO_(2) kinetics and an increasing VO_(2) deficit for higher exercise intensities within the SS domain.

Cardiopulmonary exercise testing in the evaluation of high risk patients with lung cancer

Background It is still unclear whether pulmonary function tests （PFTs） are sufficient for predicting perioperative risk,and whether all patients or only a subset of them need a cardiopulmonary exercise test （CPET） for further assessment.Thus, this study was designed to evaluate the CPET and compare the results of CPET and conventional PFTs to identify which parameters are more reliable and valuable in predicting perioperative risks for high risk patients with lung cancer.Methods From January 2005 to August 2008, 297 consecutive lung cancer patients underwent conventional PFTs （spirometry ＋ single-breath carbon monoxide diffusing capacity of the lungs （DLCOsb） for diffusion capacity） and CPET preoperatively. The correlation of postoperative cardiopulmonary complications with the parameters of PFT and CPET was retrospectively analyzed using the chi-square test, independent sample t test and binary Logistic regression analysis.Results Of the 297 patients, 78 did not receive operation due to advanced disease stage or poor cardiopulmonary function. The remaining 219 underwent different modes of operations. Twenty-one cases were excluded from this study due to exploration alone （15 cases） and operation-related complications （6 cases）. Thus, 198 cases were eligible for evaluation. Fifty of the 198 patients （25.2%） had postoperative cardiopulmonary complications. Three patients （1.5%）died of complications within 30 postoperative days. The patients were stratified into groups based on VO2max/pred respectively. The rate of postoperative cardiopulmonary complications was significantly higher in the group with cardiopulmonary complications were significantly correlated with age, comorbidities, and poor PFT and CPET results.used to stratify the patients＇ cardiopulmonary function status and to predict the risk of postoperative cardiopulmonary predicting perioperative risk. If available, cardiopulmonary exercise testing is strongly suggested for high-risk lung cancer patients in addition to conventional pulmonary function tests, and both should be combined to assess cardiopulmonary function status.

Exercise test on the patients with normokalaemic periodic paralysis from a Chinese family with a mutation in the SCN4A gene

Background Normokalaemic periodic paralysis （normoKPP） is characterized by transient and recurrent myoasthenia, and some patients also show muscle stiffness induced by cold exposure （paramyotonia congenita, PMC）. It is caused by a mutation in the muscle voltage gated sodium channel alpha subunit （SCN4A） gene. Due to the diversity of the clinical manifestations of patients, it is difficult for clinicians to differentiate some of patients with atypical normoKPP from those who suffer from other periodic paralysis and nondystrophic myotonia. So far, for normoKPP there are almost no ways to assist definite diagnosis besides genetic screening. This research was designed to evaluate an exercise test （ET） in confirming the diagnosis of normoKPP and in assessing the therapeutic effectiveness of some drugs on this disease. Methods ET, described by McMains, was performed on six subjects from a Chinese family, including four patients with overlapping disease of normoKPP and PMC caused by a mutation of SCN4A Met1592Val that is identified by genetic analysis and two normal control members. The change of compound muscle action potential （CMAP） was recorded. Besides the family, two patients were also tested during treatments with acetazolamide. Results All patients showed a slight increase in CMAP immediately after exercise, followed by an abnormal gradual decline, which reached its nadir 25-30 minutes after exercise. CMAP amplitude dropped by more than 40% in patients but less than 23% in controls. In the patients who received treatment with acetazolamide, the change of CMAP amplitude was less than 28% and, at any fixed times, less than pretreatment values. Conclusions The ET may be used as a predictive, easy and reliable method of diagnosing normoKPP under conditions without genetic screening help, and is an objective way to evaluate the therapeutic effectiveness. According to different response patterns, the ET may also be helpful in reducing the scope of genetic screening.

Limited value of recovery phase-limited ST segment depression of treadmill exercise test

Background Clinical meaning of recovery phase limited ST segment depression of a treadmill exercise test is controversial.The aim of this study was to re-assess the diagnostic and prognostic value of ST segment depression during the recovery phase with the active phase of a treadmill exercise test in suspected coronary artery disease patients.Methods Clinical,exercise and angiographic data were retrospectively collected from 602 patients in the study.Five hundred and seventy-six patients developed ST segment depression during the active phase of the treadmill exercise test （group 1） and 26 patients developed ST segment depression only during the recovery phase （group 2）.Results With similar major clinical features,the prevalence of significant coronary artery stenosis and average Gensini scores were lower in the recovery phase-limited depression patients （group 2 vs.group 1,50.0% vs.66.9%,P=0.031 and group 2 vs.group 1,1.5 vs.8.5,P=0.04）.At a median follow up of 50.9 months for 22 group 2 and 34.8 months for 438 group 1 patients,the prevalence of total cardiac events was higher in group 1 than in group 2 patients （RR 1.60,95% Cl 1.00-2.54,P=0.049）.Conclusion The present study provides preliminary evidence that the diagnostic and prognostic value of recovery phaselimited ST segment depression of treadmill exercise test is limited.

Reference value of long-time exercise test in the diagnosis of primary periodic paralysis

Background The long-time exercise test （ET） is used to diagnose the primary periodic paralyses （PPs）.However the reference values of ET are many and various.This study aimed to investigate the reference value of long-time ET in the diagnosis of PPs.Methods We recruited 108 healthy subjects,68 patients with PPs,and 72 patients with other diseases for the study.The procedure of ET was made on the basis of the McManis＆#39; method.Electrical responses were recorded from right abductor digiti minimi （ADM） muscle when stimulation of the ulnar nerve at the wrist.After the compound muscle action potential （CMAP） was monitored,subjects were then asked to contract the muscle as strongly as possible for 5 minutes.CMAPs were recorded for 2 seconds immediately after cessation of exercise,then every 5 minutes for 10 minutes,and finally every 10 minutes for 50 minutes.In general,the CMAP amplitudes will fall below the pre-exercise levels in an hour.The largest decrease was calculated and used as results of ET.Results The CMAP amplitude decreases had no significant differences between groups when the healthy adults were grouped according to age,gender,height,weight and test time.Decreases in PPs patients （57.76%） were significantly more than in healthy subjects （15.21%） and other disease patients （18.10%,P 〈0.001）.Receiver operating characteristic （ROC） curve analysis showed that the best threshold is 35.50%.Conclusions In the long-time exercise test,threshold of 35.50% for the CMAP amplitude decrease was identified for abnormal.The result is not influenced by age,gender,height,weight,and test time.About 7.4% of healthy subjects were abnormal in ET.

QT hysteresis in long-QT syndrome children with exercise testing

Background Congenital long QT syndrome （LQTS） is an inherited ion channel disorder resulting in abnormal cardiac repolarization that can cause syncope and sudden death associated with a prolonged rate-corrected QT interval and polymorphic ventricular tachycardia. Several studies in adults showed that LQTS patients have altered QT adaptation to heart rate changes compared with normal subjects which forming a ＂hysteresis loop＂ in the QT-circle length plot. This study was to observe the QT interval changing during exercise testing in children long QT syndrome （LQTS） patients, explore the new diagnosis methods of LQTS. Methods The subjects were divided into 3 groups according to 1993 LQTS diagnostic criteria. Group 1： LQTS group （n=17） who scored 〉 or = 4 points indicating definite LQTS. Group 2： Middle group （n=16）, patients who have prolonged QT interval but scored 1.5 to 3.5. Group 3： Normal control group （n=18）. The average age of all study population is （12.3±5.8） years. No case had beta-adrenergic antagonists administration before exercise testing. All subjects were underwent tread mill exercise testing and electrocardiograph in whole exercise testing and recovery were recorded. QT and heart rate changing during whole exercise testing period were recorded. /kQT, the QT interval at 1, 2, 4, 6 minutes into recovery subtract from the QT interval at a similar heart rate during exercise, were calculated. Results In all three groups, QT intervals were shortening with the increasing of heart rate, but QTc had no significant change. ΔQT at 1 minute （（45±11） ms）, 2 minutes （（37±15） ms）, 4 minutes （（23±12） ms） into recovery in LQTS group were significantly greater than that of the other two groups （P〈0.05, P〈0.01, P〈0.01, respectively）. There was no ΔQT significant difference between middle group and normal control group at recovery time. During the recovery phase in LQTS group, the QT interval remained shortened despite a decelerating heart rate, forming a hysteresis ＂loop＂ in the curve relating the QT interval to the cycle length. Conclusions In children LQTS patients, there is significant QT hysteresis loop in the relation of QT interval with heart rate during recovery of exercise testing, which could be useful to the early diagnosis for LQTS.

Research hotspots and trends of cardiopulmonary exercise test:Visualization analysis based on citespace

The study aims to grasp the hot spots and trends of global cardiopulmonary exercise research.Web of Science(WoS)core collection and Derwent Innovation Index database were retrieved to collect literature from 2002 to 2022 with Cardiopulmonary Exercise Test(CPET)as the retrieval theme.CiteSpace was used to conduct bibliometrics and visual analysis of 6679 pieces of literature in the web of science core collection database and 251 patent data in the Derwent Innovation Index database.The results show that:(1)the number of CPET theme research papers is increasing year by year,and the main research fields are cardiology,respiratory system,sports science,etc.;(2)The main research hot spots of CPET include exercise prescription,exercise and heart failure,COVID-19 cardiopulmonary rehabilitation and evaluation,etc.;(3)The development trend of CPET technology is majorly in the direction of intelligence,portability,individualization and the integration of Virtual Reality(VR)technology and evidence-based research of CPET guiding clinical decision-making.

Clinical Significance of Abnormal Heart Rate Recovery after Treadmill Exercise Test in Patients With Coronary Artery Disease

To evaluate the values of abnormal heart rate recovery （HRR） after treadmill exercise test in patients with coronary artery disease （CAD）. Methods One hundred and seventy-eight consecutive cases of suspected CAD who underwent symptom-limited treadmill exercise test （TET） and coronary angiography （CAG） were enrolled and divided into normal and abnormal HRR group based on the status of the values of HRR one or two minutes after TET. The clinical characteristics, TET parameters and CAG results of the two groups were compared attempted to assess the value of HRR on patients with CAD. Results （ 1 ） The cases of smoking, diabetes mellitus （DM） and ST segment deviation at rest in abnormal HRR group were more significantly than those in normal HRR group （ all P 〈 0. 05 ）. （2） The subjects of abnormal HRR usually had higher basal heart rate, more cases exhibited ST segment abnormality and or exercise-limited angina during or after TET（P 〈 0. 01 and P 〈 0. 05, respectively）, but lower level of peak heart rate attained （ P 〈 0. 05 ） than those in normal group. The values of metabolism equivalents and duration of TET between the two groups displayed phenomenal difference （ P 〈 0. 05 ）. There were more samples acquired moderate to high level of Duke test score and chronotropic incompetence in the group of abnormal HRR, compared to the normal HRR group （P 〈 0. 01 ）. （3） The cases of negative CAG results in the group of normal and abnormal HRR group were 73 （66. 97 % ） and 24 （34. 78 % ）. Cases of significant coronary lesions （ at least one major coronary vessel ≥ 50 % stenosis） amongst the subgroup of positive CAG were 36 （ 33.03 % ） and 45 （65.22 % ）, severe coronary lesions （ three-vessel, left main or the equivalents of left main） were 10 （9. 17 % ） and 17 （24. 64 % ） for normal and abnormal HRR respectively （P 〈 0. 01 ）. Accordingly, the Gensini scores in the subunit of abnormal HRR increased. （4）Linear correlation analysis indicate there was a negative correlation between the values of HRR in the first and second minutes and indices of severity of CAD （ all P 〈 0. 01 ）. The analysis of auxiliary diagnostic value of abnormal HRR indicated the annexed HRR standard had higher negative predictive value. Conclusions The status of HRR after TET are not only influenced by the clinical factors related to the cardiac autonomic function, but also associated with the extent of CAD. （ S Chin J Cardiol 2009 ; 10（1）：1-8）

Shortness of breath in clinical practice: A case for left atrial function and exercise stress testing for a comprehensive diastolic heart failure workup

The symptom cluster of shortness of breath(SOB) contributes significantly to the outpatient workload of cardiology services. The workup of these patients includes blood chemistry and biomarkers, imaging and functional testing of the heart and lungs. A diagnosis of diastolic heart failure is inferred through the exclusion of systolic abnormalities, a normal pulmonary function test and normal hemoglobin, coupled with diastolic abnormalities on echocardiography. Differentiating confounders such as obesity or deconditioning in a patient with diastolic abnormalities is difficult. While the most recent guidelines provide more avenues for diagnosis, such as incorporating the left atrial size, little emphasis is given to understanding left atrial function, which contributes to at least 25% of diastolic left ventricular filling; additionally, exercise stress testing to elicit symptoms and test the dynamics of diastolic parameters, especially when access to the "gold standard" invasive tests is lacking, presents clinical translational gaps. It is thus important in diastolic heart failure work up to understand left atrial mechanics and the role of exercise testing to build a comprehensive argument for the diagnosis of diastolic heart failure in a patient presenting with SOB.

Autonomic Function in Individuals with Slow Heart Rate Response following an Exercise Stress Test

Objective: To examine the autonomic function using HRV measures in apparently healthy individuals undergoing exercise stress test (EST) and demonstrating slow HRR response. Methods: HRV was measured with 12 lead ECGs during graded EST and analyzed via a post-processing method. Autonomic function was determined by Power Spectral Analysis of the very low frequency (VLF), low frequency (LF), high frequency (HF), and the ratio of LF/HF. We correlated HRV indices with resting, exercise, and recovery data. Results: No differences were found in anthropometric measurements, peak EST HR, and METS between individuals with slow HRR (below 18 b/min) compared with controls (HRR > 18 b/min). Only the VLF component of the HRV indices was statistically different (p = 0.03) at one-minute post-exercise compared with controls. Additionally, a significant correlation between HRR and resting LF and HF indices was found in the individuals with slow HRR but not in the controls. Conclusion: In apparently healthy individuals with slow HRR post-EST, autonomic function did not demonstrate any differences at any phase of the EST, including at one minute of recovery. However, a significant correlation was found between resting LF and HF powers and HRR in individuals with slow vagal reactivation post-exercise. The clinical and prognostic implications of such observation deserve further investigation.

Heart rate response and recovery during exercise predict future delirium risk——A prospective cohort study in middle-to older-aged adults

Background:Delirium is a neurocognitive disorder characterized by an abrupt decline in attention,awareness,and cognition after surgical/illness-induced stressors on the brain.There is now an increasing focus on how cardiovascular health interacts with neurocognitive disorders given their overlapping risk factors and links to subsequent dementia and mortality.One common indicator for cardiovascular health is the heart rate response/recovery(HRR)to exercise,but how this relates to future delirium is unknown.Methods:Electrocardiogram data were examined in 38,740 middle-to older-aged UK Biobank participants(mean age=58.1 years,range:40-72 years;47.3%males)who completed a standardized submaximal exercise stress test(15-s baseline,6-min exercise,and 1-min recovery)and required hospitalization during follow-up.An HRR index was derived as the product of the heart rate(HR)responses during exercise(peak/resting HRs)and recovery(peak/recovery HRs)and categorized into low/average/high groups as the bottom quartile/middle 2 quartiles/top quartile,respectively.Associations between 3 HRR groups and new-onset delirium were investigated using Cox proportional hazards models and a2-year landmark analysis to minimize reverse causation.Sociodemographic factors,lifestyle factors/physical activity,cardiovascular risk,comorbidities,cognition,and maximal workload achieved were included as covariates.Results:During a median follow-up period of 11 years,348 participants(9/1000)newly developed delirium.Compared with the high HRR group(16/1000),the risk for delirium was almost doubled in those with low HRR(hazard ratio=1.90,95%)confidence interval(95%CI):1.30-2.79,p=0.001)and average HRR(hazard ratio=1.54,95%CI:1.07-2.22,p=0.020)).Low HRR was equivalent to being 6 years older,a current smoker,or>3 additional cardiovascular disease risks.Results were robust in sensitivity analysis,but the risk appeared larger in those with better cognition and when only postoperative delirium was considered(n=147;hazard ratio=2.66,95%CI:1.46-4.85,p=0.001).Conclusion:HRR during submaximal exercise is associated with future risk for delirium.Given that HRR is potentially modifiable,it may prove useful for neurological risk stratification alongside traditional cardiovascular risk factors.

Exercise-Induced Bronchoconstriction Diagnostics:Impact of a Repeated Exercise Challenge Test

Exercise-Induced bronchoconstriction (EIB) is related to increased ventilation (VE) during exercise and describes the transient airway narrowing following exercise. A reliable diagnosis is essential for optimal treatment. The impact of a repeated exercise challenge test (ECT) in a clinical setting is not well established and conducting a repeated ECT with the possibility to adjust the exercise intensity on an individual basis may give more information. The aim of the study was to evaluate the test-retest reliability of an ECT for EIB and its association with exercise intensity. Methods: After examination by a pulmonologist, 20 referred subjects with symptoms strong indications of Exercise-Induced bronchoconstriction performed two consecutive exercise challenge tests on a treadmill. The exercise intensity of the repeated test was adjusted. Forced expiratory volume in 1 second (FEV1) was measured before and 1, 3, 6, 10, and 15 minutes after exercise. EIB was defined as a reduction of ≥ 10% in FEV1. Ventilation and heart rate were measured during exercise. Results: Five subjects tested positive in both tests, and ten subjects tested negative in both tests. Three subjects tested positive in the first test only, while two subjects tested positive in the second test only. The exercise intensity was not significantly different between the two tests for any of the subjects. Conclusion: There were 25% divergences in the diagnostic results of two consecutive exercise challenge tests. The difference in the test results was not explained by a difference in the exercise intensity.

Cardiac rehabilitation after cardiac surgery:An important underutilized treatment strategy

Physical inactivity remains in high levels after cardiac surgery,reaching up to 50%.Patients present a significant loss of functional capacity,with prominent muscle weakness after cardiac surgery due to anesthesia,surgical incision,duration of cardiopulmonary bypass,and mechanical ventilation that affects their quality of life.These complications,along with pulmonary complications after surgery,lead to extended intensive care unit(ICU)and hospital length of stay and significant mortality rates.Despite the well-known beneficial effects of cardiac rehabilitation,this treatment strategy still remains broadly underutilized in patients after cardiac surgery.Prehabilitation and ICU early mobilization have been both showed to be valid methods to improve exercise tolerance and muscle strength.Early mobilization should be adjusted to each patient’s functional capacity with progressive exercise training,from passive mobilization to more active range of motion and resistance exercises.Cardiopulmonary exercise testing remains the gold standard for exercise capacity assessment and optimal prescription of aerobic exercise intensity.During the last decade,recent advances in healthcare technology have changed cardiac rehabilitation perspectives,leading to the future of cardiac rehabilitation.By incorporating artificial intelligence,simulation,telemedicine and virtual cardiac rehabilitation,cardiac surgery patients may improve adherence and compliance,targeting to reduced hospital readmissions and decreased healthcare costs.

Rehabilitation training improves exercise tolerance after percutaneous coronary intervention

The aim of this present study was to investigate the effects of training on exercise tolerance of patients with coronary heart disease after percutaneous coronary intervention.Fifty-seven cases of coronary heart disease after percutaneous coronary intervention were divided randomly into the rehabilitation training group（26 cases） and control group（31 cases）.Patients in the rehabilitation training group received rehabilitation training at different stages and exercise intensities 3 d after percutaneous coronary intervention for 3 months.The heart rate,blood pressure,ECG changes in treadmill exercise test,and the frequency of anginal episodes were observed.The results showed that NST and ΣST of ECG and the frequency of anginal episodes were significantly reduced in the rehabilitation training group.In addition,exercise tolerance was improved and the total exercise time was lengthened in these patients.Moreover,ST segment depression time and emergence time of angina with exercise were also lengthened compared with controls（P 〈 0.05,or 0.01）.However,the heart rate and blood pressure before and after exercise of the two groups were similar.The study indicated that rehabilitation training could significantly relieve angina,amend ischemic features of ECG,and improve exercise tolerance of coronary heart disease patients after percutaneous coronary intervention.

Retrospective analysis of exercise capacity in patients with coronary artery disease after percutaneous coronary intervention or coronary artery bypass graft

Objectives:To describe the current state of exercise capacity as well as to identify its predictors in patients with coronary artery disease (CAD) following percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) in the mainland of China.Methods:A retrospective study design was employed.We evaluated 230 CAD patients following PCI or CABG in a cardiac rehabilitation center from January 2019 to October 2019.The patients were referred to undergo incremental cardiopulmonary exercise testing with a cycle ergometer.The Zung Self-Rating Anxiety Scale and the Zung Self-Rating Depression Scale were used to evaluate patients' mental health.Statistical analysis was performed using the chi-square test,Fisher's exact test,t-test,Mann-Whitney U test,and binary logistic regression.Results:Among the 230 patients,223 patients demonstrated reduced exercise capacity.Resutlts of the logistic regression analysis showed that anxiety (OR =1.13,95% CI 1.01-1.32,P =0.029) was an independent risk factor for reduced exercise capacity in patients following the PCI or CABG.Conclusions:Exercise capacity of Chinese CAD patients after PCI or CABG was relatively poor.Alleviating symptoms of anxiety and making exercise prescriptions according to the results of the cardiopulmonary exercise test should be considered during the intervention to improve CAD patients' exercise capacity.

Association between physiological responses after exercise at low altitude and acute mountain sickness upon ascent is sex-dependent

Background:Acute mountain sickness(AMS)is the mildest form of acute altitude illnesses,and consists of nonspecific symptoms when unacclimatized persons ascend to elevation of≥2500 m.Risk factors of AMS include:the altitude,individual susceptibility,ascending rate and degree of pre-acclimatization.In the current study,we examined whether physiological response at low altitude could predict the development of AMS.Methods:A total of 111 healthy adult healthy volunteers participated in this trial;and 99(67 men and 32 women)completed the entire study protocol.Subjects were asked to complete a 9-min exercise program using a mechanically braked bicycle ergometer at low altitude(500 m).Heart rate,blood pressure(BP)and pulse oxygen saturation(SpO2)were recorded prior to and during the last minute of exercise.The ascent from 500 m to 4100 m was completed in 2 days.AMS was defined as≥3 points in a 4-item Lake Louise Score,with at least one point from headache wat 6–8 h after the ascent.Results:Among the 99 assessable subjects,47(23 men and 24 women)developed AMS at 4100 m.In comparison to the subjects without AMS,those who developed AMS had lower proportion of men(48.9%vs.84.6%,P<0.001),height(168.4±5.9 cm vs.171.3±6.1 cm,P=0.019),weight(62.0±10.0 kg vs.66.7±8.6 kg,P=0.014)and proportion of smokers(23.4%vs.51.9%,P=0.004).Multivariate regression analysis revealed the following independent risks for AMS:female sex(odds ratio(OR)=6.32,P<0.001),SpO2 change upon exercise at low altitude(OR=0.63,P=0.002)and systolic BP change after the ascent(OR=0.96,P=0.029).Women had larger reduction in SpO2 after the ascent,higher AMS percentage and absolute AMS score.Larger reduction of SpO2 after exercise was associated with both AMS incidence(P=0.001)and AMS score(P<0.001)in men but not in women.Conclusions:Larger SpO2 reduction after exercise at low altitude was an independent risk for AMS upon ascent.Such an association was more robust in men than in women.Trial registration:Chinese Clinical Trial Registration,ChiCTR1900025728.Registered 6 September 2019.

Endothelial progenitor cells mobilization after maximal exercise according to heart failure severity

BACKGROUND Vascular endothelial dysfunction is an underlying pathophysiological feature of chronic heart failure(CHF).Patients with CHF are characterized by impaired vasodilation and inflammation of the vascular endothelium.They also have low levels of endothelial progenitor cells(EPCs).EPCs are bone marrow derived cells involved in endothelium regeneration,homeostasis,and neovascularization.Exercise has been shown to improve vasodilation and stimulate the mobilization of EPCs in healthy people and patients with cardiovascular comorbidities.However,the effects of exercise on EPCs in different stages of CHF remain under investigation.AIM To evaluate the effect of a symptom-limited maximal cardiopulmonary exercise testing(CPET)on EPCs in CHF patients of different severity.METHODS Forty-nine consecutive patients(41 males)with stable CHF[mean age(years):56±10,ejection fraction(EF,%):32±8,peak oxygen uptake(VO2,mL/kg/min):18.1±4.4]underwent a CPET on a cycle ergometer.Venous blood was sampled before and after CPET.Five circulating endothelial populations were quantified by flow cytometry:Three subgroups of EPCs[CD34+/CD45-/CD133+,CD34+/CD45-/CD133+/VEGFR2 and CD34+/CD133+/vascular endothelial growth factor receptor 2(VEGFR2)]and two subgroups of circulating endothelial cells(CD34+/CD45-/CD133-and CD34+/CD45-/CD133-/VEGFR2).Patients were divided in two groups of severity according to the median value of peak VO2(18.0 mL/kg/min),predicted peak VO2(65.5%),ventilation/carbon dioxide output slope(32.5)and EF(reduced and mid-ranged EF).EPCs values are expressed as median(25th-75th percentiles)in cells/106 enucleated cells.RESULTS Patients with lower peak VO2 increased the mobilization of CD34+/CD45-/CD133+[pre CPET:60(25-76)vs post CPET:90(70-103)cells/106 enucleated cells,P<0.001],CD34+/CD45-/CD133+/VEGFR2[pre CPET:1(1-4)vs post CPET:5(3-8)cells/106 enucleated cells,P<0.001],CD34+/CD45-/CD133-[pre CPET:186(141-361)vs post CPET:488(247-658)cells/106 enucleated cells,P<0.001]and CD34+/CD45-/CD133-/VEGFR2[pre CPET:2(1-2)vs post CPET:3(2-5)cells/106 enucleated cells,P<0.001],while patients with higher VO2 increased the mobilization of CD34+/CD45-/CD133+[pre CPET:42(19-73)vs post CPET:90(39-118)cells/106 enucleated cells,P<0.001],CD34+/CD45-/CD133+/VEGFR2[pre CPET:2(1-3)vs post CPET:6(3-9)cells/106 enucleated cells,P<0.001],CD34+/CD133+/VEGFR2[pre CPET:10(7-18)vs post CPET:14(10-19)cells/106 enucleated cells,P<0.01],CD34+/CD45-/CD133-[pre CPET:218(158-247)vs post CPET:311(254-569)cells/106 enucleated cells,P<0.001]and CD34+/CD45-/CD133-/VEGFR2[pre CPET:1(1-2)vs post CPET:4(2-6)cells/106 enucleated cells,P<0.001].A similar increase in the mobilization of at least four out of five cellular populations was observed after maximal exercise within each severity group regarding predicted peak,ventilation/carbon dioxide output slope and EF as well(P<0.05).However,there were no statistically significant differences in the mobilization of endothelial cellular populations between severity groups in each comparison(P>0.05).CONCLUSION Our study has shown an increased EPCs and circulating endothelial cells mobilization after maximal exercise in CHF patients,but this increase was not associated with syndrome severity.Further investigation,however,is needed.

Effect of yelling on maximal aerobic power during an incremental test of cycling performance

Background：People experiencing strong feelings of fatigue during exercise sometimes subconsciously yell to refocus their efforts and,thus,maintain exercise performance.The present study examined the influenc of yelling during high-intensity exercise by analysing cardiorespiratory reactions and integrated electromyography（i EMG） changes in the vastus lateralis during a cycle ergometer test.Methods：A total of 23 moderately trained people were recruited.The cycling test began with a resistance of 25 W/min,which was gradually increased.During the experimental trial,the participants were required to yell at least 3 times when they felt exhausted;during the controlled trial,they were not allowed to produce any yelling sounds.The testing order was randomly assigned and the 2 trials were completed within an interval between 3–10 days.Two-way repeated measures ANOVA was applied to analyse the differences within and between the trials,and interaction of trial and time.Results：The peak power and time to exhaustion（p〈0.01） in the yelling trial were higher than those in the control trial.However,the vastus lateralis iE MG values of both trials at peak power were not significant y different.During the yelling period at 90%–100% of the maximal effort,a significan time-by-trialinteraction（p〈0.05）wasobservedinoxygenconsumption（VO2）,CO2 production,O2 pulse,ventilation,andrespiratoryrate. Alltheabove measures showed a significan between-trial difference（p〈0.02）.However,heart rate,respiratory exchange ratio,end-tidal oxygen pressure,and ventilatory equivalent for oxygen showed only significan between-trial difference（p〈0.05）,but without interaction of trial and time.Conclusion：Yelling enhances the peak O2 pulse and VO2 and maintains CO2-exclusion efficien y during high-intensity exercise.It may enable maintaining muscle activation without stronger EMG signals being required during high-intensity exercise.