Association Of Exercise Capacity Research Articles

Association of exercise capacity and endothelial function in patients with severe exacerbations of chronic obstructive pulmonary disease

Severe acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with significant poor outcomes including an increased risk of cardiovascular (CV) events and exercise intolerance. Endothelial dysfunction might contribute to an impaired vascular homeostasis and consequently to CV events and exercise capacity. This study aimed to evaluate the association between exercise capacity and endothelial function in patients with severe AECOPD. Forty-five COPD patients diagnosed with severe AECOPD and admitted to the University Hospital of São Carlos from 2017 to 2019 were enrolled in this observational clinical study. Endothelial Function was assessed by brachial artery ultrasonography (M-Turbo, Sonosite, Bottle, WA, USA) and Flow Mediated Dilatation (FMD) technique in absolute (mm) and percentage values (%). Walking distance (6MWD) obtained by six-minute walk test was considered to characterize the exercise capacity. Pearson’s correlation analysis and linear regression model were applied and a significance level of 5%. There was a significant positive correlation between exercise capacity and endothelial function. Pearson correlation coefficient were 0.36 (p = 0.02) and 0.40 (p = 0.01) between 6MWD and FMD in mm and %, respectively. Linear regression model revealed 6MWD (p = 0.007), accounting for 15% of FMD (%) variance (R2 adjusted). FMD (%) = 2.11 + (0.0081*6MWD). Exercise capacity is associated with endothelial function in patients with severe AECOPD. FMD was found to be increasing with increasing walked distance. Further research is needed to provide evidence of effectiveness of rehabilitation on exercise capacity and endothelial function in these patients and its prognostic value.

Reduced Parasympathetic Activity in Patients With Different Types of Congenital Heart Disease and Associations to Exercise Capacity

Current research indicates an imbalance in the autonomic nervous system (ANS) pathway activities in patients with congenital heart disease (CHD). The heart rate variability (HRV) is a measure to quantify activities of the parasympathetic and sympathetic branches. This study evaluated the parasympathetic activity by means of HRV in patients with CHD, regarding diagnostic subgroups and CHD severity, and the association to exercise capacity. From July 2016 to August 2018, a total of 222 patients with different types of CHD (28.4 ± 10.1 yr; 44% female) received breathing-controlled HRV measurement in the supine position. Based on 130 adjacent heartbeats, the root mean square of successive differences (RMSSD), a parasympathetic activity surrogate was estimated and log-transformed. Additionally, all patients underwent a cardiopulmonary exercise test. For comparison, a control group (CG) of 57 (29.0 ± 7.1 yr; 61% female) healthy volunteers was recruited. Patients with CHD exhibited reduced parasympathetic activity in comparison to the CG (lnRMSSD CHD: 3.55 ± 0.57 ms vs CG: 3.93 ± 0.55 ms; P < .001), with the lowest parasympathetic activity in patients with Fontan circulation (3.07 ± 0.54 ms; P < .001). Complex CHD (3.40 ± 0.54 ms) had worse values compared with patients with simple (3.87 ± 0.55 ms; P < .001) and moderate severity (3.74 ± 0.54 ms; P < .001). Better parasympathetic activity in CHD patients was associated with increased exercise capacity (r = 0.322; P < .001). Impaired parasympathetic activity suggests limited function of the ANS in patients with CHD. Further studies should focus on the association of exercise capacity and ANS to possibly improve parasympathetic activity and functional outcomes.

P2498Exercise capacity and all-cause mortality in remote Indigenous and non-Indigenous populations

Abstract Background Exercise capacity is a powerful predictor of all-cause mortality. However, its association with Indigenous populations in Central Australia, who face disproportionate health burdens, is unclear. Given the isolation from tertiary centers, exercise testing could provide useful local risk-stratification. Purpose To characterize the association of exercise capacity with all-cause mortality in Indigenous and non-Indigenous individuals in remote Central Australia. Methods Demographic, medication, and all-cause mortality data were prospectively collected from patients undergoing exercise stress tests from 2007–2017. Results A total of 3,414 patients (34% Indigenous) were included. At 4.8±2.9 years of follow-up, 86 (2.5%) deaths had occurred. Each 1-MET increase in exercise capacity conferred a 14% lower risk for mortality among Indigenous individuals (HR 0.86, 95% CI 0.79–0.94) and 20% lower risk for mortality among non-Indigenous individuals (HR 0.80, 95% CI 0.73–0.89) after adjusting for age, comorbidities, and medications. Mortality risk reduction for each 1-MET increase in exercise capacity was similar (p=0.32) for Indigenous and non-Indigenous individuals. Conclusions Exercise capacity is a significant predictor of all-cause mortality in Indigenous and non-Indigenous individuals. These findings have important clinical implications towards exercise capacity for risk-stratification and preventative importance of physical activity.

Association of Exercise Capacity with Physical Functionality and Various Aspects of Fatigue in Patients with Coronary Artery Disease

ABSTRACTThe aim of this study was to examine associations between exercise capacity—indexed as the metabolic equivalent of the task—and various aspects of subjective fatigue, physical functionality, and depression in patients with coronary artery disease. A cross-sectional design was used. Patients with stable coronary artery disease (N = 240) underwent an exercise stress test and completed self-report assessments of depression, subjective physical limitations, vital exhaustion, and the impact of fatigue on physical, social, and cognitive functions. Associations between exercise capacity and these self-report variables were assessed using bivariate correlations and a series of multivariate regressions. Exercise capacity was negatively associated with vital exhaustion, physical limitations, and impact of fatigue on physical and social functioning but not on cognitive functioning. There was a marginal association between exercise capacity and depression. The associations between exercise capacity and fatigue remained significant even after controlling for effects of age, body mass index, gender, education, and comorbid diabetes mellitus. The main conclusion of the study is that in patients with coronary artery disease, exercise capacity has the strongest predictability for physical fatigue, but, importantly, it also independently predicts the feeling of loss of energy and malaise.

Chronotropic Incompetence Does Not Limit Exercise Capacity in Chronic Heart Failure

BackgroundLimited heart rate (HR) rise (HRR) during exercise, known as chronotropic incompetence (CI), is commonly observed in chronic heart failure (CHF). HRR is closely related to workload, the limitation of which is characteristic of CHF. Whether CI is a causal factor for exercise intolerance, or simply an associated feature remains unknown. ObjectivesThis study sought to clarify the role of the HR on exercise capacity in CHF. MethodsThis series of investigations consisted of a retrospective cohort study and 2 interventional randomized crossover studies to assess: 1) the relationship between HRR and exercise capacity in CHF; and 2) the effect of increasing and lowering HR on exercise capacity in CHF as assessed by symptom-limited treadmill exercise testing and measurement of peak oxygen consumption in patients with CHF due to left ventricular systolic dysfunction. ResultsThe 3 key findings were: 1) the association of exercise capacity and HRR is much weaker in severe CHF compared to normal left ventricular function; 2) increasing HRR using rate-adaptive pacing (versus fixed-rate pacing) in unselected patients with CHF does not improve peak exercise capacity; and 3) acutely lowering baseline and peak HR by adjusting pacemaker variables in conjunction with a single dose of ivabradine does not adversely affect exercise capacity in unselected CHF patients. ConclusionsThe data refute the contention that CI contributes to impaired exercise capacity in CHF. This finding has widespread implications for pacemaker programming and the use of heart-rate lowering agents. (The Influence of Heart Rate Limitation on Exercise Tolerance in Pacemaker Patients [TREPPE]; NCT02247245)

Abstract 17499: Addition of Myocardial Parameters to the Diagnosis of Stage B Heart Failure

Introduction: Stage B heart failure (BHF, asymptomatic structural heart disease) is diagnosed in the presence of myocardial scar or impaired LVEF. However, the insensitivity of LVEF may lead to under-recognition of BHF in non-ischemic heart disease. This may be important, as BHF may precede the onset of HF symptoms, and necessitates the initiation of treatment. We sought the implications of using additional LV assessment to identify BHF in pts at risk of HF (stage A HF, AHF). Methods: We studied 510 asymptomatic pts (age 58±12yrs) with AHF (diabetes, hypertension or obesity), but no history of ischemic heart disease and a normal stress echo. All pts underwent echocardiography (including assessment of strain and diastolic dysfunction) and cardiopulmonary exercise testing. Results: BHF was defined as the presence of at least one of; reduced LV longitudinal strain (&lt;18%), increased LV filling pressure (E/e’&gt;13) or moderate-to-severe LV hypertrophy (LV mass index ≥109 g/m 2 in women and 132 g/m 2 in men) in 243 patients (47%). Reduced exercise capacity (peakVO 2 and METS) was identified in BHF compared with other AHF (Table). Using this definition, BHF was associated with lower peak VO 2 (β=-0.20, p&lt;0.00001) and METS (β=-0.21, p&lt;0.0001), independent of higher BMI, insulin resistance, older patient age, male sex and treatment with beta-blockers. Conclusions: LV hypertrophy, elevated LV filling pressure elevation and abnormal myocardial deformation independently contribute to lower exercise capacity in pts at risk of HF. Given the association of exercise capacity with outcome, these factors should be considered grounds for the diagnosis of BHF.

Relation Between Self-Reported Physical Activity Level, Fitness, and Cardiometabolic Risk

Physical activity and cardiorespiratory fitness are associated with improved cardiovascular health and reduced all-cause mortality. The relation between self-reported physical activity, objective physical fitness, and the association of each with cardiometabolic risk has not been fully described. We studied 2,800 healthy Brazilian subjects referred for an employer-sponsored health screening. Physical activity level was determined as "low," "moderate," or "high" with the International Physical Activity Questionnaire: Short Form (IPAQ-SF). Fitness was measured as METs achieved on a maximal, symptom-limited, treadmill stress test. Using multivariate linear regression analysis, we calculated age, gender, and smoking-adjusted correlation coefficients among IPAQ-SF, fitness, and cardiometabolic risk factors. Mean age of study participants was 43 ± 9 years; 81% were men, and 43% were highly active. Mean METs achieved was 12 ± 2. IPAQ-SF category and fitness were moderately correlated (r = 0.377). Compared with IPAQ-SF category, fitness was better correlated with cardiometabolic risk factors including anthropomorphic measurements, blood pressure, fasting blood glucose, dyslipidemia, high-sensitivity C-reactive protein, and hepatic steatosis (all p <0.01). Among these, anthropomorphic measurements, blood pressure, high-sensitivity C-reactive protein, and hepatic steatosis had the largest discrepancies in correlation, whereas lipid factors had the least discrepant correlation. When IPAQ-SF and fitness were discordant, poor fitness drove associations with elevated cardiometabolic risk. In conclusion, self-reported physical activity level and directly measured fitness are moderately correlated, and the latter is more strongly associated with a protective cardiovascular risk profile.

Abstract 006: Fitness Status Influences the Paradoxical Association Between BMI and Mortality Risk

Introduction: In some populations, recent evidence supports a higher mortality risk in individuals with relatively low body mass index (BMI), and lower risk in some overweight or obese individuals. However, the role of fitness in this puzzling relationship, termed as the obesity paradox, has not been fully explored. Hypothesis: We assessed the hypothesis that fitness attenuates the BMI-mortality risk paradoxical association. Methods: The association of exercise capacity and mortality risk in 18,228 individuals (mean age: 58±11) was assessed. Three fitness categories were formed based on the 33 rd and 66 th percentiles of exercise capacity (METs) achieved: Low-Fit (≤6 METs; n=6,072); Moderate-Fit: 6.1-8.5 METs; n=6,158); and High-Fit: &gt;8.5 METs; n=5,998). Individuals were also classified based on BMI as Normal-Wt (BMI 18.5-24.9); Over-Wt (BMI: 25-29.9); Moderate-Obese (BMI: 30-34.9) and Obese (BMI ≥35). Results: There were 4,770 deaths (median follow-up 10.1 years). After controlling for age, risk factors and medications, we observed a paradoxical association between BMI categories and mortality risk (p&lt;0.001 for trend). We also observed an inverse and graded association between fitness status and mortality for the entire cohort and within BMI categories, with reductions in risk ranging from approximately 30% to 60% (p&lt;0.001). We then assessed mortality risk based on fitness status within each BMI category, using the Normal-Wt/High-Fit individuals as the reference group. A paradoxical BMI-mortality risk association was evident in all fitness categories. However, in Low-Fit individuals the risk was significantly increased within each BMI category (hazard ratios (HR): 2.26; 1.7; 1.7 and 1.76 for Normal-Weight, Over-Wt; Moderate-Obese and Obese categories, respectively; p&lt;0.001 for all comparisons). However, in Moderate-Fit individuals, a significantly higher risk was observed only in the Normal-Wt category (HR: 1.58; p&lt;0.001). Finally, in High-Fit individuals, mortality risk was significantly lower in Over-Wt (HR: 0.79; p=0.03) and Moderately Obese categories (HR: 0.58; p&lt;0.001). Conclusions: These findings suggest that the paradoxical association between BMI and mortality risk is strongly modulated by fitness status.

Association of exercise capacity and the heart rate profile during exercise stress testing with subclinical coronary atherosclerosis: data from the Heinz Nixdorf Recall study

Exercise capacity and heart rate profile parameters obtained from exercise stress testing as well as the subclinical coronary atherosclerosis burden from cardiac CT have been suggested to improve cardiovascular (CV) risk stratification beyond traditional risk factors (RF) in persons at risk of CV events. To study the association of exercise stress-test variables with the coronary artery calcium (CAC) burden in relation to age, sex and traditional RF in subjects without known coronary artery disease from the general population. In 3,163 subjects, CV and RF were measured, a bicycle stress test was performed and the electron beam CT-based CAC-Agatston score was quantified. Exercise capacity, chronotropic response and an abnormal HR recovery were significantly and inversely related to CAC scores in men and women in univariate unadjusted analysis. This association was diminished after adjustment for age and sex and further after adjustment for traditional risk factors. In multivariate analysis, chronotropic response in men [estimate (95% CI): 0.94 (0.91-0.97), P = 0.0005] and an abnormal HR recovery (<15 bpm after 1 min) in women [estimate: 1.34 (1.07-1.70), P = 0.013] but not exercise capacity remained associated with CAC independent of traditional RF. In subjects not taking lipid-lowering, antiarrhythmic or antihypertensive drugs, estimates for the observed associations were essentially unchanged. The clinical ability of these variables to predict a high CAC score was limited. The strong inverse association of exercise capacity, chronotropic response and abnormal HR recovery during exercise stress testing with the CAC burden in unadjusted univariate analysis is largely influenced by age, sex and cardiovascular RFs. The degree, to which exercise stress-test variables and the CAC burden independently contribute to the prediction of cardiovascular events, remains to be shown.

Association of Exercise Capacity on Treadmill With Future Cardiac Events in Patients Referred for Exercise Testing

Little is known about the association between exercise capacity and nonfatal cardiac events in patients referred for exercise treadmill testing (ETT). Our objective was to determine the prognostic importance of exercise capacity for nonfatal cardiac events in a clinical population. A cohort study was performed of 9191 patients referred for ETT. Median follow-up was 2.7 years. Exercise capacity was quantified as the proportion of age- and sex-predicted metabolic equivalents achieved and categorized as less than 85%, 85% to 100%, and greater than 100%. Individual primary outcomes were myocardial infarction, unstable angina, and coronary revascularization. All-cause mortality was a secondary outcome. Patients with lower exercise capacity were more likely to be female (55.38% vs 42.62%); to have comorbidities such as diabetes (23.16% vs 9.61%) and hypertension (59.43% vs 44.05%); and to have abnormal ETT findings such as chest pain on the treadmill (12.09% vs 7.63%), abnormal heart rate recovery (82.74% vs 64.13%), and abnormal chronotropic index (32.89% vs 12.20%). In multivariable analysis, including other ETT variables, lower exercise capacity (<85% of predicted) was associated with increased risk of myocardial infarction (hazard ratio [HR], 2.36; 95% confidence interval [CI], 1.55-3.60), unstable angina (HR, 2.39; 95% CI, 1.78-3.21), coronary revascularization (HR, 1.75; 95% CI, 1.46- 2.08), and all-cause mortality (HR, 2.90; 95% CI, 1.88-4.47) compared with exercise capacity greater than 100% of predicted. Adjusting for patient characteristics and other ETT variables, reduced exercise capacity was associated with both nonfatal cardiovascular events and mortality in patients referred for ETT.