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PubMed1989

Exercise capacity in patients 3 days after acute, uncomplicated myocardial infarction.

In a randomized, controlled trial of early hospital discharge after acute myocardial infarction (MI), a heart rate, symptom-limited exercise thallium test was performed after the onset of MI. Patients' exercise capacity was evaluated by the exercise treadmill with accompanying thallium scintigraphy. Of 507 consecutive patients screened, the condition of 179 was classified as uncomplicated, which is defined as the absence of angina, heart failure, or serious arrhythmias at 72 hours from admission. Of the patients with uncomplicated conditions, 126 had an exercise test on day 3 and 53 did not exercise on day 3. Of the 126 patients who exercised on day 3, 36 had a positive test and 90 had a negative test for ischemia. The 36 patients with a positive test result exercised a mean time of 6.71 +/- 2.8 minutes, achieved a mean peak heart rate of 120.9 +/- 21.4 beats/min, reached a peak systolic blood pressure of 144.7 +/- 33.3 mm Hg, and achieved a double product (rate-pressure product) of 183.4 +/- 67.6. The 90 patients with a negative test result for ischemia exercised 9.45 +/- 12.7 minutes, achieved a peak heart rate of 130.2 +/- 14.4 beats/min, reached a mean systolic blood pressure of 155.5 +/- 29.4 mm Hg, and achieved a rate-pressure product of 210.5 +/- 44.0. Of the 90 patients with uncomplicated conditions who had a negative exercise test for ischemia, 85 patients received reperfusion therapy, which included thrombolysis or coronary angioplasty or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Effect of atrial fibrillation on exercise capacity in mitral stenosis.

To determine the preoperative and postoperative effect of atrial fibrillation (AF) on exercise capacity in mitral stenosis, 12 digitalized patients in AF (7 women and 5 men, age 52 +/- 6.1 years) and 10 in sinus rhythm (5 women and 5 men, age 46 +/- 5 years) underwent maximal cardiopulmonary exercise testing according to Weber's protocol and Doppler echocardiographic examination before and at 3 and 6 months after mitral valve replacement. The ratio of right ventricular acceleration to ejection time was used as an estimate of mean pulmonary artery pressure. Preoperative exercise duration (6.8 +/- 1 vs 8 +/- 2 minutes), peak oxygen consumption (9.7 +/- 3 vs 12.3 +/- 3 ml/kg/min), and right ventricular acceleration to ejection time ratio (0.34 +/- 0.07 vs 0.34 +/- 0.08) were not significantly different between patients with AF and those in sinus rhythm. Postoperative improvement in these parameters was lower in patients with AF than in those in sinus rhythm: exercise duration at 3 months, 7.5 +/- 2 vs 11.9 +/- 2 minutes (p < 0.001); at 6 months, 9 +/- 2 vs 12 +/- 2 minutes (p < 0.001); peak oxygen consumption at 3 months, 10.8 +/- 3 vs 17.5 +/- 3 ml/kg/min (p < 0.001); and at 6 months, 11.9 +/- 3 vs 17.8 +/- 3 ml/kg/min (p < 0.001); right ventricular acceleration to ejection time ratio at 3 months, 0.35 +/- 0.08 vs 0.42 +/- 0.05 (p < 0.05); and at 6 months, 0.38 +/- 0.05 vs 0.44 +/- 0.05 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗

PubMed1992

Diastolic function in hypertrophic cardiomyopathy: relation to exercise capacity.

Doppler echocardiography was used to assess diastolic function in 40 patients with hypertrophic cardiomyopathy and to relate it to the patients' symptoms, anaerobic threshold and maximal oxygen consumption during cardiopulmonary exercise testing. The patients had a smaller early (E wave) (p less than 0.01), higher late (A wave) (p less than 0.05) mitral diastolic flow velocity, larger A/E ratio (p less than 0.01), longer isovolumetric relaxation time and E wave duration (p less than 0.001) and slower deceleration rate of the E wave (p less than 0.001) than 40 age- and gender-matched normal subjects. In the patients with hypertrophic cardiomyopathy, maximal oxygen consumption and anaerobic threshold were, respectively, 26.3 +/- 9.2 and 21.1 +/- 6.1 ml/kg per min compared with 47 (range 39 to 68) (p less than 0.01) and 41 (range 27 to 58) ml/kg per min (p less than 0.01) in normal subjects. There was no relation between Doppler indexes and symptoms but symptomatic patients had lower maximal oxygen consumption and anaerobic threshold compared with asymptomatic patients (21.4 +/- 7 vs. 30.7 +/- 10, p less than 0.001 and 18.6 +/- 4.7 vs. 23.1 +/- 5.7, respectively, p less than 0.001). In conclusion, Doppler echocardiography can identify abnormalities of left ventricular filling in patients with hypertrophic cardiomyopathy. However, these indexes measured at rest do not correspond to the patient's professed symptomatic status or exercise capacity measured objectively. Conversely, cardiopulmonary exercise testing reveals a depressed maximal oxygen consumption and anaerobic threshold even in the least symptomatic patients.

Adolescent↗

PubMed1996

Respiratory rehabilitation, exercise capacity and quality of life in chronic airways disease in old age.

Respiratory rehabilitation improves exercise capacity and quality of life in younger patients but is untried in the aged. We aimed to: (a) assess repeatability of the 6-minute walk test, factors affecting it and its relation to quality of life in elderly patients with chronic obstructive airways disease (COAD); (b) assess compliance of such patients with an intensive respiratory rehabilitation protocol; (c) pilot the assessment of the effect of respiratory rehabilitation on the 6-minute walk test in these patients. Seventeen subjects with stable, symptomatic COAD were recruited, 15 (six men), 70-89 (mean 76) years, completed the study. Mean (standard deviation) 1-second forced expiratory volume (FEV1) = 49 (5)% predicted. Six-minute walk tests were repeated single-blind, 2-10 days apart. Quality of life was measured using Guyatt respiratory questionnaire. Patients underwent 12 weeks incremental respiratory rehabilitation (x4/day step-ups, unweighed arm raises, inflating balloons). Baseline 6-minute walk was repeatable and was correlated with the log Guyatt dyspnoea score (r = 0.65, p = 0.006). In multiple regression neither age nor FEV1 predicted walk distance: body mass index, maximal expiratory mouth pressure; calorie intake. Mean (SEM) 6-minute walk distance after-rehabilitation was greater than baseline (p = 0.003). Elderly patients with COAD tolerate intensive respiratory rehabilitation and a controlled, blinded study is needed.

Aged↗

PubMed2002

Peak exercise capacity of electrically induced ambulation in persons with paraplegia.

INTRODUCTION: Persons with spinal cord injury (SCI) are generally limited to exercise activities using the relatively smaller, less productive upper extremities with limited benefits as compared with leg exercise training. Functional electrical stimulation (FES) assisted ambulation has previously been demonstrated to allow persons with paraplegia to stand and ambulate limited distances. PURPOSE: This study compared the peak physiological responses of persons with paraplegia during FES ambulation and voluntary arm exercise. METHODS: Fifteen subjects (T -T ) previously habituated to FES ambulation, completed peak testing of both arm cranking (AC) and FES walking to the point of exhaustion. The AC tests were performed using a graded incremental protocol to exhaustion in 3-min stages and 10-W power output increments. The FES walking test consisted of successive 10-m walking bouts, each trial progressively increased in pace. Metabolic activity was continuously monitored via open-circuit spirometry with heart rate (HR) determined by a 12-lead electrocardiograph for AC and by direct palpation during FES. RESULTS: Peak VO(2) did not differ between AC (22.9 +/- 3.8 mL x kg x min(-1)) and FES (22.7 +/- 3.9 mL x kg x min(-1)). FES ambulation elicited significantly greater peak values of HR (191 beats x min(-1) versus 179 beats x min(-1)) and lower peak values of respiratory exchange ratio (1.06 vs 1.12) compared with AC. There were no significant differences in peak values of any other variables. CONCLUSION: This study indicates that FES ambulation performance, in persons with paraplegia, elicits similar exercise capacity, as indicated by similar peak oxygen consumption, as voluntary arm exercise.

Adult↗

PubMed2002

Relation of aortic distensibility determined by magnetic resonance imaging in patients > or =60 years of age to systolic heart failure and exercise capacity.

Aortic stiffness increases with advancing age and is associated with the age-related decline in exercise capacity in healthy persons. Previous studies have suggested that aortic compliance is reduced in heart failure (HF). Older persons with systolic HF can have particularly severe exercise intolerance. However, the relation between increased aortic stiffness and exercise intolerance in elderly patients with systolic HF has not been examined. Therefore, aortic distensibility of the proximal ascending aorta (assessed by magnetic resonance imaging) and exercise tolerance (assessed by maximal exercise ergometry with expired gas analysis) was measured in 28 subjects (10 healthy subjects aged 20 to 30 years, 10 healthy subjects aged > or =60 years, and 8 subjects aged > or =60 years with systolic HF). Compared with healthy older subjects, patients with systolic HF had markedly decreased distensibility of the proximal aorta (0.5 +/- 0.4 vs 2.2 +/- 1.2 10(-3) mm Hg(-1), p <0.002), decreased peak exercise volume of oxygen consumption (VO2) (858 +/- 248 vs 1,436 +/- 344 ml/min, p <0.001), and increased aortic wall thickness (3.6 +/- 0.7 vs 2.9 +/- 0.4 mm, p <0.04). Aortic distensibility was significantly correlated with peak VO2 (r = 0.80, p <0.0001) and remained so even after being adjusted for age and left ventricular (LV) ejection fraction. These data suggest that decreased aortic distensibility may contribute to exercise intolerance in older patients with HF due to LV systolic dysfunction.

Adult↗

PubMed1993

Atrial adaptive rate pacing in sick sinus syndrome: effects on exercise capacity and arrhythmias.

OBJECTIVE: To test the hypotheses that adaptive rate atrial (AAIR) pacing: significantly increases maximal exercise capacity, and results in significant suppression of supraventricular and ventricular arrhythmia compared with fixed rate atrial (AAI) pacing. DESIGN: Prospective, randomised, single blind, crossover study with maximal treadmill exercise testing and 24 hour ambulatory electrocardiographic monitoring in AAIR and AAI modes. SETTING: Regional pacing centre. PATIENTS: 30 consecutive patients (mean SD age 65 (12) years) with sick sinus syndrome who required permanent pacing, without evidence of conduction disturbance on 12 lead electrocardiograms or 24 hour ambulatory electrocardiographic monitoring and without other cardiovascular or systemic disease. INTERVENTIONS: Activity sensing or minute ventilation driven systems (AAI/AAIR) were implanted alternately. RESULTS: The mean (SD) peak heart rate in AAI mode was 122(28)v 130(22) in AAIR mode (p < 0.02) for the whole group and 104(17) v 120(5) (p < 0.003) for the patients with chronotropic incompetence. Exercise time was 12.3 (4.1) minutes in AAI and 12.3 (3.8) minutes in AAIR mode (NS) in the chronotropically incompetent patients. There were no significant differences in the Borg scores at peak exercise in AAI v AAIR mode in either group. The frequency per hour of atrial and ventricular arrhythmias showed no significant differences between the two modes in either the group as a whole or in the subgroups with chronotropic incompetence. CONCLUSION: AAIR pacing confers little benefit in sick sinus syndrome compared with AAI pacing.

Aged↗

PubMed1994

Predictors of exercise capacity in chronic heart failure.

Abnormalities of skeletal muscle rather than of haemodynamics may be important determinants of exercise capacity in chronic heart failure. We investigated an array of indicators of central haemodynamics and peripheral muscle function to establish which resting measurements predicted exercise performance. In 20 patients quadriceps strength, resting and peak leg blood flow and leg muscle cross sectional area were measured. In 18 patients average daytime blood pressure and pulse rate, haemodynamic variables at rest and during exercise, and autonomic activity were measured. There were correlations between peak oxygen consumption and quadriceps strength (0.65; P = 0.007), thigh muscle cross sectional area (r = 0.63; P = 0.004), and average daytime systolic blood pressure (r = 0.66; P < 0.01). There were no correlations with indices of peripheral blood flow, measures of haemodynamic function, or autonomic function. Quadriceps strength was the most important individual correlate of exercise tolerance (r = 0.73). With total muscle cross sectional area and left quadriceps strength also taken into consideration, 82% of the variation in peak oxygen consumption was explained. Of the haemodynamic variables, only average daytime systolic blood pressure predicted exercise performance. The resting variables that best predict exercise performance in chronic heart failure are measures of skeletal muscle function and bulk, and average daytime systolic blood pressure. These findings suggest that abnormalities in the periphery largely determine exercise performance in chronic heart failure, and that the ability of the heart to generate an adequate blood pressure response to daily activities is also predictive of functional status.

Autonomic Nervous System↗

PubMed1983

Mechanisms for decreased exercise capacity after bed rest in normal middle-aged men.

The mechanisms responsible for the decrease in exercise capacity after bed rest were assessed in 12 apparently healthy men aged 50 +/- 4 years who underwent equilibrium gated blood pool scintigraphy during supine and upright multistage bicycle ergometry before and after 10 days of bed rest. After bed rest, echocardiographically measured supine resting left ventricular end-diastolic volume decreased by 16% (p less than 0.05). Peak oxygen uptake during supine effort after bed rest was diminished by 6% (p = not significant [NS]), whereas peak oxygen uptake during upright effort declined by 15% (p less than 0.05). After bed rest, increases in heart rate were also greater during exercise in the upright than in the supine position (p less than 0.05). Values of left ventricular ejection fraction increased normally during both supine and upright effort after bed rest and were higher than corresponding values before bed rest (p less than 0.05). After bed rest, increased left ventricular ejection fraction and heart rate largely compensated for the reduced cardiac volume during supine effort, but these mechanisms were insufficient to maintain oxygen transport capacity at levels during upright effort before bed rest. These results indicate that orthostatically induced cardiac underfilling, not physical deconditioning or left ventricular dysfunction, is the major cause of reduced effort tolerance after 10 days of bed rest in normal middle-aged men.

Bed Rest↗

PubMed1986

Exercise capacity in hemodialysis, CAPD, and renal transplant patients.

Eighteen hemodialysis, 12 chronic ambulatory peritoneal dialysis (CAPD), and 20 renal transplant patients performed maximal treadmill exercise tests. Heart rates and blood pressures were determined every minute and maximal oxygen consumption was measured directly. Exercise capacity as measured by VO2 max is low in dialysis patients and similar to sedentary normal individuals in renal transplant patients. Maximal heart rates were significantly lower in hemodialysis patients than transplant recipients. The lower exercise tolerance in end-stage renal disease indicates that most patients regardless of the treatment mode could benefit from attempts through exercise training to increase physical working capacity.

Adult↗

PubMed1994

The effect of lower body positive pressure on the exercise capacity of individuals with spinal cord injury.

The purpose of this study was to determine the effect lower body positive pressure (LBPP) has on the cardiovascular/exercise capacities of individuals with spinal cord injury (SCI) during both arm crank exercise (ACE) and wheelchair exercise performed on a treadmill (WCTM). Ten male adults (age = 31.1 +/- 10 yr) with SCI and five male nondisabled (ND) adults (31.2 +/- 10 yr) participated in this study. The ND subjects performed ACE only. For subjects with SCI, significantly higher (P < 0.025) peak VO2 (1042 +/- 212 vs 839 +/- 218 ml.min-1), peak VE (46 +/- 17 vs 35 +/- 9 l.min-1), and work rate (50 +/- 15 vs 40 +/- 13 W) were seen during ACE with LBPP. No significant differences for peak VO2, VE, or work rate were seen for the ND subjects with LBPP during ACE. In addition, significantly higher peak VO2 (960 +/- 322 vs 828 +/- 312 ml.min-1) was recorded with LBPP for the subjects with SCI during WCTM. Cardiac output (Q, l.min-1; CO2 rebreathing method) was measured at 50% peak VO2 for both ND subjects and subjects with SCI during ACE. Subjects with SCI demonstrated significantly higher SV (94 +/- 20 vs 84 +/- 20 ml) with LBPP. No differences were observed in SV at 50% peak VO2 during ACE for the ND subjects with LBPP. The results of this study suggest that for individuals with SCI, LBPP augments exercise capacity by preventing the redistribution of blood to the lower extremities.

Adolescent↗

PubMed2003

Resting lung function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure.

STUDY OBJECTIVES: The aim of this study was to examine the role of resting pulmonary function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure. MEASUREMENTS AND RESULTS: Fifty-one patients with chronic heart failure underwent resting pulmonary function testing, including inspiratory capacity (IC) and symptom-limited, treadmill cardiopulmonary exercise testing (CPET). Right-heart catheterization and radionuclide ventriculography were performed within 2 days of CPET. Mean (+/- SD) left ventricular ejection fraction was 31 +/- 12% and cardiac index was 2.34 +/- 0.77 L/min/m(2). Percentage of predicted FEV(1) was 92 +/- 14%, percentage of predicted FVC was 94 +/- 15%, FEV(1)/FVC was 81 +/- 4%, and percentage of predicted IC was 84 +/- 18%. Mean peak oxygen uptake (peak O(2)) was 17.9 +/- 5.4 mL/kg/min. Analysis of variance among the three functional Weber classes showed statistically significant differences for pulmonary capillary wedge pressure (PCWP) and IC. Specifically, the more severe the exercise intolerance, the lower was IC and the higher was PCWP. In a multivariate stepwise regression analysis, using peak O(2) (liters per minute) as the dependent variable and the pulmonary function test measurements as independent variables, the only significant predictor selected was IC (r = 0.71, p < 0.0001). In a final stepwise regression analysis including all the independent variables of the resting pulmonary function tests and hemodynamic measurements, the two predictors selected were IC and PCWP (r(2) = 0.58). CONCLUSIONS: In patients with chronic heart failure, IC is inversely related to PCWP and is a strong independent predictor of functional capacity.

Cardiac Output↗

PubMed1990

Effects of isosorbide dinitrate on exercise capacity in cardiac patients--relationship between oxygen uptake responses and hemodynamic effects.

Acute effects of oral isosorbide dinitrate on exercise capacity were evaluated in 14 patients with chronic heart disease measuring the anaerobic threshold and left ventricular function during exercise. A symptom-limited exercise test was performed on a bicycle ergometer with work rates increased by 1W every 6 seconds. Left ventricular function was continuously monitored with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Thirty minutes after the control exercise test, patients were given isosorbide dinitrate, 5 mg orally. The second exercise test was performed 30 min later. Isosorbide dinitrate improved the anaerobic threshold from 715.4 +/- 172.9 to 774.9 +/- 173.5 ml/min (p less than 0.01) and ejection fraction at peak exercise from 36.7 +/- 11.6 to 39.9 +/- 12.3% (p less than 0.05). However, there was no significant change in maximum work rate or peak oxygen uptake. Those patients for whom isosorbide dinitrate resulted in a 10% or greater improvement in the anaerobic threshold had both higher pre-treatment ejection fractions and greater increases in peak exercise ejection fraction following isosorbide dinitrate. Measurements of the anaerobic threshold and left ventricular function during exercise may be useful in the evaluation of the efficacy of vasodilators in cardiac patients.

Anaerobiosis↗

PubMed2003

Longitudinal trends in exercise capacity and health status after pulmonary rehabilitation in patients with COPD.

Pulmonary rehabilitation (PR) programmes produce initial improvements in exercise tolerance and health status in patients with chronic obstructive pulmonary disease (COPD). However, there is limited data on the longer term effects of PR. This study has examined whether the initial benefits gained in exercise tolerance and health status may be maintained after a 1-year follow-up programme. Sixty-six patients with COPD were assessed with the MRC Dyspnoea Scale and found to be moderately disabled due to dyspnoea (MRC Grades 3 and 4). These patients were then randomised to an 8 week outpatient programme of either exercise training and education (Exercise group) or to education alone (Control group). Exercise performance was assessed with the shuttle walking test and health status assessed with two disease-specific measures, the St Georges Respiratory Questionnaire and the Chronic Respiratory Disease Questionnaire. After PR, all patients were invited to attend monthly follow-up sessions for 1 year. Fifty-six patients were available for follow-up immediately after the programme and were assessed at 6 months and 1 year. This study has shown that the patients in the Exercise group maintained improvements in exercise capacity and health status up to 6 months after an 8 week programme. At 1 year there was a significant difference between the Exercise and Control groups in terms of exercise tolerance due to a considerable decline experienced by the Control group. However, neither group had maintained improvements in health status at 1 year. Further study is required to assess whether benefit may be sustained for a longer period using alternative follow-up strategies.

Activities of Daily Living↗

PubMed2005

Value of left atrial function in predicting exercise capacity in heart failure with moderate to severe left ventricular systolic dysfunction.

Left atrial (LA) function is associated with left ventricular (LV) diastolic filling and cardiac output response to exercise. But the relation between LA function and exercise performance has not been adequately evaluated. The aim of this study was to investigate the relation between LA function and exercise capacity in dilated cardiomyopathy (DCM) with cardiopulmonary exercise testing. Forty-four patients with a left ventricular end-diastolic dimension (LVDd) > or = 60 mm and an ejection fraction (EF) < or = 40%, and in normal sinus rhythm were included in this study. Patients were divided into group 1 and group 2 according to their exercise peak oxygen uptake (VO2) (group 1: peak VO2 >14 mL/kg/min, group 2: peak VO2 < or = 14 mL/ kg/min). LA function indices were defined as follows: LA end-systolic diameter (LASd), end-diastolic diameter (LADd), LA systolic volume (LASV), LA diastolic volume (LADV), LA ejection volume (LAEV), and LA ejection fraction (LAEF). LASd, LADd, LASV, and LADV were significantly increased in group 2 (P < 0.001, P < 0.001, P < 0.05, P < 0.005). Group 1 had significantly higher LAEF (P < 0.001 ) and LVEF (P < 0.05). Group 2 had significantly shorter exercise duration, and decreased anaerobic threshold levels and minute ventilation volumes (P < 0.001, P < 0.001, P < 0.005 ). There was a positive correlation between peak VO2 and LVEF (r = 0.46, P = 0.002), and LAEF (r = 0.61, P < 0.001), peak A wave velocity (r = 0.39, P = 0.009), E wave deceleration time (r = 0.56, P < 0.001), and isovolumic relaxation time (IVRT) (r = 0.35, P = 0.04). There was a negative correlation between peak VO2 and LASd (r = -0.53, P < 0.001) LADd (r = -0.59, P < 0.001), LASVI (r = -0.34, P = 0.027), LADVI (r = -0.37, P = 0.001), and the E/A ratio (r = -0.41, P = 0.006), Decreased LAEF and increased LA sizes were associated with decreased peak VO2. The results clearly demonstrate that LA functions at rest are related to exercise performance in patients with heart failure.

Atrial Function, Left↗

PubMed2005

The influence of intermittent altitude exposure to 4100 m on exercise capacity and blood variables.

This study was performed to investigate the effects of intermittent hypoxic exposure on blood and exercise parameters. Eight sea level residents were exposed to 2 h daily stimulus to 4100 m altitude in a hypobaric chamber for a total of 14 days. Exercise performance was evaluated at sea level before and after the hypoxic stimulation. Blood samples were obtained before, during, and at time points up to 14 days after the hypoxic exposure. No changes were observed in haemoglobin, haematocrit, reticulocytes, serum transferrin receptors, or EPO levels in the blood. Submaximal cycle (150 W) ergometer exercise corresponded to a oxygen uptake of 1.9+/-0.1 and 1.9+/-0.1 L min(-1) before and after the intermittent altitude exposure, respectively. At maximal exercise the workloads attained were 343+/-17 and 354+/-27 W before and after the exposure, with corresponding oxygen uptakes of 4.0+/-0.2 and 4.2+/-0.2 L min(-1). It is concluded that intermittent hypoxic exposure to 4100 m altitude for 2 h daily and a total of 14 days does not affect exercise capacity.

Adult↗

PubMed2006

Impairment of physical exercise capacity in healthy postmenopausal women.

BACKGROUND: Healthy postmenopausal women reveal a series of peripheral vascular abnormalities, whose possible consequences on exercise performance has not been yet elucidated. METHODS: We studied the response to strenuous exercise in 25 postmenopausal women (mean age 50 +/- 3 years) without cardiovascular risk factors or disease through an integrative cardiopulmonary test. RESULTS: In comparison with 25 premenopausal subjects matched for age and biophysical characteristics, postmenopausal women showed a lower maximal workload (P < .01) and maximum VO2 (P < .01), an early anaerobic threshold (P < .05), and a lower ratio between increase of VO2 consumption and work rate (P < .01). CONCLUSIONS: Our results suggest that menopause could represent an important concomitant cause in determining an impairment of exercise capacity. The set of cardiopulmonary abnormalities found in the present study seems to identify the peripheral circulation as the limiting system in postmenopausal women experiencing exercise intolerance. Finally, present findings are in favor of an early introduction of postmenopausal hormone replacement therapy.

Anaerobic Threshold↗

PubMed2002

Effects of acute and chronic alacepril treatment on exercise capacity and hemodynamics in patients with heart failure: a preliminary study.

OBJECTIVE: This study determined whether alacepril treatment improves exercise hemodynamics in patients with heart failure. METHODS: Supine bicycle ergometer exercise was performed after administration of placebo and after acute and chronic (12 weeks) alacepril treatment in 4 patients with heart failure. Oxygen uptake (VO2), arterial oxygen saturation (SaO2), and mixed venous oxygen saturation (SvO2) were measured continuously using a pulse oxymeter and a fiber optic catheter. Cardiac index was calculated with Fick's equation. RESULTS: Acute alacepril treatment did not significantly alter the VO2 or hemodynamics. After chronic alacepril treatment, peak VO2 increased (placebo vs chronic alacepril treatment: 17.7 +/- 2.8 vs 21.7 +/- 2.8 ml/min/kg, p < 0.05). Arteriovenous oxygen difference (SaO2 - SvO2) at peak exercise was not altered, however, cardiac index at peak exercise (5.07 0.67 vs 6.35 +/- 0.48 I/min/m2, p = 0.02) increased and stroke volume index at peak exercise (37.3 +/- 3.4 vs 46.5 +/- 1.1 ml/m2, p = 0.07) tended to increase. CONCLUSIONS: Chronic treatment with alacepril improved maximal exercise capacity in patients with heart failure. The increased peak VO2 was primarily due to the increased cardiac index, but not due to the widening of arteriovenous oxygen difference. Therapy-induced increase in stroke volume index may contribute to the increased cardiac index at peak exercise in our patients with heart failure.

Adult↗