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Results for “Exercise Tolerance”

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At least 343 records · Page 19Linked to original sources

PubMed1991

Transient myocardial perfusion abnormalities in diabetic patients: a prospective study using thallium exercise tolerance testing.

To determine whether diabetic patients without known cardiovascular disease have exercise-induced perfusion abnormalities without symptoms, we performed thallium-201 exercise tolerance testing (ETT) on 16 subjects with diabetes mellitus (8 men and 8 women; mean age = 51 +/- 2 years). To compare these patients to another group at risk for coronary disease and painless myocardial infarction, 13 hypertensive (7 men and 6 women; mean age = 50 +/- 2 years) patients without symptoms of atherosclerotic disease served as controls. Diabetic and hypertensive patients were similar with regard to age, sex, years since diagnosis and other cardiac risk factors. Abnormal exercise thallium testing was more common among diabetic patients (11/16 = 69%; p less than 0.05) as compared to hypertensive patients (4/13 = 31%). None of the patients reported chest pain or its equivalent. There was no difference between diabetic and hypertensive subjects in the number of minutes exercised, percentage of maximal heart rate attained or final heart rate achieved. Diabetic subjects as a group had greater evidence of peripheral neuropathy but no abnormality of autonomic nerve function. Using ETT with thallium scintigraphy, diabetic patients without known cardiovascular disease were more likely to have transient myocardial perfusion defects than were hypertensive patients.

Adult↗

PubMed1984

Accuracy of pulmonary function tests in predicting exercise tolerance in chronic obstructive pulmonary disease.

The ability of pulmonary function tests (PFTs) to predict exercise capacity was investigated by using linear regression analysis to quantify the relationships between: (1) maximum oxygen consumption during treadmill exercise and PFT parameters; and (2) total external work performed during treadmill exercise and PFT parameters. In a group containing 11 healthy subjects, nine with mild/moderate chronic obstructive pulmonary disease (COPD) and ten with severe COPD, both maximum oxygen consumption (measured directly) and total external work (calculated indirectly from the sum of its horizontal and vertical components) correlated most strongly with indices of expiratory airflow (FEV1, FEF25-75%), less strongly with indices of ventilatory output (MVV) and resting levels of oxygen (PO2, SaO2), and weakly with indices of hyperinflation (FRC) and carbon dioxide retention (PCO2). Thus, FEV1, accounting for 56 percent and 60 percent of the observed variation in oxygen consumption and external work, respectively, can predict exercise tolerance from PFT measurements with some accuracy. If a more accurate evaluation is required, exercise testing should be prescribed.

Adolescent↗

PubMed1994

Ventilatory efficiency is unchanged after physical training in healthy persons despite an increase exercise tolerance.

BACKGROUND: In chronic heart failure, exercise training results in an improvement in exercise capacity and a reduction in the ventilatory response to exercise. The effects of a physical training programme on the ventilatory response in healthy persons is not known. METHODS: Metabolic gas exchange and ventilation were measured in 27 young healthy persons aged 31.4 +/- 7.6 years before and after a 19-week training programme of aerobic exercise; exercise was undertaken three times a week for 40 min. Ventilation, the slope of the relationship between ventilation and carbon dioxide production (VE-VCO2 slope) and the ventilatory equivalent for carbon dioxide were measured using respiratory mass spectroscopy. The peak expiratory flow rate in 1 s and forced vital capacity were also measured. RESULTS: Mean +/- SEM peak oxygen consumption increased from 39.5 +/- 1.5 to 45.4 +/- 1.7 ml/kg/min(P<0.001). Exercise time increased from 817 +/- 188 to 896 +/- 186 s (P<0.001). The respiratory exchange ratio at peak exercise was slightly lower after training: 1.30 +/- 0.02 compared with 1.36 +/- 0.03 (P = 0.02). Ventilation at equivalent stages of exercise was unchanged by training. The VE-VCO2 slope did not change (24.52 +/- 0.67 before training, 25.01 +/- 0.80 after training; NS). There was no change in the ventilatory equivalent for carbon dioxide either at rest (38.6 +/- 1.4 compared with 36.2 +/- 1.1; NS) or at its lowest point (23.3 +/- 0.6 compared with 22.9 +/- 3.2; NS). Neither exercise capacity nor the training response correlated with any of the measured ventilatory variables. CONCLUSION: In contrast to the situation in patients with chronic heart failure, there is no relationship between ventilatory variables and exercise capacity in healthy persons and no change in ventilatory performance as a result of physical training.

Adult↗

PubMed1999

Role of the oxygen uptake efficiency slope in evaluating exercise tolerance.

OBJECTIVE: To investigate the interprotocol agreement of oxygen uptake efficiency slope (OUES). METHODS: 16 Japanese children and adolescents (10 boys and six girls) underwent two sessions of maximal exercise testing according to the following two treadmill protocols: the standard Bruce protocol and the rapidly increasing staged (RIS) protocol. Maximal oxygen uptake (VO2max), the ventilatory anaerobic threshold (VAT), and the OUES were obtained from the gas analysis data. Agreement between the protocols was tested by means of the Bland-Altman method. RESULTS: Interprotocol agreement was excellent for the OUES (limit of agreement, -18% to 17% of the mean value), slightly less good for VO2max (limit of agreement, -20% to 24% of the mean value), and poor for the VAT (limit of agreement, -31% to 31% of the mean value). CONCLUSION: These results confirm the clinical usefulness of the OUES as a measure of evaluating exercise tolerance in the paediatric population.

Adolescent↗

PubMed1990

Effects of glutamate on exercise tolerance and circulating substrate levels in stable angina pectoris.

The effects of glutamate on exercise tolerance, ischemic threshold and venous substrate concentrations were studied in 20 patients with stable angina pectoris and positive stress tests. Each patient underwent 4 upright bicycle exercise tests on consecutive days. The first and fourth tests were performed without medication while the second and third tests were preceded by a low and high bolus dose of monosodium glutamate, either 0.8 and 1.5 mg/kg body weight intravenously (10 patients) or 40 and 80 mg/kg orally (10 patients). Comparison of the first and fourth tests revealed good reproducibility of electrocardiographic, hemodynamic and metabolic data. Glutamate increased exercise duration (p less than 0.05) in a dose-related way when given intravenously (59 +/- 14 and 153 +/- 14 seconds) and when given orally (53 +/- 21 and 90 +/- 23 seconds; all data are mean +/- standard error of the mean). It also delayed the onset of ST-segment depression (p less than 0.05) by 73 +/- 19, 120 +/- 23, 62 +/- 27 and 80 +/- 30 seconds, respectively. Hemodynamics were not changed by glutamate at rest or at comparable workloads, but at onset of ST-segment depression the heart rate-blood pressure product was increased (p less than 0.05). Glutamate administration induced dose-related 1.5- to 10-fold elevations in plasma glutamate, 15 to 50% decreases in plasma free fatty acids (p less than 0.05) and 5 to 30% increases in plasma alanine contents. Circulating levels of glucose, lactate, citrate and albumin were not modified by glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗

PubMed2006

Chronic L-arginine supplementation enhances endurance exercise tolerance in heart failure patients.

The purpose of the study was to determine the potential beneficial effect of six weeks oral L-arginine supplementation (LAS) on endurance exercise, an important determinant of daily-life activity in patients with chronic stable heart failure (CHF). After an initial incremental maximal exercise test, CHF patients performed an identical thirty-minute interval endurance exercise test before and after six weeks with (L-arginine group; ARG) or without LAS (control group; CTL). Hemodynamic, respiratory, and metabolic parameters were determined at rest, during exercise, and during recovery. Mean heart rate decreased throughout exercise and recovery after LAS (- 8.2 +/- 1.4 b x min(-1); p = 0.003 and - 6.7 +/- 1.6 b x min(-1); p < 0.001, respectively), systemic blood pressure and respiratory parameters remaining unchanged. Resting L-argininaemia increased from 102 +/- 11 to 181 +/- 37 micromol x l(-1) (p < 0.004) and exercise-induced peak increase in plasma lactate was blunted after LAS (4.13 +/- 0.75 vs. 3.13 +/- 0.39 mmol x l(-1); p = 0.02). No significant change was observed in the control group. In heart failure patients, six weeks oral LAS enhances endurance exercise tolerance, reducing both heart rate and circulating lactates. This suggests that chronic LAS might be useful as a therapeutic adjuvant in order to improve the patient's physical fitness.

Administration, Oral↗

PubMedDate not supplied

Effect of sublingual pentrinitrol on exercise tolerance in angina pectoris.

The effects of 10 mg sublingual pentrinitrol and placebo on the exercise tolerance of 20 patients with angina pectoris were compared. The ten patients who received pentrinitrol had increases in exercise times and metabolic oxygen equivalents (METs) 15 and 60 minutes after administration, whereas no change occurred in ten comparable patients receiving placebo. Pentrinitrol produced lower preexercise systolic blood pressures and systolic blood pressures at point of angina. An increase in heart rate offset the effect of the reduced systolic blood pressure on double product (systolic blood pressure times heart rate). Sublingual pentrinitrol is an effective antianginal drug for at least 60 minutes.

Adult↗

PubMed1980

The effect of repeated supine exercise on exercise tolerance and left ventricular pump function in patients with angina pectoris.

The reproducibility of symptoms, exercise tolerance and haemodynamic variables describing left ventricular pump function have been studied at rest and during repeated supine exercise in ten patients with severe angina pectoris. Two exercise periods were performed about 20 min apart and the breaking point was in all cases determined by angina pectoris. The average working capacity was 22.5 W in both exercise periods. Duration of work, time to onset of angina and pain level at breaking point were not different in the two periods. There were no significant differences at rest nor during exercise for oxygen uptake, arterio-venous oxygen difference, heart rate, cardiac output, stroke volume, left ventricular systolic and end-diastolic pressure, pulmonary artery mean pressure, right atrial mean pressure, stroke work index or left ventricular work. Pressure-time index was significantly (P less than 0.01) higher in the second rest period but systolic pressure heart rate product was not significantly different. The high reproducibility with very small variations of the variables studied should permit the use of this protocol to study the acute haemodynamic effects of pharmacological interventions at rest and during exercise in patients with severe effort-induced angina pectoris.

Aged↗

PubMed2006

Effects of sildenafil on pulmonary hypertension and exercise tolerance in severe cystic fibrosis-related lung disease.

Cystic fibrosis (CF) patients with advanced lung disease are at risk for developing pulmonary vascular disease and pulmonary hypertension, characterized by progressive exercise intolerance beyond the exercise-limiting effects of airways disease in CF. We report on a patient with severe CF lung disease who experienced clinically significant improvements in exercise tolerance and pulmonary hypertension without changing lung function during sildenafil therapy.

Adult↗

PubMed1992

[Evaluation of the relations between exercise tolerance, dyspnea and pulmonary function in patients with chronic obstructive lung diseases].

We studied 53 patients with severe COPD (FEV1 0.92 +/- 0.40 1, PaO2 61 +/- 9 mm Hg), aged 58 +/- 9 years, to assess the relationship between ability to exercise (6 MWD), dyspnea and baseline lung function parameters. Dyspnea at rest (D1) and during exercise (D2) was evaluated using VAS. During exercise dyspnea increased by 41 +/- 28, and oxygen saturation (StcO2) decreased from 92 +/- 3% to 84 +/- 9%. The fall in the StcO2 of more than 3% was observed in 42 patients (79%). We found that 6 MWD significantly correlated with the FEV1, VC and maximal dyspnea during exercise. There was no correlation between exercise tolerance and resting PaO2, PaCO2, severity of dyspnea at rest and the increase in dyspnea during exercise as well as with the resting and exercise StcO2 and the fall in StcO2 during walk. Dyspnea at rest and during exercise significantly correlated with air flow limitation and StcO2 at rest, during exercise and the exercise decrease in StcO2. There was a significant correlation between the fall in StcO2 during exercise and blood gases at rest. No relationship between the fall in StcO2 and the increase in dyspnea during exercise was found.

Dyspnea↗

PubMedDate not supplied

Exercise training for heart failure patients improves respiratory muscle endurance, exercise tolerance, breathlessness, and quality of life.

PURPOSE: Increased respiratory muscle endurance and peak oxygen consumption (VO(2peak)) induced by respiratory muscle training support the relationship between respiratory muscle function and exercise capacity in patients with heart failure. This raises the question whether exercise-training results in increased respiratory muscle function contributing to an increased exercise tolerance, a decreased perception of breathlessness, and an improved quality of life. METHODS: Prospective cohort analysis was completed on 24 patients with New York Heart Association (NYHA) Class III heart failure [18 men, 6 women; aged = 64 (SD 7.9) years; percent ejection fraction (%EF) = 24.0 (SD 7.8)]. Maximal sustainable ventilatory capacity (MSVC), submaximal and peak exercise responses, perception of breathlessness, and quality of life were measured before (baseline) and after (end of study) 12 weeks of exercise training. RESULTS: As a result of exercise training, VO(2peak) (P=.01) and MSVC (P<.001) increased, with MSVC contributing to a larger proportion of the variability for VO(2peak) at study completion (r=0.57 vs 0.42). Although stroke volume did not increase beyond exercise at 25 W and did not change with exercise training, ventilation decreased during exercise (P<.05), perception of breathing difficulty (P<.05) was reduced, and quality of life was enhanced (P=.008). CONCLUSIONS: Despite no increase in cardiac output and stroke volume, respiratory muscle endurance improved with exercise training, contributing to increased exercise capacity, decreased breathlessness, and decreased perception of breathlessness. Practical implications can include less frequent rest periods and fatigue, greater confidence, maintenance of independence, and enhanced quality of life.

Aged↗

PubMed1988

Improvement in cardiac performance and exercise tolerance after left ventricular aneurysm surgery--a prospective study.

Forty two patients were studied prospectively by rest and exercise radionuclide ventriculography before and after (10 +/- 4 months) left ventricular aneurysm resection. Functional classification (NYHA) improved from 3.0 +/- 0.6 to 2.3 +/- 0.5 (p less than 0.0001) with an increase in double product (p less than 0.01) and total exercise workload (p less than 0.04) over preoperative values. End-diastolic volume was significantly reduced (p less than 0.0001) and resting global left ventricular ejection fraction (LVEF) improved significantly (p less than 0.03) after surgery, as did regional ejection fractions of the lateral/inferior wall (p less than 0.01). Cardiac index (CI) at rest, however, remained unchanged. Under exercise, improvement of global (p less than 0.0003) and regional ejection fractions (p less than 0.02) was more pronounced and a significant increase was also observed for CI (p less than 0.003). Improvement in left ventricular performance occurred both in patients with single and multiple vessel disease, but was more distinct in the latter group who additionally received coronary artery bypass grafts. These patients were furthermore postoperatively able to increase global LVEF at exercise (p less than 0.05). We conclude that aneurysm resection with or without coronary bypass relieves cardiac symptoms and improves exercise tolerance and left ventricular function at rest and on exercise in most patients.

Adult↗

PubMed1986

Evaluation and treatment of the asymptomatic patient with a positive exercise tolerance test.

A positive exercise study in an asymptomatic patient presents a clinical dilemma. Many of these asymptomatic positive studies are false-positive, but a subset of these patients have silent coronary artery disease. Other noninvasive tests can be used in conjunction with exercise testing to help identify this subset of patients, but coronary angiography is often ultimately necessary to ensure an accurate diagnosis. An algorithm for the evaluation and treatment of the patient with an asymptomatic positive exercise study is proposed.

Angiography↗

PubMed2006

Mitral valve repair by Alfieri's technique does not limit exercise tolerance more than Carpentier's correction.

OBJECTIVE: The main goal of this study was to evaluate if the edge-to-edge mitral repair could be a limiting factor for exercise tolerance and to compare these results to those of classical techniques. METHODS: Between 2000 and 2002, 54 consecutive patients were operated on for mitral valve regurgitation (MR). Twenty-five patients were operated with Alfieri's technique (group A) and 29 patients with Carpentier's technique (group C). The mean age was 63.9 years in group A and 63.8 years in group C (p = 0.98). After a mean follow-up of 16.2+/-12 months, survivor patients were seen at the outpatient clinic, by the same physician for a clinical evaluation, an echocardiogram at rest and at peak exercise, and received a cardiorespiratory exercise testing with maximal oxygen uptake (VO2 max) recording. RESULTS: Clinical status improved with 0% of the patients in class NYHA III or IV in either group postoperatively versus 77% preoperatively. There was no significant MR in 80% of cases in group A versus 89.6% in group C (p = 0.54). The mean mitral valve area was 2.5 and 2.9 cm2 in groups A and C, respectively (p = 0.018). The mitral gradient at rest was 3.8 and 3.3 mmHg (p = 0.31) and the mitral gradient at peak exercise was 8.5 and 9.7 mmHg (p = 0.22) in groups A and C, respectively. Cardiorespiratory exercise testing showed a mean VO2 max of 73.7+/-15% of normal value in group A versus 79.6+/-13.1% in group C (p = 0.18). CONCLUSION: Alfieri's technique has the same efficiency on improvement of MR and clinical status than classical repair. Despite a higher restriction of mitral valve area at rest in group A, gradient and mean VO2 max at peak exercise were similar in both groups.

Aged↗

PubMed2005

Delayed preconditioning-mimetic actions of nitroglycerin in patients undergoing exercise tolerance tests.

BACKGROUND: Nitroglycerin (NTG) induces delayed preconditioning (PC)-mimetic effects in animal models and in humans during coronary angioplasty. We tested the hypothesis that NTG mitigates ischemia and enhances functional capacity during an exercise tolerance test (ETT) in patients with coronary artery disease. METHODS AND RESULTS: Twenty-eight patients with stable angina and ischemia documented by a stress test were randomized in a double-masked, crossover design to receive a titrated intravenous infusion of NTG or normal saline over 4 hours. At 24 to 28 hours after study medication infusion, each patient underwent 2 ETTs separated by a 1-week washout period. Compared with control patients, pretreatment with NTG was associated with a dose-dependent increase in exercise duration averaging 40 seconds (412+/-19 versus 372+/-24 seconds, P=0.014) and an improvement in ECG manifestations of ischemia, as shown by a decrease in maximal ST-segment depression (1.84+/-0.14 versus 1.63+/-0.13 mm, P=0.011), sum of ST-segment depressions in 12 leads (7.64+/-1.01 versus 6.61+/-0.83 mm, P=0.027), and time to resolution of ST-segment depression (229+/-30 versus 207+/-28 s, P=0.018). These benefits occurred despite an increase in myocardial workload after NTG, as indicated by a higher peak rate-pressure product (24 492+/-1054 versus 22 536+/-1019 mm Hg/min, P=0.015). CONCLUSIONS: NTG produces a late PC-mimetic effect that mitigates the ECG manifestations of ischemia during exercise and improves exercise capacity. To our knowledge, this is the first study to demonstrate that NTG can alleviate exercise-induced ischemia 24 hours after its administration, long after the hemodynamic effects have subsided. The finding that nitrate-induced late PC ameliorates a common manifestation of coronary artery disease has potentially significant implications for the management of this disorder and for the design of clinical trials.

Aged↗

PubMed2001

Exercise tolerance in children with cystic fibrosis undergoing lung transplantation assessment.

The aim of this study was to compare the 6-min walk test against the recently developed 3-min step test, as measures of exercise tolerance in children with moderate to severe cystic fibrosis (CF) lung disease referred for lung transplantation assessment. Twenty-eight children with CF (16 girls, 12 boys), with a mean age of 13.7 yrs (range 7.2-17.8 yrs) and mean forced expiratory volume in one second of 34% predicted (range 17%-67%) were recruited. All subjects performed both the 6-min walk and 3-min step-tests. Outcome measures were maximum rise in heart rate (HR), and maximum fall in arterial oxygen saturation (Sa,O2). There was no significant difference in resting HR or Sa,O2 prior to starting the two tests. Both step and walk tests produced significant rises in median HR (from 114-149 min(-1), p<0.0005, and 119-138 min(-1), p<0.0005, respectively) and significant falls in Sa,O2 (both from 94-92%, p<0.0005). The step test produced a significantly greater percentage rise in HR (30% versus 18%, p<0.0005) and a significantly greater percentage fall in Sa,O2 (4% versus 2%, p=0.002). Bland-Altman analysis gave wide 95% limits of agreement (10.7-29.3% for rise in HR, -2.14.6% for fall in Sa,O2). The step test was well tolerated. The 3-min step test produced a greater fall in Sa,O2 and a greater rise in HR than the 6-min walk test in children with moderate to severe CF lung disease. It may be of value when assessing a child's suitability for lung transplantation.

Adolescent↗

PubMed2004

Reduced exercise tolerance in CHF may be related to factors other than impaired skeletal muscle oxidative capacity.

BACKGROUND: We sought to determine whether skeletal muscle oxidative capacity, fiber type proportions, and fiber size, capillary density or muscle mass might explain the impaired exercise tolerance in chronic heart failure (CHF). Previous studies are equivocal regarding the maladaptations that occur in the skeletal muscle of patients with CHF and their role in the observed exercise intolerance. Methods and results Total body O(2) uptake (VO(2peak)) was determined in 14 CHF patients and 8 healthy sedentary similar-age controls. Muscle samples were analyzed for mitochondrial adenosine triphosphate (ATP) production rate (MAPR), oxidative and glycolytic enzyme activity, fiber size and type, and capillary density. CHF patients demonstrated a lower VO(2peak) (15.1+/-1.1 versus 28.1+/-2.3 mL.kg(-1).min(-1), P<.001) and capillary to fiber ratio (1.09+/-0.05 versus 1.40+/-0.04; P<.001) when compared with controls. However, there was no difference in capillary density (capillaries per square millimeter) across any of the fiber types. Measurements of MAPR and oxidative enzyme activity suggested no difference in muscle oxidative capacity between the groups. CONCLUSIONS: Neither reductions in muscle oxidative capacity nor capillary density appear to be the cause of exercise limitation in this cohort of patients. Therefore, we hypothesize that the low VO(2peak) observed in CHF patients may be the result of fiber atrophy and possibly impaired activation of oxidative phosphorylation.

Adenosine Triphosphate↗

PubMedDate not supplied

Relationship between pulmonary function and exercise tolerance in patients with ankylosing spondylitis.

OBJECTIVE: It is a well-known fact that pulmonary function is altered in ankylosing spondylitis (AS) mainly due to the restriction of chest wall movements. The objective of this study was to investigate whether alterations in pulmonary function affected exercise capacity. METHODS: Twenty male patients with definite AS and 20 age-matched healthy male controls were recruited for the study. All subjects were assessed for functional status by BASFI and physical activity level. Measurement of chest expansion and lumbar spinal flexion by the modified Schober method were performed. Pulmonary function tests and exercise testing on a treadmill using the Bruce protocol were performed. RESULTS: The physical activity level was similar in both groups. In the AS group the mean BASFI score suggested good functional capacity, while chest expansion and modified Schober measurements were significantly lower and pulmonary function tests revealed restrictive lung disease. The results of the exercise tolerance test were similar in both groups except for the rate of perceived exertion. CONCLUSION: This study demonstrated that exercise capacity in AS patients is not influenced by the limitation of chest wall movements, probably due to the maintenance of moderate physical activity along with an active life style.

Activities of Daily Living↗