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PubMed2006

Effects of phosphatidylserine on exercise capacity during cycling in active males.

PURPOSE: The purpose of the study was to investigate the effects of 750 mg of soybean-derived phosphatidylserine, administered daily for 10 d, on exercise capacity, oxygen uptake kinetic response, neuroendocrine function, and feeling states during exhaustive intermittent exercise. METHODS: Following preliminary testing, fourteen active males completed a staged intermittent exercise protocol on two further occasions (T1 and T2) separated by 16 +/- 1 d. The protocol consisted of three 10-min stages of cycling at 45, 55, and 65% VO2max, followed by a final bout at 85% VO2max that was continued until exhaustion. Approximately 5 d after T1 the subjects were assigned, in a double-blind manner, to either phosphatidylserine (PS) or placebo (P). Breath-by-breath respiratory data and heart rate were continually recorded throughout the exercise protocol, and blood samples were obtained at rest, during the rest periods within the protocol (Post-55, Post-65), at the end of exercise (Post-85), 20 min after the completion of exercise (postexercise), and the day following exercise (Post-24 h). RESULTS: The main finding of this study was that supplementation had a significant effect on exercise time to exhaustion at 85% VO2max (P = 0.005). The exercise time to exhaustion in PS increased following supplementation (7:51 +/- 1:36 to 9:51 +/- 1:42 min:s, P = 0.001), whereas P remained unchanged (8:09 +/- 0:54 to 8:02 +/- 0:54 min:s, P = 0.670). Supplementation did not significantly affect oxygen kinetic mean response times (MRT(on) and MRT(off)), serum cortisol concentrations, substrate oxidation, and feeling states during the trial. CONCLUSION: This is the first study to report improved exercise capacity following phosphatidylserine supplementation. These findings suggest that phosphatidylserine might possess potential ergogenic properties.

Adult↗

PubMed1990

Association between recombinant human erythropoietin and quality of life and exercise capacity of patients receiving haemodialysis. Canadian Erythropoietin Study Group.

OBJECTIVE: To determine whether recombinant human erythropoietin improves the quality of life and exercise capacity of anaemic patients receiving haemodialysis. DESIGN: A double blind, randomised, placebo controlled study. SETTING: Eight Canadian university haemodialysis centres. PATIENTS: 118 Patients receiving haemodialysis aged 18-75 with haemoglobin concentrations less than 90 g/l, no causes of anaemia other than erythropoietin deficiency, and no other serious diseases. INTERVENTIONS: Patients were randomised to three groups to receive placebo (n = 40), erythropoietin to achieve a haemoglobin concentration of 95-110 g/l (n = 40), or erythropoietin to achieve a haemoglobin concentration of 115-130 g/l (n = 38). Erythropoietin was given intravenously thrice weekly, initially at 100 units/kg/dose. The dose was subsequently adjusted to achieve the target haemoglobin concentration. All patients with a serum ferritin concentration less than 250 micrograms/l received oral or intravenous iron for one month before the study and as necessary throughout the trial. MAIN OUTCOME MEASURES: Scores obtained with kidney disease questionnaire, sickness impact profile, and time trade off technique; and results of six minute walk test and modified Naughton stress test. RESULTS: The mean (SD) haemoglobin concentration at six months was 74 (12) g/l in patients given placebo, 102 (10) g/l in those in the low erythropoietin group, and 117 (17) g/l in those in the high erythropoietin group. Compared with the placebo group, patients treated with erythropoietin had a significant improvement in their scores for fatigue, physical symptoms, relationships, and depression on the kidney disease questionnaire and in the global and physical scores on the sickness impact profile. The distance walked in the stress test increased in the group treated with erythropoietin, but there was no improvement in the six minute walk test, psychosocial scores on the sickness impact profile, or time trade off scores. There was no significant difference in the improvement in quality of life or exercise capacity between the two groups taking erythropoietin. Patients taking erythropoietin had a significantly increased diastolic blood pressure despite an increase in either the dose or number of antihypertensive drugs used. Eleven of 78 patients treated with erythropoietin had their sites of access clotted compared with only one of 40 patients given placebo. CONCLUSIONS: Patients receiving erythropoietin were appreciably less fatigued, complained of less severe physical symptoms, and had moderate improvements in exercise tolerance and depression compared with patients not receiving erythropoietin. At the doses used in this trial there was a higher incidence of hypertension and clotting of the vascular access in patients treated with erythropoietin.

Adolescent↗

PubMed2004

The effects of GH replacement therapy on cardiac morphology and function, exercise capacity and serum lipids in elderly patients with GH deficiency.

OBJECTIVES: To assess effects of GH replacement therapy on cardiac structure and function, exercise capacity as well as serum lipids in elderly patients with GH deficiency (GHD). PATIENTS AND METHODS: Thirty-one patients (six females, 25 males), aged 60-79 years (mean 68 years) with GHD on stable cortisone and thyroxine substitution were studied. All men with gonadotropin deficiency had testosterone and one woman had oestrogen replacement. They were randomized in a double-blind manner to GH or placebo treatment for 6 months, followed by another 12 months GH (Humatrope, Eli Lilly & Co, Uppsala, Sweden). GH dose was 0.017 mg/kg/week for 1 month and then 0.033 mg/kg/week divided into daily subcutaneous injections at bedtime. Echocardiography, exercise capacity tests and serum lipid measurements were performed at 0, 6, 12 and 18 months. RESULTS: During the 6-month placebo-controlled period there were no significant changes in the placebo group, but in the GH-treated group there was a significant increase in IGF-I to normal levels for age, with median IGF-I from 6.9 to 18.5 nmol/l, increase in resting heart rate and maximal working capacity. During the open GH study, IGF-I increased from 8.7 to 19.2 nmol/l at 6 months and 18.8 nmol/l at 12 months (P </= 0.001). At 6 months, in the open GH study group, a minor decrease in aortic outflow tract integral (VTI) from 21.8 to 20.7 cm (P = 0.031) and an increase in heart rate at rest from 63 to 67 bpm (P = 0.017), heart rate at maximum exercise from 138 to 144 bpm (P = 0.005) and maximum load at exercise from 142 to 151 Watts (P = 0.014) were seen. These changes were temporary and returned at 12 months with no significant difference from baseline values. Left ventricular dimensions and blood pressure showed no significant changes. At 6 months, in the open GH study group, there was a significant decrease in serum low-density lipoprotein (LDL) cholesterol from 3.7 to 3.4 mmol/l (P = 0.006), a decrease in LDL/HDL ratio from 3.4 to 3.1 (P = 0.036) and a decrease in serum total cholesterol from 5.6 to 5.3 mmol/l (P = 0.036). At 12 months, serum lipids showed same changes with a significant decrease in serum LDL cholesterol (P = 0.0008), in LDL/HDL ratio (P = 0.0005) and in serum total cholesterol (P = 0.049). Serum HDL cholesterol showed no significant change at 6 months, at 12 months a significant increase was seen from 1.2 to 1.4 mmol/l (P = 0.007). There were no significant changes in serum triglycerides. CONCLUSIONS: GH substitution to elderly patients with GHD caused only a transient increase in heart rate. At the end of the 12 months there were no significant changes on cardiac noninvasive structural and functional parameters. Maximal working capacity transiently improved. Thus, the therapy was safe without negative effects on cardiac structural and functional noninvasive parameters. Lipid profiles improved with reduction of serum LDL cholesterol accompanied by significant improvement of LDL/HDL ratio and serum HDL cholesterol after 12 months treatment.

Aged↗

PubMed1999

Chronotropic competence in endurance trained heart transplant recipients: heart rate is not a limiting factor for exercise capacity.

OBJECTIVES: The purpose of this study was to show that the chronotropic potential of the well trained heart transplant recipient (HTR) does not limit exercise capacity. BACKGROUND: Chronotropic incompetence is considered to be the main limiting factor of the functional capacity of heart transplant recipients. However, no systematic study had been published on patients who had spontaneously undergone heavy endurance training for several years. METHODS: Heart rate (HR) and respiratory gas exchanges (VO2, VCO2, VE) were measured in 14 trained HTRs (T-HTRs) during exercise tests on a bicycle, on a treadmill and by Holter electrocardiography during a race. RESULTS: Peak values observed in T-HTRs during the treadmill test were higher than those reached during the bicycle test (VO2peak: 39.8+/-6.9 vs. 32.5+/-7.8 ml x kg(-1) x min(-1), p < 0.001; HRpeak: 169+/-14 vs. 159+/-16 bpm, p < 0.01). During treadmill exercise VO2peak and HRpeak values observed were very close to the mean predicted VO2pmax and HRpmax. The maximum heart rate during the race (HRrace) was greater than HRpeak values during the treadmill test (179+/-14 vs 169+/-14 bpm, p < 0.01) and slightly above the mean predicted values (HRrace/HRpmax X 100 = 101+/-10%). The treadmill exercise test yields more reliable data than does the bicycle test. CONCLUSIONS: Extensive endurance training enables heart transplant recipients to reach physical fitness levels similar to those of normal sedentary subjects; heart rate does not limit their exercise capacity.

Adult↗

PubMed1995

Effects of cardiac rehabilitation programs on exercise capacity, coronary risk factors, behavioral characteristics, and quality of life in a large elderly cohort.

Despite the limitations of our study, we believe the current data support the beneficial effects of cardiac rehabilitation and exercise training in the elderly, including modest improvements in lipids, obesity indexes, behavioral characteristics, and quality-of-life parameters, and marked improvements in exercise capacity. In fact, elderly patients had greater improvements than younger patients in both exercise capacity and mental health after cardiac rehabilitation. These data indicate that elderly patients with CAD should be routinely referred to and vigorously encouraged to pursue formal outpatient cardiac rehabilitation and exercise training programs after major CAD events.

Aged↗

PubMed1991

Cardiac function and maximal exercise capacity early after acute myocardial infarction.

The purpose of the study was to assess the relationship between left and right ventricular function measured at rest and maximal exercise capacity in patients with recent acute myocardial infarction (AMI). Forty-three male patients (Killip Class I, n = 36; Killip Class II, n = 7) with a wide range of left ventricular (LV) function and size underwent graded bicycle exercise testing less than 4 weeks after AMI (mean 21 days, 17-27). None of the patients had exercise limiting factors other than dyspnoea and fatigue. Left and right ventricular ejection fractions were determined by a radionuclide ventriculographic method which also allowed determination of absolute LV volumes and actual LV peak filling rate. LV ejection fraction had a weak association to estimated maximal oxygen uptake (VO2 max) (r = 0.37). No association was found between LV size, LV stroke volume, or LV peak filling rate and estimated VO2 max. Similarly, right ventricular ejection fraction showed no correlation to estimated VO2 max. Patients with well preserved LV function had a higher exercise induced increase in systolic blood pressure than patients with reduced LV function, but the increase in systolic blood pressure could not be used to estimate LV function with any reasonable accuracy. We conclude that the maximal exercise capacity of patients with recent AMI is virtually independent of their left and right ventricular function determined at rest, and that exercise testing and radionuclide ventriculography should be regarded as complementary procedures in the evaluation of patients with AMI.

Exercise↗

PubMed1992

Impact of chronic oral H2-antagonist therapy on left ventricular systolic function and exercise capacity.

It has been suggested that H2-antagonists may adversely affect left ventricular systolic function. To assess the effects of cimetidine, famotidine, and ranitidine on exercise capacity and left ventricular systolic function, the authors conducted a randomized, double-blind, four-way crossover study in 15 healthy male volunteers with placebo control. Each subject underwent a maximal upright treadmill exercise test, aerobic metabolic assessment, and two-dimensional stress echocardiography on six separate occasions. The initial two treadmill exercise tests with aerobic metabolic assessment and stress echocardiography were performed to minimize the learning effect. In the final four evaluations, subjects were randomized to receive 7 days of oral treatment with cimetidine 400 mg twice daily, famotidine 40 mg daily, ranitidine 150 mg twice daily, and placebo. A comparison of exercise tests, aerobic metabolic assessment, and stress echocardiography results found no significant differences between any of the H2-antagonists and placebo. In addition, there were no significant differences in test results between cimetidine, famotidine, and ranitidine. Specifically, exercise treadmill time, maximal oxygen consumption, respiratory quotient, maximal exercise systolic and diastolic blood pressure, maximal exercise heart rate, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, and ejection fraction were not different between treatments. The authors conclude that 7 days of oral treatment with cimetidine, famotidine, or ranitidine has no deleterious effect on exercise capacity or left ventricular systolic function in healthy subjects.

Administration, Oral↗

PubMed1991

Effect of exercise training on multiple respiratory variables in patients with coronary artery disease: correlation with change in exercise capacity.

Multiple measurements of pulmonary function were performed during exercise testing in 29 patients with coronary artery disease (CAD) before and after exercise training. Following training, significant increases in oxygen consumption (VO2), carbon dioxide production (VCO2), and peak flow at maximal exercise were seen as compared with pretraining values (p less than .01), but not in any other respiratory variables. Only the peak respiratory exchange ratio (RER) achieved during pretraining exercise testing and peak values of minute ventilation (VT), respiratory rate, and VCO2 during a posttraining exercise test showed significant correlations with the change in maximum VO2 following exercise training (p less than .05). Significant correlations were also found among VT, VCO2, and peak flow at peak exercise following exercise training and the change in exercise duration between pretraining and posttraining stress tests. Of 22 patients evaluated with thallium 201 scintigraphy during their pretraining exercise test, 11 developed ischemic ST depression or a reversible perfusion defect. No significant differences in pulmonary function measurements during exercise testing were seen between patients who developed ischemia and those who did not. However, the change in peak metabolic equivalents (METS) achieved between pretraining and posttraining exercise was significantly greater in patients who developed ischemia (.836 +/- 1.003 versus .091 +/- .481, p less than .05). These results indicate that exercise training in patients with CAD is not associated with significant changes in most measurements of pulmonary function and, with the exception of RER at peak exercise, pretraining measurements do no show a significant correlation with changes in exercise capacity.

Aged↗

PubMed1998

Candoxatril improves exercise capacity in patients with chronic heart failure receiving angiotensin converting enzyme inhibition.

AIMS: To assess the effect of candoxatril, a novel neutral endopeptidase inhibitor, on exercise capacity, clinical status and quality of life in patients with mild to moderate chronic heart failure receiving angiotensin converting enzyme inhibition. METHODS AND RESULTS: Patients were recruited from 16 centres throughout the United Kingdom. Following a 4-week single-blind placebo 'run-in' phase of weekly exercise tests, patients underwent double-blind randomization to receive either candoxatril (100 mg twice daily) or placebo for the next 84 days. Patients were then reassessed every 28 days. Of 110 patients randomized, 56 received candoxatril and 54 placebo. Over the study period, the overall improvement in mean total exercise time in the candoxatril group in comparison to the placebo group was 34.1 s (P=0.02: 95% confidence interval: 5.1 to 63.0). There were no significant changes in functional class, clinical status or quality of life scores between the two groups. There was a trend for a small reduction in blood pressure in the candoxatril group. CONCLUSION: Candoxatril confers an improvement in exercise capacity in patients with chronic heart failure who are receiving maintenance angiotensin converting enzyme inhibitor therapy.

Aged↗

PubMed1989

Determinants of maximum exercise capacity in patients with chronic airflow obstruction.

Patients with chronic airflow obstruction (CAO) often develop impairment of respiratory muscle function. We hypothesized that inspiratory muscle strength, as assessed by resting, peak inspiratory pressure (PIP) may be an important determinant of maximum exercise capacity in patients with CAO. Twenty ambulatory male patients (mean age, 56 +/- 3 years [+/- SE]) with CAO (FEV1, 1.72 +/- 0.21 L) comprised the studied population. Oxygen consumption at incremental cycle ergometry to tolerance (VO2max, 1.80 +/- 0.20 L/min) served as the dependent variable for regression vs measures of resting pulmonary function. Significant correlations with VO2max included power output in watts (r = 0.951), VEmax (r = 0.858), Dsb (r = 0.841), PIP (r = 0.816), age (r = -0.809), FEV1 (r = 0.763), and FVC (r = 0.663). The FEV1, Dsb, and PIP each entered into a multiple linear regression relationship describing VO2max. Also, when paired with VEmax as independent variables in multiple regression, PIP and Dsb each improved description of VO2max over VEmax alone (p less than 0.05), whereas FEV1 and FVC did not (p greater than 0.05). We conclude that factors other than ventilatory capacity also have a quantitative effect on VO2max and that PIP constitutes a determinant of maximum exercise capacity in patients with CAO.

Exercise Test↗

PubMed2002

Arm mechanical efficiency and arm exercise capacity are relatively preserved in chronic obstructive pulmonary disease.

PURPOSE: Previous studies indicate that energy expenditure related to physical activity is enhanced and that mechanical efficiency of leg exercise is reduced in patients with chronic obstructive pulmonary disease (COPD). However, it is yet unclear whether an inefficient energy expenditure is also present during other activities in COPD. This study was carried out to examine arm efficiency and peak arm exercise performance relative to leg exercise in 33 (23 male) patients with COPD ((mean +/- SEM) age: 61 +/- 2 yr; FEV : 40 +/- 2% of predicted) and 20 sex- and age-matched healthy controls. METHODS: Body composition, pulmonary function, resting energy expenditure (REE), and peak leg and arm exercise performance were determined. To calculate mechanical efficiency, subjects performed submaximal leg and arm ergometry at 50% of achieved peak loads. During exercise testing, metabolic and ventilatory parameters were measured. RESULTS: In contrast to a reduced leg mechanical efficiency in patients compared with controls (15.6 +/- 0.6% and 22.5 +/- 0.6%, respectively; < 0.001), arm mechanical efficiency was comparable in both groups (COPD: 18.3 +/- 0.9%, controls: 21.0 +/- 1.2%; NS). Arm efficiency was not related to leg efficiency, pulmonary function, work of breathing, or REE. Also, arm exercise capacity was relatively preserved in patients with COPD (ratio arm peak work rate/leg peak work rate in patients: 89% vs 53% in controls; < 0.001). CONCLUSION: Mechanical efficiency and exercise capacity of the upper and lower limbs are not homogeneously affected in COPD, with a relative preservation of the upper limbs. This may have implications for screening of exercise tolerance and prescription of training interventions in patients with COPD. Future studies need to elucidate the mechanism behind this observation.

Arm↗

PubMed1995

Exercise capacity and skeletal muscle structure and function before and after balloon mitral valvuloplasty.

This study evaluated the effects of balloon mitral valvuloplasty (BMV) on exercise capacity and skeletal muscle structure and function in 10 subjects with mitral stenosis (mean age +/- SD 33 +/- 5.5). Measurements were obtained before, and 2 weeks and 4 months after BMV to provide baseline data, to examine the effects of improved hemodynamics, and to examine the effects of resumption of normal physical activity, respectively. Valvuloplasty caused an increase in mitral valve area (0.89 +/- 0.04 to 1.75 +/- 0.07 cm2; mean +/- SE), and an increase in resting cardiac output (3.8 +/- 0.18 to 4.6 +/- 0.19 L/min, p < 0.05). At early follow-up after 2 weeks, subjects did more work (31% increase, p < 0.01) and had greater maximal oxygen consumption (11% increase, p < 0.01). However, measurements reflecting skeletal muscle histology, biochemistry, and function were unaltered at this stage. Four months after BMV, subjects had a further increase in exercise capacity compared with both baseline (58% increase, p < 0.01) and early follow-up (20% increase, p < 0.05). There were associated late increases compared with baseline in quadriceps cross-sectional area (66 +/- 5.8 vs 61 +/- 5.5 cm2, p < 0.05) and torque production (125 +/- 14 vs 118 +/- 16 Nm, p < 0.05). The percentage of slow twitch type I fibers increased compared with baseline (41 +/- 2.0% vs 33 +/- 3.1%, p < 0.05), as did the size of type II fibers (5.9 +/- 0.49 vs 4.9 +/- 0.57 microns2 x 10(3), p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[The relationship between postoperative changes of exercise capacity and pulmonary blood flow in the residual lung after lobectomy of the lung].

The purpose of this study is to investigate a relationship between the postoperative change of exercise capacity judged by the change of peal oxygen consumption and the pulmonary blood flow of the residual lung after lobectomy. Twenty eight patients undergoing lobectomy for lung cancer received an exercise tolerance test and 99mTc-MAA perfusion lung scans before and after lobectomy. The change rate in the peak level of oxygen consumption (peak VO2) did not differ depending on the number of resected sub-segments. A good correlation was found between the reduction of perfusion ratio of the lung of the operated side (delta Q) and that of the peak level of oxygen consumption (delta peak VO2) (r = 0.74, p < 0.01). A reduction in delta Q and delta peak VO2 was remarkable in patients with postoperative respiratory complications such as atelectasis and pulmonary air leakage. These results indicate that the perfusion lung scans at rest before and after surgery would be able to predict the change of exercise capacity after lobectomy.

Adult↗

PubMed2005

Poor relationship between exercise capacity and spirometric measurements in patients with more symptomatic heart failure.

BACKGROUND: The origin of exercise limitation in patients with chronic heart failure (CHF) is multifactorial, and the relative contributions of different abnormalities may vary with severity of heart failure symptoms. The aim of the current study was to determine the extent to which spirometric indices predict peak exercise capacity in patients with differing severity of symptoms. METHODS AND RESULTS: A total of 340 patients with left ventricular systolic dysfunction underwent spirometry, and a ramped, maximal exercise treadmill test with metabolic gas exchange measurements. For comparative purposes, a group of 174 aged-matched controls with no major structural heart disease (MSHD) was also included. In a stepwise linear regression model, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were independent predictors of peak oxygen uptake (pVO2) in controls (r2= 18-25%; P = .001) and New York Heart Association (NYHA) I-II patients (r2= 16-18%; P = .001). No association between spirometric indices (FEV1/FVC) and pVO2 (r2= 1-2%; P > .05) was found in NYHA III-IV patients. CONCLUSION: In aged-matched controls with no MSHD, spirometric variables (FEV1/FVC) explain 18% to 25% of the variance in pVO2, and 16% to 18% of the variance in patients with NYHA class I-II symptoms. As symptoms worsen, the influence of spirometric variables on peak exercise capacity diminishes, and there is no such relation in the NYHA class III-IV patients.

Aged↗

PubMed2005

Usefulness of left atrial emptying fraction to predict exercise capacity in patients with normal systolic left ventricular function and without myocardial ischemia.

The association of left atrial volume at rest and the left atrial emptying fraction with exercise capacity during stress echocardiography was examined in patients with normal left ventricular function and without ischemia. The left atrial emptying fraction, along with body mass index, was found to be an independent predictor of poor exercise capacity (<5 METs).

Adult↗

PubMed2005

Comparative efficacy of nebivolol versus carvedilol on left ventricular function and exercise capacity in patients with nonischemic dilated cardiomyopathy. A 12-month study.

PURPOSE: To compare the efficacy of nebivolol versus carvedilol on left ventricular (LV) function and exercise capacity in patients with nonischemic dilated cardiomyopathy (NIDC). METHODS: After enrollment in this double-blind trial, 72 patients, aged 55 +/- 9.5 years, with NIDC, LV ejection fraction (LVEF) < 45%, New York Heart Association classes II to III, were randomized to either nebivolol (34 patients) or carvedilol (38 patients) and were evaluated through echocardiography and exercise tests at baseline and 3 and 12 months after treatment. RESULTS: During follow-up, 4 patients discontinued nebivolol, although 3 patients stopped carvedilol. Patients in both the nebivolol and carvedilol groups showed a steady improvement in New York Heart Association class (P = .002 and < .001, at 12 months, respectively) and LVEF (P = .001 and < .001, at 12 months, respectively) that became significant from 3-month follow-up on. Intergroup analysis showed that carvedilol group had a greater increase in LVEF at 3 (P = .04) and 12 (P = .02) months' follow-up compared with nebivolol group. Advanced diastolic dysfunction regressed to earlier stages in carvedilol patients after 3 (P = .02) and 12 (P = .01) months' treatment, whereas in the nebivolol group, a significant improvement in diastolic dysfunction was found at the 12 months' follow-up (P = .02). Exercise duration improved in both groups at 12 months' follow-up (both P = .01), but in the nebivolol group, there was an initial deterioration at 3 months (P = .07). CONCLUSIONS: Both nebivolol and carvedilol appear relatively safe, with beneficial effects on LV systolic and diastolic function as well as exercise capacity in patients with NIDC after 12 months' treatment. However, carvedilol exhibits more favorable effects on LV function than does nebivolol.

Benzopyrans↗

PubMed1994

Exercise capacity and blood pressure response in children and adolescents after renal transplantation.

Physical working capacity and cardiovascular response to graded exercise on a bicycle ergometer were investigated in 70 children and adolescents (33F, 37M) after renal transplantation. Results of static and dynamic lung function tests were within the normal range in all patients. Systolic blood pressure, heart rate, pulmonary ventilation and oxygen uptake increased with workload and returned to pre-exercise levels after 5 m of rest. During exercise, blood pressure values were within the normal range in almost all patients. The increase in heart rate and respiratory frequency was blunted in patients receiving beta blocking agents. Maximum workloads (Wmax) were 2.00 +/- 0.48 W/kg in females and 2.38 +/- 0.54 W/kg in males, which are 78 +/- 18% and 84 +/- 18% of the normal values predicted for age. Maximum oxygen consumption (VO2max) was 23.2 +/- 5.8 ml/min/kg in females and 28.3 +/- 5.8 ml/min/kg in males. Half of the patients had height below the third percentile. For this reason exercise capacity in relation to height is probably a more relevant parameter than age. Using actual height, Wmax was 102 +/- 20% and 102 +/- 29%, and VO2max 74 +/- 14% and 80 +/- 18% of predicted values, respectively. We conclude that the adaption of the cardiovascular and respiratory system to graded exercise was influenced by beta blocking agents. Wmax and VO2max were significantly reduced for age in pediatric patients after renal transplantation. Wmax was normal, but VO2max was still reduced if corrected for height.

Adolescent↗

PubMed2005

Pulmonary pressure-flow relation as a determinant factor of exercise capacity and symptoms in patients with regurgitant valvular heart disease.

BACKGROUND: Exertional dyspnea is a frequent limiting symptom in patients with chronic heart failure. Furthermore, dyspnea and a plateau in VO(2) (oxygen consumption) at peak exercise often co-exist in chronic heart failure, especially in patients with severe regurgitant valvular heart disease (RVHD), their relevance to hemodynamics and subjective symptoms during exercise have not been fully understood. OBJECTIVES: The purpose of this study was to examine the determinant factor of exercise capacity in patients with RVHD. METHODS: We performed a symptom-limited cardiopulmonary exercise test using a sitting cycle ergometer with right heart catheterization in 20 patients with severe RVHD. VO(2) and hemodynamics were measured at rest and during exercise, and symptomatic end-point at peak exercise was evaluated by using Borg's score. RESULTS: Of the 20 patients, 11 attained a plateau in VO(2) at peak exercise (Group 1). At peak exercise, pulmonary arterial pressure (PAP) was higher, and cardiac output (CO) and VO(2) were lower in Group 1 than in patients without a plateau in VO(2) (Group 2) (mean PAP: 60+/-10 vs. 48+/-9 mm Hg, P=0.05; CO: 8.3+/-2.6 vs. 11.2+/-2.6 l/min, P=0.01; VO(2): 1059+/-259 vs. 1359+/-328 ml/min, P=0.01). In Group 1, 6 patients complaining of dyspnea rather than leg fatigue at peak exercise had lower CO (7.1+/-1.8 vs. 9.7+/-3.0 l/min, P=0.05) and higher slope of mean PAP-CO relation (P-Q slope) (10.6+/-3.6 vs. 5.4+/-1.7, P=0.01), compared with the other 5 patients with leg fatigue. CONCLUSIONS: Development of pulmonary hypertension during exercise is the important limiting factor for exercise capacity in patients with RVHD. The limitation of increase in CO concomitant with pulmonary hypertension could be an important factor in the appearance of dyspnea.

Aortic Valve Insufficiency↗