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PubMed2006

Effects of physical exercise on quality of life, exercise capacity and pulmonary function in children with asthma.

OBJECTIVE: To investigate the effects of regular submaximal exercise on quality of life, exercise capacity and pulmonary function in asthmatic children. PATIENTS AND METHODS: Sixty-two children with mild-moderate asthma (mean age 10.4 (SD 2.1) years) were randomly allocated into exercise and control groups. The exercise group underwent a moderately intensive basketball training program for 8 weeks. A home respiratory exercise program was advised to both groups. Pediatric Asthma Quality of Life Questionnaire (PAQLQ) was used for the evaluation of activity limitation, symptoms and emotional functions. Exercise capacity was evaluated through the physical work capacity (PWC 170 test) on a cycle ergometer and 6-minute walk test. Spirometric tests were also performed and medication and symptom scores were recorded. RESULTS: Although PAQLQ scores improved in both groups, the improvement in the exercise group was significantly higher. The exercise group performed better in the PWC 170 and 6-minute walk tests, whereas no improvement was detected in the control group at the end of the trial. Medication scores improved in both groups, but symptom scores improved only in the exercise group. No significant changes were detected in pulmonary function in either group, except for peak expiratory flow values in the exercise group. CONCLUSION: Eight weeks of regular submaximal exercise has beneficial effects on quality of life and exercise capacity in children with asthma. Submaximal basketball training is an effective alternative exercise program for asthmatic children.

Adolescent↗

PubMed1998

Attenuated physical exercise capacity in smokers compared with non-smokers after coronary angioplasty despite similar luminal diameters.

AIMS: To study the impact of smoking on the change in exercise capacity in patients treated with coronary angioplasty. METHODS: Three hundred and sixty-eight men below 70 years of age eligible for percutaneous transluminal coronary angioplasty without previous coronary interventions were consecutively enrolled. Of the 334 patients (90.8%) who completed the study 77 (23.1%) were current smokers. Exercise tests were performed before percutaneous transluminal coronary angioplasty, 2 and 19 +/- 2.4 weeks after percutaneous transluminal coronary angioplasty. Coronary angiography was done in 333 patients (99.7%) (at mean 19 +/- 2.4 weeks). The angiograms were analysed quantitatively. RESULTS: There were no differences in the clinical and angiographic characteristics among the groups except for age. The non-smokers were older than the smokers (55.7 vs 52.4 years (P = 0.001)). Exercise capacity was equal before percutaneous transluminal coronary angioplasty in both groups (17.6 vs 16.5 W x min-1 x kg-1). Non-smokers had a significantly higher increase in exercise capacity than smokers from baseline to 2 weeks after percutaneous transluminal coronary angioplasty (mean difference 4.3 W x min-1 x kg-1 (95% CI: 2.3 to 6.2; P < 0.001)), and from baseline to 19 weeks after percutaneous transluminal coronary angioplasty (mean difference 3.9 W x min-1 x kg-1 (95% CI: 1.6 to 6.2; P < 0.001). CONCLUSION: A clinical benefit from percutaneous transluminal coronary angioplasty was seen in both groups as judged from exercise testing. Smokers had a substantially lower increase in exercise capacity than non-smokers, indicating an attenuated benefit from percutaneous transluminal coronary angioplasty among smokers.

Adult↗

PubMed2004

Exercise capacity and cardiac function assessed by tissue Doppler imaging in chronic heart failure.

OBJECTIVE: To examine the relation between longitudinal left ventricular function assessed by tissue Doppler imaging (TDi) and exercise capacity in heart failure. SUBJECTS: 153 patients with chronic heart failure from left ventricular systolic dysfunction (ejection fraction < 45%) and 87 age and sex matched controls. METHODS: Echocardiography was used to measure conventional indices of left ventricular systolic function. TDi was used to assess left and right ventricular longitudinal function by measuring mitral and lateral tricuspid annular velocities during the cardiac cycle. Velocities measured at each point were the systolic peak (S(m)) and the diastolic troughs (E(m) and A(m)), corresponding to passive and active (atrial) left ventricular filling. Each patient also underwent treadmill exercise testing with metabolic gas exchange measurements. RESULTS: Left and right ventricular TDi velocities were greater in controls than in patients. Left ventricular ejection fraction (LVEF) correlated with S(m) (r = 0.30, p = 0.0005), but not with E(m), A(m), or the E(m)/A(m) ratio. There were no significant differences between New York Heart Association (NYHA) functional class for any of the TDi variables. Right ventricular indices were not related to exercise capacity. Systolic myocardial motion measured by TDi correlated more closely with peak oxygen consumption (pVO2) (r = 0.35, p < 0.0001) than LVEF (r = 0.21, p < 0.02). The E(m)/A(m) ratio was not correlated with pVO2. In multiple regression, S(m) was the only left ventricular TDi variable to predict exercise capacity independently (p < 0.05). CONCLUSIONS: Exercise capacity and symptoms are poorly related to conventional measures of cardiac function and more closely correlated with indices of longitudinal left ventricular function as assessed by TDi.

Case-Control Studies↗

PubMed1989

Prognosis in patients with low left ventricular ejection fraction after myocardial infarction. Importance of exercise capacity.

The measurement of left ventricular ejection fraction (LVEF) plays a key role in many strategies for managing patients after acute myocardial infarction. We tested the hypothesis that exercise capacity 1 month after myocardial infarction provides additional information in patients with a low LVEF and therefore assists in risk stratification. One hundred fifteen patients, with documented myocardial infarction and LVEF less than 35% by gated radionuclide scan 1 month after acute myocardial infarction, were followed up for 2 months to 7 years. Exercise capacity was estimated from a treadmill test 1 month after infarction. Using the Cox proportional hazards model, exercise capacity was a significant predictor of death or reinfarction. The relative risk of death, based on a comparison between the lowermost quintile (less than 4 METS) and uppermost quintile (greater than 7 METS), was 3.5 (95% confidence interval, 1.1-9.7); the relative risk in the fourth, third, and second quintile was 2.7, 2.1, and 1.6, respectively. In a multivariate analysis, the observed effect of a good exercise capacity was independent of LVEF. These data indicate that in patients with a low LVEF after myocardial infarction, useful prognostic information can be obtained from exercise testing.

Exercise↗

PubMed1999

Relationship between exercise capacity and ventilatory equivalent for carbon dioxide in patients with stable old myocardial infarction.

The aim of the present study was to evaluate the relationship between exercise capacity and ventilatory response in patients with stable old myocardial infarction. We performed cardiopulmonary exercise test in 61 patients with stable old myocardial infarction and in 30 healthy men. Each subject exercised on a bicycle ergometer until exhaustion. Patients who had anginal pain or electrocardiographic ischemic changes during exercise were excluded. The patients were classified into three groups according to peakVO2 achieved during exercise, using Weber's method: group A, peakVO2 > or = 21 ml/min/kg (n = 4); group B, 14 < or = peakVO2 < 21 ml/min/kg (n = 45); and group C, peakVO2 < 14 ml/min/kg (n = 12). With progressive increases in VCO2, VE increased linearly below the anaerobic threshold (AT) level. The slope of the linear regression line between VCO2 and VE (SLOPE) was calculated in each subject. The mean SLOPE of the healthy men (group N) and groups A, B and C were 25.8 +/- 0.5, 25.1 +/- 0.5, 28.9 +/- 0.8 and 37.1 +/- 1.7 (x 10(-3), respectively. Thus, the SLOPE was steeper in patients with lower peakVO2. It is difficult to perform a maximal exercise tolerance test on patients with chronic heart failure to evaluate their exercise capacity. We can assess exercise capacity by the slope of the linear regression line between VCO2 and VE (SLOPE) at the lower exercise level.

Aged↗

PubMedDate not supplied

Determinants of improvement in exercise capacity in patients undergoing cardiac rehabilitation.

In order to identify patients who benefit most from a cardiac rehabilitation program, we studied retrospectively all patients who completed a 3-month comprehensive cardiac rehabilitation program during a 2-year period. Questionnaires regarding physical exercise habits were sent to 122 patients and returned by 117 (96%) of them (53 post-acute myocardial infarction, 50 post-coronary artery bypass surgery, 14 post-infarction and surgery, 2 post-angioplasty). Exercise capacity (subset of 66 patients) improved by 19% after rehabilitation (7.8 +/- 3.1 to 9.3 +/- 2.7 METs, p < 0.0001). Univariate and multivariate analysis identified initial exercise capacity as the only independent variable predicting improvement in exercise performance (inverse relationship) (r2 = 0.24, p < 0.0001). The improvement was not related to age, sex, left ventricular function or time from cardiac event to rehabilitation. Patients recovering from both infarction and coronary artery bypass surgery showed a greater improvement (delta exercise capacity 2.8 +/- 1.4 METs) than patients after myocardial infarction alone (delta exercise capacity 0.8 +/- 2 METs, p < 0.02). Improvement was sustained for up to 2 years after completion of the program.

Adult↗

PubMed1989

Effects of left ventricular shape and captopril therapy on exercise capacity after anterior wall acute myocardial infarction.

The importance of left ventricular (LV) shape in determining exercise capacity was assessed in 40 male patients with LV dysfunction after anterior acute myocardial infarction (AMI). Because captopril therapy is known to improve exercise capacity in this patient population, the potential interaction between LV shape and captopril therapy was also evaluated. Patients underwent cardiac catheterization 2 to 4 weeks after AMI followed by randomization to receive placebo or captopril. LV shape was defined from biplane ventriculography by a sphericity index (volume observed/volume of sphere using long axis as diameter). Quarterly clinical assessments and maximal exercise testing were performed. A cumulative heart failure score, specific activity scale and average exercise time for the year were calculated. A greater shape distortion (increasing sphericity index) was associated with increased LV volumes, decreased ejection fraction and a larger abnormally contracting segment. Sphericity index was the only independent predictor of average exercise duration in the placebo group. Placebo-treated patients in the tercile with the most spherical ventricles had not only the lowest exercise capacity (p less than 0.01), but also accumulated the highest heart failure (p less than 0.05) and specific activity scale (p less than 0.05) scores. Captopril-treated patients with the same baseline distortion of LV shape did not manifest these shape-dependent objective and subjective measures of reduced functional capacity.

Adult↗

PubMed2004

Decreased right ventricular function after coronary artery bypass grafting and its relation to exercise capacity: a tricuspid annular motion-based study.

BACKGROUND: Decreased right ventricular (RV) function is a known echocardiographic finding after coronary artery bypass grafting (CABG). For patients with heart failure, RV dysfunction is a predictor of poor exercise capacity. The significance and time course of RV dysfunction and its relation to exercise capacity after CABG have not been elucidated, however. OBJECTIVES: In this prospective study, we assessed RV function measured from echocardiographic tricuspid annular motion (TAM) before and after CABG and its relation to exercise capacity. METHODS: In 99 patients accepted for CABG, we did a baseline echocardiographic investigation before operation, followed by repeated echocardiograms 3 months and 1 year after CABG. RV function was assessed using the magnitude of TAM measured at the RV free wall. An exercise stress test and coronary angiography were performed before and 3 months after CABG. RESULTS: RV function assessed by TAM was significantly reduced 3 months after CABG (22.4 vs 14.5 mm, P <.001) compared with preoperative measurements and remained so after 1 year (14.7 mm, P <.001). Left ventricular systolic function was unchanged 3 months after CABG. The 1-year echocardiographic follow-up showed paradoxical septal movement in 96% of the patients. Exercise capacity improved significantly 3 months after CABG compared with before (1.6 vs 1.83 W/kg, P <.001). These finding are independent of the state of the right coronary artery. CONCLUSIONS: One year after CABG, RV function remained depressed and septal motion remained paradoxical compared with the preoperative investigation, suggesting that these postoperative findings might be permanent in the majority of patients. Despite the reduced RV function, exercise performance 3 months after CABG was improved. The depressed RV function, measured from TAM after CABG, probably lacks clinical significance.

Aged↗

PubMed2004

[Quality of life and exercise capacity in lung transplant recipients].

BACKGROUND: Quality of life in lung transplant recipients (LTR) is reported to be comparable with that of the general population. However, previous studies have shown that exercise capacity was reduced to 30 - 40 % of normal values. The purpose of this study was to investigate the gap between good self-reported quality of life and reduced exercise capacity in LTR, to describe possible correlations and to compare the results with those of a control group (CG). METHODS: 27 LTR 208 +/- 67 days after bilateral lund transplantation (16 male, 11 female; age: 46 +/- 10 years; body mass index: 24 +/- 3 kg x m (- 2), FEV (1) % 75 +/- 27 %) and 30 controls (17 male 13 female; age 47 +/- 15 years; BMI: 26 +/- 4 kg x m (- 2), FEV (1) % 103 +/- 15 %) performed cardiopulmonary exercise testing and were interviewed with the standardized German "Quality of life profile for chronic disease" self-rating questionnaire. RESULTS: Significant differences were shown in objective exercise related variables (peak oxygen consumption: LTR 15.1 +/- 1.8, CG 34.5 +/- 9.1 ml x min (- 1) x kg (- 1); p < 0,01); peak workload: LTR 1.0 +/- 0.2; CG 2.4 +/- 1.0 W. kg (- 1); p < 0.01); percentage of predicted workload: LTR 44 +/- 12, CG 115 +/- 33 %; p < 0.01). The rating of subjective quality of life in physical, psychological and social domains of LTR did not differ from values of the CG or of the general population (n = 1143). The quality of life in the physical domain correlated significantly with peak exercise capacity (LTR r = 0.44, p < 0.05; CG r = 0.37; p < 0.05). CONCLUSION: Patients 7 months after lung transplantation described their physical, social and psychological quality of life as equally good as the healthy control group. However, peak exercise capacity and oxygen consumption were markedly reduced. To improve physical capacity in the range of daily activities, an exercise training program should be offered to patients after lung transplantation.

Adult↗

PubMedDate not supplied

A nomogram to select the optimal treadmill ramp protocol in subjects with high exercise capacity: validation and comparison with the Bruce protocol.

PURPOSE: Guidelines suggest that individualized ramp protocols with treadmill times targeted between 8 and 12 minutes are most suitable to estimate exercise capacity. However, previous methods to determine individualized ramp rates and comparisons between ramp and standardized protocols have been limited to clinically referred populations. METHODS: Forty-three healthy volunteers [median (interquartile range), age 36 (30-41) years; 10 women] performed an individualized ramp and a Bruce treadmill exercise protocol in random order. The Veterans Specific Activity Questionnaire [VSAQ, resulting in metabolic equivalents (METs)VSAQ] combined with a modified variant of the VSAQ nomogram (resulting in METs(NOMOGRAM)) was used to individualize the ramp protocol. Exercise capacity estimated from speed and grade of the treadmill (METs(ESTIMATED)) and that derived from directly measured peak oxygen uptake (VO2) [METs(MEASURED)] were compared with the pretest estimates of exercise capacity. RESULTS: Median values for METs(VSAQ), METs(NOMOGRAM), METs(ESTIMATED), and METs(MEASURED) for the ramp protocol were 12.0 (10-12), 15.0 (14-16.5), 16.7 (15.9-17.8), and 15.2 (13.5-16.7), respectively. For the ramp protocol, all 43 participants achieved a treadmill time between 8 and 12 minutes, whereas with the Bruce protocol only 6 (14%) participants fell within this range (P < .0001). Peak VO2 [ramp: 53.1 (47.4-58.3) versus Bruce: 53.5 (48.7-58.3) mL/kg/min; P = .008] was slightly lower using the ramp protocol. CONCLUSIONS: The modified variant of the VSAQ nomogram is a useful tool to estimate an individual's exercise capacity and to select a treadmill ramp protocol to yield the recommended exercise duration for moderately to highly fit, healthy individuals. The individualized ramp and the Bruce protocols are similar with regard to directly measured peak VO2 achieved.

Adult↗

PubMed1996

Effects of regular salmeterol on lung function and exercise capacity in patients with chronic obstructive airways disease.

BACKGROUND: The aim of this study was to evaluate the effects of single and chronic dosing with salmeterol on exercise capacity and lung function in patients with chronic obstructive pulmonary disease. METHODS: Twenty nine patients of mean (SE) age 64 (1.5) years, forced expiratory volume in one second (FEV1) 42(3)% of predicted, and 5-15% reversibility to salbutamol 200 micrograms were randomised to receive four weeks treatment with salmeterol 50 micrograms twice daily or placebo in a double blind crossover fashion with a one week washout period in between. Measurements of spirometric parameters, static lung volumes, and exercise capacity were made one and six hours after a single dose, and six hours after the final dose of salmeterol or placebo. RESULTS: Salmeterol produced a small increase in FEV1 at one and six hours after a single dose, and this was maintained after chronic dosing (mean difference and 95% CI versus placebo): single dosing at one hour 0.07 (95% CI 0.02 to 0.11) 1, single dosing at six hours 0.16 (95% CI 0.09 to 0.22) 1, chronic dosing at six hours 0.11 (95% CI 0.03 to 0.19) 1. The increase in forced vital capacity (FVC) was greater with salmeterol than with placebo six hours after single but not chronic dosing: single dosing at six hours 0.17 (95% CI 0.04 to 0.29) 1, chronic dosing at six hours 0.02 (95% CI -0.18 to 0.22) 1. Slow vital capacity was increased after treatment with salmeterol compared with placebo one and six hours after single but not after chronic dosing. There were no significant differences in static lung volumes or exercise capacity after single or chronic dosing with salmeterol compared with placebo. Patients reported a significantly lower Borg score for perceived exertion following the six minute walk after chronic treatment with salmeterol compared with placebo. CONCLUSIONS: Salmeterol produced a small improvement in spirometric values compared with placebo consistent with the degree of reversibility originally shown by the subjects to salbutamol 200 micrograms. This was not associated with improvements in static lung volumes or exercise capacity, but there was some symptomatic benefit in that patients were able to walk the same distance in six minutes with less perceived exertion.

Albuterol↗

PubMed2005

Effects of angiotensin-converting enzyme inhibitor plus irbesartan on maximal and submaximal exercise capacity and neurohumoral activation in patients with congestive heart failure.

BACKGROUND: In patients with symptomatic congestive heart failure receiving optimal therapy with an angiotensin-converting enzyme (ACE) inhibitor and a beta-blocker, the impact of using an angiotensin receptor blocker on submaximal exercise capacity and on neurohumoral activation at rest and during stress has not been investigated. METHODS: Thirty-three patients with congestive heart failure, New York Heart Association II or III symptoms, and left ventricular ejection fraction 25.5% +/- 7.2% treated with an ACE inhibitor and a beta-blocker were recruited. Patients were randomly assigned to receive irbesartan 150 mg per day (n = 22) or a placebo (n = 11) for 6 months. Maximal exercise capacity was assessed using a ramp protocol. Submaximal exercise duration was assessed using a constant load protocol, and plasma norepinephrine and angiotensin II (A-II) were measured in resting state, at 6 minutes, and at peak exercise. RESULTS: Patients treated with irbesartan presented a 26% increase in submaximal exercise time (+281 seconds, P = .08) whereas exercise duration increased by only 7% in patients treated with a placebo (+128 seconds, P = NS irbesartan vs placebo). Norepinephrine levels increased to a similar extent in both groups, whereas A-II levels did not increase or change in response to therapy. CONCLUSIONS: Dual A-II suppression with an ACE inhibitor plus irbesartan provides a small but a significant increase in submaximal exercise capacity. This beneficial effect is observed despite no significant changes in maximal exercise capacity, and in resting or exercise-induced increase in neurohumoral activation.

Adrenergic beta-Antagonists↗

PubMed1998

Effects of long-term digoxin therapy on heart rate variability, baroreceptor sensitivity, and exercise capacity in patients with heart failure.

We evaluated the effects of long-term digoxin therapy on exercise capacity and on physiological parameters reflecting autonomic tone in 23 patients with mild to moderate heart failure. Before and after maintenance digoxin treatment, all patients underwent cardiopulmonary exercise testing and indexes of heart rate variability (HRV) and baroreceptor sensitivity (BRS) were measured. Long-term digoxin therapy significantly (P < 0.05) increased time domain indexes (rMSSD, pNN50) which reflect parasympathetic activity (from 30 +/- 16 to 37 +/- 14 and from 8 +/- 9 to 12 +/- 7, respectively). High-frequency (HF) and low-frequency (LF) power spectral components also showed a significant increase (from 4.5 +/- 1 to 5.1 +/- 1 and from 5.4 +/- 1 to 5.8 +/- 1, respectively), but the ratio LF/HF decreased, indicating a predominance of vagal activity. The magnitude of these changes exhibited a strong negative Pearson correlation coefficient when compared with initial values before treatment. BRS increased from 2.95 +/- 1.2 to 5.32 +/- 3 ms/mmHg (P < 0.05). Oxygen consumption at peak exercise and at the anerobic threshold increased significantly (from 17 +/- 3 to 19 +/- 3 mL/kg/min and from 14.7 +/- 3 to 16.5 +/- 3 mL/kg/min, respectively). A persistent negative correlation was found between initial values of HRV and the magnitude of changes in exercise capacity. These findings show that long-term digoxin therapy increases vagal activity and improves exercise capacity in patients with mild to moderate heart failure and seems to exert a more marked therapeutic effect on patients with poorer initial autonomic function.

Aged↗

PubMed1992

[Importance of collateral circulation to preserve the exercise capacity in patients with coronary artery disease].

We studied the effects of coronary collaterals on exercise capacity in relation with the coronary flow reserve. Thirty-one patients with single vessel disease of the left anterior descending artery (LAD) were selected using coronary angiography. Thirteen of them had angiographical collaterals. A Doppler coronary catheter was positioned in the proximal portion of the LAD, and the resting and peak coronary flow velocity was measured using an intracoronary injection of 6 ml of contrast material. Peak to resting velocity ratio was calculated as an index of the coronary flow reserve. Multi-stage treadmill exercise ECG test was performed, and the end point of the exercise was 0.1 mV depression of ST segment. The exercise capacity was expressed as the ratio of maximal to resting double product. In patients without collaterals, peak to resting coronary flow velocity ratio was correlated with double product ratio (r = 0.94, p less than 0.01). But in patients with collaterals, double product ratios were higher than those in patients without collaterals. We conclude that coronary collaterals preserve exercise capacity in spite of the low coronary flow reserve in the recipient coronary artery.

Aged↗

PubMed1993

Relation between left ventricular shape and exercise capacity in patients with left ventricular dysfunction.

OBJECTIVES: The aim of this study was to identify dynamic predictors of exercise duration in patients with systolic left ventricular dysfunction and to test the hypothesis that left ventricular shape is an independent determinant of exercise duration in these patients. BACKGROUND: Measurements of left ventricular volumes and ejection fraction at rest do not predict exercise capacity in patients with systolic left ventricular dysfunction. Left ventricular shape at rest has been reported to be an independent determinant of exercise duration in these patients. The significance of alterations in left ventricular shape that occur during dynamic exercise has not been investigated. METHODS: Twenty-one patients with a documented ejection fraction < 40% performed symptom-limited graded upright bicycle exercise with simultaneous quantitative two-dimensional echocardiography. End-diastolic volume, end-systolic volume, stroke volume, ejection fraction and sphericity index were measured at rest and peak exercise. RESULTS: Eleven patients exercised beyond stage II (6 min, 50 W), averaging 8.9 +/- 1.9 min; 10 patients were unable to complete stage II, averaging 4.9 +/- 0.9 min. No patient developed clinical evidence of ischemia during the exercise period. Of the echocardiographic variables considered, only end-systolic and end-diastolic sphericity indexes at peak exercise (r = 0.809 and 0.711, respectively) and the change in end-systolic sphericity index during exercise (r = 0.697) were strongly correlated with exercise duration. CONCLUSIONS: Conventional descriptors of left ventricular function are poor predictors of exercise capacity. Dynamic changes in heart shape correlate strongly with exercise duration and may be important determinants of exercise capacity in patients with systolic left ventricular dysfunction.

Adult↗

PubMed2005

Limited exercise capacity in heterozygous manganese superoxide dismutase gene-knockout mice: roles of superoxide anion and nitric oxide.

BACKGROUND: We have reported that there is a limitation of exercise capacity in mice with defects in the expression of endothelial nitric oxide (NO) synthase, which is associated with a greater increase in whole-body oxygen consumption (VO2). We hypothesized that in states in which superoxide anion (O2-) is increased, especially in the mitochondria, whole-body VO2 will be increased because of the inactivation of NO, and consequently, exercise capacity will be reduced. METHODS AND RESULTS: Heterozygous manganese superoxide anion dismutase (SOD2) gene-knockout mice (SOD2+/-), in which SOD2 activity is reduced by 30% to 80%, and wild-type control mice (SOD2+/+) were treadmill-tested to measure indices defining exercise capacity. Tempol was given to each mouse for 7 days by an intraperitoneal injection to scavenge O2- before a second treadmill testing. VO2 and carbon dioxide production (VCO2) at rest were increased in SOD2+/-. The work (vertical distance run x body weight) to exhaustion was decreased in SOD2+/-. When the maximum VO2 and VCO2 were corrected to per work unit, they were increased in SOD2+/-. Tempol normalized basal VO2 and VCO2 and improved the work to exhaustion and corrected VO2 and VCO2 in SOD2+/-. VO2 of skeletal muscle was measured in vitro. Bradykinin-induced reduction in VO2 in vitro was attenuated in SOD2+/-, and was acutely restored by Tempol. There was a decrease in SOD2 protein level and a concomitant increase in lucigenin-detectable O2- production in skeletal muscle from SOD2+/-. CONCLUSIONS: These results suggest that exercise capacity is reduced in conditions in which superoxide anion is increased, and this is associated with a greater increase in whole-body oxygen consumption in SOD2+/- compared with SOD2+/+.

Animals↗

PubMed1997

Exercise capacity during and after spaceflight.

UNLABELLED: Our aim was to elucidate why astronaut's exercise capacity after spaceflight is reduced. Therefore, the kinetics of oxygen uptake (VO2) as a measure for muscular aerobic capacity, as well as maximal oxygen uptake (VO2peak), and anaerobic threshold (PAT) as overall measures for exercise capacity were determined. Measurements of VO2peak and AT were restricted to pre- and postflight sessions. METHODS: Four crew-members of the D-2 mission (10 d) were cycling with steady state phases at 20 W and 80 W, followed by 450s of pseudo random binary sequence (PRBS) changes between 20 W and 80 W, and an incremental exercise test (10 W every 30 s) up to subjective exhaustion. Breath-by-breath VO2, VCO2, ventilation, HR, and blood pressure were continuously recorded. Blood lactate samples were drawn only during the incremental phase. The VO2 kinetics were determined by evaluation of the relationship between the workload and the instantaneous oxygen uptake of each subject. The cross-correlation function between both variables showed two characteristic items, the maximum as a measure for the muscular aerobic capacity, and its lag representing time consuming processes. RESULTS AND DISCUSSION: Each subject showed an individual characteristic of VO2 kinetics. In flight, no significant changes were detected compared to preflight data. Decreases in lags of cross-correlation function maxima and decreases in mean blood pressure during exercise indicate lowered blood volumes 2 d after the flight. Lowered blood volumes can explain the losses in exercise capacity. The maximum of the cross-correlation function did not change significantly which indicates unchanged muscular oxidative capacity.

Adult↗

PubMed2002

A systematic review of the effects of bronchodilators on exercise capacity in patients with COPD.

One of the major goals of bronchodilator therapy in patients with COPD is to decrease airflow limitation in the airways and, as a consequence, improve dyspnea and exercise tolerance. The focus of this systematic review is to assess the effects of treatment with beta-agonists, anticholinergics, and theophyllines on dyspnea, and steady-state and incremental exercise capacity. Thirty-three, double-blind, randomized, placebo-controlled studies written in English were selected. This review shows that approximately half of the studies showed a significant effect of bronchodilator therapy on exercise capacity. Anticholinergic agents have significant beneficial effects in the majority of studies, especially when measured by steady-state exercise protocols. There is a trend toward a better effect of high-dose compared to low-dose anticholinergics. Short-acting beta(2)-mimetics have favorable effects on exercise capacity in more than two thirds of the studies; surprisingly, the situation is less clear for long-acting beta(2)-agents. The majority of the results of the published reports on theophyllines and their effects on exercise are negative. Direct comparisons of different classes of bronchodilators have not been made in a sufficient number of studies for a rational preference. The addition of a second bronchodilator has no proven advantage for improving exercise test results, but this has not been studied extensively and not in sufficiently large studies. The majority of studies reporting a measure of dyspnea found improvements, even in the absence of improvement in exercise capacity.

Adrenergic beta-Agonists↗