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PubMed1993

Hemodynamic determinants of exercise capacity in chronic atrial fibrillation.

To evaluate the response of patients with chronic atrial fibrillation (AF) to exercise, 79 male patients (mean age 64 +/- 1 years) with AF underwent resting two-dimensional and M-mode echocardiography and symptom-limited treadmill testing with ventilatory gas exchange analysis. Patients were classified by underlying disease into five subgroups: no underlying disease (LONE: n = 17), hypertension (HT: n = 11), ischemic heart disease (n = 13), cardiomyopathy or history of congestive heart failure (CHF: n = 26), and valvular disease (n = 12). A higher maximal heart rate than expected for age was observed (175 vs 157 beats/min), which was most notable in the LONE and HT subgroups. Maximal oxygen uptake (VO2 max) was lower than expected for age in all groups. Patients with CHF had a lower resting ejection fraction than all other patients (p < 0.001), a lower VO2 max, and a lower maximal heart rate than LONE and HT patients (p < 0.001). Stepwise regression analysis demonstrated that echocardiographic measurements at rest were poor predictors of VO2 max and VO2 at the ventilatory threshold. Among clinical, morphologic, and exercise variables, maximal systolic blood pressure accounted for the greatest variance in exercise capacity, but it explained only 35%. In patients with AF the higher than predicted maximal heart rates may be a compensatory mechanism for maintaining exercise capacity after the loss of normal atrial function. However, even in the absence of underlying disease, it does not appear to compensate fully for a compromised exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1999

Health status, dyspnea, lung function and exercise capacity in patients with chronic obstructive pulmonary disease.

SETTING: A secondary hospital outside Oslo. OBJECTIVE: To assess relationships between health status and measures of dyspnea, lung function and exercise capacity in patients with chronic obstructive pulmonary disease (COPD), to identify dimensions where lung-specific instruments associate and discriminate better than general measures. DESIGN: We assessed health status in 59 out-patients with COPD, using the following instruments: Short Form 36 (SF-36)-a general health status measure, Respiratory Quality of Life Questionnaire (RQLQ)-a lung-specific measure, the Karnofsky performance scale, and a rating scale. All patients rated their dyspnea and had spirometry and exercise capacity measured. RESULTS: Mean (SD) patient age was 57.3 (9.7) years, FEV1 47% (15%) of predicted, 6 minute walk distance 503 m (122 m). Dyspnea was the strongest predictor for health status. Both SF-36 and RQLQ had dimensions associating well with dyspnea and exercise capacity. The associations with FEV1 ranged from none to moderate. CONCLUSION: All RQLQ scales had a moderate to substantial association with indices of dyspnea and exercise capacity, while the SF-36 associated well only in dimensions related to physical health. The general measure has a broader scope and complements the lung-specific measure. These findings support the construct validity of both the SF-36 and the RQLQ, and justify using a general measure to supplement a lung-specific measure.

Adolescent↗

PubMed2006

Exercise capacity before and after an 8-week multidisciplinary inpatient rehabilitation program in lung cancer patients: a pilot study.

Although lung cancer is a highly prevalent type of cancer, the effects of an inpatient multidisciplinary rehabilitation program on pulmonary function and exercise capacity have never been studied in these patients. Pulmonary function, 6-min walking distance and peak exercise capacity of 10 patients with a severely impaired pulmonary function following treatment of lung cancer were assessed in this pilot study before and after an 8-week inpatient multidisciplinary rehabilitation program. At baseline, patients had a restrictive pulmonary function and an apparent exercise intolerance (median 6-min walking distance: 63.6% predicted; median peak cycling load: 58.5% predicted). Despite the lack of change in median pulmonary function [FEV1: -0.01L, p = 0.5469], functional exercise capacity [145 m; 43.2% of the initial values, p=0.0020] and peak exercise capacity [26 W; 34.4% of the initial values, p = 0.0078] improved significantly compared to baseline. Future trials have to corroborate the present findings. Nevertheless, patients with lung cancer have a clear indication to start a comprehensive rehabilitation program following intensive treatment of their disease. In fact, based on the results of the present pilot study it appears that these patients are good candidates for pulmonary rehabilitation programs.

Aged↗

PubMed1998

Exercise capacity in patients with beta-thalassemia major: relation to left ventricular and atrial size and function.

OBJECTIVES: The objective of this study was to examine the association between exercise capacity and echocardiographic indexes of atrial and ventricular function and size in patients with beta-thalassemia major. BACKGROUND: In patients with beta-thalassemia major, the assessment of cardiac function with echocardiography alone does not always correspond to their functional status. Peak oxygen uptake and anaerobic threshold, on the other hand, constitute 2 objective and reproducible determinants of exercise capacity in patients with heart failure. METHODS AND RESULTS: Forty consecutive patients (22 women and 18 men, 18 to 30 years old) who were in stable condition while receiving regular transfusions and 30 age- and sex-matched control subjects were studied. At 2 to 3 days after the last transfusion, each subject underwent complete echocardiographic study followed by cardiopulmonary exercise testing. Left atrial volumes (maximal [Vmax], at onset of atrial systolic [Vp], and minimal [Vmin]) and left ventricular volumes were measured with the biplane area-length method, and left atrial active emptying fraction (ACTEF) and left ventricular ejection (LVEF) fraction were calculated. Peak oxygen uptake (Vo 2 max) and anaerobic threshold (AT) were also estimated. After transfusion, patients with beta-thalassemia major had reduced Vo 2 max and AT and greater left atrial volume in comparison with control subjects. Also, ACTEF and LVEF were significantly lower in the patient group. Moreover, Vo2 max and AT were inversely related to Vmax (r = -0.74 and r = -0.80, respectively) and directly related to ACTEF (r = 0.85 and r = 0.82, respectively) in beta-thalassemia major, whereas they were poorly related to LVEF (r = 0.50 and r = 0. 53, respectively). In the control group, Vo 2 max and AT parameters were related to Vmax and ACTEF in a similar way to that in the beta-thalassemia group. CONCLUSIONS: In patients with beta-thalassemia major, exercise capacity does not correlate with left ventricular dimensions and function. On the contrary, left atrial size and systolic dysfunction are probably predictors of decreased exercise capacity.

Adolescent↗

PubMed2001

Serum HbA1c levels and exercise capacity in diabetic patients.

It is well known that cardiovascular morbidity and mortality are high in diabetic patients. Cardiac involvement is silent and early and these diabetic patients generally complain of chronic fatigue. This study was designed to evaluate the relation between glycemic control and exercise capacity in 330 diabetic patients who have no cardiac symptoms by sustaining dynamic exercise. After a cardiac examination, patients with coronary heart disease, ECG abnormalities, cardiac failure, valvular disease, cerebrovascular disease, peripheral artery disease, anaemia and peripheral neuropathy were excluded. Plasma HbA1c and lipid levels were obtained and a symptom limited exercise test based on "Bruce Protocol" was performed on all patients. Plasma HbA1c levels were significantly increased in smokers and in hypercholesterolemic patients (p<0.001, p=0.006). A moderate correlation between exercise capacity and HbA1c levels, and a weak correlation between duration of diabetes, age, sex, hypertension and plasma lipids were obtained. Multivariant regression analys is revealed that only HbA1c and hypercholesterolemia affected exercise capacity independently (r=-0.54 r=-0.30). In conclusion, poor glycemic control in diabetic patients causes earlier cellular involvement. Because of the high affinity of HbA1c to oxygen, the energy metabolism of the cell is affected, with a clinical correlation between chronic fatigue and worsening exercise capacity.

Diabetes Mellitus↗

PubMed2004

L-arginine supplementation prolongs exercise capacity in congestive heart failure.

BACKGROUND: In congestive heart failure (CHF), endothelial dysfunction may contribute to impairment of exercise induced vasodilatation and decreased exercise capacity. We hypothesised that administration of L-arginine, a precursor of nitric oxide (NO) and postulated antioxidant, may improve endothelium-dependent vasodilatation and exercise capacity and also exert antioxidant activity. AIMS: To investigate the effect of oral supplementation with L-arginine on exercise capacity and markers of oxidative stress in patients with mild to moderate CHF. METHODS: The study had a randomised double-blind cross-over design. Twenty one patients with stable NYHA II-III CHF underwent three exercise tests: initially, after oral administration of L-arginine (9 g/day for 7 days) or placebo. Blood was sampled prior to each test for plasma lipid peroxides, reduced sulphydryl groups and leukocyte oxygen free radical production. RESULTS: We found a higher prolongation of exercise duration time after L-arginine than after placebo (99+/-106 vs 70+/-99 s, p<0.05). There were no significant differences in markers of free radical activity. CONCLUSIONS: In patients with chronic stable CHF, oral supplementation with L-arginine prolongs exercise duration which may be due to NO-induced peripheral vasodilatation. The antioxidant properties of L-arginine have not been confirmed in this ex vivo study.

Aged↗

PubMed1994

Incremental evaluation of exercise capacity as an independent predictor of coronary artery disease presence and extent.

To determine the independent incremental value of exercise capacity (METS) concerning the presence and extent of coronary artery disease, we analyzed data from 800 patients with suspected coronary disease who underwent both exercise testing and coronary angiography. We performed logistic regression analysis of clinical and exercise test data with an incremental design to mimic the usual flow of data acquisition. Separate analyses were performed concerning coronary disease presence (> or = 1 vessel with a > or = 50% lesion) and extent (three-vessel/left main disease). Diagnostic accuracy was determined by calculating receiver operating characteristic (ROC) curve areas. When considered alone, METS was a significant predictor of both presence and extent of disease. Multivariate analysis revealed that METS was an independent predictor of disease extent but not presence. However, comparison of ROC curve areas failed to show any loss of accuracy when METS was removed from the coronary disease extent analysis. Despite the strong univariate relationship between exercise capacity and coronary disease presence and extent and the independence of exercise capacity as a predictor of coronary disease extent, the lack of an additional incremental accuracy attributed to its consideration virtually cancels its value as a diagnostic variable for assessing both coronary disease presence and extent.

Adult↗

PubMed2002

Left ventricular diastolic function assessed using Doppler tissue imaging in patients with hypertrophic cardiomyopathy: relation to symptoms and exercise capacity.

BACKGROUND: Conventional Doppler indices of left ventricular diastolic function do not correlate with symptoms or exercise capacity in patients with hypertrophic cardiomyopathy, because of their dependence on loading conditions. Diastolic mitral annular velocity measured using Doppler tissue imaging has been reported to be a preload independent index of left ventricular diastolic function. OBJECTIVE: To determine the relation between diastolic annular velocities combined with conventional Doppler indices and symptoms or exercise capacity in hypertrophic cardiomyopathy. METHODS: 85 patients with hypertrophic cardiomyopathy and 60 normal controls were studied. Diastolic mitral annular velocities, transmitral left ventricular filling, and pulmonary venous velocities were measured. RESULTS: Early diastolic velocities at lateral and septal annulus were lower in patients with hypertrophic cardiomyopathy than in controls (lateral Ea: 10 (3) v 18 (4) cm/s, p < 0.0001; septal Ea: 7 (2) v 12 (3) cm/s, p < 0.0001). Unlike conventional Doppler indices alone, transmitral early left ventricular filling velocity (E) to lateral Ea ratio correlated inversely with peak oxygen consumption (r = -0.42, p < 0.0001). Patients in New York Heart Association (NYHA) class III had a higher transmitral E to lateral Ea ratio (12.0 (4.6)) than those in NYHA class II (7.6 (3.1), p < 0.005) or class I (6.6 (2.6), p < 0.0001). CONCLUSIONS: Early diastolic mitral annular velocities are reduced in patients with hypertrophic cardiomyopathy. Unlike conventional Doppler indices alone, the transmitral E to lateral Ea ratio correlates with NYHA functional class and exercise capacity.

Adolescent↗

PubMed2002

Effects of somatotropin and training on indices of exercise capacity in Standardbreds.

The recent availability of recombinant equine somatotropin (eST) has led to concern about its use as an ergogenic aid in racehorses. This study was undertaken to investigate the changes in exercise capacity in maturing horses in a training programme, and to assess whether eST is an ergogenic aid to this group. We tested the hypothesis that the combination of training and eST, compared to training alone, would further improve exercise capacity in maturing Standardbreds, by virtue of ST's anabolic effects and potential to enhance cardiac function, circulating fluid volume and red cell mass. Twelve, untrained Standardbreds (mean +/- s.d. 20.7 +/- 1.1 months) were paired according to similar bodyweight and then assigned randomly to treatment or control group. The horses underwent a 12 week treadmill training programme. Methionyl eST (10 microg/kg for the first 7 days, then 20 microg/kg) was administered once daily, i.m., for 42 consecutive days (Weeks 4 to 9 inclusive) to 6 horses in the treatment group. All horses performed a standardised maximal exercise test to fatigue at Weeks 0, 3, 6, 9, and 12. During each exercise test VO2, VCO2, plasma lactate concentrations ([La]), heart rates, blood volume and total run time were measured. There was no significant effect of eST administration on VO2max, V200, V(LA4), LA9, red cell volume (RCV), plasma volume (PV), or run time to fatigue. Combining the data for all horses, training significantly altered the VO2max (mean +/- s.d. 98.2 +/- 11.1 ml/kg/min in Week 0 to 117.6 +/- 4.8 ml/kg/min in Week 12), V(LA4) (5.1 +/- 0.8 m/s to 7.4 +/- 1.0 m/s), LA9 (12.7 +/- 3.9 mmol/l to 7.1 +/- 1.9 mmol/l), RCV (46.3 +/- 4.7 ml/kg to 63.5 +/- 5.0 ml/kg), PV (46.0 +/- 4.8 ml/kg to 57.0 +/- 6.3 ml/kg), and run time to fatigue (431.8 +/- 30.9 to 490.2 +/- 30.5 s), but not V200 (5.0 +/- 0.5 m/s to 5.2 +/- 1.1 m/s). The administration of eST to young Standardbred horses in training did not significantly improve their exercise capacity or indices of fitness. However, these maturing horses demonstrated a rapid physiological response to training exercise. Further research is required to determine the relationship between exercise capacity and ST in the horse.

Age Factors↗

PubMed2001

Intensive home-based exercise training in cardiac rehabilitation increases exercise capacity and heart rate variability.

BACKGROUND: Reduced heart rate variability (HRV) is a risk factor for cardiac death. Animal studies have shown increased HRV and reduced mortality after physical training. We evaluated the change in exercise capacity and HRV in cardiac rehabilitation patients, randomised to routine or home-based intensive training. The design was prospective, stratified randomisation with pre-specified subgroup analysis. METHODS: Maximal bicycle exercise test and 24-h Holter were performed 1 (baseline), 4 and 12 months after myocardial infarction (MI) or coronary artery by-pass surgery (CABG). Patients were randomised to physical training either two (N) or six (I) times per week for 3 months Sixty-two patients (43 MI and 19 CABG patients) were evaluated. RESULTS: Exercise capacity increased significantly more after 3 months of training in group I (mean (S.E.)); 29.0 (3.4) vs. 7.2 (2.6) watts, P<0.001). One year later the difference in exercise capacity remained (26.5 (3.3) vs. 11.8 (3.8) watts, P<0.001). Global HRV measurements SDNN and SDANN increased significantly more in group I after training (17.1 (5.6) vs. 1.7 (3.7) and 16.2 (4.9) vs. 2.8 (3.1) ms, P<0.05) and 1 year later the differences were still significant. Subgroup analysis showed more pronounced HRV response in CABG than MI patients. CONCLUSION: Intensive exercise training in cardiac rehabilitation increases exercise capacity and global HRV, which could be of prognostic significance.

Coronary Artery Bypass↗

PubMed1991

Relief of right ventricular angina and increased exercise capacity with long-term oxygen therapy.

Long-term low-flow oxygen therapy can lead to improved exercise capacity and improved hemodynamics in selected patients with pulmonary hypertension. We report a patient who presented with severe exercise limitation and anginal chest pain that appeared to result from pulmonary hypertension and predominantly right ventricular ischemia. Acute oxygen therapy led to relief of pain but no change in exercise capacity or of pulmonary hypertension. After eight months of oxygen therapy, the patient's pulmonary hypertension was unchanged, but right ventricular hypertrophy and marked increases in exercise cardiac output and exercise capacity developed. Thus, oxygen can relieve right ventricular angina and facilitate the development of compensatory hypertrophy.

Angina Pectoris↗

PubMed2003

[Relationship between exercise capacity and brain natriuretic peptide in patients after cardiac surgery].

OBJECTIVES: Physical training in cardiac patients can increase exercise capacity and reduce plasma brain natriuretic peptide(BNP) concentration, but these effects may depend on the etiology of cardiac disease. The change in exercise capacity and BNP during the training period were investigated in patients with different cardiac diseases. METHODS: Ninety-one patients after coronary artery bypass grafting(CABG) and 78 patients after valve replacement (VR) underwent a symptom-limited incremental cardiopulmonary exercise test before (1 month) and 6 months after physical training. Anaerobic threshold and peak oxygen uptake(peak-Vo2) were measured during the cardiopulmonary exercise test. Before each cardiopulmonary exercise test, a blood sample was obtained in the resting condition for measuring BNP. RESULTS: Anaerobic threshold and peak-Vo2 were increased significantly from 1 month to 6 months in both groups. BNP in the CABG group indicated a tendency to decrease (194.6 +/- 155.3-->144.2 +/- 232.2 pg/ml, p < 0.1) from 1 month to 6 months. BNP in VR group was significantly decreased (159. 9 +/- 115.5-->112.8 +/- 131.7 pg/ml, p < 0.05) during the training period. The CABG group showed a significant negative correlation between peak-Vo2 and BNP at 1 month(r = -0.28, p < 0.01) and at 6 months(r = -0.39, p = 0.001). The VR group showed a significant negative correlation between peak-Vo2 and BNP at 6 months(r = -0.32, p < 0.01), but not at 1 month. CONCLUSIONS: Six months of physical training in patients after cardiac surgery may improve exercise capacity and reduce BNP. BNP concentration in the VR group before physical training did not reflect functional capacity.

Aged↗

PubMed1997

Effects of cardiac rehabilitation, exercise training, and weight reduction on exercise capacity, coronary risk factors, behavioral characteristics, and quality of life in obese coronary patients.

Obesity is strongly associated with coronary artery disease (CAD) and may be an independent risk factor; however, limited data are available on obesity intervention in patients with CAD. We studied 588 consecutive patients, including 235 (40%) who were obese by body mass index criteria (body mass index > or = 27.3 kg/m2 in women and > or = 27.8 kg/m2 in men) before and after out-patient phase II cardiac rehabilitation to determine the effects of this therapy and weight reduction on exercise capacity, CAD risk factors, behavioral characteristics, and quality of life in obese patients with CAD. At baseline, obese patients were younger (p < 0.0001) and had more systemic hypertension (p < 0.01), and diabetes mellitus (p < 0.05) and higher percent body fat (p < 0.0001), total cholesterol (p = 0.02), triglycerides (p < 0.0001), fasting glucose (p = 0.04), and low-density lipoprotein (LDL)-high-density lipoprotein (HDL) cholesterol (p < 0.0001), but had lower HDL cholesterol (p < 0.01) and exercise capacity (p = 0.07) than patients not classified as obese. After rehabilitation, obese patients had significant improvements in body mass index (-2%; p < 0.0001), percent body fat (-5%; p < 0.0001), exercise capacity (+27%; p < 0.0001), HDL cholesterol (+4%; p < 0.01), LDL/HDL ratio (-6%; p < 0.01), as well as scores for anxiety (p < 0.0001), depression (p < 0.01), somatization (p < 0.0001) and quality of life (p < 0.0001); nonobese patients, however, had significantly greater improvements in exercise capacity (+39% vs +27%; p < 0.001). In a subgroup of 45 obese patients with > or = 5% weight reduction, improvements in exercise capacity (p < 0.001), total cholesterol (p = 0.03), triglycerides (p < 0.01), HDL cholesterol (p < 0.001), LDL cholesterol (p = 0.02), and LDL/HDL ratio (p < 0.0001) were greater than improvements in 81 obese patients who did not lose weight. These data indicate that greater emphasis on more successful weight reduction programs is needed to further enhance CAD risk reduction in the 40% CAD patients with obesity.

Aged↗

PubMed1997

[Factors affecting exercise capacity after coronary bypass grafting].

In order to determine the contribution of cardiac reserve and the peripheral muscle to exercise capacity in patients after Coronary Artery Bypass Grafting (CABG), 19 patients (18 males, 1 female, mean age 63.3 +/- 7.1 years, mean numbers of grafting 2.5 +/- 0.8) performed exercise tests at 1 week, 3 weeks, and 3 months after CABG. Ventilatory gas was analyzed throughout the testing and anaerobic threshold (AT) and peak oxygen uptake (peak VO2) was determined. During exercise testing, the cardiac index (CI) was measured, and the change in CI during exercise, delta CI = (CI at peak exercise) (CI at rest), was calculated. O2 delivery was derived from the product of CO and the oxygen content of arterial blood at peak exercise. The sectional area of the thigh muscles at the level of 10 cm above the patella was measured using a computed tomography before each test. Average peak VO2 at 1 week after CABG was 867 +/- 171 ml/min and it increased to 1,214 +/- 246 ml/min at 6 months. Average AT did not change from 1 week to 3 weeks, however, it increased significantly from 665 +/- 122 ml/min at 3 weeks to 873 +/- 181 ml/min at 6 months. The muscle area of the thigh increased significantly from 170 +/- 24 cm2 at 3 weeks after CABG to 186 +/- 27 cm2 at 3 months. delta CI showed a tendency to increase from 6.6 +/- 1.2 l/min/m2 at 1 week after CABG to 7.3 +/- 1.3 l/min/m2 at 3 weeks, and also showed a tendency to increase from 3 weeks to 6 months. Peak VO2 and AT correlated to delta CI at 1 weeks and also it correlated significantly to both the muscle area of the thigh and delta CI at 3 weeks, 3 months, and 6 months after CABG. The delta value of peak VO2 from 1 week to 3 weeks showed a significant correlation to those of delta CI and O2 delivery. Moreover, the delta values of peak VO2 and AT from 3 weeks to 3 months showed a correlation to those of delta CI and O2 delivery. These results suggest that both cardiac reserve and peripheral factors contribute to the exercise capacity up to 3 months after CABG, and, in particular, O2 delivery are important to increase exercise capacity.

Cardiac Output↗

PubMed1990

Maximal exercise capacity and oxygen consumption of lambs with an aortopulmonary left-to-right shunt.

We determined maximal exercise capacity and measured hemodynamics in 10 6-wk-old lambs with an aortopulmonary left-to-right shunt [S, 57 +/- 11%, (SD)] and in 9 control lambs (C) during a graded treadmill test 8 days after surgery. Maximal exercise capacity (3.7 +/- 0.2 km/h and 10 +/- 5% inclination vs. 4.0 +/- 0.9 km/h and 15 +/- 0% inclination, P less than 0.02) and peak oxygen consumption (25 +/- 7 vs. 34 +/- 8 ml O2.min-1.kg-1, P less than 0.02) were both lower in the shunt than in the control lambs. This was due to a lower maximal systemic blood flow in the shunt lambs (271 +/- 38 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.01). Despite their high maximal left ventricular output, which was higher than in the control lambs (448 +/- 87 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.05), the left-to-right shunt could not be compensated for during maximal exercise because of a decreased reserve in heart rate (S: 183 +/- 22 to 277 +/- 38 beats/min; C: 136 +/- 25 to 287 +/- 29 beats/min) and in left ventricular stroke volume (S: 1.8 +/- 0.3 to 1.6 +/- 0.4 ml/kg; C: 1.0 +/- 0.3 to 1.3 +/- 0.2 ml/kg). We conclude that exercise capacity of shunt lambs is lower than that of control lambs, despite a good left ventricular performance, because a part of the reserves for increasing the left ventricular output is already utilized at rest.

Aging↗

PubMed2006

Elevated peak exercise systolic blood pressure is not associated with reduced exercise capacity in subjects with Type 2 diabetes.

Subjects with Type 2 diabetes without cardiovascular disease have a reduced exercise capacity compared with nondiabetic subjects. However, the mechanisms responsible for this phenomenon are unknown. The purpose of this study was to evaluate the impact of exercise systolic blood pressure (SBP) response on diverse exercise tolerance parameters in Type 2 diabetic subjects. Twenty-eight sedentary men with Type 2 diabetes were recruited for this study. Subjects were treated with oral hypoglycemic agents and/or diet. Evaluation of glycemic control and peak exercise capacity were performed for each subject. The subjects were divided into two groups according to the median value of peak SBP (210 mmHg) measured in each subject. We observed a 13, 13, and 16% reduction in the relative peak oxygen uptake (V(O2 peak)), absolute V(O2 peak), and peak work rate in the low- compared with the high-peak SBP group [26.95 (SD 5.35) vs. 30.96 (SD 3.61) ml.kg(-1).min(-1), 2.5 (SD 0.4) vs. 2.8 (SD 0.6) l/min, and 169 (SD 34) vs. 202 (SD 32) W; all P < 0.05]. After adjusting for age, relative V(O2 peak) was still significantly different (P < 0.05). There were similar peak respiratory exchange ratio (RER) [1.20 (SD 0.08) vs. 1.16 (SD 0.07); P = 0.24] and peak heart rate [160 (SD 20) vs. 169 (SD 15) beats/min; P = 0.18] between the low- compared with the high-SBP group. No difference in glycemic control was observed between the two groups. The results reported in this study suggest that in subjects with Type 2 diabetes without cardiovascular disease, an elevated exercise SBP is not associated with reduced exercise capacity and its modulation is probably not related to glycemic control.

Blood Pressure↗

PubMed1993

Relationship between exercise capacity and the severity of emphysema as determined by high resolution CT.

We investigated the relationship between exercise capacity or exercise-induced hypoxaemia and the severity of pulmonary emphysema in 20 patients with pulmonary emphysema. The patients underwent pulmonary function tests, high resolution computed tomography and incremental treadmill exercise testing. Computed tomography scans were obtained at four levels in the lungs, and emphysema scores were determined by the visual assessment of low attenuation areas as a measure of the severity of parenchymal destruction. The emphysema score correlated significantly with diffusing capacity (r = -0.69) in the pulmonary function tests. Among the exercise test parameters, the emphysema score correlated significantly with the total distance walked (r = -0.74), with maximal oxygen consumption (VO2max) (r = -0.77), with arterial oxygen tension (PaO2) at rest (r = -0.50) and at the maximum workload (r = -0.58), and with the decrement of arterial oxygen tension per litre of oxygen consumed (r = -0.64). These results suggest that exercise capacity and exercise-induced hypoxaemia are related to the extent of destruction of lung parenchyma in patients with pulmonary emphysema.

Aged↗

PubMed1998

Skeletal muscle metabolism limits exercise capacity in patients with chronic heart failure.

BACKGROUND: Several studies have indicated that skeletal muscle is important in determining the exercise capacity of patients with chronic heart failure (CHF). However, this theory has been investigated only in experiments based on local exercise involving a small muscle mass. We investigated skeletal muscle metabolism during maximal systemic exercise to determine whether muscle metabolism limits exercise capacity in patients with CHF. We also studied the relationship between muscle metabolic abnormalities during local and systemic exercise. METHODS AND RESULTS: Skeletal muscle metabolism was measured during maximal systemic exercise on a bicycle ergometer by a combination of the metabolic freeze method and 31P magnetic resonance spectroscopy in 12 patients with CHF and 7 age- and size-matched normal subjects. We also evaluated skeletal muscle metabolism during local exercise while subjects performed unilateral plantar flexion. Muscle phosphocreatine (PCr) was nearly depleted during maximal systemic exercise in patients with CHF and normal subjects (12.5+/-0.04% and 12.3+/-0.07%, respectively, of initial level). PCr depletion occurred at a significantly lower peak oxygen uptake (peak VO2) in patients with CHF than in normal subjects (CHF, 20.2+/-3.0 versus normal, 31.8+/-3.7 mL . min-1 . kg-1, P<0. 0001). Muscle metabolic capacity, evaluated as the slope of PCr decrease in relation to increasing workload, was correlated with peak VO2 during maximal systemic exercise in patients with CHF (r=0.83, P<0.001). Muscle metabolic capacity during local exercise was impaired in patients with CHF and was correlated with capacity during systemic exercise (r=0.76, P<0.01) and with peak VO2 (r=0. 83, P<0.001). CONCLUSIONS: These results suggest that impaired muscle metabolism associated with early metabolic limitation determines exercise capacity during maximal systemic exercise in patients with CHF. There was a significant correlation between muscle metabolic capacity during systemic and local exercise in patients with CHF.

Adult↗