Exercise Duration Rather than Peak Oxygen Uptake Better Correlates with Fev 1 and Inspiratory Capacity in Chronic Obstructive Pulmonary Disease (original) (raw)
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Clinical relevance of constant power exercise duration changes in COPD
European Respiratory Journal, 2009
The endurance time during constant high work-rate exercise (tLIM) is used to assess exercise capacity in patients with chronic obstructive pulmonary disease and as an outcome measure for pulmonary rehabilitation. Our study was designed to establish the minimum clinically important difference for the tLIM. tLIM was measured in 105 patients (86 males) before and after an 8-week outpatient pulmonary rehabilitation programme. Subjects were asked to identify, from a five-point Likert scale, the perceived change in their exercise performance immediately upon completion of the exercise tests. The scale ranged from ''better'' to ''worse''.
Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD
Respiratory Care, 2012
BACKGROUND: Ventilatory inefficiency increases ventilatory demand; corresponds to an abnormal increase in the ratio of minute ventilation (V E) to CO 2 production (V CO 2); represents increased dead space, deregulation of respiratory control, and early lactic threshold; and is associated with expiratory flow limitation that enhances dynamic hyperinflation and may limit exercise capacity. OBJECTIVE: To evaluate the influence of ventilatory inefficiency over exercise capacity in COPD patients. METHODS: Prospective study of 35 COPD subjects with different levels of severity, in whom cardiopulmonary stress test was performed. Ventilatory inefficiency was represented by the V E /V CO 2 relation. Its influence over maximal oxygen consumption (V O 2 max), power (W), and ventilatory threshold was evaluated. Surrogate parameters of cardiac function, like oxygen pulse (V O 2 /heart rate) and circulatory power (%V O 2 max ؋ peak systolic pressure), were also evaluated. RESULTS: Cardiopulmonary stress test was stopped due to dyspnea with elevated V E and marked reduction of breathing reserve. A severe increase in V E /V CO 2 (mean ؎ SD 35.9 ؎ 5.6), a decrease of V O 2 max (mean ؎ SD 75.2 ؎ 20%), and a decrease of W (mean ؎ SD 68.6 ؎ 23.3%) were demonstrated. Twenty-eight patients presented dynamic hyperinflation. Linear regression showed a reduction of 2.04% on V O 2 max (P < .001), 2.6% on W (P < .001), 1% on V O 2 /heart rate (P ؍ .049), and 322.7 units on circulatory power (P ؍ .02) per each unit of increment in V E /V CO 2 , respectively. CONCLUSIONS: Ventilatory inefficiency correlates with a reduction in exercise capacity in COPD patients. Including this parameter in the evaluation of exercise limitation in this patient population may mean a contribution toward the understanding of its pathophysiology.
Effect of exercise mode on oxygen uptake and blood gases in COPD patients
Respiratory Medicine, 2004
Patients with chronic obstructive pulmonary disease (COPD) are characterised by decreased exercise tolerance, and, more variably, exercise induced hypoxaemia (EIH). Evaluation of physical work capacity and physiological responses to exercise may be performed by various procedures, but there are diverging opinions as to which exercise test should be preferred. In the current study, oxygen uptake and arterial blood gases in COPD patients have been compared during submaximal and maximal exercise on treadmill and ergometer bicycle.
Physiological and clinical relevance of exercise ventilatory efficiency in COPD
The European respiratory journal, 2017
Exercise ventilation (V'E) relative to carbon dioxide output (V'CO2 ) is particularly relevant to patients limited by the respiratory system, e.g. those with chronic obstructive pulmonary disease (COPD). High V'E-V'CO2 (poor ventilatory efficiency) has been found to be a key physiological abnormality in symptomatic patients with largely preserved forced expiratory volume in 1 s (FEV1). Establishing an association between high V'E-V'CO2 and exertional dyspnoea in mild COPD provides evidence that exercise intolerance is not a mere consequence of detraining. As the disease evolves, poor ventilatory efficiency might help explaining "out-of-proportion" breathlessness (to FEV1 impairment). Regardless, disease severity, cardiocirculatory co-morbidities such as heart failure and pulmonary hypertension have been found to increase V'E-V'CO2 In fact, a high V'E-V'CO2 has been found to be a powerful predictor of poor outcome in lung resection su...
Scandinavian Journal of Medicine & Science in Sports, 2020
Functional impairment caused by chronic obstructive pulmonary disease (COPD) impacts on activities of daily living and quality of life. Indeed, patients’ submaximal exercise capacity is of crucial importance. It was the aim of this study to investigate the effects of an exercise training intervention with and without supplemental oxygen on submaximal exercise performance. This is a secondary analysis of a randomized, controlled, double‐blind, crossover trial. 29 COPD patients (63.5 ± 5.9 years; FEV1 46.4 ± 8.6%) completed two consecutive 6‐week periods of high‐intensity interval cycling and strength training, which was performed three times/week with either supplemental oxygen or medical air (10 L/min). Submaximal exercise capacity as well as the cardiocirculatory, ventilatory, and metabolic response were evaluated at isotime (point of termination in the shortest cardiopulmonary exercise test), at physical work capacity at 110 bpm of heart rate (PWC 110), at the anaerobic threshold ...
Respirology, 2004
YAZICI M, ARBAK P, BALBAY O, MADEN E, ERBAS M, ERBILEN E, ALBAYRAK S, AKDEMIR R, UYAN C. Respirology 2004; 9 : 320-325 Objective: There have been controversial reports regarding the relationship between exercise tolerance and resting pulmonary function in patients with COPD. The aim of this study was to examine the relationship between resting pulmonary function tests (rPFT) and cardiopulmonary exercise testing parameters (CETP) and their value in estimating exercise tolerance of patients. Methodology: In total, 45 patients with COPD (nine females, 36 males; mean age 61.2 ± 11.2) and 21 healthy subjects (four females, 17 males; mean age 60.3 ± 9.7) as a control group were studied. COPD patients (group I) were divided into three subgroups according to their FEV 1 (mild/group II: FEV 1 60-79% of predicted; moderate/group III: FEV 1 40-59%; severe/group IV: FEV 1 < 40%). In controls FEV 1 was ≥ 80%. Results: There were significant correlations between FEV 1 and CETP in group III (maximal O 2 consumption (mVO 2 ), r = 0.35, P < 0.005; total treadmill time (TTT), r = 0.31, P < 0.01; total metabolic equivalent values (TMET), r = 0.29, P < 0.01)) and in group IV (mVO 2 , r = 0.49, P < 0.001; TTT, r = 0.45, P < 0.005; TMET, r = 0.31, P < 0.01; peak heart rate (pHR), r = 0.29, P < 0.02; frequency of ventricular extrasystole (fVES), r = -0.27, P < 0.05). Additionally, in group IV there were significant correlations between PaO 2 and CETP (mVO 2 , r = 0.41, P < 0.02; TTT, r = 0.38, P < 0.03; TMET, r = 0.31, P < 0.05; pHR, r = 0.29, P < 0.05; fVES, r = -0.28, P < 0.05). Conclusion: There are significant correlations of resting FEV 1 % predicted and PaO 2 values with CETP in patients with moderate and severe COPD and these parameters may also have a role as indicators of exercise tolerance in these COPD patients.
Ventilatory and Cardiocirculatory Exercise Profiles in COPD
CHEST Journal, 2012
The impact of PH on exercise tolerance is largely unknown. We evaluated and compared the circulatory and ventilatory profi les during exercise in patients with COPD without PH, with moderate PH, and with severe PH. Methods: Forty-seven patients, GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages II to IV, underwent cardiopulmonary exercise testing and right-sided heart catheterization at rest and during exercise. Patients were divided into three groups based on mean pulmonary artery pressure (mPAP) at rest: no PH (mPAP, , 25 mm Hg), moderate PH (mPAP, 25-39 mm Hg), and severe PH (mPAP, Ն 40 mm Hg). Mixed venous oxygen saturation (S VO 2 ) was used for evaluating the circulatory reserve. Pa CO 2 and the calculated breathing reserve were used for evaluation of the ventilatory reserve. Results: Patients without PH (n 5 24) had an end-exercise S VO 2 of 48% Ϯ 9%, an increasing Pa CO 2 with exercise, and a breathing reserve of 22% Ϯ 20%. Patients with moderate PH (n 5 14) had an exercise S VO 2 of 40% Ϯ 8%, an increasing Pa CO 2 , and a breathing reserve of 26% Ϯ 15%. Patients with severe PH (n 5 9) had a signifi cantly lower end-exercise S VO 2 (30% Ϯ 6%), a breathing reserve of 37% Ϯ 11%, and an absence of Pa CO 2 accumulation. Conclusion: Patients with severe PH showed an exhausted circulatory reserve at the end of exercise. A profi le of circulatory reserve in combination with ventilatory impairments was found in patients with COPD and moderate or no PH. The results suggest that pulmonary vasodilation might only improve exercise tolerance in patients with COPD and severe PH.
Thorax, 2004
Background: While the acute physiological responses to continuous exercise have been well documented in individuals with chronic obstructive pulmonary disease (COPD), no previous study has examined the response to intermittent exercise in these patients. Methods: We examined the physiological responses of 10 individuals with moderate COPD (forced expiratory volume in 1 second 52 (15)% predicted) who performed both an intermittent (1 min exercise and rest intervals) and a continuous cycle ergometer test on separate days. Both intermittent and continuous exercise tests were performed at the same power output, calculated as 70% of the peak power attained during an incremental exercise test. Results: Intermittent exercise was associated with significantly lower values for oxygen uptake, carbon dioxide output, expired ventilation, heart rate, plasma lactate concentration, and ratings of breathlessness than continuous exercise. Subjects were able to complete a significantly greater total amount of work during intermittent exercise (71 (32) kJ) than during continuous exercise (31 (24) kJ). The degree of dynamic lung hyperinflation (change in end expiratory lung volume) was significantly lower during intermittent exercise (0.23 (0.07) l) than in continuous exercise (0.52 (0.13) l). Conclusions: The greater amount of work performed and lower measured physiological responses achieved with intermittent exercise may allow for greater peripheral training adaptations in individuals with more limited lung function. The results suggest that intermittent exercise may be superior to continuous exercise as a mode of training for patients with COPD.
Exercise responses during endurance testing at different intensities in patients with COPD
Respiratory Medicine, 2004
Endurance time on submaximal exercise tests is a sensitive measure in detecting changes after medical intervention and is used as an outcome in clinical trials, although there has been little discussion regarding the appropriate intensity. Therefore, we investigated whether there were differences in exercise responses between endurance tests at high versus moderate intensity, and analyzed which test was more appropriate. Thirty-seven patients with chronic obstructive pulmonary disease participated in the study. They performed cycle endurance tests at high and moderate submaximal workloads representing 80% and 60% of the maximum work rate reached on progressive cycle ergometry, respectively. Each type of exercise test was performed after inhaling salbutamol 400 mg, ipratropium bromide 80 mg or an identical placebo. Endurance time on the 80% endurance test was much shorter than on the 60% endurance test. The coefficients of variation for the endurance time were lower on the 80% test. Statistically significant improvements in the endurance time after bronchodilators in comparison to placebo were found only on the 80% test. When using the endurance time as an outcome, the high intensity endurance test is preferable to the moderate intensity endurance test, as the high intensity test demonstrated shorter exercise time, less variability and higher sensitivity.