Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients. The effects of controlled breathing during pulmonary rehabilitation in patients with COPD. Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise. Resistive inspiratory muscle training and exercise performance in COPD patients. A comparative study with conventional breathing retraining. [Effect of oxygen (FI02: 0.35) on the aerobic capacity in patients with COPD]. Supplemental oxygen during pulmonary rehabilitation in patients with COPD with exercise hypoxaemia. Respiratory muscle training improves cardiopulmonary function and exercise tolerance in subjects with subacute stroke: a randomized controlled trial. Effects of oxygen on lower limb blood flow and O2 uptake during exercise in COPD. Helium-hyperoxia, exercise, and respiratory mechanics in chronic obstructive pulmonary disease.
Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p < 0.01). After training, endurance in constant work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing. Conventional pulmonary rehabilitation programs improve exercise tolerance but have no effect on pulmonary function in patients with chronic obstructive pulmonary disease (COPD). The role of controlled breathing using respiratory biofeedback during rehabilitation of patients with COPD remains unclear.
                To compare the effects of a conventional 4-week pulmonary rehabilitation program with those of rehabilitation plus controlled breathing interventions.
                A randomized controlled trial was performed. Pulmonary function (FEV1), exercise capacity (6-min walking distance, 6 MWD), health-related quality of life (chronic respiratory questionnaire, CRQ) and cardiac autonomic function (rMSSD) were evaluated.
                Forty COPD patients (mean±SD age 66.1±6.4, FEV1 45.9±17.4% predicted) were randomized to rehabilitation (n=20) or rehabilitation plus controlled breathing (n=20). There were no statistically significant differences between the two groups regarding the change in FEV1 (mean difference -0.8% predicted, 95% CI -4.4 to 2.9% predicted, p=0.33), 6 MWD (mean difference 12.2 m, 95% CI -37.4 to 12.2 m, p=0.16), CRQ (mean difference in total score 0.2, 95% CI -0.1 to 0.4, p=0.11) and rMSSD (mean difference 2.2 ms, 95% CI -20.8 to 25.1 ms, p=0.51).
                In patients with COPD undergoing a pulmonary rehabilitation program, controlled breathing using respiratory biofeedback has no effect on exercise capacity, pulmonary function, quality of life or cardiac autonomic function.
                Copyright © 2011 S. Karger AG, Basel. Supplemental oxygen has acute beneficial effects on exercise performance in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether oxygen-supplemented training enhances the effects of training while breathing room air in patients with severe COPD. A randomized controlled trial was performed in 24 patients with severe COPD who developed hypoxaemia during incremental cycle exercise (arterial oxygen saturation (Sa,O2) <90% at peak exercise). All patients participated in an in-patient pulmonary rehabilitation programme of 10 weeks duration. They were assigned either to general exercise training while breathing room air (GET/RA group: forced expiratory volume in one second (FEV1) 38% of predicted; arterial oxygen tension (Pa,O2) 10.5 kPa at rest; Pa,O2 7.3 kPa at peak exercise), or to GET while breathing supplemental oxygen (GET/O2 group: FEV1 29% pred; Pa,O2 10.2 kPa at rest; Pa,O2 7.2 kPa at peak exercise). Sa,O2 was not allowed to fall below 90% during the training. The effects on exercise performance while breathing air and oxygen, and on quality of life were compared. Maximum workload (Wmax) significantly increased in the GET/RA group (mean (SD) 17 (15) W, p<0.01), but not in the GET/O2 group (7 (25) W). Six minute walking distance (6MWD), stair-climbing, weight-lifting exercise (all while breathing room air) and quality of life significantly increased in both groups. Acute administration of oxygen improved exercise performance before and after training. Training significantly increased Wmax, peak carbon dioxide production (V'CO2) and 6MWD while breathing oxygen in both groups. Differences between groups were not significant. Pulmonary rehabilitation improved exercise performance and quality of life in both groups. Supplementation of oxygen during the training did not add to the effects of training on room air. Twenty patients with stable COPD (mean age 67.8 yr; mean FEV1 1.08 1), all limited by ventilation at maximum exercise, were randomly allocated after a four week control period, to an eight week programme of either inspiratory resistive training (IRT), with a P Flex device, or conventional breathing retraining (BR). Exercise performance was evaluated every four weeks, using a 12-min walking test, an incremental progressive exercise on a cycle ergometer and a cycle endurance test. Inspiratory muscle endurance was measured as the highest tolerated resistance for 10 min on a P Flex device. IRT produced a significant (p less than 0.05) increase in the highest tolerated resistance, but IRT and BR failed to improve lung function or exercise performance. The present study shows that in COPD patients with ventilatory limitation on exercise an IRT programme may fail to improve exercise performance, in spite of an efficient training effect on the endurance of the inspiratory muscles. Disability in patients with chronic obstructive pulmonary disease has led to the development of rehabilitation programs to increase exercise tolerance.
                To determine, if the effect of training can be improved by giving supplemental oxygen during exercise.
                Ten male patients with COPD (mean FEV1 = 43.2 +/- 17.1% pred) underwent a five day per week cycle ergometer training program for four weeks at least 45 minutes per day at a constant workload of 80% of their highest achieved workrate--measured in an incremental exercise test before training. At this workrate all patients performed exercise above their anaerobic threshold. Five patients were breathing 35% oxygen during exercise, five were breathing roomair (randomised, single blind). To evaluate and compare the results of training before and after the program all patients performed an incremental exercise test (continuously increasing workrate) with roomair.
                In the group breathing 35% O2 during training the maximally achieved power in the incremental exercise test after training was 15.9% higher. In the group breathing roomair during training the maximally achieved power after training was 36.3% higher than before (p < 0.05). This group also showed significant reductions in lactate levels (p < 0.05) after training at the maximum workload achieved in the pre-training test.
                Training in the roomair-group resulted in a significant increase in the maximum power and total amount of work. In this group training could induce a physiologic response (increase of aerobic capacity), which was shown by significantly lower lactate levels at a comparable workload. Supplemental oxygen in patients with chronic obstructive pulmonary disease (COPD) and exercise hypoxaemia improves exercise capacity and dyspnoea. However, the benefit of oxygen during pulmonary rehabilitation in these patients is still unknown.
                Twenty five patients with stable COPD (mean (SD) forced expiratory volume in one second (FEV(1)) 0.76 (0.29) l and 30.0 (9.89)% predicted, arterial oxygen tension (PaO(2)) 8.46 (1.22) kPa, arterial carbon dioxide tension (PaCO(2)) 6.32 (1.01) kPa) and significant arterial desaturation on exercise (82.0 (10.4)%) were entered onto a pulmonary rehabilitation programme. Patients were randomised to train whilst breathing oxygen (OT) (n = 13) or air (AT) (n = 12), both at 4 l/min. Assessments included exercise tolerance and associated dyspnoea using the shuttle walk test (SWT) and Borg dyspnoea score, health status, mood state, and performance during daily activities.
                The OT group showed a significant reduction in dyspnoea after rehabilitation compared with the AT group (Borg mean difference -1.46 (95% CI -2.72 to -0.19)) but there were no differences in other outcome measures: SWT difference -23.6 m (95% CI -70.7 to 23.5), Chronic Respiratory Disease Questionnaire 3.67 (95% CI -7.70 to 15.1), Hospital Anxiety and Depression Scale 1. 73 (95% CI -2.32 to 5.78), and London Chest Activity of Daily Living Scale -2.18 (95% CI -7.15 to 2.79). At baseline oxygen significantly improved SWT (mean difference 27.3 m (95% CI 14.7 to 39.8) and dyspnoea (-0.68 (95% CI -1.05 to -0.31)) compared with placebo air.
                This study suggests that supplemental oxygen during training does little to enhance exercise tolerance although there is a small benefit in terms of dyspnoea. Patients with severe disabling dyspnoea may find symptomatic relief with supplemental oxygen. To determine whether two types of exercise--breathing retraining (BRT) and inspiratory muscle training (IMT)--improve on cardiopulmonary functions and exercise tolerance in patients with stroke.
                A randomized controlled trial.
                Education and research hospital.
                Forty-five inpatients with stroke (24 men, 21 women) were recruited for the study. The subjects were randomized into three groups: 15 assigned to receive inspiratory muscle training (IMT); 15 assigned to received breathing retraining, diaphragmatic breathing and pursed-lips breathing (BRT); 15 assigned to a control group.
                All study groups participated in a conventional stroke rehabilitation programme. For the same period, the IMT and BRT groups trained daily, six times a week, with each session consisting of one half-hour of training for six weeks.
                Each subject underwent pulmonary function and cardiopulmonary exercise tests. Subjects were also assessed for exertional dyspnoea, stages of motor recovery, ambulation status, activity of daily living and quality of life.
                After the training programme, the IMT group had significantly improved forced expiratory volume at 1 second (FEV(1)), forced vital capacity (FVC), vital capacity (VC), forced expiratory flow rate 25-75% (FEF 25-75%) and maximum voluntary ventilation (MVV) values compared with the BRT and control groups, although there were no significant differences between the BRT and control groups (P<0.01). Peak expiratory flow rate (PEF) value was increased significantly in the BTR group compared with the IMT and control groups. The IMT group also had significantly higher peak oxygen consumption (Vo(2peak)) than the BRT and control groups, although there were no significant differences between the BRT and control groups (P<0.001). There was a statistically significant increase in maximum inspiratory pressure (PI(max)) and maximum inspiratory and expiratory pressure (PE(max)) in the BRT group and, PI(max) in the IMT group compared with baseline and the control group. In the IMT group, this was associated with improvements in exercise capacity, sensation of dyspnoea and quality of life.
                Significant short-term effects of the respiratory muscle training programme on respiratory muscle function, exercise capacity and quality of life were recorded in this study. To quantify the effects of acute oxygen supplementation on lower limb blood flow (QLEG), O2 delivery (QO2LEG), and O2 uptake (VO2LEG) during exercise and to determine whether the metabolic capacity of the lower limb is exhausted at peak exercise during room air breathing in patients with COPD.
                Oxygen (FIO2 = 0.75) and air were randomly administered to 14 patients with COPD (FEV1: 35 +/- 2% pred, mean +/- SEM) during two symptom-limited incremental cycle exercise tests. Before exercise, a cannula was installed in a radial artery and a thermodilution catheter inserted in the right femoral vein. At each exercise step, five-breath averages of respiratory rate, tidal volume, and ventilation (VE), dyspnea and leg fatigue scores, arterial and venous blood gases, and QLEG were obtained. From these measurements, VO2LEG was calculated.
                Peak exercise capacity increased from 46 +/- 3 W in room air to 59 +/- 5 W when supplemental oxygen was used (P < 0.001). QLEG, QO2LEG, and VO2LEG were greater at peak exercise with O2 than with air (P < 0.05). During submaximal exercise, dyspnea score and VE were significantly reduced with O2 (P < 0.05), whereas QLEG, VO2LEG, and leg fatigue were similar under both experimental conditions. The improvement in peak exercise work rate correlated with the increase in peak QO2LEG (r = 0.66, P < 0.01), peak VO2LEG (r = 0.53, P < 0.05), and reduction in dyspnea at iso-exercise intensity (r = 0.56, P < 0.05).
                The improvement in peak exercise capacity with oxygen supplementation could be explained by the reduction in dyspnea at submaximal exercise and the increases in QO2LEG and VO2LEG, which enabled the exercising muscles to perform more external work. These data indicate that the metabolic capacity of the lower limb muscles was not exhausted at peak exercise during room air breathing in these patients with COPD. Hyperoxia and normoxic helium independently reduce dynamic hyperinflation and improve the exercise tolerance of patients with chronic obstructive pulmonary disease (COPD). Combining these gases could have an additive effect on dynamic hyperinflation and a greater impact on respiratory mechanics and exercise tolerance.
                To investigate whether helium-hyperoxia improves the exercise tolerance and respiratory mechanics of patients with COPD.
                Ten males with COPD (FEV(1) = 47 +/- 17%pred [mean +/- SD]) performed randomized constant-load cycling at 60% of maximal work rate breathing air, hyperoxia (40% O(2), 60% N(2)), normoxic helium (21% O(2), 79% He), or helium-hyperoxia (40% O(2), 60% He).
                Exercise time, inspiratory capacity (IC), work of breathing, and exertional symptoms were measured with each gas.
                Compared with air (9.4 +/- 5.2 min), exercise time was increased with hyperoxia (17.8 +/- 5.8 min) and normoxic helium (16.7 +/- 9.1 min) but the improvement with helium-hyperoxia (26.3 +/- 10.6 min) was greater than both these gases (p = 0.019 and p = 0.007, respectively). At an isotime during exercise, all three gases reduced dyspnea and both helium mixtures increased IC and tidal volume. Only helium-hyperoxia significantly reduced the resistive work of breathing (15.8 +/- 4.2 vs. 10.1 +/- 4.1 L . cm H(2)O(-1)) and the work to overcome intrinsic positive end-expiratory pressure (7.7 +/- 1.9 vs. 3.6 +/- 2.1 L . cm H(2)O(-1)). At symptom limitation, tidal volume remained augmented with both helium mixtures, but IC and the work of breathing were unchanged compared with air.
                Combining helium and hyperoxia delays dynamic hyperinflation and improves respiratory mechanics, which translates into added improvements in exercise tolerance for patients with COPD.
Breathing exercises over four to 15 weeks improve functional exercise capacity in people with COPD compared to no intervention; however, there are no consistent effects on dyspnoea or health-related quality of life. Outcomes were similar across all the breathing exercises examined. Treatment effects for patient-reported outcomes may have been overestimated owing to lack of blinding. Breathing exercises may be useful to improve exercise tolerance in selected individuals with COPD who are unable to undertake exercise training; however, these data do not suggest a widespread role for breathing exercises in the comprehensive management of people with COPD.