title: Peak exercise capacity estimated from incremental shuttle walking test in patients with COPD: a methodological study Reproducibility of the 6-Minute Walk Test for Ambulatory Oxygen Prescription Respiratory rehabilitation, exercise capacity and quality of life in chronic airways disease in old age. Modifying track layout from straight to circular has a modest effect on the 6-min walk distance. Six-minute walking versus shuttle walking: responsiveness to bronchodilation in chronic obstructive pulmonary disease Evaluating physical capacity in patients with chronic obstructive pulmonary disease: comparing the shuttle walk test with the encouraged 6-minute walk test. Adjuncts to physical training of patients with severe COPD: oxygen or noninvasive ventilation? L-carnitine as an ergogenic aid for patients with chronic obstructive pulmonary disease submitted to whole-body and respiratory muscle training programs. Exercise training decreases dyspnea and the distress and anxiety associated with it. Monitoring alone may be as effective as coaching. Six-minute walk distance in chronic obstructive pulmonary disease: reproducibility and effect of walking course layout and length. Use of 6-min and 12-min walking test for assessing the efficacy of formoterol in COPD. Effect of a walking aid on disability, oxygenation, and breathlessness in patients with chronic airflow limitation. Peak power estimated from 6-minute walk distance in Asian patients with idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease. Shuttle Walking Test and 6-Minute Walking Test Induce a Similar Cardiorespiratory Performance in Patients Recovering from an Acute Exacerbation of Chronic Obstructive Pulmonary Disease The functional impact of an individualized, graded, outpatient pulmonary rehabilitation in end-stage chronic obstructive pulmonary disease. Physiological responses to the 6-min walk test in patients with chronic obstructive pulmonary disease Comparison of different exercise tests in assessing outcomes of pulmonary rehabilitation. The minimal important difference of exercise tests in severe COPD Lung-volume reduction surgery for pulmonary emphysema: Improvement in body mass index, airflow obstruction, dyspnea, and exercise capacity index after 1 year. Walking versus cycling: sensitivity to bronchodilation in chronic obstructive pulmonary disease. Aerobic exercise training improves autonomic nervous control in patients with COPD. Six-Minute Walk Test as an Outcome Measure: Are Two Six-Minute Walk Tests Necessary Immediately After Pulmonary Rehabilitation and at Three-Month Follow-up? Validity and reliability of the modified shuttle walk test in patients with chronic obstructive pulmonary disease. A factor analysis of dyspnea ratings, respiratory muscle strength, and lung function in patients with chronic obstructive pulmonary disease. The effects of oxitropium bromide on exercise performance in patients with stable chronic obstructive pulmonary disease. A comparison of three different exercise tests. Comparison of hallway and treadmill six-minute walk tests. The use of the 12 minute walking test in assessing the effect of oral steroid therapy in patients with chronic airways obstruction. The Effects of Pulmonary Rehabilitation in the National Emphysema Treatment Trial. Optimal protocol selection for cardiopulmonary exercise testing in severe COPD. Detecting oxygen desaturation in patients with COPD: incremental versus endurance shuttle walking. Oxygen may improve dyspnea and endurance in patients with chronic obstructive pulmonary disease and only mild hypoxemia. Interval training compared with continuous training in patients with COPD. Exercises commonly used in rehabilitation of patients with chronic obstructive pulmonary disease: cardiopulmonary responses and effect over time. Advantages of endurance treadmill walking compared with cycling to assess bronchodilator therapy. Paced-Walk and Step Tests to Assess Exertional Dyspnea in COPD Comparison between an indoor and an outdoor 6-minute walk test among individuals with chronic obstructive pulmonary disease. The endurance shuttle walk test: An alternative to the six-minute walk test for the assessment of ambulatory oxygen
abstract: Background In patients with COPD , both laboratory exercise tests and field walking tests are used to assess physical performance . In laboratory tests , peak exercise capacity in watts ( W peak ) and /or peak oxygen uptake ( VO2 peak ) are assessed , whereas the performance on walking tests usually is expressed as distance walked . The aim of the study was to investigate the relationship between an incremental shuttle walking test ( ISWT ) and two laboratory cycle tests in order to assess whether W peak could be estimated from an ISWT . Methods Ninety-three patients with moderate or severe COPD performed an ISWT , an incremental cycle test ( ICT ) to measure W peak and a semi-steady-state cycle test with breath-by-breath gas exchange analysis ( CPET ) to measure VO2 peak . Routine equations for conversion between cycle tests were used to estimate W peak from measured VO2 peak ( CPET ) . Conversion equation for estimation of W peak from ISWT was found by univariate regression . Results There was a significant correlation between W peak and distance walked on ISWT × body weight ( r = 0.88 , p < 0.0001 ) . The agreement between W peak measured by ICT and estimated from ISWT was similar to the agreement between measured W peak ( ICT ) and W peak estimated from measured VO2 peak by CPET . Conclusion Peak exercise capacity measured by an incremental cycle test could be estimated from an ISWT with similar accuracy as when estimated from peak oxygen uptake in patients with COPD Background : Ambulatory oxygen is frequently prescribed for patients with chronic obstructive pulmonary disease ( COPD ) who have oxygen desaturation ≤88 % during exercise . The 6-min walk test ( 6MWT ) with continuous pulse oximetry monitoring is a common method to document this oxygen desaturation , but the reproducibility of this test in determining the need for ambulatory oxygen in patients with COPD is not well documented . Objective : The aim of this study was to establish the reproducibility of the 6MWT in determining the need for ambulatory oxygen prescription in stable COPD patients using the Centers for Medicare and Medicaid ( CMS ) criteria for ambulatory oxygen prescription . Methods : The study was design ed as a prospect i ve observational study in an academic health center and associated pulmonary rehabilitation program . Eighty-eight COPD patients referred to pulmonary rehabilitation underwent continuous pulse oximetry while performing st and ard 6MWT on 3 separate days . Results : Fifty-one ( 58 % ) of these patients desaturated by continuous pulse oximetry to an SpO2 ≤88 % on a least one of the 6MWTs . Only 26 patients ( 30 % ) demonstrated consistency in meeting the criteria for ambulatory oxygen set forth by the CMS on all three 6MWT with a κ statistic of 0.62 . The percent agreement between 6MWTs for ambulatory oxygen prescription was 72 % and the paired observation was 51 % . Conclusions : The 6MWT distance is simple and widely used as a consistent measure of functional capacity in patients with COPD ; however , the 6MWT oxygen saturation has only modest reproducibility in determining the need for ambulatory oxygen in stable COPD patients undergoing pulmonary rehabilitation Respiratory rehabilitation improves exercise capacity and quality of life in younger patients but is untried in the aged . We aim ed to : ( a ) assess repeatability of the 6-minute walk test , factors affecting it and its relation to quality of life in elderly patients with chronic obstructive airways disease ( COAD ) ; ( b ) assess compliance of such patients with an intensive respiratory rehabilitation protocol ; ( c ) pilot the assessment of the effect of respiratory rehabilitation on the 6-minute walk test in these patients . Seventeen subjects with stable , symptomatic COAD were recruited , 15 ( six men ) , 70 - 89 ( mean 76 ) years , completed the study . Mean ( st and ard deviation ) 1-second forced expiratory volume ( FEV1 ) = 49 (5)% predicted . Six-minute walk tests were repeated single-blind , 2 - 10 days apart . Quality of life was measured using Guyatt respiratory question naire . Patients underwent 12 weeks incremental respiratory rehabilitation ( x4/day step-ups , unweighed arm raises , inflating balloons ) . Baseline 6-minute walk was repeatable and was correlated with the log Guyatt dyspnoea score ( r = 0.65 , p = 0.006 ) . In multiple regression neither age nor FEV1 predicted walk distance : body mass index , maximal expiratory mouth pressure ; calorie intake . Mean ( SEM ) 6-minute walk distance after-rehabilitation was greater than baseline ( p = 0.003 ) . Elderly patients with COAD tolerate intensive respiratory rehabilitation and a controlled , blinded study is needed BACKGROUND The protocol used for the 6-min walk test ( 6MWT ) influences its results . The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks . Agreement between the distances measured on different tracks could not be examined . We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks . METHODS In a prospect i ve , r and omized , cross-over study , 27 COPD subjects ( FEV(1 ) , 38 + /- 14 % [ mean + /- SD ] ; 15 men ) attended three separate test sessions , completing six 6MWTs . To familiarize all subjects with both tracks , the first two sessions comprised two 6MWTs on either a circular or straight track . During the final session , each subject was tested once on the straight and once on the circular track . RESULTS The distance walked on the circular track exceeded the straight track by 13 + /- 17 m ( p < 0.001 ) . The limit of agreement between tracks was 33 m. Coefficient of repeatability values when the test was completed on different days for the straight and circular tracks were 51 m and 65 m , respectively . CONCLUSIONS When evaluating changes in 6-min walk distance in groups of patients , track layout should be st and ardized . However , the effect of modifying track layout on an individual 's walking distance is small compared to their daily variability in walk distance . Therefore , st and ardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days Background : The responsiveness of the endurance shuttle walk to functional changes following bronchodilation has recently been reported . The current literature suggests that the 6 min walking test ( 6MWT ) is less responsive to bronchodilation than the endurance shuttle walk . Aim : To compare bronchodilator-induced changes in exercise performance with the 6MWT and the endurance shuttle walk . Methods : In a r and omised , double-blind , placebo-controlled , crossover trial , 14 patients with chronic obstructive pulmonary disease ( forced expiratory volume in 1 s ( FEV1 ) 50 (8)% predicted ) completed two 6MWTs and two endurance shuttle walks , each preceded by nebulised placebo or 500 μg ipratropium bromide .  Cardiorespiratory parameters were monitored during each walking test with a portable telemetric gas analyser . Quadriceps twitch force was measured by magnetic stimulation of the femoral nerve before and after each walking test . Results : The 6 min walking distance did not change significantly after bronchodilation despite a significant increase in FEV1 of 0.18 ( 0.09 ) litres ( p<0.001 ) . A similar change in FEV1 ( 0.18 ( 0.12 ) litres , p<0.001 ) was associated with a significant improvement in the distance walked on the endurance shuttle walk ( Δdistance ipratropium bromide – placebo = 144 ( 219 ) m , p = 0.03 ) . Quadriceps muscle fatigue was infrequent ( < 15 % of patients ) after both walking tests . Conclusion : The endurance shuttle walk is more responsive than the 6MWT for detecting changes in exercise performance following bronchodilation OBJECTIVE To evaluate the applicability of the incremental ( shuttle ) walk test in patients with chronic obstructive pulmonary disease and compare the performance of those patients on the shuttle walk test to that of the same patients on the encouraged 6-minute walk test . METHODS A cross-sectional study was conducted , in which 24 patients with chronic obstructive pulmonary disease were selected . In r and om order , patients were , after an initial practice period , su bmi tted to a shuttle walk test and an encouraged 6-minute walk test . RESULTS The patients obtained a higher heart rate ( expressed as a percentage of that predicted based on gender and age ) on the encouraged 6-minute walk test ( 84.1 + /- 11.4 % ) than on the shuttle walk test ( 76.4 + /- 9.7 % ) ( p = 0.003 ) . The post-test sensation of dyspnea ( Borg scale ) was also higher on the encouraged 6-minute walk test . On average , the patients walked 307.0 + /- 89.3 meters on the shuttle walk test and 515.5 + /- 102.3 meters on the encouraged 6-minute walk test ( p < 0.001 ) . There was a good correlation between the two tests in terms of the distance walked ( r = 0.80 , p < 0.001 ) . CONCLUSION The shuttle walk test is simple and easy to implement in patients with chronic obstructive pulmonary disease . The encouraged 6-minute walk test produced higher post-test heart rate and greater post-test sensation of dyspnea than did the shuttle walk test BACKGROUND Previous studies have shown positive effects from noninvasive ventilation ( NIV ) or supplemental oxygen on exercise capacity in patients with COPD . However , the best adjunct for promoting physiologic adaptations to physical training in patients with severe COPD remains to be investigated . METHODS Twenty-eight patients ( mean + /- SD age 68 + /- 7 y ) with stable COPD ( FEV(1 ) 34 + /- 9 % of predicted ) undergoing an exercise training program were r and omized to either NIV ( n = 14 ) or supplemental oxygen ( n = 14 ) during group training to maintain peripheral oxygen saturation ( S(pO2 ) ) > /= 90 % . Physical training consisted of treadmill walking ( at 70 % of maximal speed ) 3 times a week , for 6 weeks . Patients were assessed at baseline and after 6 weeks . Assessment s included physiological adaptations during incremental exercise testing ( ratio of lactate concentration to walk speed , oxygen uptake [ V ( O2 ) ] , and dyspnea ) , exercise tolerance during 6-min walk test , leg fatigue , maximum inspiratory pressure , and health-related quality of life . RESULTS Two patients in each group dropped out due to COPD exacerbations and lack of exercise program adherence , and 24 completed the training program . Both groups improved 6-min walk distance , symptoms , and health-related quality of life . However , there were significant differences between the NIV and supplemental-oxygen groups in lactate/speed ratio ( 33 % vs -4 % ) , maximum inspiratory pressure ( 80 % vs 23 % ) , 6-min walk distance ( 122 m vs 47 m ) , and leg fatigue ( 25 % vs 11 % ) . In addition , changes in S(pO2)/speed , V ( O2 ) , and dyspnea were greater with NIV than with supplemental-oxygen . CONCLUSIONS NIV alone is better than supplemental oxygen alone in promoting beneficial physiologic adaptations to physical exercise in patients with severe COPD The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease ( COPD ) patients . Sixteen COPD patients ( 66 + /- 7 years ) were r and omly assigned to L-carnitine ( CG ) or placebo group ( PG ) that received either L-carnitine or saline solution ( 2 g/day , orally ) for 6 weeks ( forced expiratory volume on first second was 38 + /- 16 and 36 + /- 12 % , respectively ) . Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions , with 3 sets of 10 loaded inspirations ( 40 % ) at maximal inspiratory pressure . Nutritional status , exercise tolerance on a treadmill and six-minute walking test , blood lactate , heart rate , blood pressure , and respiratory muscle strength were determined as baseline and on day 42 . Maximal capacity in the incremental exercise test was significantly improved in both groups ( P < 0.05 ) . Blood lactate , blood pressure , oxygen saturation , and heart rate at identical exercise levels were lower in CG after training ( P < 0.05 ) . Inspiratory muscle strength and walking test tolerance were significantly improved in both groups , but the gains of CG were significantly higher than those of PG ( 40 + /- 14 vs 14 + /- 5 cmH2O , and 87 + /- 30 vs 34 + /- 29 m , respectively ; P < 0.05 ) . Blood lactate concentration was significantly lower in CG than in PG ( 1.6 + /- 0.7 vs 2.3 + /- 0.7 mM , P < 0.05 ) . The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients , as well as reduce lactate production STUDY OBJECTIVE To determine whether exercise training with coaching is more effective than exercise training alone in reducing dyspnea and the anxiety and distress associated with it and improving exercise performance , self-efficacy for walking , and dyspnea with activities of daily living . DESIGN R and omized clinical trial of 51 dyspnea-limited patients with COPD assigned to monitored ( n = 27 ) or coached ( n = 24 ) exercise groups . SETTING Outpatient area of university teaching hospital . INTERVENTION Both groups completed 12 supervised treadmill training sessions ( phase 1 ) over 4 weeks followed by 8 weeks of home walking ( phase 2 ) . The CE group also received coaching during training . MEASUREMENTS Perceived work of breathing , dyspnea intensity , distress associated with dyspnea , and anxiety associated with dyspnea were rated on a visual analog scale during incremental treadmill testing and after 6-min walks before and after phase 1 . Dyspnea with activities of daily living , self-efficacy for walking , state anxiety , and 6-min walks were measured before and after both phases . RESULTS Dyspnea and the associated distress and anxiety improved significantly for both groups relative to work performed and in relation to ventilation ( p < 0.05 ) . There were no significant differences between groups in any outcomes . The phase 1 improvement in laboratory dyspnea was accompanied by improvements in dyspnea with activities of daily living ( p < 0.01 ) and self-efficacy for home walking ( p < 0.01 ) that were sustained during the home phase . CONCLUSIONS Coaching with exercise training was no more effective than exercise training alone in improving exercise performance , dyspnea , and the anxiety and distress associated with it , dyspnea with activities , and self-efficacy for walking The 6-minute walk test is used in clinical practice and clinical trials of lung diseases ; however , it is not clear whether replicate tests need to be performed to assess performance . Furthermore , little is known about the impact of walking course layout on test performance . We conducted 6-minute walks on 761 patients with severe emphysema ( mean + /- SD FEV1 % predicted = 26.3 + /- 7.2 ) who were participants in the National Emphysema Treatment Trial . Four hundred seventy participants had repeated walks on a separate day . The second test was improved by an average of 7.0 + /- 15.2 % ( 66.1 + /- 146 feet , p < 0.0001 , by paired t test ) , with an intraclass correlation coefficient of 0.88 between days . The course layout had an effect on the distance walked . Participants tested on continuous ( circular or oval ) courses had a 92.2-foot longer walking distance than those tested on straight ( out and back ) courses . Course length had no significant effect on walking distance . The training effect found in these patients with severe emphysema is less than in previous reports of patients with chronic obstructive pulmonary disease . Furthermore , the layout of the track may influence the 6-minute walk performance Exercise tolerance is an important outcome measure in patients with COPD , mostly because there is evidence that exercise testing is superior to other functional measurements obtained at rest in demonstrating the positive effect of a specific intervention . We assessed the effect of a 5-day treatment with formoterol 12 microg twice daily on lung function , exercise capacity and dyspnea in 22 stable COPD patients , and compared 6-MWT with 12-MWT in evaluating formoterol efficacy . All subjects entered a crossover design . They underwent 6-MWT or 12-MWT in a r and omised order and soon after started the 5-day treatment . After a 3-day washout , patients who had first performed 6-MWT , underwent 12-MWT , and the contrary . Formoterol induced a progressively significant increase in pre-drug FEV1 and IC and also significant changes in these parameters 2 h after its inhalation at each test day . Moreover , it increased the walked distance by 53.6 m at the end of 6-MWT and 59.9 m at the end of 12-MWT . Formoterol also induced a significant change in Borg score for dyspnea caused by the 6-MWT when compared with the pre-treatment values , whereas it significantly changed dyspnea induced by 12-MWT only after the first dose . Our study not only strengthens the importance of walking tests as a useful tool for evaluating the impact of a bronchodilator on some COPD patient-centred outcomes , but also indicates that 6-MWT seems to be a more appropriate instrument than 12-MWT for assessing the exercise response to a bronchodilator in COPD PURPOSE This study assessed the effect of a wheeled walking aid on disability , oxygenation , and breathlessness in patients with severe disability secondary to chronic irreversible airflow limitation . METHODS Eleven subjects with chronic irreversible airflow limitation , mean forced expired volume in 1 second ( FEV1 ) 0.71 L + /- .33 L , were studied . Subjects performed four 6-minute walk tests , two on each of two study days , twice unaided and twice with the assistance of a wheeled walking aid . A r and omized cross-over design was used . All subjects were oriented to 6-minute walk tests , use of bronchodilators was controlled , and st and ard encouragement was given during each walk test . Outcome measures were the distance walked in 6 minutes , change in oxyhemoglobin saturation during the walk , and breathlessness using a modified Borg Scale . RESULTS The use of a wheeled walker result ed in a significant increase in 6-minute walking distance , a significant reduction in hypoxemia with walking and a significant reduction in breathlessness during the walk test . CONCLUSIONS The use of a wheeled walker result ed in significant decreases in disability , hypoxemia , and breathlessness during a 6-minute walk test . By reducing disability and breathlessness , a wheeled walker may improve quality of life in individuals with severe impairment in lung function BACKGROUND AND OBJECTIVE Pulmonary rehabilitation guidelines recommend cycle ergometry training at an intensity that exceeds 60 % of peak power ( P(peak ) ) with the aim of achieving a physiologic response . However , many clinicians do not have access to an incremental cycle ergometry test ( ICET ) to allow prescription of training intensity . No studies have investigated whether the 6MWT can be used to estimate the P(peak ) achieved during an ICET in subjects with IPF or in Asian subjects with COPD . METHODS A total of 90 Japanese subjects ( IPF n = 45 , COPD n = 45 ) undertook a 6MWT and a symptom-limited ICET in r and om order . Anthropometry , quadriceps strength and lung function were measured . RESULTS Exercise tests were prematurely terminated in 10 subjects with IPF due to profound oxygen desaturation ( SpO(2 ) < 80 % ) . The ICET elicited higher peak heart rates , dyspnea and leg fatigue in both subject cohorts ( all P < 0.01 ) . The magnitude of oxygen desaturation was greater during the 6MWT ( P < 0.01 ) . 6MWD was strongly associated with P(peak ) ( r = 0.80 , P < 0.01 ) in both subject cohorts . In subjects with IPF , the predictive equation that accounted for the greatest proportion of variance in P(peak ) included 6MWD and FVC % pred ( R(2 ) = 0.70 ) . In the COPD subjects , 6MWD alone accounted for 64 % of the variance in P(peak ) and the inclusion of other variables did not increase R(2 ) . CONCLUSIONS P(peak ) can be estimated from the 6MWT in Japanese subjects with IPF and COPD . This may allow individualized prescription of the intensity for cycle-based training based on the 6MWT Background : The incremental shuttle walking test ( SWT ) has recently been proposed as a more valid and reproducible alternative to the conventional 6-min walking test ( 6MWT ) in the evaluation of exercise tolerance in patients with chronic obstructive pulmonary disease ( COPD ) . Objective : To compare the cardiorespiratory performance obtained during two sessions of SWT with that obtained during two sessions of 6MWT . Methods : We examined 18 patients ( forced expiratory volume in 1 s : 48 ± 14 % ) recovering from an acute exacerbation of COPD that had required hospitalization . In the same afternoon , each patient performed two SWT and two 6MWT , with an interval of at least 30 min between each test ; the sequence of the tests was r and omized . Results : Mean walking distance was greater in the second SWT test than in the first SWT . The changes from baseline in systolic blood pressure , heart rate , respiratory rate , oxygen saturation and dyspnea Borg index at the end of the test were similar between the two 6MWT and the two SWT . There was a highly significant correlation between walking distances measured during SWT and during 6MWT ( ρ : 0.85 , p < 0.0005 ) . Neither SWT nor 6MWT correlated with functional data of COPD . Conclusions : SWT , though being considered to be closer to a submaximal exercise test than 6MWT , does not induce a greater cardiorespiratory performance  than 6MWT in patients recovering from acute exacerbation of COPD OBJECTIVE To evaluate the functional impact of an individualized outpatient pulmonary rehabilitation program in end-stage chronic obstructive pulmonary disease ( COPD ) . METHODS Patients with end-stage COPD were admitted into a 6-week comprehensive outpatient pulmonary rehabilitation program that was " packaged " for each patient . We compared spirometric parameters , exercise tolerance , level of breathlessness , and intensity of work before and after rehabilitation . RESULTS Of 45 eligible patients , only 14 consented to participate in the study . All 14 patients had forced expiratory volume in 1 second < 35 % of predicted , and 10 patients ( 72 % ) had a 6-minute walk test < 180 m. The level of breathlessness was between 7 ( moderate to severely breathless ) and 10 ( maximally breathless ) on the Visual Analogue Scale in all patients . After the program , there was significant improvement in the FEV 1 P = 0.04 ) , forced vital capacity P = 0.0045 ) , 6-minute walk test P = 0.00047 ) , and shuttle-walk test ( 9 of 14 patients ) . All patients had some improvement in level of dyspnea . CONCLUSIONS Individualized outpatient pulmonary rehabilitation in end-stage COPD can produce a measurable improvement in spirometry and exercise tolerance with a favorable impact on the level of physical activity The 6-min walking test ( 6MWT ) is frequently used to assess functional capacity in chronic cardiopulmonary disorders because of its simplicity . The study examines the physiological responses during encouraged 6MWT in patients with chronic obstructive pulmonary disease . Pulmonary oxygen ( O2 ) uptake ( V′O2 ) was measured in 20 male patients ( age 66±6 yrs , forced expiratory volume in one second 45±14 % predicted ) during 6MWT and incremental cycling  , in r and om order  . O2 tension in arterial blood , carbon dioxide tension in arterial blood and arterial lactate concentration ( [La]art ) were obtained in the last 10 patients . During the 6MWT  , V′O2 showed a plateau after the 3rd min ( 1.39±0.28 , 1.42±0.31 , and 1.40±0.30 L·min−1 , 4th , 5th and 6th min , respectively ) , and minute ventilation ( V′E ) ( 42±8 L·min−1 ) was 91 % maximal voluntary ventilation . No differences were shown between 6MWT ( 6th min ) and peak cycling exercise in V′O2 ( 1.40±0.30 versus 1.41±0.28 L·min−1 , respectively ) , cardiac frequency ( 126±13 versus 130±12 beats·min−1 ) , or arterial respiratory blood gases . The two tests were significantly different in V′E ( 42±8 versus 47±8 L·min−1 , 6MWT versus cycling , respectively ) , carbon dioxide production ( 1.30±0.31 versus 1.45±0.18 L·min−1 ) and [La]art ( 2.9±1.99 versus 5.9±1.51 M ) . The study demonstrates that an encouraged 6-min walking test  generates a high but sustainable oxygen uptake . Since the oxygen uptake plateau reflects the integrated response of the system , it may explain the high prognostic value of the 6-min walking test INTRODUCTION Common modalities of clinical exercise testing for outcome measurement after pulmonary rehabilitation ( PR ) include walk tests , progressive cycle ergometry , and cycle endurance testing . We hypothesized that patients ' responses to PR , as measured by those 3 tests , are differentially correlated , and we design ed a study to investigate the tests ' capacity to detect changes after PR . METHODS We prospect ively tested 37 male patients with stable chronic obstructive pulmonary disease who completed a comprehensive 6-week PR program that included supervised exercise training that emphasized steady-state lower-limb aerobic exercise . Before and after the PR program the patients underwent 6-minute walk test , progressive cycle ergometry , and cycle endurance testing ( at 80 % of the peak work rate achieved during progressive cycle ergometry ) . The exercise performance indices of interest were the peak oxygen uptake ( VO2max ) and maximum work-rate ( Wmax ) during progressive cycle ergometry , the cycling endurance time , and the 6-minute walk distance ( 6MWD ) . RESULTS After PR there were statistically significant improvements in 6MWD ( 16 % , p < 0.001 ) , VO2max ( 53 % , p=0.004 ) , Wmax ( 30 % , p=0.001 ) , and cycling endurance time ( 144 % , p < 0.001 ) . The changes in VO2max and Wmax were significantly correlated ( r=0.362 , p=0.027 ) , as were the changes in endurance time and Wmax ( r=0.406 , p=0.013 ) . There was no significant correlation between changes in any other exercise index . CONCLUSIONS Among the frequently used exercise tests in PR , the most responsive index is the endurance time . The correlation between the post-PR changes in the various exercise indices is poor Our aim was to determine the minimal important difference ( MID ) for 6-min walk distance ( 6MWD ) and maximal cycle exercise capacity ( MCEC ) in patients with severe chronic obstructive pulmonary disease ( COPD ) . 1,218 patients enrolled in the National Emphysema Treatment Trial completed exercise tests before and after 4–6 weeks of pre-trial rehabilitation  , and 6 months after r and omisation to surgery or medical care .  The St George 's Respiratory Question naire ( domain and total scores ) and University of California San Diego Shortness  of Breath Question naire ( total score ) served as anchors for anchor-based MID estimates . In order to calculate distribution-based estimates , we used the st and ard error of measurement , Cohen 's effect size and the empirical rule effect size . Anchor-based estimates for the 6MWD were 18.9 m ( 95 % CI 18.1–20.1 m ) , 24.2 m ( 95 % CI 23.4–25.4 m ) , 24.6 m ( 95 % CI 23.4–25.7 m ) and 26.4 m ( 95 % CI 25.4–27.4 m ) , which were similar to distribution-based MID estimates of 25.7 , 26.8 and 30.6 m. For MCEC , anchor-based estimates for the MID were 2.2 W ( 95 % CI 2.0–2.4 W ) , 3.2 W ( 95 % CI 3.0–3.4 W ) , 3.2 W ( 95 % CI 3.0–3.4 W ) and 3.3 W ( 95 % CI 3.0–3.5 W ) , while distribution-based estimates were 5.3 and 5.5 W. We suggest a MID of 26±2 m for 6MWD and 4±1 W for MCEC for patients with severe COPD OBJECTIVES We hypothesized that lung-volume reduction surgery for pulmonary emphysema would improve body mass index , airflow obstruction , dyspnea , and exercise capacity ( BODE ) index , a multidimensional predictor of survival in chronic obstructive pulmonary disease . We also aim ed to identify preoperative predictors of improvement in the BODE index . METHODS In a prospect i ve cohort study of patients undergoing lung-volume reduction surgery at our center , with the methodology of the National Emphysema Treatment Trial , we compared clinical characteristics before and 1 year after surgery with the Wilcoxon signed rank test . Changes in the BODE index were correlated with preoperative variables with the Spearman correlation coefficient . RESULTS Twenty-three patients with predominantly upper-lobe pulmonary emphysema underwent lung-volume reduction surgery  ( 14 by video-assisted thoracoscopic surgery , 9 by median sternotomy ) . There were no postoperative or follow-up deaths . The BODE index improved from a median of 5 ( interquartile range 4 - 5 ) before surgery to 3 ( interquartile range 2 - 4 ) 1 year after surgery ( P < .0001 ) . Improvements were seen in the lung function and dyspnea components of the BODE index . Lower preoperative 6-minute walk distance and lower postwalk Borg fatigue scores were each associated with greater improvement in the BODE index after 1 year . CONCLUSION Lung-volume reduction surgery for pulmonary emphysema improved the BODE index in patients with predominantly upper-lobe disease . Lower preoperative 6-minute walk distance correlated with greater improvement in the BODE index RATIONALE There is no consensus regarding which exercise test to use to evaluate the functional impact of bronchodilators in patients with chronic obstructive pulmonary disease . OBJECTIVE AND METHODS Bronchodilator-induced changes in endurance time were evaluated during cycling and walking in 17 patients with chronic obstructive pulmonary disease who completed two cycle endurance tests and two endurance shuttle walks at 80 % of peak capacity . Each endurance test was preceded by the nebulization of a placebo or 500 microg of ipratropium bromide using a r and omized , double-blind , crossover design . Quadriceps twitch force was measured with magnetic stimulation of the femoral nerve before and after each endurance test . RESULTS Cycling endurance time did not improve significantly after bronchodilation despite a significant increase in FEV1 ( delta endurance time ipratropium bromide - placebo : 51 + /- 255 s , p = 0.42 ) . A similar change in FEV1 was associated with a significant improvement in walking endurance time ( delta endurance time ipratropium bromide - placebo : 164 + /- 177 s , p < 0.01 ) . A 22 + /- 17 % fall in quadriceps twitch force was observed after cycling , whereas no significant change was seen after walking . CONCLUSION The endurance shuttle walk is a sensitive test to detect changes in exercise tolerance after bronchodilation . Differences in the occurrence of quadriceps muscle fatigue may explain , in part , the different responsiveness to change between cycling and walking OBJECTIVES Autonomic modulation is adversely impacted in patients with chronic obstructive pulmonary disease ( COPD ) . The purpose of the present investigation is to assess the effects of a 6-week aerobic exercise training program on autonomic modulation of heart rate in patients with COPD . METHODS Forty patients of both sexes with moderate-to-severe COPD were r and omly allocated to aerobic exercise training ( PT , n=20 ) or to usual care ( Control , n=20 ) . The training program consisted of lower and upper limb stretching and 30 min of treadmill exercise , 3 times per week for a 6-week period . Physiological data during symptom-limited exercise testing and the six-minute walk test ( 6MWT ) were assessed . In addition , R-R intervals were obtained at rest and during the 6MWT . Heart rate variability was analyzed by time ( rMSSD and SDNN index ) and frequency domains ( high frequency -- HF , low frequency -- LF and HF/LF ratio ) . RESULTS Peak oxygen consumption significantly improved in the training group only ( p<0.05 ) . Moreover , the training group demonstrated significant improvements ( p<0.05 ) in blood lactate , minute ventilation , dyspnea at peak exercise , sympathetic activity , and parasympathetic activity at rest and during submaximal exercise . Lastly , a positive and significant correlation was found between change in 6MWT distance and rMSSD index ( r=0.65 and p=0.001 ) . CONCLUSIONS Neural control of heart rate , in addition to other clinical ly valuable measures , is positively altered in moderate-severe COPD patients following 6 weeks of aerobic exercise training . The improvement in submaximal performance after exercise training was associated with parasympathetic activity Spencer LM , Alison JA , McKeough ZJ :  Six-minute walk test as an outcome measure : are two six-minute walk tests necessary immediately after pulmonary rehabilitation and at three-month follow-up ? Am J Phys Med Rehabil 2008;87:224–228.A 3-mo prospect i ve , longitudinal , repeated- measures study was undertaken in subjects with chronic obstructive pulmonary disease ( COPD ) . The study aim ed to determine whether there was a difference in 6-min walk distance ( 6MWD ) when two 6-min walk tests were performed after pulmonary rehabilitation ( n = 44 ) and at 3-mo follow-up ( n = 40 ) , and whether the results reflected the program outcomes . There was a significant increase in 6MWD between two 6-min walk tests before rehabilitation ( P < 0.001 ) , and at 3-mo follow-up ( P < 0.001 ) , but not immediately after rehabilitation ( P = 0.1 ) . In terms of program outcomes , there was an increase in 6MWD from before to after pulmonary rehabilitation ( P < 0.001 ) ; however , the increase was greater if the better of two tests was reported .  Six-minute walk tests  performed twice before and after pulmonary rehabilitation programs and at 3-mo follow-up assessment s ensure accuracy of measurement of the 6MWD and program outcomes OBJECTIVES ( 1 ) To examine the concurrent criterion validity of the modified shuttle walk test ( MSWT ) by using the 6- ( 6MWT ) and 12-minute walk test ( 12MWT ) , ( 2 ) to examine the concurrent criterion validity of the estimated maximum oxygen uptake ( Vo2max ) of the MSWT with actual Vo2max , and ( 3 ) to determine test-retest reliability of the MSWT in patients with chronic obstructive pulmonary disease ( COPD ) . DESIGN Validation study . SETTING Outpatient pulmonary rehabilitation program . PARTICIPANTS Thirty clinical ly stable adults with COPD . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Subjects were r and omly assigned to receive either the 6MWT and 12MWT or the MSWT first . The MSWT was repeated 1 week later ( N = 30 ) . Estimated Vo2max was calculated , and actual Vo2max was conducted by using the Jones test . Validity of the MSWT was assessed by comparing endurance scores and Vo2max with results from the 6MWT and 12MWT and Jones test , respectively . RESULTS There was a moderately high correlation between the  MSWT  and the 6MWT and 12MWT at initial testing ( .82 and .74 , respectively ) . Correlation between estimated and actual Vo2max was r equal to .68 . Test-retest reliability for the entire sample was high ( intraclass correlation coefficient , .88 ) . Results remained quite stable across severity , age , and sex subgroups . CONCLUSIONS The MSWT is a st and ardized externally paced submaximal endurance walking test . The results indicate that the MSWT has high concurrent validity and test-retest reliability for patients with COPD The purpose of this study was to demonstrate that clinical ratings of dyspnea and physiologic function are separate dimensions underlying the pathophysiology of chronic obstructive pulmonary disease ( COPD ) . We used principal-components factor analysis to confirm these dimensions using data collected prospect ively in 86 symptomatic patients with COPD . Three different instruments were used to rate dyspnea : a modified Medical Research Council ( MRC ) scale , the oxygen cost diagram ( OCD ) , and the baseline dyspnea index ( BDI ) . Measures of physiologic function included st and ard spirometric measures ( forced vital capacity [ FVC ] and forced expiratory volume in one second [ FEV1 ] ) and maximal inspiratory ( PImax ) and expiratory ( PEmax ) mouth pressures .  Age of the 65 male and 21 female subjects was 62.9 + /- 1.2 yr ( mean + /- SEM ) . All three clinical scales were significantly correlated with physiologic function ( range of r values , 0.32 to 0.45 ; p less than 0.05 ) , except for the relationship between the MRC scale and PEmax ( r = -0.14 ; p = NS ) . The factor analysis yielded three factors that accounted for 71.9 % of the total variance of the data : clinical ratings of dyspnea ( MRC scale , OCD , and BDI ) loaded on the first factor ; maximal respiratory pressures and gender loaded on the second factor ; and lung function and age loaded on the third factor . Additional post hoc factor analysis provided similar results when the sample was divided into two subgroups by r and omization , by severity of dyspnea ratings , or by severity of airflow obstruction . We conclude that dyspnea ratings , maximal respiratory pressures , and lung function are separate factors or quantities that independently characterize the condition of patients with COPD . ( ABSTRACT TRUNCATED AT 250 WORDS The purpose of the present study was to compare the characteristics of three different exercise tests in evaluating the effects of oxitropium bromide on exercise performance . Thirty-eight males with stable chronic obstructive pulmonary disease ( COPD ) ( FEV(1 ) = 40.8 + /- 16.5 % predicted ; mean + /- SD ) completed r and omized , double-blind , placebo-controlled , crossover studies for each exercise test . The exercise tests were performed 60 min after the inhalation of either oxitropium bromide 400 microg or placebo . The patients performed 6-min walking tests ( 6MWT ) on Days 1 and 2 , progressive cycle ergometry ( PCE ) on Days 3 and 4 , and cycle endurance tests at 80 % of the maximal workload of PCE on Days 5 and 6 . Spirometry was conducted before and at 45 and 90 min after the inhalation . Oxitropium bromide significantly increased FEV(1 ) as compared with placebo . Oxitropium bromide increased the endurance time significantly , by 19 % ( p < 0.001 ) , and caused a small but significant increase in the 6-min walking distance by 1 % ( p < 0.05 ) , but induced no significant increase in maximal oxygen consumption ( V O(2)max ) in PCE . The responses in these three exercise tests were different , and we conclude that the endurance test was the most sensitive in detecting the effects of inhaled anticholinergic agents on exercise performance in patients with stable COPD . An endurance procedure may be performed to detect clinical changes in evaluating the effects of oxitropium bromide on exercise performance The 6-min walk test ( SMWT ) performed in the hallway ( HW ) is used as a clinical indicator of functional capacity in patients with lung disease . A 6-min walk test utilizing a treadmill ( TM ) is easier to perform and allows easier patient monitoring . Therefore , we formulated a st and ardized TM SMWT protocol and compared the results with those of a HW SMWT .  All patients were enrolled in a pulmonary rehabilitation program . Patients with current infection , recent change in inhaled medications or oral steroid use , and significant cardiovascular disease were excluded . Each subject performed three HW SMWTs and three TM SMWTs assigned r and omly on subsequent days . There was a 30-min rest between each walk and at least a 48-h rest between each test day . All patients completed both HW and TM SMWT within 7 d. Supplemental oxygen was utilized or increased if the saturation fell below 88 % . The best of the three tests was used for data analysis . Twenty-one subjects completed the protocol . The mean age was 65 + /- 10.9 yr ( range , 35 to 79 yr ) . Ten subjects were receiving supplemental oxygen . The mean FEV(1 ) was 1.07 + /- 0.53 L. The mean HW SMWT distance was 1,228 + /- 255 ft ( range , 612 to 1,679 ft ) and the mean TM SMWT distance was 1,060 + /- 389 ft ( range , 475 to 1,819 ft ) , which were statistically different ( p = 0.01 ) . The mean difference was 168 + /- 280 ft ( range , -326 to 743 ft ) . Oxygen saturation and supplemental oxygen requirements did not differ significantly . The intra-test variability of the three HW SMWTs was similar to the three TM SMWTs and no significant difference in the coefficient of variation was found . A st and ardized TM SMWT is feasible and allows easier patient monitoring , but there is a statistically significant difference between the HW and TM SMWT distance and therefore they are not interchangeable . However , the intratest reproducibility of the TM and HW SMWTs are similar when three walks are performed in a single test session . The role of the TM SMWT in pulmonary rehabilitation requires further exploration The reproducibility of the 12 minute walking distance ( 12 MD ) was assessed in ten men with chronic airways obstruction , and the 12 MD was used , together with spirometry , transfer factor and three subjective assessment s of breathlessness to evaluate the effects on respiratory function of prednisone 30 mg daily given orally in double-blind placebo-controlled fashion for two weeks . Like others , we found the 12 MD reproducible on a single day with a mean variation of 3.1 % . Tests performed two weeks apart showed greater variability ranging from 0.2 % to 30.9 % , ( mean 9.1 % ) . During placebo and prednisone therapy the 12 MD and assessment s of breathlessness correlated significantly with each other and with TLCO , but not with spirometry . Following steroid therapy there was a significant increase in mean TLCO but no significant change in 12 MD , spirometry or subjective assessment s. Changes in 12 MD and TLCO correlated significantly with each other and with changes in subjective assessment s. Changes in FEV1 correlated with changes in breathlessness , and also with variability in FEV1 while receiving placebo . Individuals with the greatest changes in 12 MD and FEV1 were those with the greatest variability on placebo . The variability of the 12 MD and FEV1 should be measured in individuals before using these tests to assess response to steroid therapy STUDY OBJECTIVES Pulmonary rehabilitation is an established treatment in patients with chronic lung disease but is not widely utilized . Most trials have been conducted in single centers . The National Emphysema Treatment Trial ( NETT ) provided an opportunity to evaluate pulmonary rehabilitation in a large cohort of patients who were treated in centers throughout the United States . DESIGN Prospect i ve observational study of cohort prior to r and omization in a multicenter clinical trial . SETTING University-based clinical centers and community-based satellite pulmonary rehabilitation programs . PATIENTS AND INTERVENTION A total of 1,218 patients with severe emphysema underwent pulmonary rehabilitation before and after r and omization to lung volume reduction surgery ( LVRS ) or continued medical management .  Rehabilitation was conducted at 17 NETT centers supplemented by 539 satellite centers . MEASUREMENTS AND RESULTS Lung function , exercise tolerance , dyspnea , and quality of life were evaluated at regular intervals . Significant ( p < 0.001 ) improvements were observed consistently in exercise ( cycle ergometry , 3.1 W ; 6-min walk test distance , 76 feet ) , dyspnea ( University of California , San Diego Shortness of Breath Question naire score , -3.2 ; Borg breathlessness score : breathing cycle , -0.8 ; 6-min walk , -0.5 ) and quality of life ( St. George Respiratory Question naire score , -3.5 ; Quality of Well-Being Scale score , + 0.035 ; Medical Outcomes Study 36-item short form score : physical health summary , + 1.3 ; mental health summary , + 2.0 ) . Patients who had not undergone prior rehabilitation improved more than those who had . In multivariate models , only prior rehabilitation status predicted changes after rehabilitation . In 20 % of patients , exercise level changed sufficiently after rehabilitation to alter the NETT subgroup predictive of outcome . Overall , changes after rehabilitation did not predict differential mortality or improvement in exercise ( primary outcomes ) by treatment group . CONCLUSIONS The NETT experience demonstrates the effectiveness of pulmonary rehabilitation in patients with severe emphysema who were treated in a national cross-section of programs . Pulmonary rehabilitation plays an important role in preparing and selecting patients for surgical interventions such as LVRS BACKGROUND The current recommendations of 8 to 12 min for the optimal targeted duration of symptom-limited maximal cardiopulmonary exercise testing ( CPET ) to attain maximal oxygen consumption are based on results from healthy individuals and may not be applicable to patients with severe COPD . We aim ed to determine the optimal duration for a CPET to attain the peak oxygen consumption ( VO2peak ) in a group of patients with severe COPD using different carefully conducted workload protocol s. METHODS We studied 11 subjects with severe COPD ( mean FEV1 , 32 % predicted ; 95 % confidence interval [ CI ] , 27 to 38 % predicted ) . They completed four incremental , symptom-limited exercise tests on a cycle ergometer using four protocol s ( 4 , 8 , and 16 W/min continuous ramp protocol s , and 8 W/min step protocol ) using a r and omized double-blind design . RESULTS The mean duration of these 44 tests was 6.3 min ( 95 % CI , 5.0 to 9.0 min ) . The duration of the exercise tests differed significantly for the protocol s used , as follows : 16-W ramp protocol , 4.0 min ( 95 % CI , 3.0 to 5.1 min ) ; 8-W ramp protocol , 6.6 min ( 95 % CI , 5.0 to 9.0 min ) ; 8-W step protocol , 6.0 min ( 95 % CI , 4.0 to 8.0 min ) ; and 4-W ramp protocol , 8.7 min ( 95 % CI , 4.4 to 13.0 min ; p<0.001 ) . The maximal workload significantly increased as the ramp slope increased from 4 to 8 to 16 W/min ( maximal workload , 35.6 vs 50.7 vs 64.3 W , respectively ; p<0.001 ) . Maximal minute ventilation , heart rate , Borg ratings , and VO2 peak , were not different among the four protocol s. No differences were found between the ramp and step protocol s. CONCLUSIONS In patients with severe COPD ( Global Initiative for Chronic Obstructive Lung Disease stages III-IV ) , a targeted duration of 5 to 9 min for a CPET appears to be more appropriate than the 8 to 12 min proposed in the current guidelines . Maximal workload , in contrast to VO2peak , is highly dependent on the ramp incrementation rate BACKGROUND There has been no direct comparison between an incremental and endurance walking test to detect the relative oxygen desaturation in patients with chronic obstructive pulmonary disease ( COPD ) . This is of some importance as current guidelines have suggested that ambulatory oxygen should only be prescribed after a st and ard assessment and desaturation documented . No clear advice about the nature of the required exercise task is given . This study therefore compared the relative desaturation between the incremental shuttle walking test ( ISWT ) and the constant speed walking test ( ESWT ) and response to ambulatory oxygen . METHODS Forty-one patients ( 29 male ) , mean ( SD ) , age 71.18 ( 7.48 ) yrs , FEV(1 ) 0.85 ( 0.29 ) l with stable COPD were recruited after completion of a 7-week pulmonary rehabilitation programme . Patients completed a baseline ( without carrying a cylinder ) ISWT and ESWT and then , in r and om order in double blind fashion , completed the walk tests with a cylinder of air or a cylinder of oxygen . Measurements included distance walked , oxygen saturation , heart rate , perceived breathlessness and exertion ( Borg scale ) . RESULTS All patients desaturated ( < 4 % below 90 % ) . There was no significant difference in desaturation between the ISWT and the ESWT . There was a significant improvement in performance with supplementary oxygen compared to cylinder air ( p<0.05 ) for both tests . However , compared to the baseline walk , supplementary oxygen did not enhance the distance walked for either test . There was a significant decrease in walking performance on both the ISWT and the ESWT when carrying an air cylinder compared with the control walk . When comparing the percentage difference between oxygen and air for responders ( i.e. those that achieve a 10 % or more increase ) , the ESWT showed a greater percentage change 42.1 % compared to 26.1 % for the ISWT . CONCLUSIONS This study identifies that incremental and endurance walking provokes significant desaturation and that there is a short-term benefit of oxygen versus air in enhancing exercise performance . There was no significant difference in the level of desaturation between tests . Therefore the ISWT is a suitable exercise test that can be used to evaluate desaturation and is practically more realistic Oxygen ( O2 ) has been reported to improve exercise tolerance in some patients with chronic obstructive pulmonary disease ( COPD ) despite only mild resting hypoxemia ( PaO2 greater than 60 mm Hg ) . To confirm these prior studies and evaluate potential mechanisms of benefit , we measured dyspnea scores by numeric rating scale during cycle ergometry endurance testing and correlated the severity of dyspnea with right ventricular systolic pressure ( RVSP ) measured by Doppler echocardiography during a separate supine incremental exercise test . Both sets of exercise were performed according to a r and omized double-blind crossover protocol in which patients breathed compressed air or 40 % O2 . We studied 12 patients with severe COPD ( FEV1 0.89 + /- 0.09 L [ mean + /- SEM ] , FEV1/FVC 37 + /- 2 % , DLCO 9.8 + /- 1.5 ml/min/mm Hg[47 % of predicted ] , PaO2 71 + /- 2.6 mm Hg ) . With endurance testing on compressed air , PaO2 did not change significantly in the group as whole ( postexercise PaO2 63 + /- 5.1 mm Hg , p = NS ) , but did fall to less than 55 mm Hg in four patients from this group . Duration of exercise increased on 40 % O2 from 10.3 + /- 1.6 to 14.2 + /- 1.5 min ( p = 0.005 ) , and the rise in dyspnea scores was delayed . Oxygen delayed the rise in RVSP with incremental exercise in all patients and lowered the mean RVSP at maximum exercise from 71 + /- 8 to 64 + /- 7 mm Hg ( p less than 0.03 ) . Improvement in duration of exercise correlated with decrease in dyspnea ( r2 = 0.66 , p = 0.001 ) but not with decreases in heart rate , minute ventilation , or RVSP . ( ABSTRACT TRUNCATED AT 250 WORDS The aim of this study was to compare the effects of interval training ( 3-min intervals ) with continuous training on peak exercise capacity ( W peak ) , physiological response , functional capacity , dyspnoea , mental health and health-related quality of life ( HRQoL ) in patients with moderate or severe COPD . Sixty patients exercised twice weekly for 16 weeks after r and omisation to interval- or continuous training . Target intensity was 80 % of baseline W peak in the interval group ( I-group ) and 65 % in the continuous group ( C-group ) . Patients were tested by spirometry , ergometer cycle test , cardiopulmonary test and a 12 min walk test . Dyspnoea was measured by the dyspnoea scale from Chronic Obstructive Disease Question naire ( CRDQ ) , mental health by Hospital Anxiety and Depression scale ( HAD ) and HRQoL by the Medical Outcomes Survey Short Form 36 ( SF-36 ) . After training , W peak , peak oxygen uptake ( VO(2 ) peak ) and exhaled carbon dioxide ( VCO(2 ) peak ) increased significantly in both groups , no significant differences between the groups . Minute ventilation ( V(E ) peak ) increased only in the C-group . At identical work rates ( isotime ) VO(2 ) , VCO(2 ) and V(E ) were significantly more decreased in the I-group than in the C-group ( p<0.05 ) . Functional capacity , dyspnoea , mental health , and HRQoL improved significantly in both groups , no difference between the groups . Interval training and continuous training were equally potent in improving peak exercise capacity , functional exercise capacity , dyspnoea , mental health and HRQoL in patients with moderate or severe COPD . At isotime , the physiological response to training differed between the groups , in favour of the interval training OBJECTIVES To compare conventional exercise-based assessment of pulmonary rehabilitation ( PR ) with improvement in training exercises employed during a PR program , and to describe the cardiopulmonary response of different training exercises during PR of patients with chronic obstructive pulmonary disease ( COPD ) . DESIGN Observational study . SETTING Inpatient PR . PARTICIPANTS Patients with moderate to very severe COPD ( N=18 ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Cardiopulmonary responses to interval cycling , arm exercise , and a test of functional activities of daily living ( ADLs )  were evaluated during the PR training program using a mobile telemetric breath-by-breath system . The effects of PR were evaluated by comparing pre-PR and post-PR training activities , incremental and constant work-rate cycling , and a 6-minute walk test . RESULTS Interval cycling and the ADLs test were moderate-intensity to heavy-intensity exercises ( 70%-80 % of maximal oxygen consumption ) , while the arm exercise was a low-intensity activity ( 40 % of maximal oxygen consumption ) . After 12 weeks of PR , cycle load , arm weights , and walking distances during training activities had increased alongside increased muscle mass . At iso-intensities , no cardiopulmonary changes in the training exercises were observed . Exercise duration of constant work-rate cycling and 6-minute walk distance increased by 160 % and 14 % , respectively , after PR , with concurrent right-shifts of anaerobic threshold and a decrease in heart rate . CONCLUSIONS Supervised increases in weight , load , and walking distance during training activities were useful clinical outcomes for patients , demonstrating the beneficial effects of progressive training on physical performance . However , for physiologic evaluation of PR , conventional tests , such as maximal incremental cycling , endurance cycling , and a 6-minute walk test , had greater validity . Physiologic evaluation of the training exercises showed that the training program complied with the training recommendations for PR BACKGROUND Walking is a familiar daily activity that is generally limited by breathlessness , whereas cycling is an uncommon physical effort typically limited by leg discomfort . The hypothesis was that patients with COPD would exhibit greater improvements in exercise endurance and relief of breathlessness with bronchodilator therapy during treadmill walking compared with cycling . METHODS In this r and omized , 2 x 2 , double-blind , placebo-controlled , crossover trial , 20 patients with COPD ( age , 64 + /- 7 years ; FEV(1 ) , 56 + /- 14 % predicted ) performed constant-load endurance exercise on the treadmill and cycle ergometer at 85 % of capacity after inhaling normal saline ( NS ) or arformoterol ( ARF ) ( 15 microg ) . RESULTS Increases in endurance times and consistency of responses were greater with treadmill walking ( Delta : 157 + /- 286 s ; P = .024 ; 80 % improved ) than with cycle exercise ( Delta : 110 + /- 219 s ; P = .038 ; 65 % improved ) with ARF compared with NS . However , these changes were not significantly different . The slope of breathlessness-time ( mean Delta = -29 % ; P = .007 ) and the magnitude of oxygen desaturation were significantly lower with ARF compared with NS during treadmill , but not cycle , exercise . Inspiratory capacity values were similar between modes of exercise when comparing the same study medication . CONCLUSIONS Improved endurance times support both constant-load treadmill and cycle exercise to assess the efficacy of bronchodilator therapy in patients with COPD . Unique differences in physiologic and perceptual responses with bronchodilation demonstrate advantages of treadmill walking as an exercise stimulus . TRIAL REGISTRATION clinical trials.gov ; Identifier : NCT00754546 This study reports on the development and test-retest reproducibility of a modified shuttle walking and step testing protocol s to assess exertional dyspnea in patients with COPD . Patients with COPD r and omly performed four externally paced 3-min bouts of shuttle walking at 1.5 , 2.5 , 4.0 and 6.0 km·h− 1 or stepping at constant rate of 18 , 22 , 26 and 32 steps·min− 1 . Walking and stepping procedures were repeated once , on a separate occasion . Ventilation , heart rate , gas exchange parameters and dyspnea Borg scores were obtained at the end of each exercise bout . Most patients completed walking or stepping at the slow and middle speed cadences but only 33 % completed walking at 6.0 km·h− 1 and 40 % completed stepping at 32 steps·min− 1 . Walking and stepping at progressively faster pace caused a progressive increase in ventilation and dyspnea . Test-retest Pearson correlation coefficients for ventilation , heart rate , gas exchange parameters and dyspnea scores over the four exercise bouts , all exceeded 0.80 . Intra-class correlation coefficients were at least as strong as Pearson coefficients . Bl and & Altman representation showed that for repeated Borg scores , 92 and 96 % of points lied within 2 SD of the mean difference between test-retest values for walking and stepping . The majority of moderate and severe COPD patients completed the 3-min shuttle waking testing at 1.5 to 4.0 km·h− 1 and the 3-min of step testing at rates between 18 and 26 steps·min− 1 . Both field tests were highly reproducible in patients with COPD OBJECTIVES To investigate the feasibility of an outdoor 6-minute walk test ( 6MWT ) as a measure of functional status among individuals with chronic obstructive pulmonary disease ( COPD ) , and to examine the relationship between performance on an indoor and an outdoor 6MWT . DESIGN An experimental , repeated- measures crossover design . Subjects were studied on 2 separate days in the same week . Two 6MWTs-one indoors and the other outdoors-were performed on each study day , with a rest in between . The test order was r and omly selected on the first day and reversed on the second day . Outdoor tests were performed on days of moderate weather conditions ( mean temperature + /- st and ard deviation , 21 degrees + /-3 degrees C ; mean wind speed , 15+/-7 km/h ; no precipitation ) and on a flat surface ( sidewalk ) . SETTING  Outpatient rehabilitation program in Ontario . PARTICIPANTS Eighteen subjects with COPD ( 10 men , 8 women ; age , 70+/-8y ) , 5 using supplemental oxygen at rest ( forced expiratory volume in 1s , 1.0+/-0.3L ; 42%+/-8 % of predicted ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Distance walked in 6 minutes ( in meters ) , duration of rest ( in seconds ) , and change in rate of perceived dyspnea . RESULTS There was no significant effect of setting ( indoors vs outdoors ) on distance walked ( 394+/-86 m vs 398+/-84 m , P=0.4 ) , duration of rest ( 13+/-28s vs 9+/-20s , P=0.4 ) , or change in rate of perceived dyspnea ( 2.3+/-1.7 vs 2.3+/-2.0 , P=0.8 ) . Testing day had no significant effect on walk test performance ( all P>0.1 ) . CONCLUSIONS The results indicate that the 6MWT performed outdoors within reasonable climatic parameters may be reflective of 6MWT performance indoors UK guidelines for domiciliary oxygen have suggested the six-minute walk test or shuttle walk tests as suitable functional measures for the clinical assessment of ambulatory oxygen ( AO ) . To date , there is limited evidence that would support the use of shuttle walk tests as assessment tools for AO . The endurance shuttle walk test ( ESWT ) is used increasingly as an assessment tool within pulmonary rehabilitation ( PR ) but its potential as an investigative test for AO has not been explored . Using the same test for both PR and AO assessment is appealing since it would improve efficiency and act to st and ardise outcome measures in this patient population . The aim of this study was to examine the responsiveness and repeatability of the ESWT to AO and to compare the response with that of the six-minute walk test ( 6MWT ) .  Twenty-three patients with chronic obstructive pulmonary disease ( COPD ) performed , in r and om order , the ESWT and the 6MWT on air and whilst breathing AO . Oxygen saturation and Borg ratings of breathlessness and perceived exertion were recorded . On a third day , eleven patients repeated the ESWT with AO in order to measure repeatability . There was a significantly greater change in the ESWT with oxygen than the change recorded from the 6MWT ( 66 [ 91 ] vs 6 [ 28 ] m respectively ; P < .05 ) . When repeated on a separate day , the mean difference ( 95 % CI ) between distances walked on the ESWT with AO was 0.91 ( -47 , 49 ) m. The ESWT was more responsive than the 6MWT for detecting improvements in walking endurance whilst breathing AO
target: Good repeatability ( for the 6MWT and ESWT ) and reproducibility ( for the 6MWT , 12-minute walk test , ISWT , ESWT , and incremental cycle ergometer test ) were reported by most studies assessing these tests , providing patients were familiarized with them beforeh and .
  The 6MWT , ISWT , and particularly the ESWT were reported to be sensitive to therapeutic intervention .
background: Exercise tests are often used to evaluate the functional status of patients with COPD .
  However , to the best of our knowledge , a comprehensive systematic comparison of these tests has not been performed .
  We systematic ally review ed studies reporting the repeatability and /or reproducibility of these tests , and studies comparing their sensitivity to therapeutic intervention .