title: Relationship between field walking tests and incremental cycle ergometry in COPD. 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 The six-minute walk test and body weight-walk distance product in healthy Brazilian subjects. The COPD assessment test (CAT): response to pulmonary rehabilitation. A multicentre, prospective study Predicting Survival in Pulmonary Arterial Hypertension: Insights From the Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management (REVEAL) Ground walk training improves functional exercise capacity more than cycle training in people with chronic obstructive pulmonary disease (COPD): a randomised trial. Ambulatory oxygen improves the effectiveness of pulmonary rehabilitation in selected patients with chronic obstructive pulmonary disease Lack of Specificity of the 6-Minute Walk Test as an Outcome Measure for Patients with Systemic Sclerosis The effect of walking aids on exercise capacity and oxygenation in elderly patients with chronic obstructive pulmonary disease. Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. Regression equations to predict 6-minute walk distance in middle-aged and elderly adults Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise. Repeatability of the 6-minute walk test in adolescents and adults with cystic fibrosis. Six-minute walk distance in chronic obstructive pulmonary disease: reproducibility and effect of walking course layout and length. [Reference Equations for the 6-Minute Walk Test in Healthy Individuals.] 6-minute walk work for assessment of functional capacity in patients with 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. Prescription of Walking Exercise Intensity from the Incremental Shuttle Walk Test in People with Chronic Obstructive Pulmonary Disease Heart rate responses during the 6-minute walk test in pulmonary arterial hypertension Relationship of shuttle walk test and lung cancer surgical outcome. Effect of encouragement on walking test performance. Distance saturation product predicts health–related quality of life among sarcoidosis patients Physiological responses to the 6-min walk test in patients with chronic obstructive pulmonary disease Energy Expenditure at Rest and during Walking in Patients with Chronic Respiratory Failure: A Prospective Two-Phase Case-Control Study Comparison of oxygen uptake during a conventional treadmill test and the shuttle walking test in chronic airflow limitation. Validation and comparison of reference equations for the 6-min walk distance test The minimal important difference of exercise tests in severe COPD Endurance shuttle walking test: responsiveness to salmeterol in COPD The acute effects of a rollator in individuals with COPD. OXYGEN RELIEVES BREATHLESSNESS IN "PINK PUFFERS" Walking versus cycling: sensitivity to bronchodilation in chronic obstructive pulmonary disease. Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease. The relationship of the 6-min walk test to maximal oxygen consumption in transplant candidates with end-stage lung disease. Mechanisms of improvement in exercise capacity using a rollator in patients with COPD. The incremental shuttle walking test in elderly people with chronic airflow limitation 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. 6-minute walk distance in healthy North Africans older than 40 years: influence of parity. Physiologic responses to incremental and self-paced exercise in COPD: a comparison of three tests. Submaximal exercise testing in the assessment of interstitial lung disease secondary to systemic sclerosis: reproducibility and correlations of the 6-min walk test The effects of oxitropium bromide on exercise performance in patients with stable chronic obstructive pulmonary disease. A comparison of three different exercise tests. Effects of supplemental oxygen during activity in patients with advanced COPD without severe resting hypoxemia. Relationship between daily physical activity and exercise capacity in patients with COPD. The minimal important difference in the 6-minute walk test for patients with pulmonary arterial hypertension. Comparison of hallway and treadmill six-minute walk tests. Portable liquid oxygen and exercise ability in severe respiratory disability. Exertional oxygen of limited benefit in patients with chronic obstructive pulmonary disease and mild hypoxemia. Six-minute walk, maximal exercise tests: reproducibility in fibrotic interstitial pneumonia. The influence of alternative instruction on 6-min walk test distance. Detecting oxygen desaturation in patients with COPD: incremental versus endurance shuttle walking. Randomized controlled trial of ambulatory oxygen and an ambulatory ventilator on endurance exercise in COPD. Updating the minimal important difference for six-minute walk distance in patients with chronic obstructive pulmonary disease. The Incremental Shuttle Walk Test in Older Brazilian Adults The short-term effect of a rollator on functional exercise capacity among individuals with severe COPD. Course length of 30 metres versus 10 metres has a significant influence on six-minute walk distance in patients with COPD: an experimental crossover study. Baseline 6‐Min Walk Distance Predicts Survival in Lung Transplant Candidates Heart rate recovery after 6-min walk test predicts survival in patients with idiopathic pulmonary fibrosis. The effect of helium and oxygen on exercise performance in chronic obstructive pulmonary disease: a randomized crossover trial. Six-Minute Walking Distance in Women with COPD The body weight-walking distance product as related to lung function, anaerobic threshold and peak VO2 in COPD patients. Assessment of functional capacity in patients with chronic obstructive pulmonary disease: correlation between cardiopulmonary exercise, 6 minute walk and 15 step exercise oximetry test. Fatigue in patients with chronic obstructive pulmonary disease. 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 Activity levels after pulmonary rehabilitation - what really happens? The effects of a "new" walking aid on exercise performance in patients with COPD: a randomized crossover trial.
abstract: BACKGROUND AND OBJECTIVE Cycle ergometer training is an important component of pulmonary rehabilitation for patients with COPD . However , incremental cycle tests from which individualized cycle training intensity can be prescribed may not be readily available to clinicians . The aims of the study were to ( i ) investigate the physiological and psychophysical responses to the 6-min walk test ( 6MWT ) , incremental shuttle walk test ( ISWT ) and cycle ergometer test ( CET ) ; and ( ii ) determine whether the distance walked in either the 6MWT or the ISWT could be used to estimate peak work rate on a cycle ergometer . METHODS A repeated measures study was undertaken in COPD patients in a stable condition . The 6MWT , ISWT and CET were performed in r and om order , and physiological responses , rate of perceived exertion and dyspnoea were measured . RESULTS Twenty-two patients with COPD completed the study . There was no significant difference in peak oxygen uptake between the 6MWT , ISWT and CET . The significant correlation between the 6MWD and incremental shuttle walk distance with peak watts on the CET ( r = 0.63 , P = 0.002 and r = 0.75 , P < 0.001 , respectively ) was strengthened by the inclusion of weight , age and gender ( r = 0.89 P = 0.001 and r = 0.91 , P < 0.001 ) . Bl and -Altman analysis demonstrated a strong agreement between peak work rate measured on the CET and that estimated from either the 6MWT or the ISWT . CONCLUSIONS The significant relationships found between the three exercise tests , and the regression equations predicting peak work rate on the CET from the 6MWT or the ISWT , may allow for the estimation of intensity of cycle exercise training from walk tests in COPD patients 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 We assessed the  6-min walk distance ( 6MWD ) and  body weight x distance product ( 6MWw ) in healthy Brazilian subjects and compared measured 6MWD with values predicted in five reference equations developed for other population s. Anthropometry , spirometry , reported physical activity , and two walk tests in a 30-m corridor were evaluated in 134 subjects ( 73 females , 13 - 84 years ) .  Mean 6MWD and 6MWw were significantly greater in males than in females ( 622 + /- 80 m , 46,322 + /- 10,539 kg.m vs 551 + /- 71 m , 36,356 + /- 8,289 kg.m , P < 0.05 ) . Four equations significantly overestimated measured 6MWD ( range , 32 + /- 71 to 137 + /- 74 m ; P < 0.001 ) , and one significantly underestimated it ( -36 + /- 86 m ; P < 0.001 ) . 6MWD significantly correlated with age ( r = -0.39 ) , height ( r = 0.44 ) , body mass index ( r = -0.24 ) , and reported physical activity ( r = 0.25 ) . 6MWw significantly correlated with age ( r = -0.21 ) , height ( r = 0.66 ) and reported physical activity ( r = 0.25 ) . The reference equation devised for walk distance was 6MWDm = 622.461 - ( 1.846 x Ageyears ) + ( 61.503 x Gendermales = 1 ; females = 0 ) ; r2 = 0.300 . In an additional group of 85 subjects prospect ively studied , the difference between measured and the 6MWD predicted with the equation proposed here was not significant ( -3 + /- 68 m ; P = 0.938 ) . The measured 6MWD represented 99.6 + /- 11.9 % of the predicted value . We conclude that 6MWD and 6MWw variances were adequately explained by demographic and anthropometric attributes . This reference equation is probably most appropriate for evaluating the exercise capacity of Brazilian patients with chronic diseases Background The COPD ( chronic obstructive pulmonary disease ) assessment test ( CAT ) is a recently introduced , simple to use patient-completed quality of life instrument that contains eight questions covering the impact of symptoms in COPD . It is not known how the CAT score performs in the context of clinical pulmonary rehabilitation ( PR ) programmes or what the minimum clinical ly important difference is . Methods The introduction of the  CAT score as an outcome measure was prospect ively studied by PR programmes across London . It was used alongside other measures including the St George 's Respiratory Question naire , the Chronic Respiratory Disease Question naire , the Clinical COPD Question naire , the Hospital Anxiety and Depression score , the Medical Research Council ( MRC ) dyspnoea score and a range of different walking tests . Patients completed a 5-point anchor question used to assess overall response to PR from ‘ I feel much better ’ to ‘ I feel much worse ’ . Results Data were available for 261 patients with COPD participating in seven programmes : mean ( SD ) age 69.0 ( 9.0 ) years , forced expiratory volume in 1 s ( FEV1 ) 51.1 ( 18.7 ) % predicted , MRC score 3.2 ( 1.0 ) . Mean change in CAT score after PR was 2.9 ( 5.6 ) points , improving by 3.8 ( 6.1 ) points in those scoring ‘ much better ’ ( n=162 ) , and by 1.3(4.5 ) in those who felt ‘ a little better ’ ( n=88 ) ( p=0.002 ) . Only eight individuals reported no difference after PR and three reported feeling ‘ a little worse ’ , so comparison with these smaller groups was not possible . Conclusion The CAT score is simple to implement as an outcome measure , it improves in response to PR and can distinguish categories of response Background — Factors that determine survival in pulmonary arterial hypertension ( PAH ) drive clinical management . A quantitative survival prediction tool has not been established for research or clinical use . Methods and Results — Data from 2716 patients with PAH enrolled consecutively in the US Registry to Evaluate Early and Long-Term PAH Disease Management ( REVEAL ) were analyzed to assess predictors of 1-year survival . We identified independent prognosticators of survival and derived a multivariable , weighted risk formula for clinical use . One-year survival from the date of enrollment was 91.0 % ( 95 % confidence interval [ CI ] , 89.9 to 92.1 ) . In a multivariable analysis with Cox proportional hazards , variables independently associated with increased mortality included pulmonary vascular resistance > 32 Wood units ( hazard ratio [ HR ] , 4.1 ; 95 % CI , 2.0 to 8.3 ) , PAH associated with portal hypertension ( HR , 3.6 ; 95 % CI , 2.4 to 5.4 ) , modified New York Heart Association/World Health Organization functional class IV ( HR , 3.1 ; 95 % CI , 2.2 to 4.4 ) , men > 60 years of age ( HR , 2.2 ; 95 % CI , 1.6 to 3.0 ) , and family history of PAH ( HR , 2.2 ; 95 % CI , 1.2 to 4.0 ) . Renal insufficiency , PAH associated with connective tissue disease , functional class III , mean right atrial pressure , resting systolic blood pressure and heart rate , 6-minute walk distance , brain natriuretic peptide , percent predicted carbon monoxide diffusing capacity , and pericardial effusion on echocardiogram all predicted mortality . Based on these multivariable analyses , a prognostic equation was derived and vali date d by bootstrapping technique . Conclusions — We identified key predictors of survival based on the patient 's most recent evaluation and formulated a contemporary prognostic equation . Use of this tool may allow the individualization and optimization of therapeutic strategies . Serial follow-up and re assessment are warranted . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00370214 QUESTIONS Does an eight-week program of walk training improve endurance walking capacity in people with COPD compared to cycle training ? Does walk training improve peak walking capacity , cycle capacity , and quality of life compared to cycle training ? Is the endurance shuttle walk test ( ESWT ) responsive to change in walking capacity elicited by exercise training ? DESIGN R and omised trial with concealed allocation , assessor blinding , and intention-to-treat analysis . PARTICIPANTS 36 people with stable COPD recruited with four dropouts . INTERVENTION Participants were r and omised into either a walk or cycle training group . Both groups trained indoors for 30 to 45 minutes per session , three times weekly over eight weeks at Concord Hospital . Training intensities were based on baseline peak exercise tests and progressed as able . OUTCOME MEASURES The primary outcome was endurance walking capacity measured by the ESWT . Secondary outcomes included peak walking capacity , peak and endurance cycle capacity , and health-related quality of life . Measures were taken at baseline ( Week 0 ) and following training ( Week 8) . RESULTS The walk training group increased their endurance walking time by 279 seconds ( 95 % CI 70 to 483 ) more than the cycle training group . No significant differences between the groups were found for any other outcome . CONCLUSION Ground walk training increased endurance walking capacity more than cycle training and was similar to cycle training in improving peak walking capacity , peak and endurance cycle capacity and quality of life . This study provides evidence for ground walking as a mode of exercise training in pulmonary rehabilitation programs The effect of ambulatory oxygen use during pulmonary rehabilitation ( PR ) has not yet been clearly established , but many studies have shown benefit from oxygen acutely . Two small studies to date demonstrated no clear benefit when oxygen was used in patients who desaturated on exertion during a PR programme . One study showed the benefit of using oxygen during PR in patients who were normoxic at rest and desaturated to a minimum of 88 % on exertion . We conducted a single-blind , r and omised controlled trial comparing PR undertaken either with or without ambulatory oxygen , in those with demonstrable benefit from oxygen at baseline . Subjects from three PR services were recruited who , during baseline assessment , desaturated by more than 4 % and to less than 90 % on exertion , and walked 10 % or more further with ambulatory oxygen on endurance shuttle walk test . Patients were r and omised to either room air or oxygen via portable cylinder , titrated to optimise pulse oxygen saturation but up to a maximum flow rate of 6 L/min . All patients then completed a twice weekly , 6- to 7-week PR programme . Data were analysed as per protocol . Totally 51 patients completed the study . At the end of PR , both groups improved with PR , with patients in the oxygen group demonstrating a highly statistically significantly greater mean improvement in endurance walking distance than the controls , 490 m ( 95 % confidence interval 228–750 ; p ≤ 0.001 ) , as well as clinical ly , although not statistically , significant changes in quality of life .  The use of ambulatory oxygen during a 6- to 7-week PR programme greatly improved endurance walking distance in patients who desaturated on exertion with a positive acute response to ambulatory oxygen at baseline Objective . The 6-minute walk test ( 6MWT ) is an important prognostic tool in various cardiovascular diseases and has been considered as a surrogate endpoint . However , conflicting results have been reported in systemic sclerosis ( SSc ) . Our objective was to evaluate the relationships of the 6-min walking distance  ( 6MWD ) and organ damage in SSc . Methods . Eighty-seven consecutive patients with SSc were included and prospect ively investigated ; they underwent 6MWT in addition to conventional assessment of possible lung , heart , kidney , skin , and muscle involvement , and disease activity scoring , severity , and quality of life determination . Results . Twenty-six patients ( 30 % ) had an abnormal 6MWT and the mean 6MWD was 461.8 ± 103.0 m. When considering 6MWT as a binary variable — normal or abnormal — C-reactive protein ( CRP ) was the only independent variable associated with abnormal 6MWT . Considered as a continuous variable , the 6MWD was associated with measures of lung involvement and inflammation , with the activity and severity of disease , and also with quality of life ; nevertheless , calcinosis was the only independent factor associated in multivariate analyses with a trend for an association for CRP . Conclusion . The 6MWD relates to broad factors in SSc and these results raise doubts about the specificity of the 6MWD in this systemic disease , and its relevance to monitoring therapy BACKGROUND high walking frames may improve exercise capacity in young patients with chronic obstructive pulmonary disease ( COPD ) . We have assessed the effect of Zimmer , rollator and gutter frames on 6-min walking distance and on arterial oxygenation during exercise in elderly patients with COPD . METHODS 27 out- patients ( 15 men ) aged 70 - 82 ( mean 75 ) years were recruited . Exclusions comprised : COPD exacerbation or oral steroid use within 6 weeks , confusional state , participation in a pulmonary rehabilitation programme and exercise limitation by other diseases . Subjects completed 6-min walk tests unaided and with the three frames on four separate days in r and om order 30 min after nebulized salbutamol ( 5 mg ) and ipratropium ( 0.5 mg ) and were accompanied by an investigator blinded to results of all other walk tests undertaken .  Oxygen saturation ( SaO2 ) was monitored by finger probe during exercise . Grouped t-tests were used to compare distances and reductions in SaO2 . RESULTS Unaided , the mean ( SEM ) 6-min walk distance was 210 ( 16 ) m and fall in oxygen saturation was 6.0 (1.1)% . Use of a rollator frame did not significantly affect either of these values . Using the Zimmer frame reduced the mean distance to 165 ( 13 ) m ( t=5.2 , P < 0.001 vs unaided walk ) with an SaO2 fall similar to that recorded during the unaided walk . Using the gutter frame increased the mean distance to 234 ( 150 ) m ( t=3 . 1 , P=0.004 vs unaided walk ) and reduced the fall in SaO2 to 3.7 (0.8)% ( t=2.3 , P=0.03 vs unaided walk ) . CONCLUSIONS gutter frames improve exercise capacity and SaO2 during exercise in elderly COPD patients who remain symptomatic on optimal therapy , whereas unwheeled Zimmer frames have a deleterious effect in such patients RATIONALE The 6-minute-walk test ( 6MWT ) is a practical and clinical ly meaningful measure of exercise tolerance with favorable performance characteristics in various cardiac and pulmonary diseases . Performance characteristics in patients with idiopathic pulmonary fibrosis ( IPF ) have not been systematic ally evaluated . OBJECTIVES To assess the reliability , validity , and responsiveness of the 6MWT and estimate the minimal clinical ly important difference ( MCID ) in patients with IPF . METHODS The study population included all subjects completing a 6MWT in a clinical trial evaluating interferon gamma-1b ( n = 822 ) .  Six-minute walk distance ( 6MWD )  and other parameters were measured at baseline and at 24-week intervals using a st and ardized protocol . Parametric and distribution-independent correlation coefficients were used to assess the strength of the relationships between 6MWD and measures of pulmonary function , dyspnea , and health-related quality of life . Both distribution-based and anchor-based methods were used to estimate the MCID . MEASUREMENTS AND MAIN RESULTS Comparison of two proximal measures of 6MWD ( mean interval , 24 d ) demonstrated good reliability ( coefficient = 0.83 ; P < 0.001 ) . 6MWD was weakly correlated with measures of physiologic function and health-related quality of life ; however , values were consistently and significantly lower for patients with the poorest functional status , suggesting good construct validity . Importantly , change in 6MWD was highly predictive of mortality ; a 24-week decline of greater than 50 m was associated with a fourfold increase in risk of death at 1 year ( hazard ratio , 4.27 ; 95 % confidence interval , 2.57- 7.10 ; P < 0.001 ) . The estimated MCID was 24 - 45 m. CONCLUSIONS The 6MWT is a reliable , valid , and responsive measure of disease status and a valid endpoint for clinical trials in IPF Six-minute walk distance ( 6MWD ) is commonly used as a measure of functional exercise capacity in clinical practice and research . Regression equations to predict 6MWD in healthy individuals are available , but the equations predict distances that vary considerably for an individual . The aims of this study were to 1 ) measure 6MWDs in healthy Caucasian Australians aged 45 - 85 years ; 2 ) determine whether evidence exists for Australian-specific prediction equations for Caucasian individuals by comparing measured 6MWDs with predicted 6MWDs derived by using published regression equations ; and 3 ) develop regression equations for males and females . One hundred nine subjects ( 48 males ) completed the 6-minute walk test ( 6MWT ) . Measurements of height , leg length , weight , habitual physical activity , and peak heart rate ( HR ) achieved during the 6MWT were obtained . 6MWD ( better of two tests ) was 682 ± 73 m ( mean ± SD ) and 643 ± 70 m in the males and females , respectively ( p<0.01 ) . Published regression equations underestimated 6MWDs in female subjects . Gender-specific regression equations using age and anthropometric data explained 40 % and 43 % of the variance in 6MWD in males and females , respectively . Validation of the regression equations in a prospect i ve subject cohort is required 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 r and omized 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 OBJECTIVE To determine the repeatability of the 6-minute walk test ( 6MWT ) in adolescents and adults with cystic fibrosis ( CF ) . METHODS This was a prospect i ve cross-sectional study . We included consecutive patients ages > or=15 years attending an adult CF program . The patients underwent the 6MWT , pulmonary function tests , and clinical evaluation . The second 6MWT was performed following a rest period of 60 min . RESULTS Thirty-one patients were included . The mean+/-SD age was 23.5+/-6.7 y , and the mean FEV1 was 61+/-28 % of predicted . The mean+/-SD walked distance in the first 6MWT was 583.6+/-68.6 m and in the second 6MWT was 590.0+/-72.2 m. The mean difference between the first and second 6MWT was -6.5 m , with limits of agreement between -74.9 m and 61.9 m , and the coefficient of variation was 4.3 % . The mean oxygen desaturation in the first 6MWT was 2.5+/-4.5 % , and in the second test it was 1.8+/-4.0 % . The mean difference between the first and second test was 0.6 % , and the coefficient of variation was 104 % . CONCLUSIONS Although the 6MWT distance was reproducible , the wide limits of agreement exceeded the minimum important difference for this test . These findings indicate that , in the routine evaluation of CF patients , at least two 6MWTs are required on any testing occasion to obtain a reliable estimate of the 6MWT distance 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 The six-minute walk test ( 6MWT ) has been broadly used in clinical setting s. Several reference equations for prediction of the total distance walked during the test ( 6MWD ) are available in literature . The present review aim ed to critically discuss studies , published in Portuguese and English ( LILACS , SCIELO , MEDLINE , PUBMED ) , which evaluated normal values and created reference equations for predicting 6MWD in healthy subjects , comparing them with the results that were recently obtained in Brazilian individuals . Age , sex , weight , height and body mass index were the main demographic and anthropometric features more often correlated with 6MWD . The equations derived from these characteristics were able to explain between 25 and 66 % of the total variability in the 6MWD . Unfortunately , the foreign equations were not applicable to the Brazilian population . Even when the 6MWT was performed following strict st and ardization , the difference in 6MWT performance between foreign and Brazilian individuals remains , indicating the necessity of providing specific reference equations for each population and /or ethnic group . Accordingly , these equations developed in Brazil are probably the most appropriate for interpreting 6MWT performance in Brazilian patients with chronic diseases affecting the exercise capacity . Future studies are necessary with larger sample sizes ( e.g. multicentric ones ) and r and omized design for the reference values of the 6MWD to be considered reliable UNLABELLED The 6-min walk ( 6MW ) test is commonly used to assess exercise capacity in patients with COPD and to track functional change result ing from disease progression or therapeutic intervention . Not surprisingly , distance covered has been the preferred outcome for this test . However , distance walked does not account for differences in body weight that are known to influence exercise capacity . OBJECTIVE The aim of this study was to evaluate the  6-min distance x body weight product ( 6MWORK ) as an improved outcome measure with a solid physiologic foundation . PATIENTS AND METHODS One hundred twenty-four men and women with moderate-to-severe COPD volunteered and completed the testing sequence , which included pulmonary function , a peak effort ramp cardiopulmonary exercise study with gas exchange , and the 6MW . Means and SD were generated for the variables of interest . Differences were analyzed using analysis of variance techniques . Correlation coefficients and receiver operating characteristic ( ROC ) curves were calculated for the 6-min walk distance ( 6MWD ) and 6MWORK with indexes of pulmonary function , work performance , and Borg scores for dyspnea and effort . RESULTS Men and women presented with a significant smoking history that also differed by gender ( 48 vs 66 pack-years , respectively ; p < 0.01 ) . The mean ( + /- SD ) FEV(1 ) values were 45 + /- 12.6 % and 48 + /- 12.1 % , respectively ( not significant ) , while the diffusing capacity of the lung for carbon monoxide ( DLCO ) was 14.7 + /- 6.1 vs 10.3 + /- 3.9 mL/min/mm Hg , respectively ( p < 0.001 ) , for men and women . The 6MWD averaged 416.8 + /- 79.0 m for men and 367.8 + /- 78.6 m for women , and these differences were significant ( p < 0.002 ) . When 6MWD was compared as the percent predicted of normal values , each gender presented with a similar reduction of 78.6 + /- 14.5 % vs 79.9 + /- 17.5 % ( p > 0.05 ) , respectively . 6MWORK averaged 35,370 + /- 9,482 kg/m and 25,643 + /- 9,080 kg/m ( p < 0.0001 ) for men and women , respectively . 6MWORK yielded higher correlation coefficients than did 6MWD when correlated with DLCO , lung diffusion for alveolar ventilation , FEV(1 ) , FEV(1)/FVC ratio , watts , peak oxygen uptake , peak minute ventilation , and peak tidal volume . The ROC curve demonstrated that 6MWORK had a significantly larger calculated area under the curve ( p < 0.05 ) [ plot of 100-sensitivity to specificity for each variable of interest for all subjects ] than 6MWD when differentiating an objective ly selected definition of low work capacity vs high work capacity ( bike ergometry work , < 55 vs > 55 W , respectively ) . CONCLUSIONS We conclude that work calculated as the product of distance x body weight is an improved outcome measure for the 6MW . 6MWORK can be used whenever the 6MW is required to estimate a patient 's functional capacity . This measure is also a common measure , which can be converted to indexes of caloric expenditure for direct cross-modality comparisons 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 Objective This study determined the intensity of walking exercise prescribed from 70 % of peak speed achieved during the incremental shuttle walk test ( ISWT ) in people with chronic obstructive pulmonary disease and whether a steady-state response was achieved when exercising at this intensity . Design Each participant performed lung function tests , an incremental cycle test , two ISWTs , and a 10-min continuous walking exercise at 70 % peak ISWT speed . Oxygen consumption ( V˙O2 ) was collected using a portable system ( Cosmed K4b2 , Rome , Italy ) . The V˙O2 from the 10-min walking exercise was compared with V˙O2peak from the better ISWT as a measure of walking exercise intensity . Results Thirty-four participants completed the study .  The mean intensity achieved during the 10-min walking exercise was 76 % ( 11 % ) V˙O2peak . Steady-state V˙O2 was achieved by minute 5 in the 10-min walking exercise . Conclusions Prescription of walking exercise at 70 % of the peak ISWT speed provided an intensity appropriate for achieving physiologic training responses Patients with pulmonary arterial hypertension ( PAH ) exhibit a limited increase in stroke volume on exercise , and the heart rate ( HR ) increases may reflect the main mechanism that allows cardiac output to increase . The current prospect i ve study documented the contribution of HR to the 6-min walking distance ( 6MWD ) in idiopathic ( IPAH ) and nonidiopathic PAH . Eighty-three patients ( 46 IPAH and 37 nonidiopathic PAH ) underwent haemodynamic evaluation and a 6MWD test . Chronotropic response ( peak walking HR minus resting HR ) and peripheral oxygen saturation were monitored . Fifty-seven patients were also assessed after 5±2 months of treatment ( bosentan n = 38 , epoprostenol n = 14 , bosentan-epoprostenol n = 3 , iloprost n = 2 ) . Before treatment , the 6MWD was related to numerous demographic , haemodynamic and walking test characteristics . Stepwise regression analysis indicated that the only factors significantly associated with the 6MWD were stroke volume and chronotropic response in both IPAH and nonidiopathic PAH patients . Following treatment , changes in 6MWD were significantly related to changes in chronotropic response in both IPAH and nonidiopathic PAH . In conclusion , baseline stroke volume and chronotropic response were independently associated with the 6-min walking distance in pulmonary arterial hypertension . The lack of chronotropic response may reflect the loss in normal physiological reserve in more unwell patients OBJECTIVE Surgery remains the treatment of choice in patients with potentially resectable lung carcinoma . Both the British Thoracic Society and American Chest Physician guidelines for the selection of patients with lung cancer surgery suggest the use of a shuttle walk test to predict outcome in patients with borderline lung function . The guidelines suggest that if the patient is unable to walk 250 m during a shuttle walk test , they are high risk for surgery . However , there is no published evidence to support this recommendation . Therefore , we undertook a prospect i ve study to examine the relationship between shuttle walk test  and surgical outcome in 139 patients undergoing assessment for possible lung cancer surgery . METHODS The shuttle walk test was performed in 139 potentially resectable patients , recruited over a 2 year period , prior to surgery . One hundred and eleven patients underwent surgery . Outcome of surgery , including duration of hospital stay , complication and mortality rates was recorded . Student 's t-test was used to compare the shuttle walk distance in patients with good and poor outcome from surgery . RESULTS Mean age of patients undergoing surgery was 69 years ( 42 - 85 ) .  Mean shuttle walk distance was 395 m ( 145 - 780 ) , with a mean oxygen desaturation of 4 % ( 0 - 14 ) during the test . Sixty nine patients had a good surgical outcome and 34 had a poor outcome . The shuttle walk distance was not statistically different in the two outcome groups . CONCLUSION Shuttle walk distance  should not be used to predict poor surgical outcome in lung cancer patients , contrary to current recommendations . It is therefore advisable to perform a formal cardiopulmonary exercise test if at all possible . The usefulness of a shuttle walk test might be improved . It could be compared to a predicted value , as for a formal cardiopulmonary exercise test Walking tests , frequently used to document effects of treatment on exercise capacity , have never been st and ardised . We studied the effects of encouragement on walking test performance in a r and omised study that controlled for the nature of the underlying disease , time of day , and order effects . We r and omised 43 patients with chronic airflow limitation or chronic heart failure or both to receive or not receive encouragement as they performed serial two and six minute walks every fortnight for 10 weeks . Simple encouragement improved performance ( p less than 0.02 for the six minute walk ) , and the magnitude of the effect was similar to that reported for patients in studies purporting to show beneficial effects of therapeutic manoeuvres . Age and test repetition also affected performance . These results demonstrate the need for careful st and ardisation of the performance of walking tests , and suggest caution in interpreting studies in which st and ardisation is not a major feature of the study design Background Sarcoidosis is a chronic disease with different phenotypic manifestations . Health-related quality of life is an important aspect in sarcoidosis , yet difficult to measure . The objective of this study was to identify clinical markers predictive of poor quality of life in sarcoidosis patients that can be followed over time and targeted for intervention . Methods We assessed the quality of life of 162 patients with confirmed sarcoidosis in a prospect i ve , cross-sectional study using the Sarcoidosis Health Question naire ( SHQ ) and Short Form-36 Health Survey ( SF-36 ) . We evaluated the validity of these question naires and sought to identify variables that would best explain the performance scores of the patients . Results On multivariate regression analyses , the very best composite model to predict total scores from both surveys was a model containing the distance-saturation product and Borg Dyspnea Scale score at the end of a 6-min walk test . This model could better predict SF-36 scores ( R2 = 0.33 ) than SHQ scores ( R2 = 0.24 ) . Substitution of distanced walked in 6 min for the distance-saturation product in this model result ed in a lesser ability to predict both scores ( R2 = 0.26 for SF-36 ; R2 = 0.22 for SHQ ) . Conclusions Both the SHQ and SF-36 surveys are valuable tools in the assessment of health-related quality of life  in sarcoidosis patients . The best model to predict quality of life among these patients , as determined by regression analyses , included the distance-saturation product and Borg score after the 6-min walk test . Both variables represent easily obtainable clinical parameters that can be followed over time and targeted for intervention 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 Background Measurements of Energy Expenditure ( EE ) at rest ( REE ) and during physical activities are increasing in interest in chronic patients . In this study we aim ed at evaluating the validity/reliability of the SenseWear ® Armb and ( SWA ) device in terms of REE and EE during assisted walking in Chronic Respiratory Failure ( CRF ) patients receiving long-term oxygen therapy ( LTOT ) . Methodology /Principal Findings In a two-phase prospect i ve protocol we studied 40 severe patients and 35 age-matched healthy controls . In phase-1 we determined the validity and repeatability of  REE  measured by SWA ( REEa ) in comparison with st and ard calorimetry ( REEc ) . In phase-2 we then assessed EE and Metabolic Equivalents-METs by SWA during the 6-minute walking test while breathing oxygen in both assisted ( Aid ) or unassisted ( No-Aid ) modalities . When compared with REEc , REEa was slightly lower in patients ( 1351±169 vs 1413±194 kcal/day respectively , p<0.05 ) , and less repeatable than in healthy controls ( 0.14 and 0.43 coefficient respectively ) . COPD patients with CRF patients reported a significant gain with Aid as compared with No-Aid modality in terms of meters walked , perceived symptoms and EE . Conclusions / Significance SWA provides a feasible and valid method to assess the energy expenditure in CRF patients on LTOT , and it shows that aided walking results in a substantial energy saving in this population The purpose of this study was to investigate the relationship between performance on the shuttle walking test and maximal oxygen uptake ( VO2max ) during a conventional treadmill test in patients with chronic airflow limitation . Two different techniques were used to measure oxygen consumption , i.e. conventional Douglas bag techniques ( treadmill test ) and a portable oxygen consumption meter ( shuttle test ) . Initially , 19 patients performed a shuttle walking test ( after one practice walk ) and a maximal treadmill walking test , in a r and omized , balanced design . Subsequently , 10 patients , ( after one practice ) completed an unencumbered shuttle walking test and one supporting the portable oxygen consumption meter , in r and om order . The results of the first experiment revealed a strong relationship between performance during the shuttle walking test and VO2max during the treadmill walking test ( r = 0.88 ) . The results of the second experiment consistently demonstrated an incremental increase in oxygen consumption and ventilation in response to the increasing intensity of the shuttle walking test . Again , a strong relationship between VO2max and performance on the shuttle test was demonstrated ( r = 0.81 ) . We concluded that the shuttle walking test is a valid field exercise test of functional capacity . Performance on the test relates strongly to VO2max , the traditional indicator of cardiorespiratory capacity Exercise impairment as measured by the 6-min walk distance ( 6MWD ) test afflicts many patients with chronic obstructive pulmonary disease ( COPD ) and is known to predict mortality . Reference equations for the 6MWD in adults have been published but not yet vali date d. The present authors prospect ively followed 1,379 COPD patients for 55±30 months and tested the predictive value of the baseline 6MWD in metres , the 6MWD work ( kg·m−1 ) and as a percentage of predicted values the 6MWD in meters according to two reference equations . All-cause mortality was the validating outcome . The best threshold values were identified for each of the tests using receiver operating characteristic ( ROC ) curves . The threshold values obtained were : 350 m for the 6MWD , 25,000 kg·m−1 for the 6MWD work , and 67 and 54 % predicted for the two reference equations . All modalities of the testing were similar at predicting COPD mortality and correlated well with the 6MWD test . In conclusion , all modalities of testing predict mortality in chronic obstructive pulmonary disease equally well . In the 6-min walk distance test , a value < 350 m is associated with increased mortality and should be regarded as abnormal 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 Few studies have shown that the endurance shuttle walking test ( ESWT ) is responsive to treatment in patients with chronic obstructive pulmonary disease ( COPD ) . This exercise test needs to be further investigated because of its relevance for activity of daily living . The aim of the present study was to evaluate , in patients with COPD , the responsiveness of the ESWT in detecting improvement in walking performance after a single dose of salmeterol . In a r and omised , double-blind , placebo-controlled crossover trial , 20 patients with COPD performed two ESWT at 80 % of peak capacity 2.5 h after inhaling either a placebo or 50 µg of salmeterol  . Cardiorespiratory parameters were monitored during each walking test . Inspiratory capacities and Borg ratings for dyspnoea were obtained every other minute throughout the tests . Compared with placebo , salmeterol produced a significant change in lung function and a significant improvement in walking performance ( mean±sd difference in time : 117±20 s ; difference in distance : 160±277 m ) . At isotime ( the latest exercise time that was reached on both ESWT ) , a significant reduction in dyspnoea was observed after bronchodilation . Bronchodilation with salmeterol reduced dyspnoea during walking and improved walking capacity in patients with chronic obstructive pulmonary disease . These findings provide further support for the use of the endurance shuttle walking test as an evaluative tool in chronic obstructive pulmonary disease PURPOSE To investigate whether the acute benefits of rollator use are consistent over time in individuals with moderate to severe chronic obstructive pulmonary disease . METHODS Thirty-one stable subjects with chronic obstructive pulmonary disease ( 13 men , 18 women ) , aged 68 + /- 8 years , with a forced expiratory volume in 1 second of 0.7 + /- 0.2 L ( 33 % + /- 12 % predicted ) and a baseline 6-minute walk ( 6MW ) of 261 + /- 68 m , were recruited from a respiratory clinic after completion of a pulmonary rehabilitation program . Two 6MWs were performed at baseline , 4 weeks , and 8 weeks , one walking unaided and the other walking with the assistance of a rollator . The test order was r and omly chosen at baseline , and the same test order was used at each time point . The primary outcome measures were distance walked in 6 minutes ( meters ) , perceived dyspnea using a modified Borg scale , and number of rests taken . RESULTS Subjects achieved higher 6MW distances during assisted compared with unassisted walking at baseline ( 292 + /- 67 vs 263 + /- 67 m ) , 4 weeks ( 296 + /- 62 vs 275 + /- 63 m ) , and 8 weeks ( 283 + /- 65 vs 259 + /- 68 m ) ( P = .013 ) , with no time effect ( P = .5 ) . In addition , use of a rollator result ed in a significant improvement in dyspnea ( P = .004 ) at baseline , 4 weeks , and 8 weeks , with no time effect ( P = .7 ) . The use of a rollator also reduced the number of rests taken during the 6MW ( P < .001 ) , with no time effect ( P = .9 ) . CONCLUSIONS Rollator use result ed in improvements in performance in the 6MW , which were consistent over time among individuals with moderate to severe chronic obstructive pulmonary disease who walk less than 375 m during an unaided 6MW The effect of oxygen on breathlessness and exercise tolerance was examined in " pink and puffing " patients with fixed airways obstruction . When breathing oxygen , patients were less breathless and walked further . This was true whether the cylinder was carried by the patient or by an assistant . It was not possible to identify those patients who would benefit most . The best method of assessing improvement was by comparing breathlessness on a st and ardised progressive exercise test on a treadmill .  Four patients had a greater than 30 % reduction in breathlessness on submaximum exercise when breathing oxygen . Breathing oxygen for five or fifteen minutes before exercise but not during exercise ( predose ) result ed in a similar improvement in exercise tolerance . For short periods of exercise predosing with oxygen provides a convenient alternative to continuous oxygen . For longer periods of exercise the benefits of portable oxygen in selected patients have been previously underestimated 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 BACKGROUND Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test ( 6MWT ) . To improve the utility of the 6MWT for patient and health care system management , the interpretation of the functional status measure in relation to death and hospitalization should be eluci date d. METHODS Three-year , prospect i ve , multicenter observational study to evaluate the predictive power of 6MWD for death or exacerbation-related hospitalization and to evaluate the factors that help determine 6MWD . RESULTS We measured 6MWD at baseline and annually in 2110 patients with clinical ly stable Global Initiative for Obstructive Lung Disease ( GOLD ) stage II-IV COPD and recorded exacerbation-related hospitalizations and all-cause mortality .  During the study , 200 patients died and 650 were hospitalized .  Using receiver operating characteristics , the best predictive thresholds of the 6MWD were 334 m for increased risk of death and 357 m for exacerbation-related hospitalization ( area under the curve 0.67 and 0.60 respectively ) ; however , the discriminatory thresholds , especially for mortality , were influenced by age . The mean ( SE ) 6MWD declined by 1.6 ( 1.2 ) m per year in GOLD II , 9.8 ( 1.3 ) m per year in GOLD III , and 8.5 ( 2.4 ) m per year in GOLD IV . CONCLUSION The 6MWD provides prognostic information that may be useful for identifying high-risk patients with COPD STUDY OBJECTIVE To assess the relationship of distance ambulated during the 6-min walk test ( 6'WT ) to maximal oxygen consumption ( VO2 max ) . DESIGN Multivariate analysis of patient characteristics to VO2 max . SETTING Pre-lung transplant evaluation . PATIENTS 60 patients ( 22 men , 38 women ; mean age , 44 years ) with end-stage lung disease ( mean FEV1 and forced vital capacity of 0.97 and 1.93 , respectively ) . MEASUREMENTS AND RESULTS The 6'WT was performed on a level hallway surface , and VO2 max was obtained during maximal cycle ergometry exercise testing with respiratory gas analysis . Multivariate analysis of patient characteristics ( age , sex , weight , FEV1 , FVC , diffusing capacity for carbon monoxide ( DCO ) ,  6'WT distance ambulated  , number of rests per 6'WT  , and the  maximal heart rate , blood pressure , rate-pressure product , respiratory rate , oxygen saturation , rating of perceived exertion , and amount of supplemental oxygen  used during the 6'WT ) was performed on two groups of 30 patients each ( group A or B ) who were r and omly assigned to either group by a process of r and om selection using a computer-generated r and om numbers program . Distance ambulated was the strongest independent predictor of VO2 max ( r = 0.73 ; p < 0.0001 ) in both groups , and adding age , weight , and pulmonary function test results ( FVC , FEV1 , and DCO ) to the regression equation increased the correlation coefficient to 0.83 . Because of the significant correlation of distance ambulated during the 6'WT to VO2 max , the prediction equation obtained from the multivariate analysis of group A , VO2 max = 0.006 x distance ( feet ) + 3.38 , was used to estimate the VO2 max of the group B patients . No significant difference was observed between the estimated ( x + /- SD = 8.9 + /- 2.4 mL/kg/min ) and observed ( x + /- SD = 9.4 + /- 3.8 mL/kg/min ) VO2 max ( mean difference , 0.5 mL/kg/min ; SD of the difference = 2.88 ) . CONCLUSIONS The distance ambulated during a 6'WT can predict VO2 max in patients with end-stage lung disease . The addition of several patient characteristics can increase the ability to predict VO2 max and account for more of the variability . Such information is valuable when assessing patient response to therapeutic intervention if respiratory gas analysis is unavailable or impractical STUDY OBJECTIVE We analyzed the effects of the use of a rollator on walking distance and physiologic variables : pulmonary gas exchange , heart rate , minute ventilation ( Ve ) , oxygen saturation , and symptoms during the 6-min walk test ( 6MWT ) in patients with COPD . SETTING Outpatient clinic at university hospital . PATIENTS Fourteen patients with COPD in stable clinical condition . One patient had mild COPD , five patients had moderate COPD , six patients had severe COPD , and two patients had very severe COPD . INTERVENTIONS Two 6MWTs were performed with a portable metabolic system ( VmaxST 1.0 ; Viasys Healthcare ; MEDA ; Aartselaar , Belgium ) with a rollator and without a rollator , in r and om order . In addition , maximal voluntary ventilation ( MVV ) was measured with and without a rollator , r and omly . RESULTS The median 6MWT distance increased significantly with a rollator : 416 m without a rollator ( interquartile range [ IQR ] , 396 to 435 m ) , vs 462 m with a rollator ( IQR , 424 to 477 m ) [ p = 0.04 ] . Significant increases were also seen in oxygen uptake ( 0.04 L/min [ IQR , - 0.002 to 0.09 L/min ] ) ; tidal volume ( 0.06 L/min [ IQR , - 0.001 to 0.11 L/min ] ) ; and Ve ( 0.95 L/min [ IQR , - 0.67 to 7.1 L/min ] ) , recorded in the last minute of the 6MWT ; as well as in MVV ( 3 L/min [ IQR , 0 to 12 L/min ] ) [ p < 0.05 for all ] . Borg dyspnea scores tended to be lower with a rollator : 6 ( IQR , 4 to 7 ) without a rollator , vs 5 ( IQR , 4 to 7 ) with a rollator ( p = 0.10 ) . The variation in the 6MWT was explained by individual changes in walking efficiency ( partial R(2 ) = 0.31 ) and changes in Ve ( partial R(2 ) = 0.36 ) [ p model < 0.04 ] . CONCLUSION The use of a rollator improves walking distance of patients with COPD through an increased ventilatory capacity and /or better walking efficiency Background : There is a concern that comorbidity or frailty in older people could limit the usefulness of currently available exercise tests for chronic lung disease . This study evaluated the feasibility and reproducibility of the incremental shuttle walking test ( SWT ) in people aged 70 years or over , compared exercise tolerance with other disability markers , and assessed whether the SWT is responsive to change after bronchodilators . Methods : Fifty elderly patients with chronic airflow limitation ( CAL ) and 32 controls without airflow limitation attempted the SWT before and after combined nebulised salbutamol/ipratropium bromide . Subjects also completed the Nottingham Extended Activities of Daily Living index ( NEADL ) and the London H and icap score ( LHS ) . Results : Forty four subjects with CAL ( 88 % ) and 29 controls ( 84 % ) completed the SWT , including many with co-morbidities . Two week repeatability was good and the SWT was strongly associated with EADL ( r=0.51 , p<0.001 ) and LHS ( r=0.43 , p<0.004 ) , but only weakly with forced expiratory volume in 1 second ( FEV1 ) ( r=0.31 , p=0.05 ) . Subjects with CAL walked a mean distance of 177.7 m compared with 243.3 m in controls ( p<0.001 ) ; following bronchodilator therapy the distance walked increased in the CAL group by 13.2 % ( p=0.009 ) . Conclusion : The SWT is a feasible and reproducible measure of exercise tolerance in elderly people with and without airflow obstruction and correlates with other markers of disability . It is sensitive to change following bronchodilation in subjects with CAL , although the change correlates less well with improvements in FEV1 . Overall , these results suggest that the SWT might be an appropriate measure to assess interventions in elderly people 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 need for a 6-min walk distance ( 6-MWD ) reference equation for healthy North African adults older than 40 years was assessed in a prospect i ve cross-sectional study .  Anthropometric data and 6-MWD  were measured in 229 healthy Tunisian adults ( 125 women ) over 40 years old . Two subgroups of 38 women were identified according to the parity ( low < or=5 ; high > or=6 ) . The published reference equations did not reliably predict measured 6-MWD . The 6-MWD was significantly correlated with gender , age , weight and height ( p<0.001 ) . The combination of these parameters explained 77 % of the 6-MWD variability in the equation : 6-MWD (m)=-160.27 x gender ( 0 : men ; 1 : women ) - 5.14 x age ( yr ) - 2.23 x weight (kg)+2.72 x height (cm)+720.50 . Parity accelerated the 6-MWD decline ( r=-0.39 , p<0.05 ) and women distinguished only by parity ( < or=5 vs. > or=6 ) showed different 6-MWD ( 589+/-60 m vs. 555+/-57 m , p<0.05 ) . In an additional group of 30 adults prospect ively studied to vali date the equation , the agreement between the measured and equation-predicted 6-MWD was satisfactory . In conclusion , this reliable 6-MWD reference equation enriches the World Bank and provides an important element of interpretation for women with high parity OBJECTIVES To investigate cardiorespiratory and dyspnea responses to incremental and self-paced exercise tests in patients with COPD . DESIGN A prospect i ve within-subject design was used . PATIENTS Twenty stable subjects ( 15 men ) , with a mean ( + /- SD ) age of 64.0 + /- 7.5 years and moderate-to-severe COPD ( ie , mean FEV(1 ) , 0.8 + /- 0.3 L and 28.9 + /- 7.9 % predicted ) were studied . METHODS Each subject completed a 6-min walk test ( 6MWT ) , an incremental shuttle walking test ( ISWT ) , and a cycle ergometer test ( CET ) , within a 2-week period . The tests were performed at least 24 h apart . St and ardized encouragement was utilized in each test with the aim of maximizing performance . Heart rate ( HR ) and dyspnea were measured each minute throughout the tests , and pulse oximetric saturation ( Spo(2 ) ) was measured before and immediately after each test . The distances walked in the 6MWT and ISWT were compared to peak oxygen uptake ( Vo(2 ) ) values from the CET . RESULTS HR increased linearly with increasing workload during the CET and ISWT , but increased alinearly with a disproportionate increase early in the 6MWT . In contrast , dyspnea scores increased linearly during the 6MWT , but increased alinearly with a disproportionate increase late during the CET and ISWT . Peak HR and dyspnea were not significantly different between tests . Spo(2 ) was significantly lower at the end of both walking tests compared to that at the end of the CET ( p < 0.001 ) . The distance walked in both the ISWT and 6MWT were related to peak Vo(2 ) values on the CET ( for both tests , r = 0.73 ; p < 0.001 ) . CONCLUSIONS The patterns of response in HR and dyspnea seen during the 6MWT suggest that patients with COPD titrate exertion against dyspnea to achieve a peak tolerable intensity . This strategy is not possible in an externally paced ISWT or CET . However , it is a limited strategy , with performance converging at higher workloads . Similar peak exercise responses were achieved in the 6MWT , ISWT , and CET . Greater oxygen desaturation was observed during the field walking tests , suggesting that both the ISWT and 6MWT are more sensitive than the CET in detecting exercise-induced hypoxemia and in assessing ambulatory oxygen therapy needs Background : The 6-min walk test ( 6MWT ) is increasingly used as an outcome measure in interstitial lung disease ( ILD ) . Aim : To evaluate the usefulness of the 6MWT in a cohort of patients with ILD secondary to systemic sclerosis ( SSc ) and to correlate with established physiological parameters . Methods : 163 patients with SSc-ILD were recruited for a multicentre , r and omised , double-blind clinical trial . Available data at protocol screening included repeated 6MWTs , pulmonary function testing with diffusing capacity , Doppler echocardiography and high-resolution computed tomography of the thorax . Borg Dyspnoea Index was evaluated before and after 6MWT . Results : Mean ( st and ard deviation ( SD ) ) distance walked during walk test 1 was 396.6 ( 84.55 ) m compared with 399.5 ( 86.28 ) m at walk test 2 . The within-subject , intertest correlation as determined by Pearson ’s correlation coefficient testing was 0.95 ( p<0.001 ) . However , only weak correlations of 6MWT with percentage forced vital capacity and the Borg Dyspnoea Index were observed , and no correlation was observed with percentage diffusing capacity . Conclusion : These data confirm the high reproducibility of the  6MWT in patients with SSc-ILD and therefore the validity of the test in this cohort . The lack of correlation of 6MWT with st and ard physiological parameters of ILD suggests a multifactorial basis for limited exercise capacity in patients with SSc and calls into question the utility of the 6MWT as a measure of outcome in future studies on SSc-ILD 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 STUDY OBJECTIVES To assess oxygen desaturation during activities and to evaluate the short-term effects of supplemental O(2 ) use in patients with severe COPD who do not qualify for long-term O(2 ) therapy . DESIGN A double-blind , r and omized , placebo-controlled trial . SETTING Out patients from the pulmonary diseases division of a tertiary-care university hospital . PATIENTS Twenty patients with stable COPD with FEV(1)/FVC ratios of < 50 % , FEV(1 ) levels < 55 % of the predicted normal value , and PaO(2 ) levels of > 60 mm Hg when resting . INTERVENTIONS Patients were initially evaluated with  pulmonary function tests , blood gas analysis , and Doppler echocardiography  , and they underwent the following three 6-min walking tests ( WTs ) in a r and om sequence : basal WT ( BWT ) ; WT while breathing compressed air ( CAWT ) ; and WT while breathing O(2 ) ( O(2)WT ) . MEASUREMENTS AND RESULTS The distance walked was recorded in meters . Dyspnea was measured by Borg scale measurement before and after the tests , and arterial oxygen saturation measured by pulse oximetry ( SpO(2 ) ) was continuously monitored . Results were analyzed by grouping patients in the following manner : desaturators ( DSs ) ( ie , patients with a drop in SpO(2 ) of at least 5 % and < 90 % during the WT ) vs nondesaturators ( NDSs ) ; and O(2 ) responders ( ie , patients with an increase of at least 10 % in the distance walked and /or a decrease of at least 3 points in Borg index score ) vs nonresponders . During the BWT , 11 of 20 patients ( 55 % ) were defined as desaturators . During the O(2)WT , the SpO(2 ) remained at > 90 % in every patient . The distance walked increased by 22 % ( p < 0.02 ) , and dyspnea decreased 36 % ( p < 0.01 ) in DS patients . In NDS patients , O(2 ) administration reduced dyspnea by 47 % ( p < 0.001 ) , but the distance walked did not improve . Responses were markedly different from one patient to another . No significant differences were noticed between the results of the BWT and CAWT in any of the groups . Thirteen O(2 ) responders did not differ from 7 nonresponders either in basal data or in desaturation measure during the BWT , except that all walking responders ( five patients ) were above the median of basal left ventricle performance . CONCLUSIONS Most of the studied COPD patients desaturated during the BWT . O(2 ) administration avoided desaturation and could increase the distance walked and reduce dyspnea , but these effects were not related to walking desaturation in individual cases . Improvements were not a placebo effect . The therapeutic role of O(2 ) during activities in some patients with severe COPD needs to be individually assessed BACKGROUND Exercise training programmes for patients with COPD are effective in improving exercise capacity . The few trials that have investigated the effects of exercise programmes on daily physical activity show contradictory results . AIM To investigate the relation between daily physical activity level and exercise capacity in patients with COPD using data of a r and omised controlled trial in which the exercise intervention was aim ed at improvement of both physical activity and exercise capacity ( the COPE-II study ) . METHODS These are secondary analyses of the COPE-II study , a r and omised controlled trial in which a community-based physiotherapeutic exercise programme was evaluated .  Daily physical activity  was measured with a pedometer ( steps/day ) . Exercise capacity  was measured with an incremental maximal cycle ergometer test , the incremental ( ISWT ) and endurance shuttle walk test ( ESWT ) . Pearson correlation coefficients were calculated . RESULTS At baseline , correlations between steps/day and VO(2peak ) , ISWT ( m ) , ESWT ( m ) and ESWT ( s ) were 0.54 , 0.59 , 0.44 , and 0.34 , respectively ( all p < 0.01 ) . In the  intervention group , correlations between change in steps/day over 7 months and change in ISWT ( m ) , ESWT ( m ) and ESWT ( s ) were 0.47 , 0.41 , and 0.38 , respectively ( all p < 0.01 ) . In the  control group , these same correlations were weak to non-existent . CONCLUSIONS A moderate to weak relationship was found between daily physical activity and exercise capacity . These results strengthen our beliefs that exercise interventions need to target not only exercise capacity but also behaviour change with regard to daily physical activity to achieve improvements in both parameters RATIONALE Although commonly used as the primary outcome measure of clinical trials in pulmonary arterial hypertension ( PAH ) , the minimal important difference ( MID ) of the 6-minute walk test ( 6MWT ) has not been well defined for this population of patients . OBJECTIVES To estimate the MID in the 6MWT in patients with PAH . METHODS Study subjects from the clinical trial of tadalafil in PAH , a 16-week , parallel-group , r and omized clinical trial of patients who were treatment naive or on background therapy with an endothelin receptor antagonist , were eligible . 6MWT was performed using a st and ardized protocol . Distributional and anchor-based methods were used to estimate the MID ; the latter method used the Physical Component Summary Score ( PCS ) of the Medical Outcomes Study 36-item short form ( SF-36 ) . MEASUREMENTS AND MAIN RESULTS Four hundred five subjects were analyzed .  Domains of the SF-36 were weakly to modestly associated with 6MWT . Change in the PCS of the SF-36 was most strongly associated with change in 6MWT ( r = 0.40 , P < 0.001 ) and thus was selected as the anchor for subsequent anchor-based analyses . Distributional analyses yielded estimates of the MID ranging from 25.1 to 38.5 m , whereas anchor-based analyses yielded an estimate of 38.6 m. CONCLUSIONS Using both distributional and anchor-based methods , the estimated consensus MID in the 6MWT for PAH is approximately 33 m. These results have important implication s for ( 1 ) assessing treatment responses from clinical trials and metaanalyses of specific PAH therapy , and ( 2 ) sample size calculations for future study design 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 BACKGROUND : The development of portable liquid oxygen systems , capable of delivering high flow rate oxygen for long periods , justifies re assessment of the value of supplemental oxygen to aid exercise tolerance in patients with chronic respiratory insufficiency . The type of exercise test and the low oxygen flow rates previously used may account for the variable and often poor responses to supplemental oxygen reported in earlier studies . METHODS : The walking tolerance of 30 patients with severe respiratory disability was measured while they were breathing air and increasing doses of supplemental oxygen ( 2 , 4 , 6 1/min ) by using both the st and ard six minute walking test and an endurance walking test . To assess the initial learning effect and repeatability of the walking tests , three six minute walks and three endurance walks were performed on day 1 and a single walk of each type on days 2 , 3 , and 14 . In addition , oxygen dosing studies were performed on days 2 and 3 after the initial baseline walking tests . Each dosing study comprised four endurance walking tests or four six minute walking tests with patients breathing either air at a flow rate of 4 1/min from a portable cylinder or supplemental oxygen at a flow rate of 2 , 4 or 6 1/min from a portable liquid oxygen supply . The order of the tests was r and omised . Walking distance with each flow rate of oxygen was compared with walking distance with patients carrying cylinder air and for the initial unburdened walks . Breathlessness was assessed by visual analogue scoring on completion of each walk . RESULTS : Exercise ability and breathlessness were significantly improved with supplemental oxygen and this benefit outweighed the reduction in performance result ing from carrying the portable device . Supplemental oxygen at flow rates of 2 , 4 , and 6 1/min increased mean endurance walking distances by 37.9 % , 67.7 % and 85.0 % and six minute walking distances by 19.2 % , 34.5 % , and 36.3 % by comparison with distances when the patient was carrying air with a flow rate of 4 1/min . The additional work of carrying the portable gas supply reduced endurance walking distance by 22.2 % and six minute walking distance by 14.1 % by comparison with a baseline unburdened walk . Comparison of supplemental oxygen at 2 , 4 , and 6 1/min with the baseline unburdened performance showed increased endurance walking distances of 7.3 % , 30.4 % , and 43.9 % and six minute walking distances of 2.3 % , 15.5 % , and 17.0 % . Walking distance was increased by more than 50 % by comparison with an unburdened walk in seven patients with the endurance walking test but in only three patients with the six minute walking test . The benefit was similar in patients with obstructive and with interstitial lung disease . Individual responses were variable and only desaturation during the baseline walk in patients with obstructive lung disease had any predictive value for benefit with oxygen . CONCLUSION : As there was no clear relation between response to oxygen therapy and the patients ' characteristics , assessment for supplemental oxygen therapy will depend on exercise testing . It is suggested that portable oxygen should be considered only if a patient shows a 50 % improvement in exercise ability with high flow rate oxygen ( 4 - 6 1/min ) by comparison with an unburdened walk It is unclear whether short-term benefits from supplemental oxygen translate into improved quality of life in patients with severe COPD . In a 12 wk double-blind r and omized crossover study , we assessed the effects of supplemental air and oxygen on exercise performance ( step tests and 6 min walking distance [ 6MWD ] ) initially and after two 6 wk periods at home using exertional cylinder air or oxygen . We measured quality of life at baseline and after the two 6 wk domiciliary periods . The 26 patients ( 24 males ) had a mean age of 73 + /- 6 yr ; mean FEV1 , 0.9 + /- 0.4 L ; mean DLCO , 10.6 + /- 2.4 ml/min/mm Hg ; mean resting PO2 , 69 + /- 8.5 ( range 58 to 82 ) mm Hg ; mean PCO2 , 41 + /- 3.3 mm Hg ; and mean resting SaO2 , 94 + /- 2.1 ( mean + /- SD ) . Laboratory tests were performed breathing intranasal air or oxygen at 4 L/min , and measurements were made of SaO2 and Borg dysnea scores .  Supplemental oxygen increased 6MWD and steps by small , statistically significant increments acutely at baseline and after 6 and 12 wk , without corresponding falls in Borg score . Degree of desaturation at baseline did not correlate with increase in 6MWD or steps achieved at baseline or at 6 or 12 wk , nor with the domiciliary gas used . There was no difference in 6MWD or steps achieved while breathing supplemental oxygen after 6 wk of domiciliary oxygen compared with domiciliary air . Small improvements in quality of life indices were found after domiciliary oxygen , and mastery also improved after domiciliary air . There were no differences in quality of life , however , when domiciliary oxygen was compared with domiciliary air . Although oxygen supplementation induced small acute increments in laboratory exercise performance , such improvements had little impact on the patients ' daily lives Resting pulmonary function and exercise variables are widely used to stage and monitor idiopathic interstitial pneumonia ( IIP ) . However , the variability of exercise data ( maximal exercise and the 6-minute walk test ) has not been evaluated definitively . We have prospect ively quantified the reproducibility of resting and exercise functional data in fibrotic IIP ( idiopathic pulmonary fibrosis , fibrotic nonspecific interstitial pneumonia ) and have evaluated interrelationships between variables . Thirty consecutive patients with fibrotic IIP underwent serial resting pulmonary function tests , 6-minute walk ( n = 29 ) , and maximal exercise ( n = 24 ) at an interval of 1 week , with all testing performed in accordance with American Thoracic Society st and ards . Within-subject reproducibility was excellent for 6-minute walk distance ( SD/mean = 4.2 % ) and clinical ly acceptable for resting pulmonary function indices and VO(2)max on maximal exercise testing . However , the amplitude of oxygen desaturation at the end of exercise was poorly reproducible in both 6-minute walk and maximal exercise testing ( SD/mean > 25 % ) . There was a highly significant relationship between VO2max on maximal exercise testing and 6-minute walk distance ( r(s ) = 0.78 , p < 0.0001 ) . In fibrotic IIP , the excellent reproducibility of the 6-minute walk distance is a major advantage in routine staging and monitoring , whereas maximal exercise variables are poorly reproducible BACKGROUND The goal of the 6-min walk test ( 6MWT ) is to enable patients to walk " as far as possible " as a measure of their functional ability . The impact of the specific walk instructions on patient 6MWT performance is unknown . METHODS Patients with pulmonary arterial hypertension ( PAH ) , idiopathic pulmonary fibrosis ( IPF ) , and other forms of interstitial lung disease ( ILD ) were recruited to perform four identical 6MWTs with one differing instructional phrase . The st and ard instruction to walk " as far as possible " was substituted in r and om order with " as fast as possible , " " at your normal pace , " or " at a leisurely pace . " RESULTS Twenty-four patients ( 10 with PAH , eight with IPF , six with other ILD ) were enrolled and completed all four 6MWTs . Patients attained the greatest distance with the fast instruction , exceeding the st and ard instruction distance by a mean of 52.7 m ( P < .001 ) . The mean difference between the fast and st and ard walks was 41.5 m in the PAH group , 66.5 m in the IPF group , and 53 m in the other ILD group . CONCLUSIONS Patients do not walk as far as they are able with the st and ard American Thoracic Society instruction for 6MWT . Changing the wording from " far " to " fast " may facilitate a better effort and greater distance during the test . It is possible that this modified 6MWT instruction may result in improved accuracy and reproducibility , thereby enhancing its clinical and research trial usefulness 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 In a prospect i ve , r and omized study we examined the effect of ( i ) ambulatory oxygen and ( ii ) a portable , inspiratory pressure support ( IPS ) device on the endurance shuttle walk test ( ESWT ) in patients with severe chronic obstructive pulmonary disease ( COPD ) . Ten out patients [ median ( range ) FEV1 0.60 l(0.35 , 1.45 ) ] performed the ESWT under five test conditions : baseline walk ( no assistance ) , IPS at 14 cmH2O from a portable ventilator ( the HIPPY , Friday Medical , U.K. ) , sham IPS ( < 8 cmH2O ) , ambulatory oxygen at 2 l min(-1 ) , and sham oxygen ( carrying the portable oxygen cylinder and breathing air ) . There were significant improvements in the ESWT with  ambulatory oxygen  , but a negative effect with the HIPPY device [ mean ( SD ) time : baseline 172 ( 48 ) sec ; oxygen 242 ( 62 ) sec ; HIPPY 84 ( 35 ) sec ] . The ESWT appeared sensitive to the effect of cylinder weight although differences in endurance capacity were not significant [ sham oxygen 151 ( 45 ) sec ] . The ESWT was sensitive to the acute application of oxygen , demonstrating a beneficial effect on endurance performance in patients with severe COPD . The ESWT could form the basis of a st and ardized assessment for ambulatory oxygen OBJECTIVE To establish the minimal important difference ( MID ) for the six-minute walk distance ( 6MWD ) in persons with chronic obstructive pulmonary disease ( COPD ) . DESIGN Analysis of data from an observational study using distribution- and anchor-based methods to determine the MID in 6MWD . SETTING Outpatient pulmonary rehabilitation program at 2 teaching hospitals . PARTICIPANTS Seventy-five patients with COPD ( 44 men ) in a stable clinical state with mean age 70 years ( SD 9 y ) , forced expiratory volume in one second 52 % ( SD 21 % ) predicted and baseline walking distance 359 meters ( SD 104 m ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Participants completed the  six-minute walk test  before and after a 7-week pulmonary rehabilitation program . Participants and clinicians completed a global rating of change score while blinded to the change in 6MWD . RESULTS The mean change in 6MWD in participants who reported themselves to be unchanged was 17.7 meters , compared with 60.2 meters in those who reported small change and 78.4 meters in those who reported substantial change ( P=.004 ) . Anchor-based methods identified an MID of 25 meters ( 95 % confidence interval 20 - 61 m ) . There was excellent agreement with distribution-based methods ( 25.5 - 26.5 m , kappa=.95 ) . A change in 6MWD of 14 % compared with baseline also represented a clinical ly important effect ; this threshold was less sensitive than for absolute change ( sensitivity .70 vs .85 ) . CONCLUSIONS The MID for 6MWD in COPD is 25 meters . Absolute change in 6MWD is a more sensitive indicator than percentage change from baseline . These data support the use of 6MWD as a patient-important outcome in research and clinical practice Background : Despite widespread use of the incremental shuttle walk distance ( ISWD ) , there are no reference equations for predicting it . Objectives : We aim ed to evaluate ISWD in healthy subjects and to establish a reference equation for its prediction . Methods : 131 Brazilian individuals ( 61 males ; 59 ± 10 years ) performed 2 walk tests in a 10-m long corridor . We assessed height , weight , body mass index , forced expiratory volume in 1 s , forced vital capacity and self-reported physical activity  . Results : Mean ISWD was greater in males than in females ( 606 ± 167 vs. 443 ± 117 m ; p < 0.001 ) . ISWD correlated significantly ( p < 0.05 ) with age ( r = –0.51 ) , height ( r = 0.54 ) and weight ( r = 0.20 ) . A predictive model including age , height , weight and gender explained 50.3 % of the ISWD variance . In an additional group of 20 subjects prospect ively studied , the difference between measured and predicted ISWD was not statistically significant ( 534 ± 84 vs. 552 ± 87 m , respectively ) , representing 97 ± 12 % of the predicted value calculated with our reference equation for ISWD . Conclusions : This reference equation including demographic and anthropomorphic attributes could be useful for interpreting the walking performance of patients with chronic diseases that affect exercise capacity STUDY OBJECTIVES This study was conducted to examine the short-term effects of using a rollator on functional exercise capacity among individuals with COPD and to characterize which individuals benefit most from its use . DESIGN Repeated- measures r and omized crossover design using the 6-min walk test ( 6MWT ) as the primary outcome measure . SETTING Respiratory rehabilitation center . PATIENTS Forty stable subjects who had received a diagnosis of COPD . INTERVENTIONS Two 6MWTs were performed on each study day . One 6MWT was performed unaided , and the other was performed with a rollator . The order was r and omized on the first day and reversed on the second day . RESULTS Use of the rollator was associated with a significant reduction in dyspnea ( p < 0.001 ) and duration of rest ( reduction for the total group , 19 s ; and reduction for those who walked < 300 m unaided , 40 s ; p = 0.001 ) during the 6MWT . For subjects who walked < 300 m unaided , there was also a significant improvement in distance walked ( p = 0.02 ) . No changes were found for the measures of cardiorespiratory function or gait ( p > 0.05 ) . The requirement to rest during an unaided 6MWT was a significant predictor of improved functional exercise capacity with the use of the rollator ( p < 0.005 ) . The majority of subjects whose unaided 6MWT distance was < 300 m preferred using the rollator to walking unaided . CONCLUSIONS Use of a rollator was effective in improving functional exercise capacity by reducing dyspnea and rest duration among stable individuals with severe COPD . Individuals who walked < 300 m and individuals who required a rest during an unaided 6MWT benefited the most from using a rollator in terms of reduced dyspnea , reduced rest time , and improved distance walked QUESTIONS Do patients with chronic obstructive pulmonary disease ( COPD ) achieve a different distance on the six minute walk test ( 6MWT ) conducted on a 10 m course versus on a 30 m course ? When assessing the distance on a 6MWT conducted on a 10 m course , is it valid to use existing reference equations that were generated on longer courses ? DESIGN A r and omised double-crossover experimental study . PARTICIPANTS Forty-five patients with COPD in primary physiotherapy care . INTERVENTION All patients performed a 6MWT twice over a 10 m course and twice over a 30 m course . The 6MWTs were performed in accordance with the American Thoracic Society guidelines . OUTCOME MEASURES 6MWD was assessed and predicted distance was calculated based on a range of reference equations . RESULTS The 6MWD on the 10 m course was 49.5 m shorter than on the 30 m course , which was statistically significant ( 95 % CI 39.4 to 59.6 ) . By using existing reference equations for a 6MWT conducted on the 10 m course , the predicted distance is highly overestimated ( with a range of 30 % to 33 % ) and the average distance as a percentage of the predicted value is 8%pred lower compared to a 6MWT conducted on the 30 m course , result ing in a worse representation of a COPD patient 's functional exercise capacity . CONCLUSION This study shows that the impact of course length on the 6MWD and on the use of reference equations in patients with COPD is substantial and clinical ly relevant ( based on the most conservative published minimum clinical ly important difference ) . Therefore , existing reference equations established for a 6MWT conducted over a 30 m ( or longer ) course can not be applied to predict the distance achieved on the 6MWT on a 10 m course , which is frequently used in primary care physiotherapy practice s for patients with COPD In a large , prospect ively followed , two‐center cohort of patients listed for lung transplantation ( n = 376 ) , we used Cox proportional hazards models to determine the importance of baseline 6‐min walk distance ( 6MWD ) in predicting patient survival . 6MWD used as a continuous variable was a significant predictor of survival after adjusting for other important covariates when transplant was considered as a time‐varying covariate ( HR for each 500 ft increase in 6MWD = 0.57 , 95 % CI : 0.43–0.77 , p = 0.0002 ) . 6MWD remained an important predictor of survival in models that considered only survival to transplant ( HR for each 500 ft increase in 6MWD = 0.41 , 95 % CI : 0.27–0.62 , p < 0.0001 ) or survival only after transplant ( HR for each 500 ft increase in 6MWD = 0.40 , 95 % CI : 0.22–0.72 , p = 0.002 ) . Unadjusted Kaplan‐Meier analysis demonstrates significantly different survival by 6MWD tertiles ( < 900 , 900–1200 , or > 1200 ft , p‐value = 0.0001 ) . In the overall model , 6MWD prediction of survival was relatively homogeneous across disease category ( 6MWD by disease interaction term , p‐value = 0.63 ) . Our results demonstrate a significant relationship between baseline 6MWD and survival among patients listed for lung transplantation that exists across all native disease categories and extends through transplantation . The 6MWD is thus a useful measure of both urgency and utility among patients awaiting lung transplantation BACKGROUND In patients with idiopathic pulmonary fibrosis ( IPF ) , our objectives were to identify predictors of abnormal heart rate recovery ( HRR ) at 1 min after completion of a 6-min walk test ( 6MWT ) [ HRR1 ] and 2 min after completion of a 6MWT ( HRR2 ) , and to determine whether abnormal HRR predicts mortality . METHODS From 2003 to 2008 , we identified IPF patients who had been evaluated at our center ( n = 76 ) with a pulmonary physiologic examination and the 6MWT .  We used logistic regression to identify predictors of abnormal HRR , the product-limit method to compare survival in the sample stratified on HRR , and Cox proportional hazards analysis to estimate the prognostic capability of abnormal HRR . RESULTS Cutoff values were 13 beats for abnormal HRR1 and 22 beats for HRR2 . In a multivariable model , predictors of abnormal HRR1 were diffusing capacity of the lung for carbon monoxide ( odds ratio [ OR ] , 0.4 per 10 % predicted ; 95 % confidence interval [ CI ] , 0.2 to 0.7 ; p = 0.003 ) , change in heart rate from baseline to maximum ( OR , 0.9 ; 95 % CI , 0.8 to 0.97 ; p = 0.01 ) , and having a right ventricular systolic pressure > 35 mm Hg as determined by transthoracic echocardiogram ( OR , 12.7 ; 95 % CI , 2.0 to 79.7 ; p = 0.01 ) . Subjects with an abnormal HRR had significantly worse survival than subjects with a normal HRR ( for HRR1 , p = 0.0007 [ log-rank test ] ; for HRR2 , p = 0.03 [ log-rank test ] ) ; these results held for the subgroup of 30 subjects without resting pulmonary hypertension ( HRR1 , p = 0.04 [ log-rank test ] ) . Among several c and i date variables , abnormal HRR1 appeared to be the most potent predictor of mortality ( hazard ratio , 5.2 ; 95 % CI , 1.8 to 15.2 ; p = 0.004 ) . CONCLUSION Abnormal HRR after 6MWT predicts mortality in IPF patients . Research is needed to confirm these findings prospect ively and to examine the mechanisms of HRR in IPF patients RATIONALE Breathing supplemental oxygen reduces breathlessness during exercise in patients with chronic obstructive pulmonary disease ( COPD ) . Replacing nitrogen with helium reduces expiratory flow resistance and may improve lung emptying . Combining these treatments should be independently effective . OBJECTIVES Study the effect of changing oxygen or helium concentration in inspired gas during exercise in patients with stable COPD . METHODS In 82 patients ( mean age , 69.7 yr ; mean FEV(1 ) , 42.6 % predicted ) , we measured endurance shuttle walking distance , resting and exercise oxygen saturation , and end-exercise dyspnea ( Borg scale ) while patients breathed  Heliox28  ( 72 % He/28 % O(2 ) ) , Heliox21 ( 79 % He/21 % O(2 ) ) , Oxygen28 ( 72 % N(2)/28 % O(2 ) ) , or medical air ( 79 % N(2)/21 % O(2 ) ) . Gases were administered using a r and omized , blinded , crossover design via a face mask and an inspiratory dem and valve . RESULTS Breathing Heliox28 increased walking distance ( mean+/-SD , 147+/-150 m ) and reduced Borg score ( -1.28+/-1.30 ) more than any other gas mixture . Heliox21 significantly increased walking distance ( 99+/-101 m ) and reduced dyspnea ( Borg score , -0.76+/-0.77 ) compared with medical air . These changes were similar to those breathing Oxygen28 . The effects of helium and oxygen in Heliox28 were independent . The increase in walking distance while breathing Heliox28 was inversely related to baseline FEV(1 ) breathing air . CONCLUSION Reducing inspired gas density can improve exercise performance in COPD as much as increasing inspired oxygen . These effects can be combined as Heliox28 and are most evident in patients with more severe airflow obstruction Background : The 6-minute walk distance ( 6MWD ) has been useful in the evaluation of men with COPD . Little is known about 6MWD in women with the disease . Objectives : Using healthy women as a reference , to evaluate the factors that help determine 6MWD in women with COPD . To explore if the 350 meters threshold differentiates survival in women as it does in men . Methods : Healthy women ( n = 164 ) and with COPD ( n = 223 ) were included in the study . Age , pack-years history , smoking status , comorbidities ( Charlson Index ) , BMI , MRC dyspnea , spirometry and 6MWD were recorded in all participants and PaO2 and IC/TLC in COPD women . The patients were prospect ively followed and deaths registered . Factors predicting 6MWD were determined by multiple regression analysis . ROC analysis was used to calculate the best threshold value for the 6MWD with mortality as gold st and ard . Kaplan-Meier curves compared survival of patients that walked more or less than 350 m by age categories . Results : The 6MWD is decreased in women with COPD . Values decrease with age and GOLD stages . Age , BMI , smoking status , comorbidities , MRC and FEV1 % are statistical significant predictors of 6MWD . A 350 m cut-off value has a good sensitivity and specificity to predict ( 73 % and 80 % respectively ) and differentiate survival ( p < 0.001 for log rank comparisons ) in these patients . Conclusions : In women with COPD , the 6MWD decreases with age and GOLD stages . A 350 m distance is a valid threshold to differentiate survival . Further studies in different setting s should confirm our findings The product of walking distance and body weight ( D x W ) mimics the work of walking . We hypothesized the superiority of D x W to walking distance ( D ) alone in any correlation with lung function , anaerobic threshold ( AT ) and maximal oxygen uptake ( VO2max ) . We further hypothesized that the D x W product for a 6-min walk test ( 6 MWT ) would correlate with the AT and VO2max because all three are markers of exercise ability . Thirty-three male chronic obstructive pulmonary disease ( COPD ) patients with mean forced expiratory volume in 1 sec ( FEV1 ) of 1.2+/-0.4 l ( range 0.58 - 1.86 l ) were enrolled . Six patients were excluded due to inability to achieve a maximal test .  Lung function and self-assessed every-day activities using a oxygen-cost diagram were evaluated before entry of the study . A maximal effort ramp-pattern cardiopulmonary exercise test ( CPET ) and a 6 MWT were conducted in r and om order . Borg score , heart rate , and O2 saturation with pulse oximetry ( SpO2 ) were measured during both exercise tests . VO2 AT and minute ventilation were also measured during the CPET . Correlations were sought between the distance covered in the 6 MWT , and the D x W product with AT , VO2max and other variables . The average D and D x W were 456 m and 27.5 kg km(-1 ) , respectively . D x W was superior to D alone when correlated with the VO2max and AT determined from the CPET , while modestly correlated with the change ( delta ) in Borg score and delta SpO2 in the 6 MWT and self-assessed every-day activities . Distance x weight product was correlated with the AT and VO2max . In addition , D x W was better correlated with diffusing capacity for carbon monoxide and vital capacity than D alone . We conclude that D x W mimics the work of walking better than D and is suggested as a parameter for evaluation of patients ' fitness if gas exchange measurements are not available BACKGROUND Different exercise tests are used to evaluate the functional capacity in chronic obstructive pulmonary disease . The cardiopulmonary exercise test is considered the gold st and ard , but the 6 minute walk and the 15 step exercise oximetry test are considerably less expensive . OBJECTIVES To determine whether reliable data could be obtained at lower cost . METHODS The study sample consisted of 50 patients with mild to severe stable COPD . All underwent pulmonary function test and the cardiopulmonary exercise test , 6 minute walk and 15 step exercise oximetry test as part of their regular follow-up visit . Functional capacity was grade d according to each test separately and the functional capacities obtained were correlated . RESULTS The results showed that most of the patients had severe COPD according to pulmonary function tests ( mean forced expiratory volume in the first second 46.3 + /- 19.9 % of predicted value ) . There was a good correlation between the cardiopulmonary exercise test and the 6 minute walk functional capacity classes ( r = 0.44 , P = 0.0013 ) . We did not find such correlation between the 15  step exercise oximetry test and the cardiopulmonary exercise test ( r = 0.07 , P = 0.64 ) . CONCLUSIONS The study shows that the 6 minute walk is a reliable and accurate test in the evaluation of functional capacity in COPD patients BACKGROUND Fatigue is a frequently occurring symptom in patients with chronic obstructive pulmonary disease ( COPD ) . Despite this , relatively few studies have objective ly assessed patients ' perceptions of fatigue and the impact of perceived fatigue on their everyday lives . OBJECTIVE The purpose of this study was to describe the prevalence , duration and severity of fatigue among patients with COPD and the impact of perceived fatigue on cognitive , physical and psychosocial functioning in comparison with controls . METHOD The  Fatigue Impact Scale , including physical , psychosocial and cognitive dimension and structured questions about the frequency , duration , and severity of fatigue  was mailed to 44 out patients with COPD and 88 r and omly selected age- and sex-matched controls . In total 36 patients and 37 controls completed the question naire . RESULTS Almost half of the patients ( 47.2 % ) , reported fatigue every day during the preceding month compared with 13.5 % of the control group ( P < 0.001 ) . The duration of fatigue was more than 6 hours in 52.7 % of the patients and 44.4 % reported that fatigue was either the worst or one of the worst symptoms they had , compared with 18.9 % ( P < 0.001 ) and 10.8 % ( P < 0.01 ) in the control group . The patients reported a significantly greater impact of fatigue on cognitive , physical and psychosocial functioning compared with the control group ( P < 0.001 ) . CONCLUSION These findings indicate that fatigue is a highly prevalent symptom , which impacts on patients ' functional condition and needs to be professionally assessed and managed 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 OBJECTIVES To assess the changes in  physical activity  in subjects with chronic obstructive pulmonary disease over 6months after pulmonary rehabilitation . DESIGN Prospect i ve , observational study .  Activity  was measured over 2-day periods at the end of rehabilitation , and repeated every 6weeks for 6months using the ActivPAL uni-axial accelerometer . These results were compared with the shuttle walking test ( SWT ) and the St. George 's Respiratory Disease Question naire ( SGRDQ ) . SETTING UK community hospital . PARTICIPANTS Adults completing a community rehabilitation programme . MAIN OUTCOME MEASURE Time spent st and ing and mobilising ( ' uptime ' ) . RESULTS Of 34 subjects recruited , 28 completed the 6-month study period ( mean age 69years , mean forced expiratory volume in 1second 1.3l ) . Participants wore the monitor for 13.8 to 14.2hours/day . At baseline ( post-rehabilitation ) , participants spent 1.7 [ st and ard deviation ( SD ) 1.3]hours/day walking and 3.5 ( SD 2.6)hours/day st and ing . Taking the group as a whole , mean uptime decreased marginally by 13.6minutes after 24weeks compared with baseline , with significant individual variability . In all but one subject who showed decreased activity , this was apparent after 6weeks . There were no significant changes in the mean SWT or SGRDQ . Significant associations between total uptime and the SWT were found , but coefficients were weak . It was not possible to predict individual responses from baseline data . CONCLUSION The accelerometer provides useful supplementary data in patients completing rehabilitation programmes , and the results reveal wide variation . The weak associations between activity data and the SWT suggest that monitors provide additional information . More work is required to determine the factors associated with early deterioration in activity in order to design appropriate interventions BACKGROUND Generally , the use of a rollator improves mobility in patients with COPD . Nevertheless , not all patients benefit from its use , and many patients feel embarrassed about using it . Therefore , other walking aids are worthwhile to consider . We compared the direct effects of a " new " ambulation aid ( a modern draisine ) with the effects of a rollator on 6-min walk distance ( 6MWD ) in patients with COPD . METHODS Twenty-one patients with COPD performed two 6-min walk tests ( 6MWTs ) during prerehabilitation assessment ( best 6MWD : 369 ± 88 m ) . Additionally , two extra 6MWTs were performed on two consecutive days in r and om order : one time with a rollator and one time with a modern draisine . Walking pattern ( n = 21 ) was determined using an accelerometer , and metabolic requirements ( n = 10 ) were assessed using a mobile oxycon . RESULTS Walking with the modern draisine result ed in a higher 6MWD compared with walking with the rollator ( 466 ± 189 m vs 383 ± 85 m ) . Moreover , patients had fewer strides ( 245 ± 61 vs 300 ± 49 ) and a greater stride length ( 1.89 ± 0.73 m vs 1.27 ± 0.14 m ) using the modern draisine compared with the rollator  ( all P ≤ .001 ) . Oxygen uptake , ventilation , heart rate , oxygen saturation , and Borg symptom scores were comparable between both walking aids . Ten percent of the patients felt embarrassed using the modern draisine compared with 19 % for the rollator , and a significantly smaller proportion of patients would use the modern draisine in daily life . CONCLUSIONS The mean difference in 6MWD between a modern draisine and a rollator seems clinical ly relevant , with the same metabolic requirements and symptom Borg scores . Therefore , this " new " ambulation aid could be a good alternative to the rollator to improve functional exercise performance in patients with COPD . TRIAL REGISTRY The Netherl and s National Trial Registry ; No. : NTR1542 ; URL : www.trialregister.nl
target: Method ological factors affecting 6MWD include track length , encouragement , supplemental oxygen and walking aids .
  Supplemental oxygen also affects ISWT and ESWT performance .
  Responsiveness was moderate to high for all tests , with greater responsiveness to interventions that included exercise training .
  The findings of this review demonstrate that the 6MWT , ISWT and ESWT are robust tests of functional exercise capacity in adults with chronic respiratory disease
background: This systematic review examined the measurement properties of the 6-min walk test ( 6MWT ) , incremental shuttle walk test ( ISWT ) and endurance shuttle walk test ( ESWT ) in adults with chronic respiratory disease .