Repeat six-minute walk tests in patients with chronic heart failure: are they clinically necessary? Determining the minimal clinically important difference for the six-minute walk test and the 200-meter fast-walk test during cardiac rehabilitation program in coronary artery disease patients after acute coronary syndrome. Lack of Specificity of the 6-Minute Walk Test as an Outcome Measure for Patients with Systemic Sclerosis Heart rate recovery after the 6 min walk test rather than distance ambulated is a powerful prognostic indicator in heart failure with reduced and preserved ejection fraction: a comparison with cardiopulmonary exercise testing. Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure. The minimal important difference in the 6-minute walk test for patients with pulmonary arterial hypertension. [Reference Equations for the 6-Minute Walk Test in Healthy Individuals.] Usefulness of the 6-minute walk test and the 200-metre fast walk test to individualize high intensity interval and continuous exercise training in coronary artery disease patients after acute coronary syndrome: a pilot controlled clinical study Preliminary report of the 6-minute walk test as a predictor of radiation-induced pulmonary toxicity. Six-Minute Walk Test and Cardiopulmonary Exercise Testing in Patients With Chronic Heart Failure: A Comparative Analysis on Clinical and Prognostic Insights The influence of alternative instruction on 6-min walk test distance. Daily walking performance as an independent predictor of advanced heart failure: Prediction of exercise capacity in chronic heart failure. Reproducibility of the six-minute walking test in chronic heart failure patients. A comparison of the shuttle and 6 minute walking tests with measured peak oxygen consumption in patients with heart failure. The endurance shuttle walk test: An alternative to the six-minute walk test for the assessment of ambulatory oxygen Comparison between an indoor and an outdoor 6-minute walk test among individuals with chronic obstructive pulmonary disease.
Background : Owing to a reported learning effect in patients with chronic cardiopulmonary disease , performance of at least two six-minute walk tests ( 6MWT ) are recommended as st and ard practice . Patients with chronic heart failure ( CHF ) are typically elderly and frail and it is unknown whether current guidelines are practical in a clinical setting . Aims : The aim of this study was to determine whether repeat performance of 6MWTs in patients with CHF is related to between-test interval or baseline performance . Methods : This was a multisite observational study enrolling participants entering into heart failure rehabilitation programmes . Participants performed two 6MWTs with r and omly allocated inter-test intervals between 15 and 90 minutes . Distance walked in the second test was compared with the first test using a paired t test . Results : Eighty-eight participants ( 45 females , age 65 ± 14 years ) with stable CHF were enrolled . Mean distance walked increased from 301 metres in test 1 to 313 metres in test 2 ( p < 0.001 ) . No significant change was recorded between test 1 and test 2 for those whose baseline distance was < 300 metres . The interval between tests had no significant effect on the distance walked . Conclusion : The change in 6MWT distance was significantly associated with better baseline performance but not with the interval between tests OBJECTIVE To estimate the minimal clinical ly important difference ( MCID ) for the 6-minute walk test ( 6MWT ) and the 200-m fast-walk test ( FWT ) in patients with coronary artery disease ( CAD ) during a cardiac rehabilitation program . DESIGN Prospect i ve study using distribution- and anchor-based methods . SETTING Out patients from a cardiac rehabilitation unit . PARTICIPANTS Stable patients with CAD ( N=81 ; 77 men ; mean±SD age , 58.1±8.7y ) enrolled 31±12.1 days after an acute coronary syndrome ( ACS ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES  6MWT and 200-m FWT results before and after an 8-week cardiac rehabilitation program and at the 6th and 12th sessions . Patients and physiotherapists who supervised the training were asked to provide a global rating of perceived change in walking ability while blinded to changes in walk test performances . RESULTS Mean change in 6MWT distance ( 6MWD ) in patients who reported no change was -6.5 m versus 23.3 m in those who believed their performance had improved ( P<.001 ) . This result was consistent with the MCID determined by using the distribution method ( 23 m ) . Considering a 25-m cutoff , positive and negative predictive values were 0.9 and .63 , respectively . Conversely , there was no difference in 200-m FWT performance between these 2 groups ( 0.1 vs -1.4s , respectively ) . There was poor agreement with the physiotherapist 's perceived change . CONCLUSIONS The MCID for 6MWD in patients with CAD after ACS was 25 m . This result will help physicians interpret 6MWD change and help research ers estimate sample sizes in further studies using 6MWD as an endpoint 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 AIMS Heart rate recovery ( HRR ) appears to be a robust prognostic marker in heart failure ( HF ) . When using the 6 min walk test ( 6MWT ) in HF , distance ambulated is generally the reference prognostic variable . We hypothesized that HRR after the 6MWT would be a better prognostic measure than distance ambulated . METHODS AND RESULTS A 6MWT and cardiopulmonary exercise testing ( CPX ) were r and omly performed in 258 HF patients [ 216 HF with reduced EF ( HFrEF ) and 42 HF preserved EF ( HFpEF ) ] , after which HRR was measured . HRR was defined as the difference between heart rate at peak exercise and 1 min following test termination . Patients were assessed for major cardiac events during a mean follow-up period of 22.8 ± 22.1 months . There were 50 major cardiac events during the tracking period . Univariate Cox regression analysis results identified HRR after both the 6MWT and CPX as a significant ( P < 0.001 ) predictor of adverse events . Multivariate Cox regression analysis revealed that dichotomized HRR after the 6MWT and CPX was the strongest predictor of survival ( χ(2 ) 61.1 and 53.8 , respectively ; P < 0.001 ) , with LVEF ( residual χ(2 ) 6.1 , P < 0.05 ) adding significant prognostic value to the 6MWT model and ventilatory efficiency ( the VE/VCO2 slope ) ( residual χ(2 ) 6.6 , P < 0 .05 ) adding significant prognostic value to the CPX model . CONCLUSIONS HRR after the 6MWT is a powerful prognosticator that performs similarly to HRR after maximal exercise . If confirmed in subsequent studies , 6MWT HRR should replace 6MWT distance as the reference criterion 6MWT measure to consider when grading cardiovascular risk in HF 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 BACKGROUND Our purpose was to evaluate the reliability , validity , and responsiveness of the 6-minute walk test ( 6MWT ) in patients with heart failure ( HF ) enrolled in the R and omized Evaluation of Strategies for Left Ventricular Dysfunction ( RESOLVD ) pilot study . METHODS A total of 768 patients was enrolled in a multicenter r and omized clinical trial evaluating the effect of c and esartan , enalapril , and metoprolol on left ventricular ejection fraction ( LVEF ) , 6MWT distance , neurohormones , and quality of life . The 6MWT was performed once at screening and twice at baseline , 18 weeks , and 43 weeks by a st and ardized method . RESULTS Test-retest reliability at baseline ( intraclass correlation coefficient [ ICC ] = 0.90 ) , 18 weeks ( ICC = 0.88 ) , and 43 weeks ( ICC = 0.91 ) was very good . Baseline 6MWT distance was weakly inversely correlated to the quality -of-life cumulative score ( r = -0.26 , P = .0001 ) and moderately inversely correlated to the New York Heart Association functional classification ( NYHA-FC ) ( r = -0.43 , P = .001 ) . In the RESOLVD study , the 6MWT was not responsive to change when effect sizes and st and ardized response means were used . Disease-specific quality of life was responsive to change in patients treated with c and esartan and enalapril and NYHA-FC was responsive to change in the c and esartan and enalapril combination and for enalapril alone with small effect sizes . The 6MWT , NYHA-FC , and quality of life were not responsive to change during the metoprolol or placebo phase . CONCLUSIONS The 6MWT is highly reproducible in patients with symptoms of HF . It is somewhat correlated to NYHA-FC and quality of life . Overall , quality of life was most responsive to change , whereas 6MWT and NYHA-FC were comparable but less responsive to change in the RESOLVD study 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 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 Objective : To study the effects of three individualized exercise training prescriptions using either a percentage of maximal heart rate ( HR ) , maximal 6-minute walk test ( 6MWT ) HR , or maximal 200-metre fast walk test ( 200-mFWT ) HR , on walking performance and exercise capacity in coronary artery disease ( CAD ) patients . Design : Controlled clinical study . Participants : Twenty-seven out patients enrolled in a rehabilitation programme after an acute coronary syndrome . Setting : Cardiac rehabilitation unit . Interventions : Three groups : ( A ) : moderate intensity continuous exercise ( MICE ) at 70 % of the maximal HR of the grade d maximal exercise test ( n = 10 ) ; ( B ) : MICE at the maximal 6MWT HR ( n = 8) ; ( C ) : high intensity interval training ( HIIT ) based on the 6MWT and the 200-mFWT maximal HR ( n = 9 ) . Group B and C performed walk tests every 2 weeks , to readjust training HR ( THR ) if needed . Measures : 6MWT and 200-mFWT performances , peak VO2 and peak power ( Pmax ) . Results : 6MWT and 200-mFWT performances improved significantly and similarly in all groups ( P < 0.05 ) . Peak VO2 improved significantly in all groups ( P < 0.05 ) , this improvement being higher in group C ( HIIT ) versus A ( P < 0.05 ) . Group B was closer to the recommended THR during exercise sessions compared to group A. Conclusion : This pilot study showed that using the 6MWT and 200-mFWT HR to individualize MICE or HIIT prescription is feasible in CAD patients , and could lead them closer to THR objective , to similar improvements in walking performance , and greater peak VO2 increase for HIIT . Future r and omised studies should investigate long-term effects of programmes prescribed from walk tests HR , especially for HIIT modality PURPOSE To assess the 6-minute walk test ( 6MWT ) as a predictor of  radiation therapy-induced lung injury ( RTLI ) .  METHODS AND MATERIAL S The 6MWT is a simple , economical , and reproducible test that measures both how far a person can walk in 6 min and any associated changes in vital signs . As part of a prospect i ve trial to study RTLI , a pre-RT 6MWT was performed in 41 patients . The predictive capacities of pre-RT 6MWT , forced expiratory volume in 1 s ( FEV1 ) , and single-breath diffusing capacity for carbon monoxide ( DLCO ) for the development of RTLI were assessed with receiver operating curve ( ROC ) techniques . To evaluate the 6MWT , alone or with mean lung dose ( MLD ) of radiation , as a predictor of RTLI , the rates of RTLI in patient subgroups defined by 6MWT results were compared by using Fisher 's exact test . RESULTS Thirty-one patients with > or =3 months ' follow-up were evaluable . The median baseline 6MWT result was 1400 ft . Of 31 patients , 7 developed Grade > or = 2 RTLI . Of 15 patients with an MLD > 18 Gy ( the median ) , 5 developed RTLI , compared with 2 of 16 with MLD < or = 18 Gy ( p = 0.22 ) . Among those with an MLD < or = 18 Gy , the RTLI rates were 0 of 8 and 2 of 8 for 6MWT results > or = 1400 ft or < 1400 ft , respectively , p = 0.46 . The ROC area under the curve for individual metrics was as follows : FEV1 0.66 , MLD 0.70 , DLCO 0.61 , and 6MWT 0.47 . Combining FEV1 with 6MWT increased the ROC to 0.71 , suggesting that the ratio might be a better predictor than the individual values . Patients with a high 6MWT/FEV1 ratio had a lower rate of RTLI than those with a relatively low ratio . CONCLUSIONS The 6MWT might provide prognostic information beyond pulmonary function tests and dosimetric parameters in predicting RTLI . Additional work is needed to better assess the utility of these functional metrics Background —The six-minute walk test ( 6MWT ) and cardiopulmonary exercise testing ( CPET ) are the 2 testing modalities most broadly used for assessing functional limitation in patients with heart failure ( HF ) . A comprehensive comparison on clinical and prognostic validity of the 2 techniques has not been performed and is the aim of the present investigation . Methods and Results —Two hundred fifty-three patients diagnosed with systolic ( n=211 ) or diastolic ( n=42 ) HF ( age : 61.9±10.1 years ; New York Heart Association Class : 2.2±0.78 ) underwent a 6MWT and a symptom-limited CPET evaluation and were prospect ively followed up . During the 4-year tracking period , there were 43 cardiac-related deaths with an annual cardiac mortality rate of 8.7 % . The 6MWT distance correlated with CPET-derived variables ( ie , peak Vo2 , Vo2 at anaerobic threshold , and Ve/Vco2 slope ) and was significantly reduced in proportion with lower peak Vo2 and higher Ve/Vco2 slope classes and presence of an exercise oscillatory breathing ( EOB ) pattern ( P<0.01 ) . However , no significant differences were observed in distance covered between survivors and nonsurvivors ( 353.2±95.8 m versus 338.5±76.4 m ; P = NS ) . At univariate and multivariate Cox proportional analyses , the association of the 6MWT distance with survival was not significant either as a continuous or dicotomized variable ( ≤300 m ) . Conversely , CPET-derived variables emerged as prognostic with the strongest association found for EOB ( systolic HF ) and Ve/Vco2 slope ( entire population with HF and patients with a 6MWT≤300 m ) . Conclusions —The 6MWT is confirmed to be a simple and reliable first-line test for quantification of exercise intolerance in patients with HF . However , there is no supportive evidence for its use as a prognostic marker in alternative to or in conjunction with CPET-derived variables 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 PURPOSE The purpose of this study was to use an accelerometer to measure daily walking  performance in patients with chronic heart failure ( CHF ) to investigate if this parameter is a determinant of New York Heart Association class and indicative of maximal and functional exercise capacity . METHODS Fifty patients with CHF were instructed to wear an accelerometer for 7 consecutive days while going about their daily business . Maximal and functional exercise capacity was assessed by cardiopulmonary ( VO(2peak ) ) and 6-minute walk testing , respectively . RESULTS Patients in New York Heart Association I , II , and III reached an average total walking time ( TWT ) of 160.6 + /- 35.8 minutes , 133.9 + /- 59.0 minutes , and 76.1 + /- 22.5 minutes per day of which 19 % , 19 % , and 9 % where spent in the fast walking mode ( > 83 m/minute ) , respectively . The TWT correlated strongly with VO(2peak ) ( r = 0.72 ; P < .001 ) and 6-minute walk testing distance ( r = 0.68 ; P < .001 ) . The TWT and time spent in fast walking mode were the strongest determinants in discriminating moderate CHF . CONCLUSION Daily walking performance is a clear determinant of maximal and functional exercise capacities in patients with CHF .  Walking intensity in particular is an independent predictor in discriminating patients with advanced heart failure . Monitoring of daily walking performance might aid in detecting disease progression and improve clinical outcome The six-minute walking test ( WT ) is used in trials and clinical practice as an easy tool to evaluate the functional capacity of chronic heart failure ( CHF ) patients . As WT measurements are highly variable both between and within individuals , this study aims at assessing the contribution of the different sources of variation and estimating the reproducibility of the test . A statistical model describing WT measurements as a function of fixed and r and om effects is proposed and its parameters estimated . We considered 202 stable CHF patients who performed two baseline WTs separated by a 30 minute rest ;  49 of them repeated the two tests 3 months later ( follow-up control ) . They had no changes in therapy or major clinical events . Another 31 subjects performed two baseline tests separated by 24 hours . Collected data were analysed using a mixed model methodology . There was no significant difference between measurements taken 30 minutes and 24 hours apart ( p = 0.99 ) . A trend effect of 17 ( 1.4 ) m ( mean ( SE ) ) was consistently found between duplicate tests ( p < 0.001 ) . REML estimates of variance components were : 5189 ( 674 ) for subject differences in the error-free value ; 1280 ( 304 ) for subject differences in spontaneous clinical evolution between baseline and follow-up control , and 266 ( 23 ) for the within-subject error . Hence , the st and ard error of measurement was 16.3 m , namely 4 per cent of the average WT performance ( 403 m ) in this sample . The intraclass correlation coefficient was 0.96 . We conclude that WT measurements are characterized by good intrasubject reproducibility and excellent reliability . When follow-up studies > or = 3 months are performed , unpredictable changes in individual walking performance due to spontaneous clinical evolution are to be expected . Their clinical significance , however , is not known This study investigated the use of an incremental , externally-paced 10 m shuttle walk test ( SWT ) as an objective , reliable and predictive test of functional capacity in patients with heart failure ( CHF ) . The SWT was compared to a 6 minute walk test ( 6WT ) and a maximal symptom-limited treadmill peak oxygen consumption ( VO2peak ) test . Experiment 1 examined the reproducibility of the SWT . Two SWF trials were performed and distance ambulated ( DA ) , heart rate ( HR ) and  rate of perceived exertion ( RPE ) results compared . In experiment 2 , SWT , 6WT , and VO2 peak tests were performed and HR . RPE and ambulatory VO2 compared . The SWT demonstrated strong test/retest reliability for DA ( r = 0.98 ) . HR ( r = 0.96 ) and RPE ( r = 0.89 ) . Treadmill VO2 peak was significantly correlated with DA during the SWT ( r = 0.83 , P < 0.05 ) , but not the 6WT . SWT peak VO2 ( 18.5 + /- 1.8 ml.kg(-1 ) x min(-1 ) ) and treadmill VO2 peak ( 18.3 + /-2.0 ml.kg(-1 ) x min(-1 ) ) were also highly correlated ( r = 0.78 , P < 0.05 ) . Conversely , 6WT peak VO2 and treadmill VO2 peak were not significantly correlated . This study suggests the SWT is a reliable , objective test , highly predictive of VO2 peak which may be a more optimal field exercise test than the self paced 6WT 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 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
Pharmacological trials including patients with more severe heart failure were more likely to show a significant improvement with therapy than trials of milder heart failure .
Using mean values in these trials , the age of patients appeared a more important determinant of 6MWT distance than New York Heart Association classification .
The 6MWT has not yet been proven to be a robust test for the identification of effective pharmacological interventions although it appears useful for the assessment of cardiac resynchronization therapy .
The results of the 6MWT were concordant with changes in symptoms , suggesting that it may be used as supportive evidence for symptom benefit .
AIMS The 6 min walk test ( 6MWT ) is commonly used in clinical trials to assess treatments for heart failure , but its ability to distinguish between effective and ineffective treatments is question able .
The aim of this study is to investigate , using a systematic literature review , the utility of the 6MWT as a measure of the effectiveness of treatment in r and omized controlled trials of heart failure .