Repeat six-minute walk tests in patients with chronic heart failure: are they clinically necessary? Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. 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 Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure. [Reference Equations for the 6-Minute Walk Test in Healthy Individuals.] 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. Which field walking test should be used to assess functional exercise capacity in lung cancer? an observational study Impaired 6-min walk test, heart rate recovery and cardiac function post pulmonary embolism in long-term survivors. Validity and reliability of the modified shuttle walk test in patients with chronic obstructive pulmonary disease. Six-minute walk test versus two-minute walk test in children with Duchenne muscular dystrophy: Is more time more information? Six-Minute Walk Test and Cardiopulmonary Exercise Testing in Patients With Chronic Heart Failure: A Comparative Analysis on Clinical and Prognostic Insights The minimal important difference in the 6-minute walk test for patients with pulmonary arterial hypertension. Reproducibility and responsiveness of quality of life assessment and six minute walk test in elderly heart failure patients Prognostic value of 6-minute walk test in stable outpatients with heart failure. The endurance shuttle walk test: An alternative to the six-minute walk test for the assessment of ambulatory oxygen
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 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 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 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 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 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 Background There is emerging evidence regarding the efficacy of exercise training to improve exercise capacity for individuals with non-small cell lung cancer ( NSCLC ) .  Cardiopulmonary exercise testing ( CPET ) is the gold st and ard measure of exercise capacity ; however this laboratory test has limitations for use in research and clinical practice . Alternative field walking tests are the six-minute walk test ( 6MWT ) , incremental-shuttle walk test ( ISWT ) and endurance-shuttle walk test ( ESWT ) ; however there is limited information about their clinimetric properties in NSCLC . Aims : In NSCLC to determine the 1 ) criterion validity of the 6MWT , ISWT and ESWT against CPET ; 2 ) construct validity of the 6MWT , ISWT and ESWT against measures of function , strength , respiratory function and health-related quality of life ( HRQoL ) ; and 3 ) clinical applicability of the tests . Methods Twenty participants ( 40 % male , mean ± SD age 66.1 ± 6.5 years ) with stage I-IIIb NSCLC completed the 6MWT , ISWT , ESWT and CPET within six months of treatment . Testing order was r and omised . Additional measures included Eastern Cooperative Oncology Group Performance-Status ( ECOG-PS , function ) , respiratory function , h and -grip dynamometry and HRQoL. Correlations and regression analyses were used to assess relationships . Results The ISWT demonstrated criterion validity with a moderate relationship between ISWT distance and CPET peak oxygen consumption ( r = 0.61 , p = 0.007 ) . Relationships between CPET and six minute walk distance ( 6MWD ) ( r = 0.24 , p = 0.329 ) or ESWT time ( r = 0.02 , p = 0.942 ) were poor . Moderate construct validity existed for the 6MWD and respiratory function ( forced vital capacity % predicted r = 0.53 , p = 0.019 ; forced expiratory volume in the first second % predicted r = 0.55 , p = 0.015 ) . There were no relationships between the walking tests and measures of function , strength or HRQoL. The ESWT had a ceiling effect with 18 % reaching maximum time . No floor effects were seen in the tests . The mean ± SD time required to perform the individual 6MWT , ISWT and ESWT was 12.8 ± 2.5 , 14.7 ± 3.7 and 16.3 ± 5.0 min respectively ; in comparison to CPET which was 51.2 ± 12.7 min . Only one assessor was required to perform all field walking tests and no adverse events occurred . Conclusions The ISWT is a promising measure of functional exercise capacity in lung cancer . Findings need to be confirmed in a larger sample prior to translation into practice BACKGROUND The functional capacity of long-term survivors of submassive pulmonary embolism ( PE ) is unreported . A six-minute walk distance ( 6MWD ) < 350 m and reduced heart rate recovery ( HRR ) indicate adverse prognosis in various chronic diseases . METHODS Long-term survivors of acute PE ( January 2000-June 2005 ) were invited to undergo prospect ively planned six-minute walk test ( 6MWT ) , transthoracic echocardiogram ( TTE ) , clinical and biochemical evaluation with cardiac biomarkers .  HRR was calculated as the difference between heart rate at 6-min during and at 1-min post 6MWT . RESULTS 120 patients ( 52 males ; mean age [ ±st and ard deviation ] - 65 ± 14 years ) were identified 7.7 ± 1.4 years after PE . 6MWD was significantly lower than that predicted after adjustment for age , sex , and height ( 448 ± 114 m vs 475 ± 89 m , p = 0.005 ) , and 16 % ( 17/104 ) had 6MWD < 350 m. Among patients with no baseline comorbidities at follow-up ( Charlson comorbidity index = 0 ) , 8 % ( 4/52 ) had 6MWD < 350 m. Resting TTE identified 29 % of patients had raised right ventricular ( RV ) pulmonary pressure ( pulmonary arterial systolic pressure [ PASP ] > 36 mmHg ) and 13 % had impaired RV function . Patients with 6MWD < 85 % predicted had significantly greater impairment of RV longitudinal function ( p < 0.001 ) , higher PASP ( p < 0.001 ) and pulmonary vascular resistance ( p < 0.001 ) , elevated NT-proBNP ( p = 0.03 ) and high-sensitivity troponin-T ( HsTropT , p = 0.03 ) , but similar left ventricular systolic and diastolic function , to those with normal 6MWT . CONCLUSIONS Apparently well , long-term survivors of PE demonstrate impaired exercise capacity , heart rate recovery , mild pulmonary hypertension , raised PVR and right ventricular dysfunction associated with elevated NT-proBNP and 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 BACKGROUND / PURPOSE The six minute walk test is a widely accepted primary outcome parameter in most studies in Duchenne muscular dystrophy ( DMD ) . To compare information obtained by the six minute walk distance ( 6MWD ) test and the two minute walk distance ( 2MWD ) in patients with DMD , a cohort of 13 voluntary DMD boys did a repeated six minute walking test . METHODS Patients had to be ambulatory with a physical disability according to Levels 1 - 3 on the Vignos-Scale for lower extremity . Measurements were taken at one minute intervals . Reliability was measured by intraclass correlation . RESULTS Test-retest reliability for 6MWD and 2MWD in two different age classes was very good for both subgroups . Test-retest-reliability was lower in patients with more advanced disability in both tests . Walking speed remained completely stable from time points 1 - 6 minutes in the whole study patient collective , which indicates that physical exhaustion is not reached after six minutes even in more disabled patients . CONCLUSION Thus the 6MWD in DMD patients does not give additional information as compared to a 2MWD 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 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 Objective To examine the reproducibility and responsiveness to change of a six minute walk test and a quality of life measure in elderly patients with heart failure . Design Longitudinal within patient study . Subjects 60 patients with heart failure ( mean age 82 years ) attending a geriatric outpatient clinic , 45 of whom underwent a repeat assessment three to eight weeks later . Main outcome measures Subjects underwent a st and ardised six minute walk test and completed the chronic heart failure question naire ( CHQ ) , a heart failure specific quality of life question naire .  Intraclass correlation coefficients ( ICC ) were calculated using a r and om effects one way analysis of variance as a measure of reproducibility . Guyatt ’s responsiveness coefficient and effect sizes were calculated as measures of responsiveness to change . Results 24 patients reported no major change in cardiac status , while seven had deteriorated and 14 had improved between the two clinic visits . Reproducibility was satisfactory ( ICC > 0.75 ) for the six minute walk test , for the total CHQ score , and for the dyspnoea , fatigue , and emotion domains of the CHQ . Effect sizes for all measures were large ( > 0.8 ) , and responsiveness coefficients were very satisfactory ( > 0.7 ) . Effect sizes for detecting deterioration were greater than those for detecting improvement . Conclusions Quality of life assessment and a six minute walk test are reproducible and responsive measures of cardiac status in frail , very elderly patients with heart failure The study was design ed to evaluate the prognostic value of the 6-minute walk test in stable out patients with heart failure . We prospect ively studied 43 patients ( 6 women and 37 men ) who had chronic heart failure secondary to ischemic heart disease or idiopathic cardiomyopathy . All patients had left ventricular systolic dysfunction ( ejection fraction , < or = 0.40 ) , and they were in stable New York Heart Association functional class II or III heart failure . All patients were evaluated by M-mode and 2-dimensional echocardiography . At the outset , walking distances of all the patients were evaluated by the 6-minute walk test . The patients were divided into 2 groups : Group I , patients with a 6-minute walk test distance of < or = 300 m ; and Group II , patients with a 6-minute walk test distance of > 300 m. The patients were then monitored for a period of 2 years in regard to cardiac death . The mortality rate was significantly higher in patients with a 6-minute walk test distance of < or = 300 m than in patients with a 6-minute walk test distance of > 300 m ( 79 % vs 7 % ; P < 0.001 ) . The death risk was found to be significantly higher in patients with a distance of < or = 300 m ( P=0.005 ) . The death risk was also higher in patients whose left ventricular ejection fraction was < or = 0.30 ( P=0.02 ) . We conclude that a 6-minute walk test distance of < or = 300 m is a simple and useful prognostic marker of subsequent cardiac death in patients with mild-to-moderate heart failure 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
Comparison of the studies investigating reliability shows that the 6MWT has good reproducibility .
The 6MWT demonstrates moderate correlation with peak VO(2 ) levels , and ability to predict VO(2 ) ( functional capacity ) dependent on distance walked .
Cut-off distances vary from 300 to 490 meters depending on the study ; if total distance walked remains equal or less than these values , the 6MWT retains its strong predictive value .
The 6MWT has good reliability , moderate validity , and a significant ability to predict functional capacity in patients with CHF who do not walk greater than 490 meters
PURPOSE To evaluate the reliability and validity of the six-minute walk test ( 6MWT ) with respect to its ability to predict functional capacity in patients with chronic heart failure .