The endurance shuttle walk test: An alternative to the six-minute walk test for the assessment of ambulatory oxygen Shuttle Walking Test and 6-Minute Walking Test Induce a Similar Cardiorespiratory Performance in Patients Recovering from an Acute Exacerbation of Chronic Obstructive Pulmonary Disease Endurance shuttle walking test: responsiveness to salmeterol in COPD Changes in the endurance shuttle walk test in COPD patients with chronic respiratory failure after pulmonary rehabilitation: the minimal important difference obtained with anchor- and distribution-based method Which field walking test should be used to assess functional exercise capacity in lung cancer? an observational study Prescription of Walking Exercise Intensity from the Incremental Shuttle Walk Test in People with Chronic Obstructive Pulmonary Disease Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. Validity and reliability of the modified shuttle walk test in patients with chronic obstructive pulmonary disease. Detecting oxygen desaturation in patients with COPD: incremental versus endurance shuttle walking. Comparison of hallway and treadmill six-minute walk tests. Evaluating physical capacity in patients with chronic obstructive pulmonary disease: comparing the shuttle walk test with the encouraged 6-minute walk test. Lack of Specificity of the 6-Minute Walk Test as an Outcome Measure for Patients with Systemic Sclerosis Relationship between field walking tests and incremental cycle ergometry in COPD. A comparison of the shuttle and 6 minute walking tests with measured peak oxygen consumption in patients with heart failure. Six-minute walking versus shuttle walking: responsiveness to bronchodilation in chronic obstructive pulmonary disease Physiological responses to the 6-min walk test in patients with chronic obstructive pulmonary disease Validation and comparison of reference equations for the 6-min walk distance test
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 Background : The incremental shuttle walking test ( SWT ) has recently been proposed as a more valid and reproducible alternative to the conventional 6-min walking test ( 6MWT ) in the evaluation of exercise tolerance in patients with chronic obstructive pulmonary disease ( COPD ) . Objective : To compare the cardiorespiratory performance obtained during two sessions of SWT with that obtained during two sessions of 6MWT . Methods : We examined 18 patients ( forced expiratory volume in 1 s : 48 ± 14 % ) recovering from an acute exacerbation of COPD that had required hospitalization . In the same afternoon , each patient performed two SWT and two 6MWT , with an interval of at least 30 min between each test ; the sequence of the tests was r and omized . Results : Mean walking distance was greater in the second SWT test than in the first SWT . The changes from baseline in systolic blood pressure , heart rate , respiratory rate , oxygen saturation and dyspnea Borg index at the end of the test were similar between the two 6MWT and the two SWT . There was a highly significant correlation between walking distances measured during SWT and during 6MWT ( ρ : 0.85 , p < 0.0005 ) . Neither SWT nor 6MWT correlated with functional data of COPD . Conclusions : SWT , though being considered to be closer to a submaximal exercise test than 6MWT , does not induce a greater cardiorespiratory performance  than 6MWT in patients recovering from acute exacerbation of COPD 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 Background Although the endurance shuttle walk test ( ESWT ) has proven to be responsive to change in exercise capacity after pulmonary rehabilitation ( PR ) for COPD , the minimally important difference ( MID ) has not yet been established . We aim ed to establish the MID of the ESWT in patients with severe COPD and chronic hypercapnic respiratory failure following PR . Methods Data were derived from a r and omized controlled trial , investigating the value of noninvasive positive pressure ventilation added to PR . Fifty-five patients with stable COPD , GOLD stage IV , with chronic respiratory failure were included ( mean ( SD ) FEV1 31.1 ( 12.0 ) % pred , age 62 ( 9 ) y ) . MID estimates of the ESWT in seconds , percentage and meters change were calculated with anchor based and distribution based methods .  Six minute walking distance ( 6MWD ) , peak work rate on bicycle ergometry ( Wpeak ) and Chronic Respiratory Question naire ( CRQ ) were used as anchors and Cohen ’s effect size was used as distribution based method . Results The estimated MID of the ESWT with the different anchors ranged from 186–199 s , 76–82 % and 154–164 m. Using the distribution based method the MID was 144 s , 61 % and 137 m. Conclusions Estimates of the MID for the ESWT after PR showed only small differences using different anchors in patients with COPD and chronic respiratory failure . Therefore we recommend using a range of 186–199 s , 76–82 % or 154–164 m as MID of the ESWT in COPD patients with chronic respiratory failure . Further research in larger population s should eluci date whether this cut-off value is also valid in other COPD population s and with other interventions .Trial registration Clinical Trials . Gov ( ID NCT00135538 ) 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 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 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 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 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 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 OBJECTIVE To evaluate the applicability of the incremental ( shuttle ) walk test in patients with chronic obstructive pulmonary disease and compare the performance of those patients on the shuttle walk test to that of the same patients on the encouraged 6-minute walk test . METHODS A cross-sectional study was conducted , in which 24 patients with chronic obstructive pulmonary disease were selected . In r and om order , patients were , after an initial practice period , su bmi tted to a shuttle walk test and an encouraged 6-minute walk test . RESULTS The patients obtained a higher heart rate ( expressed as a percentage of that predicted based on gender and age ) on the encouraged 6-minute walk test ( 84.1 + /- 11.4 % ) than on the shuttle walk test ( 76.4 + /- 9.7 % ) ( p = 0.003 ) . The post-test sensation of dyspnea ( Borg scale ) was also higher on the encouraged 6-minute walk test . On average , the patients walked 307.0 + /- 89.3 meters on the shuttle walk test and 515.5 + /- 102.3 meters on the encouraged 6-minute walk test ( p < 0.001 ) . There was a good correlation between the two tests in terms of the distance walked ( r = 0.80 , p < 0.001 ) . CONCLUSION The shuttle walk test is simple and easy to implement in patients with chronic obstructive pulmonary disease . The encouraged 6-minute walk test produced higher post-test heart rate and greater post-test sensation of dyspnea than did the shuttle walk test 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 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 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 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 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 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
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
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 .