[Reference Equations for the 6-Minute Walk Test in Healthy Individuals.] Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. Regression equations to predict 6-minute walk distance in middle-aged and elderly adults Lack of Specificity of the 6-Minute Walk Test as an Outcome Measure for Patients with Systemic Sclerosis Course length of 30 metres versus 10 metres has a significant influence on six-minute walk distance in patients with COPD: an experimental crossover study. Which field walking test should be used to assess functional exercise capacity in lung cancer? an observational study Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease. Six-minute walking test and the assessment of cardiorespiratory responses during weight-loss programmes in obese children.
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 RATIONALE The 6-minute-walk test ( 6MWT ) is a practical and clinical ly meaningful measure of exercise tolerance with favorable performance characteristics in various cardiac and pulmonary diseases . Performance characteristics in patients with idiopathic pulmonary fibrosis ( IPF ) have not been systematic ally evaluated . OBJECTIVES To assess the reliability , validity , and responsiveness of the 6MWT and estimate the minimal clinical ly important difference ( MCID ) in patients with IPF . METHODS The study population included all subjects completing a 6MWT in a clinical trial evaluating interferon gamma-1b ( n = 822 ) .  Six-minute walk distance ( 6MWD )  and other parameters were measured at baseline and at 24-week intervals using a st and ardized protocol . Parametric and distribution-independent correlation coefficients were used to assess the strength of the relationships between 6MWD and measures of pulmonary function , dyspnea , and health-related quality of life . Both distribution-based and anchor-based methods were used to estimate the MCID . MEASUREMENTS AND MAIN RESULTS Comparison of two proximal measures of 6MWD ( mean interval , 24 d ) demonstrated good reliability ( coefficient = 0.83 ; P < 0.001 ) . 6MWD was weakly correlated with measures of physiologic function and health-related quality of life ; however , values were consistently and significantly lower for patients with the poorest functional status , suggesting good construct validity . Importantly , change in 6MWD was highly predictive of mortality ; a 24-week decline of greater than 50 m was associated with a fourfold increase in risk of death at 1 year ( hazard ratio , 4.27 ; 95 % confidence interval , 2.57- 7.10 ; P < 0.001 ) . The estimated MCID was 24 - 45 m. CONCLUSIONS The 6MWT is a reliable , valid , and responsive measure of disease status and a valid endpoint for clinical trials in IPF Six-minute walk distance ( 6MWD ) is commonly used as a measure of functional exercise capacity in clinical practice and research . Regression equations to predict 6MWD in healthy individuals are available , but the equations predict distances that vary considerably for an individual . The aims of this study were to 1 ) measure 6MWDs in healthy Caucasian Australians aged 45 - 85 years ; 2 ) determine whether evidence exists for Australian-specific prediction equations for Caucasian individuals by comparing measured 6MWDs with predicted 6MWDs derived by using published regression equations ; and 3 ) develop regression equations for males and females . One hundred nine subjects ( 48 males ) completed the 6-minute walk test ( 6MWT ) . Measurements of height , leg length , weight , habitual physical activity , and peak heart rate ( HR ) achieved during the 6MWT were obtained . 6MWD ( better of two tests ) was 682 ± 73 m ( mean ± SD ) and 643 ± 70 m in the males and females , respectively ( p<0.01 ) . Published regression equations underestimated 6MWDs in female subjects . Gender-specific regression equations using age and anthropometric data explained 40 % and 43 % of the variance in 6MWD in males and females , respectively . Validation of the regression equations in a prospect i ve subject cohort is required 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 QUESTIONS Do patients with chronic obstructive pulmonary disease ( COPD ) achieve a different distance on the six minute walk test ( 6MWT ) conducted on a 10 m course versus on a 30 m course ? When assessing the distance on a 6MWT conducted on a 10 m course , is it valid to use existing reference equations that were generated on longer courses ? DESIGN A r and omised double-crossover experimental study . PARTICIPANTS Forty-five patients with COPD in primary physiotherapy care . INTERVENTION All patients performed a 6MWT twice over a 10 m course and twice over a 30 m course . The 6MWTs were performed in accordance with the American Thoracic Society guidelines . OUTCOME MEASURES 6MWD was assessed and predicted distance was calculated based on a range of reference equations . RESULTS The 6MWD on the 10 m course was 49.5 m shorter than on the 30 m course , which was statistically significant ( 95 % CI 39.4 to 59.6 ) . By using existing reference equations for a 6MWT conducted on the 10 m course , the predicted distance is highly overestimated ( with a range of 30 % to 33 % ) and the average distance as a percentage of the predicted value is 8%pred lower compared to a 6MWT conducted on the 30 m course , result ing in a worse representation of a COPD patient 's functional exercise capacity . CONCLUSION This study shows that the impact of course length on the 6MWD and on the use of reference equations in patients with COPD is substantial and clinical ly relevant ( based on the most conservative published minimum clinical ly important difference ) . Therefore , existing reference equations established for a 6MWT conducted over a 30 m ( or longer ) course can not be applied to predict the distance achieved on the 6MWT on a 10 m course , which is frequently used in primary care physiotherapy practice s for patients with COPD 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 Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test ( 6MWT ) . To improve the utility of the 6MWT for patient and health care system management , the interpretation of the functional status measure in relation to death and hospitalization should be eluci date d. METHODS Three-year , prospect i ve , multicenter observational study to evaluate the predictive power of 6MWD for death or exacerbation-related hospitalization and to evaluate the factors that help determine 6MWD . RESULTS We measured 6MWD at baseline and annually in 2110 patients with clinical ly stable Global Initiative for Obstructive Lung Disease ( GOLD ) stage II-IV COPD and recorded exacerbation-related hospitalizations and all-cause mortality .  During the study , 200 patients died and 650 were hospitalized .  Using receiver operating characteristics , the best predictive thresholds of the 6MWD were 334 m for increased risk of death and 357 m for exacerbation-related hospitalization ( area under the curve 0.67 and 0.60 respectively ) ; however , the discriminatory thresholds , especially for mortality , were influenced by age . The mean ( SE ) 6MWD declined by 1.6 ( 1.2 ) m per year in GOLD II , 9.8 ( 1.3 ) m per year in GOLD III , and 8.5 ( 2.4 ) m per year in GOLD IV . CONCLUSION The 6MWD provides prognostic information that may be useful for identifying high-risk patients with COPD PURPOSE We assessed the exercise tolerance and cardiorespiratory responses during 2-month weight-loss programmes using the 6-minute walking test ( 6MWT ) in obese children . METHODS Twenty-eight male obese children were r and omly assigned to either a control group ( C ) , an energy restriction group ( R ) , an exercise training at maximum lipid-oxidation ( LIPOXmax ) group ( E ) , or an energy restriction/training group ( RE ) . The body composition , the submaximal incremental cycling exercise , and the 6MWT were performed before and after the 2-month programme . RESULTS . After the programme , RE group showed a significant improvement of body composition ( body weight reduced by 6.3 ± 1.5 kg , p < 0.01 ) , and an increase of 6-minute walking distance ( 6MWD ) ( + 13.7 % , p < 0.01 ) . Similarly , maximum oxygen uptake calculated according to the American College of Science Medicine guideline ( VO(2max ) ACSM ) and VO(2max ) predicted from 6MWD were respectively higher ( + 12.9 % and + 10.0 % , p < 0.01 ) than the R or E groups . Bl and -Altman analysis highlighted an agreement of these two methods of VO(2max ) measurement . Moreover , in all participants the 6MWD was significantly correlated with VO(2max ) ACSM and LIPOXmax ( r = 0.77 , p < 0.001 and r = 0.67 , p < 0.01 ; respectively ) before the programme as well as their changes in percentage over the programme ( r = 0.85 and r = 0.86 , p < 0.0001 ; respectively ) . CONCLUSIONS We concluded that a 2-month weight-loss programme including energy restriction and exercise training targeted at LIPOXmax improved body composition and cardiorespiratory tolerance in obese children . Furthermore , the 6MWT could be considered as a useful and reliable tool for the assessment and the follow-up of cardiorespiratory responses during weight-loss programme in obese children
The 6MWD is usually negatively associated with a higher Body Mass Index , increased cigarette consumption , higher doses of antipsychotic medication and lower physical self-worth in individuals with schizophrenia .
The 6MWT demonstrates high reliability .
IMPLICATION S FOR REHABILITATION The Six-Minute Walk Test reliably assesses the functional exercise capacity in patients with schizophrenia .
The impact of therapeutic interventions on patients , as measured by the 6MWT , can not be confirmed .
PURPOSE The six-minute walk test ( 6MWT ) is a sub-maximal exercise test measuring the distance that a patient can walk quickly in a period of 6 minutes ( 6MWD ) .
The objectives of this systematic review are to evaluate the 6MWT 's suitability for measuring the impact of an intervention , to compare the 6MWD walked by patients with schizophrenia with data for the general population or matched controls , to identify the determinants of 6MWD and to examine the measurement properties and quality procedures of the 6MWT .