human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background In patients with COPD , both laboratory exercise tests and field walking tests are used to assess physical performance . In laboratory tests , peak exercise capacity in watts ( W peak ) and /or peak oxygen uptake ( VO2 peak ) are assessed , whereas the performance on walking tests usually is expressed as distance walked . The aim of the study was to investigate the relationship between an incremental shuttle walking test ( ISWT ) and two laboratory cycle tests in order to assess whether W peak could be estimated from an ISWT . Methods Ninety-three patients with moderate or severe COPD performed an ISWT , an incremental cycle test ( ICT ) to measure W peak and a semi-steady-state cycle test with breath-by-breath gas exchange analysis ( CPET ) to measure VO2 peak . Routine equations for conversion between cycle tests were used to estimate W peak from measured VO2 peak ( CPET ) . Conversion equation for estimation of W peak from ISWT was found by univariate regression . Results There was a significant correlation between W peak and distance walked on ISWT × body weight ( r = 0.88 , p < 0.0001 ) . The agreement between W peak measured by ICT and estimated from ISWT was similar to the agreement between measured W peak ( ICT ) and W peak estimated from measured VO2 peak by CPET . Conclusion Peak exercise capacity measured by an incremental cycle test could be estimated from an ISWT with similar accuracy as when estimated from peak oxygen uptake in patients with COPD Background : Ambulatory oxygen is frequently prescribed for patients with chronic obstructive pulmonary disease ( COPD ) who have oxygen desaturation ≤88 % during exercise . The 6-min walk test ( 6MWT ) with continuous pulse oximetry monitoring is a common method to document this oxygen desaturation , but the reproducibility of this test in determining the need for ambulatory oxygen in patients with COPD is not well documented . Objective : The aim of this study was to establish the reproducibility of the 6MWT in determining the need for ambulatory oxygen prescription in stable COPD patients using the Centers for Medicare and Medicaid ( CMS ) criteria for ambulatory oxygen prescription . Methods : The study was design ed as a prospect i ve observational study in an academic health center and associated pulmonary rehabilitation program . Eighty-eight COPD patients referred to pulmonary rehabilitation underwent continuous pulse oximetry while performing st and ard 6MWT on 3 separate days . Results : Fifty-one ( 58 % ) of these patients desaturated by continuous pulse oximetry to an SpO2 ≤88 % on a least one of the 6MWTs . Only 26 patients ( 30 % ) demonstrated consistency in meeting the criteria for ambulatory oxygen set forth by the CMS on all three 6MWT with a κ statistic of 0.62 . The percent agreement between 6MWTs for ambulatory oxygen prescription was 72 % and the paired observation was 51 % . Conclusions : The 6MWT distance is simple and widely used as a consistent measure of functional capacity in patients with COPD ; however , the 6MWT oxygen saturation has only modest reproducibility in determining the need for ambulatory oxygen in stable COPD patients undergoing pulmonary rehabilitation Respiratory rehabilitation improves exercise capacity and quality of life in younger patients but is untried in the aged . We aim ed to : ( a ) assess repeatability of the 6-minute walk test , factors affecting it and its relation to quality of life in elderly patients with chronic obstructive airways disease ( COAD ) ; ( b ) assess compliance of such patients with an intensive respiratory rehabilitation protocol ; ( c ) pilot the assessment of the effect of respiratory rehabilitation on the 6-minute walk test in these patients . Seventeen subjects with stable , symptomatic COAD were recruited , 15 ( six men ) , 70 - 89 ( mean 76 ) years , completed the study . Mean ( st and ard deviation ) 1-second forced expiratory volume ( FEV1 ) = 49 (5)% predicted . Six-minute walk tests were repeated single-blind , 2 - 10 days apart . Quality of life was measured using Guyatt respiratory question naire . Patients underwent 12 weeks incremental respiratory rehabilitation ( x4/day step-ups , unweighed arm raises , inflating balloons ) . Baseline 6-minute walk was repeatable and was correlated with the log Guyatt dyspnoea score ( r = 0.65 , p = 0.006 ) . In multiple regression neither age nor FEV1 predicted walk distance : body mass index , maximal expiratory mouth pressure ; calorie intake . Mean ( SEM ) 6-minute walk distance after-rehabilitation was greater than baseline ( p = 0.003 ) . Elderly patients with COAD tolerate intensive respiratory rehabilitation and a controlled , blinded study is needed BACKGROUND The protocol used for the 6-min walk test ( 6MWT ) influences its results . The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks . Agreement between the distances measured on different tracks could not be examined . We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks . METHODS In a prospect i ve , r and omized , cross-over study , 27 COPD subjects ( FEV(1 ) , 38 + /- 14 % [ mean + /- SD ] ; 15 men ) attended three separate test sessions , completing six 6MWTs . To familiarize all subjects with both tracks , the first two sessions comprised two 6MWTs on either a circular or straight track . During the final session , each subject was tested once on the straight and once on the circular track . RESULTS The distance walked on the circular track exceeded the straight track by 13 + /- 17 m ( p < 0.001 ) . The limit of agreement between tracks was 33 m. Coefficient of repeatability values when the test was completed on different days for the straight and circular tracks were 51 m and 65 m , respectively . CONCLUSIONS When evaluating changes in 6-min walk distance in groups of patients , track layout should be st and ardized . However , the effect of modifying track layout on an individual 's walking distance is small compared to their daily variability in walk distance . Therefore , st and ardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days Background : The responsiveness of the endurance shuttle walk to functional changes following bronchodilation has recently been reported . The current literature suggests that the 6 min walking test ( 6MWT ) is less responsive to bronchodilation than the endurance shuttle walk . Aim : To compare bronchodilator-induced changes in exercise performance with the 6MWT and the endurance shuttle walk . Methods : In a r and omised , double-blind , placebo-controlled , crossover trial , 14 patients with chronic obstructive pulmonary disease ( forced expiratory volume in 1 s ( FEV1 ) 50 (8)% predicted ) completed two 6MWTs and two endurance shuttle walks , each preceded by nebulised placebo or 500 μg ipratropium bromide .  Cardiorespiratory parameters were monitored during each walking test with a portable telemetric gas analyser . Quadriceps twitch force was measured by magnetic stimulation of the femoral nerve before and after each walking test . Results : The 6 min walking distance did not change significantly after bronchodilation despite a significant increase in FEV1 of 0.18 ( 0.09 ) litres ( p<0.001 ) . A similar change in FEV1 ( 0.18 ( 0.12 ) litres , p<0.001 ) was associated with a significant improvement in the distance walked on the endurance shuttle walk ( Δdistance ipratropium bromide – placebo = 144 ( 219 ) m , p = 0.03 ) . Quadriceps muscle fatigue was infrequent ( < 15 % of patients ) after both walking tests . Conclusion : The endurance shuttle walk is more responsive than the 6MWT for detecting changes in exercise performance following bronchodilation 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 BACKGROUND Previous studies have shown positive effects from noninvasive ventilation ( NIV ) or supplemental oxygen on exercise capacity in patients with COPD . However , the best adjunct for promoting physiologic adaptations to physical training in patients with severe COPD remains to be investigated . METHODS Twenty-eight patients ( mean + /- SD age 68 + /- 7 y ) with stable COPD ( FEV(1 ) 34 + /- 9 % of predicted ) undergoing an exercise training program were r and omized to either NIV ( n = 14 ) or supplemental oxygen ( n = 14 ) during group training to maintain peripheral oxygen saturation ( S(pO2 ) ) > /= 90 % . Physical training consisted of treadmill walking ( at 70 % of maximal speed ) 3 times a week , for 6 weeks . Patients were assessed at baseline and after 6 weeks . Assessment s included physiological adaptations during incremental exercise testing ( ratio of lactate concentration to walk speed , oxygen uptake [ V ( O2 ) ] , and dyspnea ) , exercise tolerance during 6-min walk test , leg fatigue , maximum inspiratory pressure , and health-related quality of life . RESULTS Two patients in each group dropped out due to COPD exacerbations and lack of exercise program adherence , and 24 completed the training program . Both groups improved 6-min walk distance , symptoms , and health-related quality of life . However , there were significant differences between the NIV and supplemental-oxygen groups in lactate/speed ratio ( 33 % vs -4 % ) , maximum inspiratory pressure ( 80 % vs 23 % ) , 6-min walk distance ( 122 m vs 47 m ) , and leg fatigue ( 25 % vs 11 % ) . In addition , changes in S(pO2)/speed , V ( O2 ) , and dyspnea were greater with NIV than with supplemental-oxygen . CONCLUSIONS NIV alone is better than supplemental oxygen alone in promoting beneficial physiologic adaptations to physical exercise in patients with severe COPD The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease ( COPD ) patients . Sixteen COPD patients ( 66 + /- 7 years ) were r and omly assigned to L-carnitine ( CG ) or placebo group ( PG ) that received either L-carnitine or saline solution ( 2 g/day , orally ) for 6 weeks ( forced expiratory volume on first second was 38 + /- 16 and 36 + /- 12 % , respectively ) . Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions , with 3 sets of 10 loaded inspirations ( 40 % ) at maximal inspiratory pressure . Nutritional status , exercise tolerance on a treadmill and six-minute walking test , blood lactate , heart rate , blood pressure , and respiratory muscle strength were determined as baseline and on day 42 . Maximal capacity in the incremental exercise test was significantly improved in both groups ( P < 0.05 ) . Blood lactate , blood pressure , oxygen saturation , and heart rate at identical exercise levels were lower in CG after training ( P < 0.05 ) . Inspiratory muscle strength and walking test tolerance were significantly improved in both groups , but the gains of CG were significantly higher than those of PG ( 40 + /- 14 vs 14 + /- 5 cmH2O , and 87 + /- 30 vs 34 + /- 29 m , respectively ; P < 0.05 ) . Blood lactate concentration was significantly lower in CG than in PG ( 1.6 + /- 0.7 vs 2.3 + /- 0.7 mM , P < 0.05 ) . The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients , as well as reduce lactate production STUDY OBJECTIVE To determine whether exercise training with coaching is more effective than 
    Output:
    
agent
Good repeatability ( for the 6MWT and ESWT ) and reproducibility ( for the 6MWT , 12-minute walk test , ISWT , ESWT , and incremental cycle ergometer test ) were reported by most studies assessing these tests , providing patients were familiarized with them beforeh and .
The 6MWT , ISWT , and particularly the ESWT were reported to be sensitive to therapeutic intervention .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background In patients with COPD , both laboratory exercise tests and field walking tests are used to assess physical performance . In laboratory tests , peak exercise capacity in watts ( W peak ) and /or peak oxygen uptake ( VO2 peak ) are assessed , whereas the performance on walking tests usually is expressed as distance walked . The aim of the study was to investigate the relationship between an incremental shuttle walking test ( ISWT ) and two laboratory cycle tests in order to assess whether W peak could be estimated from an ISWT . Methods Ninety-three patients with moderate or severe COPD performed an ISWT , an incremental cycle test ( ICT ) to measure W peak and a semi-steady-state cycle test with breath-by-breath gas exchange analysis ( CPET ) to measure VO2 peak . Routine equations for conversion between cycle tests were used to estimate W peak from measured VO2 peak ( CPET ) . Conversion equation for estimation of W peak from ISWT was found by univariate regression . Results There was a significant correlation between W peak and distance walked on ISWT × body weight ( r = 0.88 , p < 0.0001 ) . The agreement between W peak measured by ICT and estimated from ISWT was similar to the agreement between measured W peak ( ICT ) and W peak estimated from measured VO2 peak by CPET . Conclusion Peak exercise capacity measured by an incremental cycle test could be estimated from an ISWT with similar accuracy as when estimated from peak oxygen uptake in patients with COPD Background : Ambulatory oxygen is frequently prescribed for patients with chronic obstructive pulmonary disease ( COPD ) who have oxygen desaturation ≤88 % during exercise . The 6-min walk test ( 6MWT ) with continuous pulse oximetry monitoring is a common method to document this oxygen desaturation , but the reproducibility of this test in determining the need for ambulatory oxygen in patients with COPD is not well documented . Objective : The aim of this study was to establish the reproducibility of the 6MWT in determining the need for ambulatory oxygen prescription in stable COPD patients using the Centers for Medicare and Medicaid ( CMS ) criteria for ambulatory oxygen prescription . Methods : The study was design ed as a prospect i ve observational study in an academic health center and associated pulmonary rehabilitation program . Eighty-eight COPD patients referred to pulmonary rehabilitation underwent continuous pulse oximetry while performing st and ard 6MWT on 3 separate days . Results : Fifty-one ( 58 % ) of these patients desaturated by continuous pulse oximetry to an SpO2 ≤88 % on a least one of the 6MWTs . Only 26 patients ( 30 % ) demonstrated consistency in meeting the criteria for ambulatory oxygen set forth by the CMS on all three 6MWT with a κ statistic of 0.62 . The percent agreement between 6MWTs for ambulatory oxygen prescription was 72 % and the paired observation was 51 % . Conclusions : The 6MWT distance is simple and widely used as a consistent measure of functional capacity in patients with COPD ; however , the 6MWT oxygen saturation has only modest reproducibility in determining the need for ambulatory oxygen in stable COPD patients undergoing pulmonary rehabilitation Respiratory rehabilitation improves exercise capacity and quality of life in younger patients but is untried in the aged . We aim ed to : ( a ) assess repeatability of the 6-minute walk test , factors affecting it and its relation to quality of life in elderly patients with chronic obstructive airways disease ( COAD ) ; ( b ) assess compliance of such patients with an intensive respiratory rehabilitation protocol ; ( c ) pilot the assessment of the effect of respiratory rehabilitation on the 6-minute walk test in these patients . Seventeen subjects with stable , symptomatic COAD were recruited , 15 ( six men ) , 70 - 89 ( mean 76 ) years , completed the study . Mean ( st and ard deviation ) 1-second forced expiratory volume ( FEV1 ) = 49 (5)% predicted . Six-minute walk tests were repeated single-blind , 2 - 10 days apart . Quality of life was measured using Guyatt respiratory question naire . Patients underwent 12 weeks incremental respiratory rehabilitation ( x4/day step-ups , unweighed arm raises , inflating balloons ) . Baseline 6-minute walk was repeatable and was correlated with the log Guyatt dyspnoea score ( r = 0.65 , p = 0.006 ) . In multiple regression neither age nor FEV1 predicted walk distance : body mass index , maximal expiratory mouth pressure ; calorie intake . Mean ( SEM ) 6-minute walk distance after-rehabilitation was greater than baseline ( p = 0.003 ) . Elderly patients with COAD tolerate intensive respiratory rehabilitation and a controlled , blinded study is needed BACKGROUND The protocol used for the 6-min walk test ( 6MWT ) influences its results . The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks . Agreement between the distances measured on different tracks could not be examined . We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks . METHODS In a prospect i ve , r and omized , cross-over study , 27 COPD subjects ( FEV(1 ) , 38 + /- 14 % [ mean + /- SD ] ; 15 men ) attended three separate test sessions , completing six 6MWTs . To familiarize all subjects with both tracks , the first two sessions comprised two 6MWTs on either a circular or straight track . During the final session , each subject was tested once on the straight and once on the circular track . RESULTS The distance walked on the circular track exceeded the straight track by 13 + /- 17 m ( p < 0.001 ) . The limit of agreement between tracks was 33 m. Coefficient of repeatability values when the test was completed on different days for the straight and circular tracks were 51 m and 65 m , respectively . CONCLUSIONS When evaluating changes in 6-min walk distance in groups of patients , track layout should be st and ardized . However , the effect of modifying track layout on an individual 's walking distance is small compared to their daily variability in walk distance . Therefore , st and ardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days Background : The responsiveness of the endurance shuttle walk to functional changes following bronchodilation has recently been reported . The current literature suggests that the 6 min walking test ( 6MWT ) is less responsive to bronchodilation than the endurance shuttle walk . Aim : To compare bronchodilator-induced changes in exercise performance with the 6MWT and the endurance shuttle walk . Methods : In a r and omised , double-blind , placebo-controlled , crossover trial , 14 patients with chronic obstructive pulmonary disease ( forced expiratory volume in 1 s ( FEV1 ) 50 (8)% predicted ) completed two 6MWTs and two endurance shuttle walks , each preceded by nebulised placebo or 500 μg ipratropium bromide .  Cardiorespiratory parameters were monitored during each walking test with a portable telemetric gas analyser . Quadriceps twitch force was measured by magnetic stimulation of the femoral nerve before and after each walking test . Results : The 6 min walking distance did not change significantly after bronchodilation despite a significant increase in FEV1 of 0.18 ( 0.09 ) litres ( p<0.001 ) . A similar change in FEV1 ( 0.18 ( 0.12 ) litres , p<0.001 ) was associated with a significant improvement in the distance walked on the endurance shuttle walk ( Δdistance ipratropium bromide – placebo = 144 ( 219 ) m , p = 0.03 ) . Quadriceps muscle fatigue was infrequent ( < 15 % of patients ) after both walking tests . Conclusion : The endurance shuttle walk is more responsive than the 6MWT for detecting changes in exercise performance following bronchodilation 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 BACKGROUND Previous studies have shown positive effects from noninvasive ventilation ( NIV ) or supplemental oxygen on exercise capacity in patients with COPD . However , the best adjunct for promoting physiologic adaptations to physical training in patients with severe COPD remains to be investigated . METHODS Twenty-eight patients ( mean + /- SD age 68 + /- 7 y ) with stable COPD ( FEV(1 ) 34 + /- 9 % of predicted ) undergoing an exercise training program were r and omized to either NIV ( n = 14 ) or supplemental oxygen ( n = 14 ) during group training to maintain peripheral oxygen saturation ( S(pO2 ) ) > /= 90 % . Physical training consisted of treadmill walking ( at 70 % of maximal speed ) 3 times a week , for 6 weeks . Patients were assessed at baseline and after 6 weeks . Assessment s included physiological adaptations during incremental exercise testing ( ratio of lactate concentration to walk speed , oxygen uptake [ V ( O2 ) ] , and dyspnea ) , exercise tolerance during 6-min walk test , leg fatigue , maximum inspiratory pressure , and health-related quality of life . RESULTS Two patients in each group dropped out due to COPD exacerbations and lack of exercise program adherence , and 24 completed the training program . Both groups improved 6-min walk distance , symptoms , and health-related quality of life . However , there were significant differences between the NIV and supplemental-oxygen groups in lactate/speed ratio ( 33 % vs -4 % ) , maximum inspiratory pressure ( 80 % vs 23 % ) , 6-min walk distance ( 122 m vs 47 m ) , and leg fatigue ( 25 % vs 11 % ) . In addition , changes in S(pO2)/speed , V ( O2 ) , and dyspnea were greater with NIV than with supplemental-oxygen . CONCLUSIONS NIV alone is better than supplemental oxygen alone in promoting beneficial physiologic adaptations to physical exercise in patients with severe COPD The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease ( COPD ) patients . Sixteen COPD patients ( 66 + /- 7 years ) were r and omly assigned to L-carnitine ( CG ) or placebo group ( PG ) that received either L-carnitine or saline solution ( 2 g/day , orally ) for 6 weeks ( forced expiratory volume on first second was 38 + /- 16 and 36 + /- 12 % , respectively ) . Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions , with 3 sets of 10 loaded inspirations ( 40 % ) at maximal inspiratory pressure . Nutritional status , exercise tolerance on a treadmill and six-minute walking test , blood lactate , heart rate , blood pressure , and respiratory muscle strength were determined as baseline and on day 42 . Maximal capacity in the incremental exercise test was significantly improved in both groups ( P < 0.05 ) . Blood lactate , blood pressure , oxygen saturation , and heart rate at identical exercise levels were lower in CG after training ( P < 0.05 ) . Inspiratory muscle strength and walking test tolerance were significantly improved in both groups , but the gains of CG were significantly higher than those of PG ( 40 + /- 14 vs 14 + /- 5 cmH2O , and 87 + /- 30 vs 34 + /- 29 m , respectively ; P < 0.05 ) . Blood lactate concentration was significantly lower in CG than in PG ( 1.6 + /- 0.7 vs 2.3 + /- 0.7 mM , P < 0.05 ) . The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients , as well as reduce lactate production STUDY OBJECTIVE To determine whether exercise training with coaching is more effective than 
    Output:
    