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: Limited information is available regarding the physiological responses to different types of exercise training in patients with severe chronic obstructive pulmonary disease ( COPD ) . The aim of this study was two fold : firstly , to investigate the physiological response to training at 60 % of achieved peak load in patients with severe COPD ; and secondly to study the effects of interval ( I ) versus continuous ( C ) training in these patients . Twenty-one patients with COPD ( mean+/-SD forced expiratory volume in one second : 37+/-15 % of predicted , normoxaemic at rest ) were evaluated at baseline and after 8 weeks ' training . Patients were r and omly allocated to either I or C training . The training was performed on a cycle ergometer , 5 days a week , 30 min daily . The total work load was the same for both training programmes . C training result ed in a significant increase in oxygen consumption ( V'O2 ) ( 17 % , p<0.05 ) and a decrease in minute ventilation (V'E)/V'O2 ( p<0.01 ) and V'E/carbon dioxide production ( V'CO2 ) ( p<0.05 ) at peak exercise capacity , while no changes in these measures were observed after interval training . During submaximal exercise a significant decrease was observed in lactic acid production , being most pronounced in the C-trained group ( -31 % , p<0.01 versus -20 % , p<0.05 ) . Only in the I-trained group did a significant increase in peak work load ( 17 % , p<0.05 ) and a decrease in leg pain ( p<0.05 ) occur . Training did not result in a significant improvement in lung function , but maximal inspiratory mouth pressure increased in both groups by 10 % ( C : p<0.05 ) and 23 % ( I : p<0.01 ) . The present study shows a different physiological response pattern to interval or continuous training in chronic obstruction pulmonary disease , which might be a reflection of specific training effects in either oxidative or glycolytic muscle metabolic pathways . Further work is required to determine the role of the different exercise programmes and the particular category of patients for whom this might be beneficial Abstract Objective : The aim of this study was to investigate the effects of moderate continuous training ( MCT ) and high intensity aerobic interval training ( AIT ) on systolic ventricular function and aerobic capacity in COPD patients . Methods : Seventeen patients with COPD ( 64 ± 8 years , 12 men ) with FEV1 of 52.8 ± 11 % of predicted , were r and omly assigned to isocaloric programs of MCT at 70 % of max heart rate ( HR ) for 47 minutes ) or AIT ( ∼90 % of max HR for 4 × 4 minutes ) three times per week for 10 weeks . Baseline cardiac function was compared with 17 age- and sex-matched healthy individuals . Peak oxygen uptake ( VO2-peak ) and left ( LV ) and right ventricular ( RV ) function examined by echocardiography , were measured at baseline and after 10 weeks of training . Results : At baseline , the COPD patients had reduced systolic function compared to healthy controls ( p < 0.05 ) . After the training , AIT and MCT  increased VO2-peak by 8 % and 9 % and work economy by 7 % and 10 % , respectively ( all p < 0.05 ) . LV and RV systolic function both improved ( p < 0.05 ) , with no difference between the groups after the two modes of exercise training . Stroke volume increased by 17 % and 20 % , LV systolic tissue Doppler velocity ( S ’ ) by 18 % and 17 % and RV S ’ by 15 % after AIT and MCT , respectively ( p < 0.05 ) . Conclusion : Systolic cardiac function is reduced in COPD . Both AIT and MCT  improved systolic cardiac function . In contrast to other patient groups studied , higher exercise intensity does not seem to have additional effects on cardiac function or aerobic capacity in COPD patients Context Exercise training improves quality of life in patients with chronic obstructive pulmonary disease , but many of these patients can not tolerate continuous exercise . The effects of intermittent exercise are not known . Contribution The authors r and omly assigned 100 in patients with chronic obstructive pulmonary disease in a 3-week respiratory rehabilitation program to receive either high-intensity continuous exercise or high-intensity exercise alternating with low-intensity exercise ( interval exercise ) . After 5 weeks , the 2 groups had similar respiratory symptoms in daily activities and 6-minute walking distance , but the interval exercise group adhered better to the exercise protocol . Caution s The study focused on initiation of exercise and not on outpatient or home-based maintenance of exercise . Implication s For pulmonary rehabilitation , interval exercise is as effective as continuous high-intensity exercise and is better tolerated . The Editors Low exercise capacity is an important systemic manifestation of advanced chronic obstructive pulmonary disease ( COPD ) associated with poor health-related quality of life , exacerbations , and death ( 14 ) . Physical exercise , therefore , represents an important element of COPD management ( 5 , 6 ) . If performed under supervision during respiratory rehabilitation , exercise training improves health-related quality of life and may improve prognosis ( 79 ) . Dyspnea and leg fatigue limit the ability of patients with COPD to exercise , and patient response to exercise is highly variable ( 10 ) . It is challenging to find endurable exercise programs that are still effective . Current guidelines recommend endurance exercise at constant and high intensity ( 70 % of maximum exercise capacity ) ( 11 , 12 ) . For example , if a patient achieves 100 watts in an incremental exercise test , workload would be set at 70 watts for the entire exercise session of at least 20 minute 's duration . Strong evidence from r and omized trials shows that patients achieve clinical ly important improvements of health-related quality of life and exercise capacity with a continuous exercise protocol ( 1316 ) . However , patients with severe COPD are often unable to tolerate continuous exercise ( 17 ) , which can be frustrating for them and can limit their long-term adherence to exercise programs . Effective alternatives to continuous exercise are required to offer this important intervention to more patients with COPD . The American Thoracic Society and the European Respiratory Society state , on the basis of 2 r and omized trials ( 18 , 19 ) , that interval exercise may be an alternative . The benefits of interval exercise may be similar to those of continuous training , but this method is associated with less dyspnea ( 11 , 12 ) . Although studies indicated that interval exercise is well tolerated ( 1821 ) , evidence about its effectiveness relative to continuous exercise is inconclusive ; previous trials had method ological limitations and were small ( 22 ) . Because of perceived better tolerability of interval exercise , r and omized trials should be explicitly design ed to show that interval exercise is no less effective ( clinical noninferiority ) ( 22 ) . Thus , the aim of our trial was to assess whether interval exercise is no less effective than high-intensity continuous exercise in patients with severe COPD and whether patient tolerance of the interval exercise protocol is superior to that of continuous exercise . Methods Design Overview We conducted a r and omized , controlled noninferiority trial to compare the effects of interval exercise with those of high-intensity continuous exercise in patients with severe COPD . We previously described the detailed study protocol ( 23 ) and report this trial following the recommendations of the extended Consoli date d St and ards of Reporting Trials ( CONSORT ) statement for noninferiority and equivalence trials ( 24 ) . Setting The trial took place in a public rehabilitation clinic , Klinik Barmelweid , in Aargau , Switzerl and . The ethics committee of the Kantonsspital Aarau , Aargau , Switzerl and , approved the study protocol , and all study participants provided written informed consent . Participants We screened patients admitted to the respiratory medicine unit and included consecutive patients following inclusion criteria similar to those of previous respiratory rehabilitation trials ( 7 ) : COPD as defined by FEV1FVC ratio less than 70 % of predicted , FEV1 less than 50 % of predicted after bronchodilation corresponding to Global Initiative for Chronic Obstructive Lung Disease ( GOLD ) stage III to IV ( 5 ) , and German as first or daily language . Exclusion criteria included cardiovascular , musculoskeletal , or neurologic disorders that inhibited physical exercise or the performance of exercise tests ( 6 ) . We also excluded patients who had received a diagnosis of cancer ( excluding skin cancer ) within the past 2 years and were undergoing treatment . R and omization and Interventions A third party not involved in the execution of the trial ( DatInf GmbH , Tuebingen , Germany ) provided online central r and omization using a computerized minimization procedure , thereby ensuring concealment of r and omization ( 25 ) . Stratification variables were exercise capacity ( 6-minute walking distance < 300 or 300 meters ) , the presence of affective disorders ( Hospital Anxiety Depression Scale scores < or 8) , stability of pulmonary condition ( stable or exacerbation within the last 8 weeks ) , and the need for oxygen at rest ( Pao 2 < 55 mm Hg or 55 mm Hg ) . Patients followed an inpatient respiratory rehabilitation of approximately 3 week 's duration that included 12 to 15 exercise sessions . On weekdays , patients usually participated in 1 exercise session .  Twelve physical therapists worked with an approximately equal number of patients from both treatment groups . Apart from exercise , the rehabilitation program was identical for both groups and included breathing therapy , relaxation therapy , guided walking tours , and patient education ( 23 ) . At discharge , physiotherapists prescribed home-based exercise for each patient . Patients with cycle ergometers at home were instructed to exercise for at least 20 minutes per day . If no cycle ergometers were available , daily walking , swimming , or stair climbing was prescribed . High-Intensity Continuous Exercise Patients r and omly assigned to this intervention exercised on electromagnetically braked cycle ergometers ( Ergometrics 900S , Ergoline , Bitz , Germany ) with a target workload of 70 % or more of maximum exercise capacity ( Figure 1 ) . This exercise protocol has been used in earlier respiratory rehabilitation trials ( 7 ) . To determine maximum exercise capacity , patients pedaled unloaded for 3 minutes at 20 watts to warm up . Then , we used increments of 7.5 watts per minute until patients had to stop because of symptoms or cardiovascular stopping criteria . In each exercise session , patients completed a warm-up period of 2 minutes at 20 % of maximum exercise capacity , high-intensity exercise for 20 minutes , and a run-out phase of 2 minutes ( gradual decrease from 70 % to 0 % ) . If patients could not sustain the workload because of perceived dyspnea ( modified Borg [ 26 ] ratings > 5 on a scale from 0 to 10 ) or because heart rate exceeded safety limits , physical therapists let patients rest for 1 minute before continuing in the assigned phase . If patients had to rest more than twice per session , physical therapists lowered the workload by steps of 10 % of baseline maximum exercise capacity for the following exercise sessions . If workload was too low ( modified Borg ratings < 3 or patients or physical therapists considered the workload to be too low ) , physical therapists increased the workload by steps of 10 % of baseline maximum exercise capacity . Figure 1 . Exercise protocol s. Interval Exercise The target workload for this group was 50 % ( high-intensity intervals ) and 10 % ( low-intensity intervals ) of short-term maximum exercise capacity as determined by a steep ramp test ( 27 , 28 ) . The steep ramp test is an incremental cycle ergometer test in which patients pedal cycle ergometers unloaded for 2 minutes and then at increments of 25 watts every 10 seconds until they can not maintain a pedaling frequency above 50 pedals per minute or their heart rate exceeds the limit set by the normal incremental exercise test . We used the steep ramp test because workload for interval exercise can be underestimated if it is based on normal incremental exercise tests ( 28 ) . Fifty percent of short-term maximum exercise capacity corresponds , on average , to 90 % to 100 % of normal maximum exercise capacity ( 27 ) . We chose a workrecovery ratio of 1:2 that prevents high lactate accumulation and is well tolerated by patients ( 28 ) . In each session , patients had a warm-up period of 2 minutes at 10 % of the short-term maximum exercise capacity and then exercised for 20 minutes alternating between high-intensity intervals for 20 seconds and low-intensity intervals for 40 seconds ( Figure 1 ) . Patients also had a slowdown period of 2 minutes before completing the training session . We adjusted the exercise load for each patient individually if workload was too high or too low as described earlier ; physiotherapists lowered or increased the workload by steps of 10 % of short-term maximum exercise capacity , but the length of intervals remained constant ( 23 ) . Outcomes and Measurements Our primary outcome for effectiveness was the difference from baseline in Chronic Respiratory Question naire ( CRQ ) scores 5 weeks after r and omization as measured by the self-administered German- language version ( 29 , 30 ) with st and ardized dyspnea questions ( 31 ) . The CRQ is a widely used instrument in respiratory rehabilitation and measures dyspnea , fatigue , emotional functioning , and ability to cope with COPD ( 7 , 32 ) . Domain and total ( average of domains ) scores are presented on a Likert-type scale from 1 ( most severe impairment ) to 7 ( no impairment ) . We selected assessment at 5 weeks after r and omization as the primary outcome STUDY OBJECTIVES To compare the effect 
    Output:
    
agent
The effects of HIIT appear to be comparable to those of continuous exercise in relation to functional and cardiovascular responses .
***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: Limited information is available regarding the physiological responses to different types of exercise training in patients with severe chronic obstructive pulmonary disease ( COPD ) . The aim of this study was two fold : firstly , to investigate the physiological response to training at 60 % of achieved peak load in patients with severe COPD ; and secondly to study the effects of interval ( I ) versus continuous ( C ) training in these patients . Twenty-one patients with COPD ( mean+/-SD forced expiratory volume in one second : 37+/-15 % of predicted , normoxaemic at rest ) were evaluated at baseline and after 8 weeks ' training . Patients were r and omly allocated to either I or C training . The training was performed on a cycle ergometer , 5 days a week , 30 min daily . The total work load was the same for both training programmes . C training result ed in a significant increase in oxygen consumption ( V'O2 ) ( 17 % , p<0.05 ) and a decrease in minute ventilation (V'E)/V'O2 ( p<0.01 ) and V'E/carbon dioxide production ( V'CO2 ) ( p<0.05 ) at peak exercise capacity , while no changes in these measures were observed after interval training . During submaximal exercise a significant decrease was observed in lactic acid production , being most pronounced in the C-trained group ( -31 % , p<0.01 versus -20 % , p<0.05 ) . Only in the I-trained group did a significant increase in peak work load ( 17 % , p<0.05 ) and a decrease in leg pain ( p<0.05 ) occur . Training did not result in a significant improvement in lung function , but maximal inspiratory mouth pressure increased in both groups by 10 % ( C : p<0.05 ) and 23 % ( I : p<0.01 ) . The present study shows a different physiological response pattern to interval or continuous training in chronic obstruction pulmonary disease , which might be a reflection of specific training effects in either oxidative or glycolytic muscle metabolic pathways . Further work is required to determine the role of the different exercise programmes and the particular category of patients for whom this might be beneficial Abstract Objective : The aim of this study was to investigate the effects of moderate continuous training ( MCT ) and high intensity aerobic interval training ( AIT ) on systolic ventricular function and aerobic capacity in COPD patients . Methods : Seventeen patients with COPD ( 64 ± 8 years , 12 men ) with FEV1 of 52.8 ± 11 % of predicted , were r and omly assigned to isocaloric programs of MCT at 70 % of max heart rate ( HR ) for 47 minutes ) or AIT ( ∼90 % of max HR for 4 × 4 minutes ) three times per week for 10 weeks . Baseline cardiac function was compared with 17 age- and sex-matched healthy individuals . Peak oxygen uptake ( VO2-peak ) and left ( LV ) and right ventricular ( RV ) function examined by echocardiography , were measured at baseline and after 10 weeks of training . Results : At baseline , the COPD patients had reduced systolic function compared to healthy controls ( p < 0.05 ) . After the training , AIT and MCT  increased VO2-peak by 8 % and 9 % and work economy by 7 % and 10 % , respectively ( all p < 0.05 ) . LV and RV systolic function both improved ( p < 0.05 ) , with no difference between the groups after the two modes of exercise training . Stroke volume increased by 17 % and 20 % , LV systolic tissue Doppler velocity ( S ’ ) by 18 % and 17 % and RV S ’ by 15 % after AIT and MCT , respectively ( p < 0.05 ) . Conclusion : Systolic cardiac function is reduced in COPD . Both AIT and MCT  improved systolic cardiac function . In contrast to other patient groups studied , higher exercise intensity does not seem to have additional effects on cardiac function or aerobic capacity in COPD patients Context Exercise training improves quality of life in patients with chronic obstructive pulmonary disease , but many of these patients can not tolerate continuous exercise . The effects of intermittent exercise are not known . Contribution The authors r and omly assigned 100 in patients with chronic obstructive pulmonary disease in a 3-week respiratory rehabilitation program to receive either high-intensity continuous exercise or high-intensity exercise alternating with low-intensity exercise ( interval exercise ) . After 5 weeks , the 2 groups had similar respiratory symptoms in daily activities and 6-minute walking distance , but the interval exercise group adhered better to the exercise protocol . Caution s The study focused on initiation of exercise and not on outpatient or home-based maintenance of exercise . Implication s For pulmonary rehabilitation , interval exercise is as effective as continuous high-intensity exercise and is better tolerated . The Editors Low exercise capacity is an important systemic manifestation of advanced chronic obstructive pulmonary disease ( COPD ) associated with poor health-related quality of life , exacerbations , and death ( 14 ) . Physical exercise , therefore , represents an important element of COPD management ( 5 , 6 ) . If performed under supervision during respiratory rehabilitation , exercise training improves health-related quality of life and may improve prognosis ( 79 ) . Dyspnea and leg fatigue limit the ability of patients with COPD to exercise , and patient response to exercise is highly variable ( 10 ) . It is challenging to find endurable exercise programs that are still effective . Current guidelines recommend endurance exercise at constant and high intensity ( 70 % of maximum exercise capacity ) ( 11 , 12 ) . For example , if a patient achieves 100 watts in an incremental exercise test , workload would be set at 70 watts for the entire exercise session of at least 20 minute 's duration . Strong evidence from r and omized trials shows that patients achieve clinical ly important improvements of health-related quality of life and exercise capacity with a continuous exercise protocol ( 1316 ) . However , patients with severe COPD are often unable to tolerate continuous exercise ( 17 ) , which can be frustrating for them and can limit their long-term adherence to exercise programs . Effective alternatives to continuous exercise are required to offer this important intervention to more patients with COPD . The American Thoracic Society and the European Respiratory Society state , on the basis of 2 r and omized trials ( 18 , 19 ) , that interval exercise may be an alternative . The benefits of interval exercise may be similar to those of continuous training , but this method is associated with less dyspnea ( 11 , 12 ) . Although studies indicated that interval exercise is well tolerated ( 1821 ) , evidence about its effectiveness relative to continuous exercise is inconclusive ; previous trials had method ological limitations and were small ( 22 ) . Because of perceived better tolerability of interval exercise , r and omized trials should be explicitly design ed to show that interval exercise is no less effective ( clinical noninferiority ) ( 22 ) . Thus , the aim of our trial was to assess whether interval exercise is no less effective than high-intensity continuous exercise in patients with severe COPD and whether patient tolerance of the interval exercise protocol is superior to that of continuous exercise . Methods Design Overview We conducted a r and omized , controlled noninferiority trial to compare the effects of interval exercise with those of high-intensity continuous exercise in patients with severe COPD . We previously described the detailed study protocol ( 23 ) and report this trial following the recommendations of the extended Consoli date d St and ards of Reporting Trials ( CONSORT ) statement for noninferiority and equivalence trials ( 24 ) . Setting The trial took place in a public rehabilitation clinic , Klinik Barmelweid , in Aargau , Switzerl and . The ethics committee of the Kantonsspital Aarau , Aargau , Switzerl and , approved the study protocol , and all study participants provided written informed consent . Participants We screened patients admitted to the respiratory medicine unit and included consecutive patients following inclusion criteria similar to those of previous respiratory rehabilitation trials ( 7 ) : COPD as defined by FEV1FVC ratio less than 70 % of predicted , FEV1 less than 50 % of predicted after bronchodilation corresponding to Global Initiative for Chronic Obstructive Lung Disease ( GOLD ) stage III to IV ( 5 ) , and German as first or daily language . Exclusion criteria included cardiovascular , musculoskeletal , or neurologic disorders that inhibited physical exercise or the performance of exercise tests ( 6 ) . We also excluded patients who had received a diagnosis of cancer ( excluding skin cancer ) within the past 2 years and were undergoing treatment . R and omization and Interventions A third party not involved in the execution of the trial ( DatInf GmbH , Tuebingen , Germany ) provided online central r and omization using a computerized minimization procedure , thereby ensuring concealment of r and omization ( 25 ) . Stratification variables were exercise capacity ( 6-minute walking distance < 300 or 300 meters ) , the presence of affective disorders ( Hospital Anxiety Depression Scale scores < or 8) , stability of pulmonary condition ( stable or exacerbation within the last 8 weeks ) , and the need for oxygen at rest ( Pao 2 < 55 mm Hg or 55 mm Hg ) . Patients followed an inpatient respiratory rehabilitation of approximately 3 week 's duration that included 12 to 15 exercise sessions . On weekdays , patients usually participated in 1 exercise session .  Twelve physical therapists worked with an approximately equal number of patients from both treatment groups . Apart from exercise , the rehabilitation program was identical for both groups and included breathing therapy , relaxation therapy , guided walking tours , and patient education ( 23 ) . At discharge , physiotherapists prescribed home-based exercise for each patient . Patients with cycle ergometers at home were instructed to exercise for at least 20 minutes per day . If no cycle ergometers were available , daily walking , swimming , or stair climbing was prescribed . High-Intensity Continuous Exercise Patients r and omly assigned to this intervention exercised on electromagnetically braked cycle ergometers ( Ergometrics 900S , Ergoline , Bitz , Germany ) with a target workload of 70 % or more of maximum exercise capacity ( Figure 1 ) . This exercise protocol has been used in earlier respiratory rehabilitation trials ( 7 ) . To determine maximum exercise capacity , patients pedaled unloaded for 3 minutes at 20 watts to warm up . Then , we used increments of 7.5 watts per minute until patients had to stop because of symptoms or cardiovascular stopping criteria . In each exercise session , patients completed a warm-up period of 2 minutes at 20 % of maximum exercise capacity , high-intensity exercise for 20 minutes , and a run-out phase of 2 minutes ( gradual decrease from 70 % to 0 % ) . If patients could not sustain the workload because of perceived dyspnea ( modified Borg [ 26 ] ratings > 5 on a scale from 0 to 10 ) or because heart rate exceeded safety limits , physical therapists let patients rest for 1 minute before continuing in the assigned phase . If patients had to rest more than twice per session , physical therapists lowered the workload by steps of 10 % of baseline maximum exercise capacity for the following exercise sessions . If workload was too low ( modified Borg ratings < 3 or patients or physical therapists considered the workload to be too low ) , physical therapists increased the workload by steps of 10 % of baseline maximum exercise capacity . Figure 1 . Exercise protocol s. Interval Exercise The target workload for this group was 50 % ( high-intensity intervals ) and 10 % ( low-intensity intervals ) of short-term maximum exercise capacity as determined by a steep ramp test ( 27 , 28 ) . The steep ramp test is an incremental cycle ergometer test in which patients pedal cycle ergometers unloaded for 2 minutes and then at increments of 25 watts every 10 seconds until they can not maintain a pedaling frequency above 50 pedals per minute or their heart rate exceeds the limit set by the normal incremental exercise test . We used the steep ramp test because workload for interval exercise can be underestimated if it is based on normal incremental exercise tests ( 28 ) . Fifty percent of short-term maximum exercise capacity corresponds , on average , to 90 % to 100 % of normal maximum exercise capacity ( 27 ) . We chose a workrecovery ratio of 1:2 that prevents high lactate accumulation and is well tolerated by patients ( 28 ) . In each session , patients had a warm-up period of 2 minutes at 10 % of the short-term maximum exercise capacity and then exercised for 20 minutes alternating between high-intensity intervals for 20 seconds and low-intensity intervals for 40 seconds ( Figure 1 ) . Patients also had a slowdown period of 2 minutes before completing the training session . We adjusted the exercise load for each patient individually if workload was too high or too low as described earlier ; physiotherapists lowered or increased the workload by steps of 10 % of short-term maximum exercise capacity , but the length of intervals remained constant ( 23 ) . Outcomes and Measurements Our primary outcome for effectiveness was the difference from baseline in Chronic Respiratory Question naire ( CRQ ) scores 5 weeks after r and omization as measured by the self-administered German- language version ( 29 , 30 ) with st and ardized dyspnea questions ( 31 ) . The CRQ is a widely used instrument in respiratory rehabilitation and measures dyspnea , fatigue , emotional functioning , and ability to cope with COPD ( 7 , 32 ) . Domain and total ( average of domains ) scores are presented on a Likert-type scale from 1 ( most severe impairment ) to 7 ( no impairment ) . We selected assessment at 5 weeks after r and omization as the primary outcome STUDY OBJECTIVES To compare the effect 
    Output:
    