***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 Although question naires are used frequently with patients to self-report the severity of dyspnea as related to activities of daily living , the reliability of these instruments has not been established . The two purpose s of this study were to examine the test-retest reliability of three widely used dyspnea instruments and to compare dyspnea scores at different stages of disease . METHODS At paired baseline visits , 101 stable patients with COPD were tested ; at paired follow-up visits at 3 months , 89 of these patients were tested . At each visit , patients rated dyspnea with three instruments presented in r and om order and then performed post-bronchodilator therapy lung function tests . RESULTS Patient-reported dyspnea scores and lung function were similar at baseline ( interval , 6 + /- 5 days ) and follow-up visits ( interval , 4 + /- 2 days ) . Intraclass correlation coefficients at baseline and at follow-up were 0.82 and 0.82 , respectively , for the modified Medical Research Council scale ; 0.90 and 0.84 , respectively , for the self-administered computerized versions of the baseline dyspnea index and transition dyspnea indexes ; and 0.95 and 0.89 for the University of San Diego Shortness of Breath Question naire results . Dyspnea ratings were significantly related to the stage of disease severity based on percent predicted FEV(1 ) ( p < 0.001 ) . CONCLUSIONS Test-retest reliability was acceptable for patient-reported dyspnea scores using three clinical instruments at baseline and at the 3-month follow-up . Our results demonstrate for the first time that patient-reported dyspnea ratings are related to the stage of disease severity Reproducibility and validity are prerequisites for a useful clinical scale . We therefore prospect ively tested the reproducibility and validity of the New York Heart Association criteria and the Canadian Cardiovascular Society criteria for the assessment of cardiac functional class  and compared these criteria with a new Specific Activity Scale based on the metabolic costs of specific activities . The New York Heart Association estimates made by two physicians had a reproducibility of only 56 % , and only 51 % of the estimates agreed with treadmill exercise performance . Functional estimates based on the Canadian Cardiovascular Society criteria were significantly more reproducible ( 73 % ) , but not significantly more valid . The Specific Activity Scale was as reproducible as the Canadian Cardiovascular Society criteria , and its 68 % validity was significantly higher than the validities of the other systems . The easily administered Specific Activity Scale was equally reproducible and valid when used by a nonphysician . It was especially better than the other systems for the evaluation of true class II patients and was significantly less likely to underestimate treadmill performance . Although no set of questions can perfectly predict exercise tolerance , the Specific Activity Scale deserves wider prospect i ve testing PURPOSE Overweight and obese subjects often perceive increased breathlessness during minor exertion and therefore avoid exercise . Respiratory muscle endurance training ( RMET ) can reduce the perception of breathlessness . We hypothesized that RMET 1 month before and during a 6-month ( 3 months supervised + 3 months unsupervised ) exercise and nutrition counseling program ( EN ) would improve the benefits of EN . METHODS Twenty-six overweight and obese subjects with significant perception of breathlessness during exercise ( age = 33 ± 9 yr , body mass index ( BMI ) = 31.3 ± 4.9 kg·m(-2 ) ) were r and omized to RMET+EN ( R+EN ) or EN alone . R+EN performed 30 min of normocapnic hyperpnea 5 wk(-1 ) before and 2 wk(-1 ) during EN . EN consisted of two strength and three endurance training sessions per week , as well as prescribed nutritional composition and a 2.1-kJ ( 500-kcal ) energy deficit per day . Both groups had an equal number of laboratory visits during the 7 months . Before and after 4 and 7 months , subjects performed a 12-min time trial ( TT ; 6 + 6 min , 2-min pause ) and an incremental cycling test ( ICT ) to exhaustion , and blood lipids were assessed . RESULTS Weight loss was significant and similar in both groups ( -4.2 vs -3.7 kg ; both P < 0.05 ) . During the first 4 months , distance covered in 12 min improved more ( P < 0.05 ) with R+EN ( 1678 vs 1824 m ; P < 0.001 ) than with EN alone ( 1638 vs 1698 m ; P < 0.05 ) , whereas after R+EN  , breathlessness during the ICT was reduced . Blood lipids of the pooled group improved in those subjects with pathologic values before the study . Despite reduced training compliance during the unsupervised period , subjects of both groups maintained the benefits attained during the supervised period . CONCLUSIONS R+EN  improved TT performance more than EN alone , despite similar weight loss , possibly owing to the reduced perception of breathlessness OBJECTIVE Our objective was to study the effects of physical training combined with dietary measures in obese adults . In a second step , we sought to compare two training protocol s and establish the additional contribution of strength training . METHODS We performed a r and omized , prospect i ve survey from July 2004 to November 2007 . Included patients were r and omized into three groups : a control group ( G1 ) , a group ( G2 ) performing dietary measures and a programme of treadmill training at 60 % of each individual 's maximum heart rate ( HRmax ) and a group ( G3 ) who followed the G2 programme supplemented with strength training . All patients underwent an initial and final assessment of anthropometric & cardiovascular parameters , muscle strength , dyspnoea during activities of daily living , metabolic disorders , psychological status and quality of life . RESULTS The greatest weight loss ( 7.24 % ) was observed in G3 . Reduction in waistline measurement ( WL ) of 4.3 % and 10.26 % were noted in G2 and G3 , respectively ( p < 0.001 ) . The percentage fat body mass fell by 10.4 % in G3 ( p < 0.001 ) and 8.6 % in G2 ( p = 0.03).We particularly noted an improvement in physical condition in groups 2 and 3 , with lower HR and blood pressure values at rest and at maximum effort . The overall improvement in both arm and leg muscle strength was greater for G3 than for G2 . Likewise , we noted an improvement in the metabolic parameters and depression & anxiety scores for the trained groups ( G2 , G3 ) , relative to the control group ( G1 ) . We also noted improvements in the total impact of weight on quality of life ( IWQOL ) lite score of 15.2 % in G2 and 18 % in G3 . CONCLUSION Our survey demonstrated the beneficial effect of combining dietary measures and physical training in obese patients . In addition to weight loss , the programme enabled a reduction in the patients ' body fat mass and abdominal obesity , a correction of metabolic disorders and an improvement in aerobic capacity . The improvement in all these parameters also enhanced the patients ' psychological status and quality of life . The addition of strength training produced notable improvements in weight loss , arm muscle strength and abdominal obesity We mimicked important mechanical and ventilatory aspects of restrictive lung disorders by employing chest wall strapping ( CWS ) and dead space loading ( DS ) in normal subjects to gain mechanistic insights into dyspnea causation and exercise limitation . We hypothesized that thoracic restriction with increased ventilatory stimulation would evoke exertional dyspnea that was similar in nature to that experienced in such disorders . Twelve healthy young men [ 28 + /- 2 ( SE ) yr of age ] completed pulmonary function tests and maximal cycle exercise tests under four conditions , in r and omized order : 1 ) control , 2 ) CWS to 60 % of vital capacity , 3 ) added DS of 600 ml , and 4 ) CWS + DS . Measurements during exercise included cardiorespiratory parameters , esophageal pressure , and Borg scale ratings of dyspnea . Compared with control , CWS significantly reduced the tidal volume response to exercise , increased dyspnea intensity at any given work rate or ventilation , and thus limited exercise performance .  DS  stimulated ventilation but had minimal effects on dyspnea and exercise performance . Adding DS to CWS further increased dyspnea by 1.7 + /- 0.6 st and ardized Borg units ( P = 0.012 ) and decreased exercise performance ( total work ) by 21 + /- 6 % ( P = 0.003 ) over CWS alone . Across conditions , increased dyspnea intensity correlated best with decreased resting inspiratory reserve volume ( r = -0.63 , P < 0.0005 ) . Dyspnea during CWS was described primarily as " inspiratory difficulty " and " unsatisfied inspiration , " similar to restrictive disorders . In conclusion , severe dyspnea and exercise intolerance were provoked in healthy normal subjects when tidal volume responses were constrained in the face of increased ventilatory drive during exercise BACKGROUND Maximal incremental exercise testing should be completed within 8 - 12 minutes . The ramp-slope influences the exercise duration . Oxygen-cost diagram ( OCD ) is a scoring scale for the capability of daily activity performed and therefore can be used to estimate the ramp-slope . METHODS The OCD-algorithm and the reported-algorithm were used prospect ively in r and om order for selecting optimal ramp-slope : Ramp-slope(OCD)=Score(OCD)xweight in kg/40 for men and weight/50 for women and Ramp-slope(reported)=(Predicted V(O2peak)-V(O2unloaded))/100 . Fifty-three dyspneic patients and 16 normal controls were enrolled to perform a ramp-pattern exercise .  Fourteen patients not reaching maximum exercise levels were excluded . The exercise capacity , exercise time , and success rate of loaded exercise between 8 and 12 minutes were measured . RESULTS Comparing the reported-algorithm to the OCD-algorithm in normal controls , the only difference was that the ramp-slope was higher in males ; in patients , the ramp-slope was higher in males , the exercise time shorter and the success rate lower ( 8.6+/-3.3 vs. 9.4+/-2.1 min , 61.5 % vs. 84.6 % , both p<0.05 ) ; in obese patients , the ramp-slope was lower and the exercise time longer . CONCLUSION OCD score can predict the ramp-slope selection for exercise testing in normal controls and dyspneic patients . This may be affected by gender and body weight when using the reported-algorithm for dyspneic patients AIM To describe changes in chest pain and dyspnoea during a period of 15 years after coronary artery bypass grafting ( CABG )  and to define factors at the time of operation that were associated with the occurrence of these symptoms after 15 years . DESIGN Prospect i ve observational study in western Sweden . SUBJECTS All patients who underwent first-time CABG , without simultaneous valve surgery , between 1 June 1988 and 1 June 1991 . There were no exclusion criteria . FOLLOW-UP All patients were followed up prospect ively for 15 years . The evaluation of symptoms took place through postal question naires prior to and 5 , 10 and 15 years after the operation . RESULTS Totally , 2000 patients were included in the survey and 904 ( 45 % ) of them survived to 15 years . Among these 904 survivors , the percentage of patients with chest pain increased from 44 % to 50 % between the 5- and 15-year follow-up ( p=0.004 ) . The percentage of patients who reported symptoms of dyspnoea increased from 60 % after 5 years to 74 % after 15 years ( p<0.001 ) . Factors at the time of surgery that independently tended to predict chest pain after 15 years were higher age ( p=0.04 ) and prolonged duration of symptoms prior to surgery ( p=0.04 ) . Predictors of dyspnoea after 15 years were higher age ( p<0.0001 ) , the use of inotropic drugs at the time of surgery ( p=0.001 ) , a history of diabetes ( p=0.01 ) and obesity ( p=0.01 ) . CONCLUSION After CABG , relief from chest pain and dyspnoea is generally maintained over a long period of time . Eventually , however , functional-limiting symptoms tend to recur and about half the patients report symptoms of chest pain , while three-quarters report dyspnoea after 15 years . Even if no clear predictor of chest pain was found at the time of surgery , age , the use of inotropic drugs , diabetes and obesity predicted dyspnoea The primary purpose of this study was to determine if there are three distinct factors representing ratings of dyspnea during laboratory exercise , clinical ratings of dyspnea , and pulmonary function in patients with moderate to severe chronic obstructive pulmonary disease ( COPD ) ( n = 92 ) using factor analysis . Subjects ( mean age 66 + /- 7 yrs ; FEV1 % predicted 44.7 + /- 14.0 ) were r and omly assigned to one of three treatment groups to test the effects of three education and exercise training programs . Outcomes were evaluated at baseline and at 2 months after the intervention .  Dyspnea ratings with laboratory exercise ( SOB )  were measured during incremental ( ITT ) and endurance ( ETT ) treadmill tests , and a six-minute walk ( 6MW ) using the modified Borg scale . Clinical measures of dyspnea were measured with the Baseline and Transitional Dyspnea Index ( BDI 
    Output:
    
If sensation drives behavior , comprehensive data on the sensation of breathlessness might assist in underst and ing the behavioral consequences of interventions