The relationship between exercise capacity and different functional markers in pulmonary rehabilitation for COPD

Abstract

RationaleThe relationship of functional parameters such as lung mechanics, chest kinematics, metabolism and peripheral and respiratory muscle function with the level of exercise tolerance remains a controversial subject. While it has been previously shown that pulmonary rehabilitation is capable of improving exercise tolerance in patients afflicted by COPD, as expressed by values of 6-minute walking test (6MWT), the degree of contribution to this change by each of the aforementioned parameters remains unclear.AimsTo investigate the correlation between changes in exercise capacity and other functional markers following pulmonary rehabilitation in COPD and to determine which parameters are more closely related to improvements of exercise tolerance.Materials and methodsThree hundred and twenty-seven patients with COPD (with average, 95% CI for forced expiratory volume in the first second [FEV1]: 45% [25%–83%] predicted, age: 64 [48–80] years, and BMI: 27 [13.5–40.4] kg/m2) participated in this study. Thirty percent of the patients had pulmonary hypertension as comorbidity. Patients underwent a pulmonary rehabilitation program with 20–30 minutes sessions two to three times per day for 4 weeks. The program was composed of chest wall-stretching, controlled breathing exercises, and a personalized training schedule for cycling and treadmill use. Measurements of 6MWT, lung function, chest wall expansion, grip strength, maximal inspiratory pressure, and breath holding time were taken. The Body mass index, airflow Obstruction, Dyspnea and Exercise capacity (BODE-index), body mass index [BMI], FEV1, 6MWT, modified Medical Research Dyspnea Scale score, and an alternative scale score (for BMI, FEV1, 6MWT, and COPD Assessment Test) were calculated.ResultsRehabilitation resulted in a generalized improvement in 6MWT among patients (average: 360 [95% CI: 178–543 m] vs average: 420 [95% CI: 238–601 m], p<0.05). Improvements in exercise tolerance were found to be most closely associated with changes in composite BODE-index (R2=−0.6), Alternative Scale (R2=−0.56), dyspnea score (modified Medical Research Dyspnea Scale R2=−0.54), and health status (COPD Assessment Test R2=−0.4, p<0.05). In addition, improvements in exercise tolerance were found to moderately correlate with improvements in inspiratory vital capacity (IVC, R2=0.34, p<0.05). Post-rehabilitation changes in IVC displayed a connection with grip strength (R2=0.6) and chest expansion (R2=0.48).ConclusionEnhancements in exercise tolerance had correlation with changes in IVC, BODE-index, and the new Alternative Scale. However, comprehensive assessment needs to include considerations of chest kinematics and peripheral and respiratory muscle function as well.

The 6-minute walk-test in type 2 diabetics predicts to some extent maximal aerobic capacity but not its training-induced improvement

“…This study shows that, as already reported other sedentary populations [5][6][7][8] This study is part of a wider study investigating the effects of exercise training at the level of VT 1 and one of the fi ndings was that VO 2max declined by 16.4%, over 1 year without training while this decline was prevented by training. Although it is well accepted that diabetes is a progressive disease [23], such a rapid decline highlights the "vicious circle" of a sedentary lifestyle in chronic diseases [24], and characterized by rapid deterioration even at the stage of disease where patients are comparatively healthy.…”

“…Since it has been widely studied and validated in chronic pathologies associated to sedentary lifestyles [5][6][7][8], it appears to be logically more and more employed in diabetes studies [9]. However, the basis for this use was until recently poorly documented.…”

“…By contrast the measurement of VO 2max requires a maximal exercise-test which cannot be performed everywhere and requires a specifi c and expensive material. Therefore, reliable surrogates providing an evaluation of cardiorespiratory fi tness are useful for a comprehensive assessment of an individual's health, and 6MWT is surely one of the most attractive because it is simple to realize and costless [1,[5][6][7][8]. If it were also a good refl ect of health improvement after treatment its interest would be even greater but this remains unknown for diabetics, since in this disease there are several factors of disability (eg, neuropathy, retinopathy).…”

A comparative study of the five-repetition sit-to-stand test and the 30-second sit-to-stand test to assess exercise tolerance in COPD patients

“…The performances using their cutoff values demonstrated that the two STSTs are good tools for predicting a poor 6MWD (<350 m). Nevertheless, in addition to having a strong relationship with elements of a patient’s health status, including poor exercise tolerance 30 , 31 and poor pulmonary function, 12 , 32 and reflecting the response to pulmonary rehabilitation, 33 , 34 the role of 6MWT has been demonstrated in predicting long-term mortality 35 and quality of life 12 and in indicating the need for long-term oxygen therapy 36 in COPD patients. The 5STS and 30STS may have potential capacity to predict poor prognosis because 6MWD <350 m is a predictor for high mortality.…”

Effectiveness of a 4-week rehabilitation program on endothelial function, blood vessel elasticity in patients with chronic obstructive pulmonary disease

“…Patients performed a complex pulmonary rehabilitation programme with chest wall-stretching, controlled breathing techniques and training, as well as personalized exercise training 2-3 times for 20-30 minutes per day by cycling and treadmill for 4 weeks (28)(29)(30)(31). 6MWD (23), lung function (22), CWE (24), GS (27), MIP (25) and BHT (26) were measured.…”