Eighteen patients with severe COPD and seven healthy control subjects 64.0 +/- 2.2 and 66.8 +/- 1.4 yr of age, respectively (mean +/- SEM), were investigated. Arterial blood gas analysis, dynamic lung volumes, and muscle biopsy specimens from the quadriceps femoris muscle were performed. The muscle biopsies were analyzed for citrate synthase (CS), succinic acid dehydrogenase (SDH), 3-hydroxyacyl-CoA dehydrogenase (HAD), phosphofructokinase (PFK), and lactate dehydrogenase (LDH) activities and related to protein content. The PFK activity was higher in the COPD group than in the control group (+34%, p < 0.05). CS showed a group difference in the opposite direction (-29%, p < 0.05). LDH activity followed PFK and tended to be higher in the patient group (+27%, NS), whereas SDH (-31%, NS) and HAD (-28%, NS) mirrored the CS results. Muscle protein concentration tended to be lower in the COPD group (-14%, NS). There were no significant changes in enzyme activity after 7 mo of long-term oxygen therapy (n = 6). These results indicate adaptation in the form of augmented glycolysis (PFK), and decreased aerobic metabolism (CS) in the quadriceps femoris muscle in patients with advanced COPD.

Eighteen patients with advanced chronic obstructive pulmonary disease (COPD), 8 with chronic respiratory failure (CRF group) and 10 without (NCRF group) were investigated using arterial blood analyses before, during and after progressive exercise. Dynamic spirometry was also performed. The arterial blood was analyzed for free fatty acids (FFA), glycerol, 3-hydroxybutyrate, alanine, glucose and lactate concentrations as well as PO₂ and PCO₂. In the CRF group the concentrations of FFA, glycerol and 3-hydroxybutyrate were lower and the concentrations of glucose and lactate higher than in the NCRF group. Analysis of the whole material revealed that the arterial FFA, glycerol and 3-hydroxybutyrate concentrations correlated positively to arterial PO₂ and negatively to arterial PCO₂ at rest, as well as during exercise and recovery. The results indicate that lipolysis is decreased in patients with advanced COPD with chronic respiratory failure. An altered glucose metabolism may also exist in these patients

Study objectivesPatients with chronic obstructive pulmonary disease (COPD) have low exercise capacity and low content of high energetic phosphates in their skeletal muscles. The aim of the present study was to investigate whether creatine supplementation together with exercise training may increase physical performance compared with exercise training in patients with COPD.DesignIn a randomized, double-blind, placebo-controlled study, 23 patients with COPD (forced expiratory volume in one second [FEV1] < 70% of predicted) were randomized to oral creatine (n = 13) or placebo (n = 10) supplementation during an 8-week rehabilitation programme including exercise training. Physical performance was assessed by Endurance Shuttle Walking Test (ESWT), dyspnea and leg fatigue with Borg CR-10, quality of life with St George’s Respiratory Questionnaire (SGRQ). In addition, lung function test, artery blood gases, grip strength test, muscle strength and fatigue in knee extensors were measured.ResultsCOPD patients receiving creatine supplementation increased their average walking time by 61% (ESWT) (p < 0.05) after the training period compared with 48% (p = 0.07) in the placebo group. Rated dyspnea directly after the ESWT decreased significantly from 7 to 5 (p < 0.05) in the creatine group. However, the difference between the groups was not statistically significant neither in walking time nor in rated dyspnea. Creatine supplementation did not increase the health related quality of life, lung function, artery blood gases, grip strength and knee extensor strength/fatigue.ConclusionsOral creatine supplementation in combination with exercise training showed no significant improvement in physical performance, measured as ESWT, in patients with COPD compared with exercise training alone.

Background:The aim of this study was to determine the influence of selected physiological, psychological and situational factors on experience of fatigue, and functional limitations due to fatigue in patients with stable chronic obstructive pulmonary disease (COPD).Methods:In total 101 patients with COPD and 34 control patients were assessed for experience of fatigue, functional limitation due to fatigue (Fatigue Impact Scale), physiological [lung function, 6-minute walk distance (6MWD), body mass index (BMI), dyspnoea, interleukin (IL)-6, IL-8, high sensitivity C-reactive protein (hs-CRP), surfactant protein D], psychological (anxiety, depression, insomnia), situational variables (age, sex, smoking, living alone, education), and quality of life.Results:Fatigue was more common in patients with COPD than in control patients (72% versus 56%, p < 0.001). Patients with COPD and fatigue had lower lung function, shorter 6MWD, more dyspnoea, anxiety and depressive symptoms, and worse health status compared with patients without fatigue (all p < 0.01). No differences were found for markers of systemic inflammation. In logistic regression, experience of fatigue was associated with depression [odds ratio (OR) 1.69, 95% confidence interval (CI) 1.28–2.25) and insomnia (OR 1.75, 95% CI 1.19–2.54). In linear regression models, depression, surfactant protein D and dyspnoea explained 35% (R2) of the variation in physical impact of fatigue. Current smoking and depression explained 33% (R2) of the cognitive impact of fatigue. Depression and surfactant protein D explained 48% (R2) of the psychosocial impact of fatigue.Conclusions:Experiences of fatigue and functional limitation due to fatigue seem to be related mainly to psychological but also to physiological influencing factors, with depressive symptoms, insomnia problems and dyspnoea as the most prominent factors. Systemic inflammation was not associated with perception of fatigue but surfactant protein D was connected to some dimensions of the impact of fatigue

Although the pulmonary rehabilitation programme had an immediate effect, it was not sustained.