Additional Effects of Nutritional Antioxidant Supplementation on Peripheral Muscle during Pulmonary Rehabilitation in COPD Patients: A Randomized Controlled Trial.

BACKGROUND: Skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD) is not fully reversed by exercise training. Antioxidants are critical for muscle homeostasis and adaptation to training. However, COPD patients experience antioxidant deficits that worsen after training and might impact their muscle response to training. Nutritional antioxidant supplementation in combination with pulmonary rehabilitation (PR) would further improve muscle function, oxidative stress, and PR outcomes in COPD patients. METHODS: Sixty-four COPD patients admitted to inpatient PR were randomized to receive 28 days of oral antioxidant supplementation targeting the previously observed deficits (PR antioxidant group; α-tocopherol: 30 mg/day, ascorbate: 180 mg/day, zinc gluconate: 15 mg/day, selenomethionine: 50 µg/day) or placebo (PR placebo group). PR consisted of 24 sessions of moderate-intensity exercise training. Changes in muscle endurance (primary outcome), oxidative stress, and PR outcomes were assessed. RESULTS: Eighty-one percent of the patients (FEV1 = 58.9 ± 20.0%pred) showed at least one nutritional antioxidant deficit. Training improved muscle endurance in the PR placebo group (+37.4 ± 45.1%, p < 0.001), without additional increase in the PR antioxidant group (-6.6 ± 11.3%; p = 0.56). Nevertheless, supplementation increased the α-tocopherol/γ-tocopherol ratio and selenium (+58 ± 20%, p < 0.001, and +16 ± 5%, p < 0.01, respectively), muscle strength (+11 ± 3%, p < 0.001), and serum total proteins (+7 ± 2%, p < 0.001), and it tended to increase the type I fiber proportion (+32 ± 17%, p = 0.07). The prevalence of muscle weakness decreased in the PR antioxidant group only, from 30.0 to 10.7% (p < 0.05). CONCLUSIONS: While the primary outcome was not significantly improved, COPD patients demonstrate significant improvements of secondary outcomes (muscle strength and other training-refractory outcomes), suggesting a potential "add-on" effect of the nutritional antioxidant supplementation (vitamins C and E, zinc, and selenium) during PR. This trial is registered with NCT01942889.

Effect of weight reduction on quality of life and eating behaviors in obese women.

OBJECTIVE: To examine the impact of a 3-week weight-reducing program on body composition, physical condition, health-related quality of life, and eating behaviors of sedentary, obese (body mass index, 29-35 kg/m) women, according to menopausal status and menopause duration (<5, >or=5, and >or=10 y). DESIGN: Thirteen premenopausal and 27 postmenopausal women received a dietary plan of 1,400 +/- 200 kcal/day and completed 110-minute endurance exercise 6 days per week. Body mass index, fat mass, lean mass, distance walked in the Six-Minute Walk Test, health-related quality of life estimated by the 36-item Short Form Health Survey (SF-36), and eating behaviors (restriction, disinhibition, and susceptibility to hunger) assessed by the Three-Factor Eating Questionnaire were determined before and after weight reduction. RESULTS: Body mass index and fat mass decreased (P < 0.0001), whereas distance walked increased in both groups after weight reduction (P < 0.001). Although the SF-36 mental component score increased after weight loss in both groups (P < 0.0001), the SF-36 physical component score increased in postmenopausal women only (P < 0.001). Restriction increased (P < 0.0001), whereas disinhibition and susceptibility to hunger decreased after weight reduction (P < 0.001 and P < 0.01, respectively) in both groups. Distance walked and SF-36 physical component score after weight loss were higher in women whose menopause ranged between 5 and 9 years and exceeded 10 years, respectively (P < 0.01). CONCLUSIONS: Our study shows that a short-term weight-reducing program combining caloric restriction and physical activity has a favorable impact on women's body composition, physical condition, health-related quality of life, and eating behaviors irrespective of their menopausal status.

The effect of obesity on chronic respiratory diseases: pathophysiology and therapeutic strategies.

Sedentary lifestyles and increased pollution brought about by industrialization pose major challenges to the prevention of both obesity and chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, obstructive sleep apnea and obesity hypoventilation syndrome. Obesity has emerged as an important risk factor for these respiratory diseases, and in many instances weight loss is associated with important symptomatic improvement. Moreover, obesity may influence the development and presentation of these diseases. In this article, we review the current understanding of the influence of obesity on chronic respiratory diseases and the clinical management of obesity concurrent with asthma, COPD, obstructive sleep apnea or obesity hypoventilation syndrome.

Gender difference in coping strategies among patients enrolled in an inpatient rehabilitation program.

BACKGROUND: Previous research has not addressed gender differences in coping strategies among patients with mild to moderate chronic obstructive pulmonary disease (COPD) who are enrolled in inpatient and multidisciplinary rehabilitation programs. METHODS: The coping strategies of 182 consecutive patients (61 women aged 61.1 years; 121 men aged 62.7 years) with mild to moderate COPD were assessed on admission and then at discharge after 29 days of pulmonary rehabilitation, using the Coping Inventory for Stressful Situations. A one-way analysis of variance for repeated measures was used to test the differences in coping scores. RESULTS: During the rehabilitation program, problem-focused strategies increased (+2.54 [95% confidence interval: 1.41-3.67] with F=23.77, P<.0001), emotion-focused strategies decreased (-2.75 [95% confidence interval: -4.06, -1.45], F=15.37, P<.001), and avoidance strategies were differently (t=2.97, P<.05) influenced in women (+2.43 [95% confidence interval: .66-4.19]) compared with men (-1.30 [95% confidence interval: -2.82-.22]). The prevalence of COPD in women is increasing, and rehabilitation professionals need a greater awareness of how women cope differently than men with this disease.

6-minute walk testing is more sensitive than maximal incremental cycle testing for detecting oxygen desaturation in patients with COPD.

STUDY OBJECTIVES: Some respiratory patients exhibit oxygen desaturation during rehabilitative walking but not during maximal cardiopulmonary exercise testing (CPET). We evaluated exercise-induced desaturation during 6-min walk testing (6MWT) in comparison with CPET in patients with COPD and determined the reproducibility of the phenomenon. PATIENTS: We tested 80 consecutive patients with COPD (FEV(1), 62.4 +/- 2% predicted) and 10 patients with supplementary COPD (FEV(1), 59.1 +/- 5% predicted) [mean +/- SEM] to determine the reproducibility. MEASUREMENTS AND RESULTS: First, patients with COPD performed cycle CPET (first CPET [CPET-1]). Three days later, they performed two 6MWTs (first 6MWT [6MWT-1] and second 6MWT [6MWT-2]). Pulse oximetric saturation (SpO(2)) was recorded every minute in both tests. Three groups emerged: desaturation at 6MWT not observed at CPET (DND) [n = 23], desaturation in both tests (n = 16), and no desaturation in either test (n = 41). Second, to evaluate reproducibility, 10 additional subjects with COPD who exhibited desaturation during two successive 6MWTs but not in CPET performed a second CPET (CPET-2) and a single-bout 6MWT (6MWT-3) in a supplementary trial. When two CPETs were performed, lack of O(2) desaturation was noted in both. O(2) desaturation was confirmed in 6MWT-2 and 6MWT-3 (7.4 +/- 1% and 7.4 +/- 1.5%, respectively). CONCLUSION: Twenty-eight percent of patients with COPD presented DND. The phenomenon was reproducible and not protocol dependent, emphasizing the clinical interest of the 6MWT.

Endurance training improves skeletal muscle electrical activity in active COPD patients.

The effect of endurance training on muscle electrical activity during general exercise testing was investigated in physically active patients with chronic obstructive pulmonary disease (COPD). Before and after rehabilitation, patients performed identical incremental exercise tests. Pulmonary gas exchange, venous lactate and pyruvate concentrations, and the quadriceps electromyographic signal were sampled every minute throughout exercise testing. Three weeks of rehabilitation increased exercise capacity without modifying pulmonary function. M-wave amplitude, root mean square (RMS) of electromyographic activity, and RMS/oxygen uptake were increased significantly during post-rehabilitation testing at the same exercise intensity compared to pre-rehabilitation. Median frequency was significantly lower after training. These modifications reflect greater muscle excitability, greater muscle activation for the same level of exercise, and higher recruitment of slow-twitch fibers. Pulmonary rehabilitation in active COPD patients may normalize the electrical activity of skeletal muscles during incremental dynamic exercise. The electromyographic signal confirms neuromuscular changes after endurance training.

Electrophysiologic changes during exercise testing in patients with chronic obstructive pulmonary disease.

To determine whether skeletal muscle is involved in the exercise limitation of chronic obstructive pulmonary disease (COPD), we investigated electrical adaptations in muscle during incremental cycling exercise testing. Changes in quadriceps activity were compared using surface electromyography (SEMG) and motor point stimulation in ten COPD patients and ten healthy subjects. Patients showed significantly lower exercise capacity, and M-wave duration was increased from exercise onset (P < 0.05) with a parallel decrease in amplitude (P < 0.05). The SEMG power spectrum median frequency was always higher (P < 0.04) in patients and its decline was earlier (P < 0.01). The ratio of the root mean square of the SEMG to oxygen uptake was decreased (P < 0.001) during exercise in patients, although it remained constant in controls. Electromyographic parameters were significantly more involved in the exercise limitation than ventilatory factors. Thus, modified electrical activity in muscle appeared in COPD patients from exercise onset, indicating that skeletal muscle function is clearly implicated in the exercise intolerance of these patients.