Objective: To develop regression equations for predicting six-minute and incremental shuttle walk distances (6MWD and ISWD, respectively), based on demographic characteristics, anthropometric variables, and grip strength. Methods: We evaluated 6MWD and ISWD in 98 healthy adults. Height, weight, and grip strength were also assessed. Using data from 90 of the participants (40 males; 60 ± 9 years of age), we devised linear equations adjusted for age, gender, height, and weight, and we developed alternate models that included grip strength. We prospectively applied the equations in the 8 remaining participants (4 males; 59 ± 10 years), who had been randomly separated from the initial sample. Results: Age, gender, height, and weight collectively explained 54.5% and 64.9% of the variance in 6MWD and ISWD, respectively, whereas age, height, weight, and grip strength collectively explained 54.4% and 69.0% of the respective variances. There was no significant difference between the measured and predicted 6MWD using equations with and without grip strength (14 ± 57 vs. 13 ± 67 m). Similar results were observed for ISWD (25 ± 104 vs. 25 ± 93 m). Conclusions: Grip strength is a determinant of ISWD and 6MWD; however, it could not improve the power of equations adjusted by demographic and anthropometric variables. The validity of our models including grip strength should be further evaluated in patients with skeletal muscle dysfunction.

Keywords: Walking; Exercise; Reference Values; Exercise test.

Background: There is currently no consensus regarding which factors influence the quality of life of patients suffering from chronic obstructive pulmonary disease (COPD). However, identifying such factors could orient approaches to improving the quality of the lives of these patients. Objective: To evaluate factors that can interfere with quality of life in COPD patients selected for pulmonary rehabilitation. Methods: Twenty-one patients with moderate to severe COPD were evaluated. Maximal inspiratory pressure (MIP), 6-minute walk test (6MWT), body mass index (BMI), pulmonary function, blood gases, grip strength (measured with a dynamometer), quadriceps strength and St. George's Respiratory Questionnaire (SGRQ) scores were assessed. Results: Statistically significant negative correlations with quality of life were found for the following factors: "impact" scores of: forced expiratory volume in one second (FEV1) (r = -0.68; p = 0.004), FEV1 to forced vital capacity ratio (FEV1/FVC) (r = -0.61; p = 0.014), peak expiratory flow (PEF) (r = -0.53 (p = 0.015), 6MWT (r = -0.63; p = 0.001) and BMI (r = -0.64; p = 0.002); "activity" scores for: MIP (r = -0.57; p = 0.007), baseline arterial oxygen saturation by pulse oximetry (SpO2) (r = -0.52; p = 0.018) and 6MWT (r = -0.58; p = 0.007); "symptom" score for: BMI (r = -0.60; p = 0.005); and "total" scores for: FEV1 (r = -0.64; p = 0.01), PEF (r = -0.47; p = 0.033) and BMI (r = -0.57; p = 0.009). Multiple linear regression revealed the primary factors influencing quality of life to be: BMI, which presented a significant influence on "symptom", "impact" and "total" scores (p = 0.002, p = 0.009 and p = 0.024, respectively); and 6MWT, which had a significant influence on "activity" and "impact" scores (p = 0.048 and p = 0.010, respectively). Conclusions: The BMI and 6MWT were shown to have an influence on quality of life in the COPD patients studied. Therefore, therapeutic approaches to improving the quality of life of COPD patients should take these indices into consideration.

Keywords: Lung diseases, obstructive/rehabilitation. Quality of life

Objective: To identify factors associated with the minimal clinically important difference (MCID) for health-related quality of life (HRQoL) after physical conditioning in patients with COPD. Methods: Thirty-five patients were submitted to a 12-week program of physical conditioning (strength training plus low-intensity aerobic exercise). Body composition, incremental treadmill test results, endurance treadmill test results, six-minute walk test results, peripheral muscle strength, MIP, baseline dyspnea index (BDI) and Saint George's Respiratory Questionnaire (SGRQ) scores were assessed at baseline and after the program, thus allowing the variations (Δ) to be calculated. The MCID for HRQoL was defined as a reduction of ≥ 4% in the SGRQ total score. Subjects who responded to the program, achieving the MCID for HRQoL, were allocated to the responders (R) group (n = 24), and the remainder were allocated to the non-responders (NR) group (n = 11). Results: The values obtained for the following variables were significantly higher in group R than in group NR (p < 0.05): FEV1 (1.48 ± 0.54 L vs. 1.04 ± 0.34 L); VEF1/FVC (47.9 ± 11.7% vs. 35.5 ± 10.7%); PaO2 (74.1 ± 9.7 mmHg vs. 65.0 ± 8.9 mmHg); and ΔBDI, expressed as median and interquartile range (2.0 [0.0-3.5] vs. 0.0 [0.0-1.0]). The ΔBDI correlated significantly with the ΔSGRQ symptoms domain score, activity domain score and total score (r = 0.44, 0.60 and 0.62, respectively, p < 0.01 for all). After logistic regression, only ΔBDI remained as a predictor of MCID for HRQoL. Conclusions: Achieving the MCID for HRQoL after physical conditioning is associated with dyspnea reduction in COPD patients. Therefore, there is a need to develop treatment strategies designed to interrupt the dyspnea-inactivity-dyspnea cycle in such patients.

Keywords: Pulmonary disease, chronic obstructive; Quality of life; Dyspnea; Exercise; Rehabilitation.

Chronic obstructive pulmonary disease is progressive and is characterized by abnormal inflammation of the lungs in response to inhalation of noxious particles or toxic gases, especially cigarette smoke. Although this infirmity primarily affects the lungs, diverse extrapulmonary manifestations have been described. The likely mechanisms involved in the local and systemic inflammation seen in this disease include an increase in the number of inflammatory cells (resulting in abnormal production of inflammatory cytokines) and an imbalance between the formation of reactive oxygen species and antioxidant capacity (leading to oxidative stress). Weakened physical condition secondary to airflow limitation can also lead to the development of altered muscle function. Chronic obstructive pulmonary disease presents diverse systemic effects including nutritional depletion and musculoskeletal dysfunction (causing a reduction in exercise tolerance), as well as other effects related to the comorbidities generally observed in these patients. These manifestations have been correlated with survival and overall health status in chronic obstructive pulmonary disease patients. In view of these facts, the aim of this review was to discuss findings in the literature related to the systemic manifestations of chronic obstructive pulmonary disease, emphasizing the role played by systemic inflammation and evaluating various therapeutic strategies.

Keywords: Pulmonary disease, chronic obstructive/complications; Nutritional status; Exercise tolerance;

Objective: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. Methods: We evaluated 103 healthy participants ≥ 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). Results: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R2 values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R2 values for predicting peak VO2, although the use of those models did result in slight increases in the R2 values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD Î body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. Conclusions:áOur results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults ≥ 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs.

Keywords: Reference values; Pulmonary gas exchange; Walking; Exercise test.