Objective: To compare MIP and MEP determined in healthy subjects with those predicted using the equations proposed in another study, and, if necessary, to suggest new equations for MIP and MEP to be used in the Brazilian population. Methods: The study sample comprised 60 healthy males and 60 healthy females, 20-80 years of age (20 subjects per ten-year age bracket). Maximal respiratory pressures were determined following a standardized protocol. Results: Regarding MIP, the measured values were significantly lower than those predicted for both males (31%) and females (24%). There were no significant differences between measured and predicted MEP in either gender. We found that age presented the greatest power to predict MIP and MEP in both genders. New equations were proposed. Conclusions: The previously proposed equations were unable to predict MIP and MEP for all of the subjects in our sample. Therefore, the results of this study can facilitate the prediction of respiratory muscle strength in healthy adult subjects in Brazil. Further studies, involving subjects from different regions of the country, could lead to the development of better tables or equations for maximal respiratory pressures in the Brazilian population.

Keywords: Respiratory muscles; Muscle strength; Reference values.

Background: Patients with chronic obstructive pulmonary disease usually present intolerance to physical exertion due to ventilatory limitation. L-carnitine has been used to enhance aerobic capacity in patients with chronic diseases, but no study seems to be available for this patient population. Objective: To evaluate the influence of L-carnitine supplementation (2 g/day) in chronic obstructive pulmonary disease patients undergoing physical training three times a week for six weeks. Method: Patients (mean age 69 ± 7 years, n = 30) with stable chronic obstructive pulmonary disease and < 65% of predicted forced expiratory volume in 1 second (FEV1) were separated into three groups of 10 patients each. Group 1 (G1, n = 10) received physical training and L-carnitine (2 g/day), group 2 (G2, n = 10) received physical training and placebo, and group 3 (G3, n = 10) received only L-carnitine (2 g/day). Spirometry and a 6-minute walking distance test were performed before and after intervention. Plasma levels of free carnitine were measured at the beginning and end of the study. Results: A significant increase in walking distance was found only in G1 and G2 (421 ± 100 to 508 ± 80.7 and 496 ± 78.7 to 526 ± 64.3 respectively). In addition, heart rates during physical training sessions were found to be significantly lower in G1 when compared to G2. There were no significant changes in spirometric variables, oxygen saturation or dyspnea in any group. Plasma levels of free L-carnitine were found to increase only in G3 (59.2 ± 13.8 to 102.3 ± 15.3 mmol/L). Conclusion: Oral L-carnitine supplementation combined with physical training may improve tolerance to physical exertion in chronic obstructive pulmonary disease patients.

Keywords: Chronic obstructive pulmonary disease. Carnitine/therapeutic use. Spirometry/methods. Exercise. Walking.

Objective: To determine whether the quality of life of adolescents with asthma correlates with parameters obtained prior to and after the six-minute step test (6MST); spirometric results after the 6MST; and level of physical activity. Methods: Nineteen adolescents with asthma, ranging from 11-15 years of age, were assessed with spirometry, 6MST, the International Physical Activity Questionnaire (IPAQ), the Pediatric Asthma Quality of Life Questionnaire (PAQLQ), and the 10-point Borg category-ratio scale. Results: Sensation of dyspnea correlated negatively with the total PAQLQ score (r = −0.54) and with the scores of its activity limitation (AL) and symptoms domains (r = −0.64 and r = −0.63, respectively), leg fatigue also correlating negatively with those same domains (r = −0.49 and r = −0.56, respectively). The total IPAQ score correlated with the total PAQLQ score (r = 0.47) and with the PAQLQ AL domain (r = 0.51); IPAQ time spent walking correlated with the PAQLQ symptoms domain (r = 0.45); and IPAQ time spent in vigorous activity correlated with the AL domain (r = 0.50). In the regression analysis, only sensation of dyspnea remained significantly correlated with the total PAQLQ score and the PAQLQ AL domain; leg fatigue remained significantly correlated with the symptoms domain. Conclusions: Higher levels of physical activity indicate better quality of life, as do lower perception of dyspnea and less leg fatigue. The 6MST proved to be a viable option for evaluating exercise capacity in adolescents with asthma, because it reflects the discomfort that asthma causes during activities of daily living.