RESUMEN
BACKGROUND: Oxidative stress plays an important role in the pathogenesis of bronchial asthma. Antioxidant nutrition and supplementation have been used to reduce oxidative stress. However, a clinical trial with antioxidant supplementation showed no beneficial effects in patients with asthma. On the other hand, physical activity is related to the prognosis of chronic obstructive pulmonary disease (COPD) and is also related to oxidant status. We investigated the relationships between oxidative stress, serum levels of vitamins, dietary vitamin intake, daily activities, and pulmonary functions in patients with asthma. METHODS: Eighteen patients with bronchial asthma were enrolled in this study. Reactive oxidative stress was assessed by measuring organic hydroperoxides (diacron reactive oxygen metabolites: dROM) in sera and by measuring H2O2 levels in exhaled breath condensates. The biological antioxidant capacity in serum was evaluated by measuring antioxidant potential capacity against ferric ion. We also assessed pulmonary functions, fraction of exhaled nitric oxide, serum levels of vitamins, dietary vitamin intake, and physical activities. RESULTS: There were no relationships between the index of oxidative stress (dROM and H2O2 in exhaled breathe condensates) and pulmonary functions, serum levels of vitamins, daily vitamin intakes, and activity levels in patients with asthma. CONCLUSION: The status of transient oxidative stress may not be related to daily activities, vitamin levels, and pulmonary functions in patients with asthma in a real-life setting. However, our results were obtained in the short-term period from a small number of subjects, so a large longitudinal study is required to ascertain the relationships between oxidative stress, physical activity and vitamin intake in patients with asthma.
RESUMEN
OBJECTIVE: The purpose of this study was to investigate the effect of different recumbent positions on pulmonary function, chest wall motion, and feelings of discomfort in young nonobese healthy volunteers. METHODS: Twenty healthy volunteers (age, 28.0±1.4 years; height, 167.5±10.1 cm; weight, 62.3±10.2 kg) were studied in the sitting position and in the following 6 recumbent positions: supine, left retroversion at a 45° tilt, left anteversion at a 45° tilt, right retroversion at a 45° tilt, right anteversion at a 45° tilt, and prone. After 5 minutes of a selected position, pulmonary functions, including vital capacity (VC), forced expiratory volume in 1 second, maximal inspiratory and expiratory mouth pressures (MIP and MEP, respectively), and breathing pattern components at the chest wall were assessed. Discomfort was assessed using a modified Borg scale. RESULTS: When participants changed position from sitting to each of the 6 recumbent positions, forced expiratory volume in 1 second values decreased significantly (P < .05). None of the participants showed changes in the MIP or MEP in any of the 6 recumbent positions. Rib cage motion was restricted in all recumbent positions except supine, left anteversion at a 45° tilt, and prone. In all 6 recumbent positions, discomfort was experienced during the pulmonary tests. However, in the left retroversion at a 45° tilt position, no discomfort was experienced during the MIP and MEP assessments. CONCLUSION: In young, nonobese, healthy volunteers, recumbent positions caused diminished pulmonary functions and induced feelings of discomfort.