Limiting factors during exercise and effect of a pulmonary rehabilitation in the clinical control and Health Related Quality of Life in obese asthmatics

Abstract

Asthma is a chronic inflammatory disease of the airways, and obesity is a metabolic syndrome. Both have become increasingly prevalent in several countries in the last decades, turning to be a serious global health problem. The association between asthma and obesity seems to lead to a "unique phenotype" that is characterized by more severe symptoms and altered responsiveness to medications. Studies suggest that weight reduction by surgery in asthmatics obese reduces asthma symptoms. However, the anti-inflammatory and immunoregulatory effects of exercise to asthma control in obese are not well-know, despite many studies suggest that such effects are important to disease control in asthmatic. In addition, the limiting factors of exercise in asthmatics obese are not known. Objective: This study will be conducted in two phases: in the first it will be evaluated and compared the limiting factors during exercise in patients with severe persistent asthma, asthmatic obese and asthmatics eutrophic; in the second phase it will be assessed the effect of weight loss with or not to exercise training in clinical management and health factors related to quality of life in obese asthmatics. Methods: In the first phase it will be evaluated 24 asthmatic obese females (BMI 35 to 39.9 kg/m2) and 24 normal weight females with asthma. They will be evaluated on 3 nonconsecutive days for quantification of physical, clinical and anthropometric characteristics. Patients will perform a cardiopulmonary exercise test to determine maximal aerobic capacity and then it will be held a submaximal exercise (75% of maximum) to assess the presence of lung hyperinflation. The inspiratory muscle strength, the endurance of the quadriceps muscle and pulmonary function tests will also be fully evaluated. The limitation to exercise will be classified as respiratory, cardiac and peripheral based on criteria previously established in the literature. In the second phase it will be studied 56 asthmatic adults (BMI 35 to 39.9 kg/m2) of both genders randomly divided into 2 groups: control (nutrition and psychological programs, stretching and breathing exercises) and trained (nutrition and psychological program and aerobic and resistance exercise). The program will be held in 32 sessions, twice per week, during 90 minutes. Everybody will be evaluated before and after the intervention with respect to clinical control, health related quality of life, levels of pulmonary and systemic inflammation, levels of anxiety and depression, sleep disorders, lung function, physical capacity, body composition and anthropometric indexes. The sample size calculation for each study has been computed. In the first phase, it will be performed Student's t-test to compare the continuous variables and chi-square test to compare the categorical ones. In the second phase, the ANOVA test with two factors will be performed to make a comparison between the initial and final variables. In the case that any difference is identified, it will be performed a post-hoc Bonferroni test. The significance level will be set to 5% (p <0.05) for all tests. (AU)