Incentive Spirometer

The goal of this clinical trial is to evaluate whether two types of breathing training can improve symptoms of gastroesophageal reflux disease (GERD) in adults. The main research questions are: * Do volume-oriented incentive spirometry (VIS) or diaphragmatic breathing exercise (DBE) improve GERD symptoms compared with usual care? * Do these breathing exercises reduce the symptoms of GERD? * Does volume-oriented incentive spirometry (VIS) produce greater improvement in GERD symptoms compared with DBE? * Do these exercises increase the strength of the lower esophageal sphincter (LES)? Researchers will compare VIS training, DBE training, and usual care to determine whether breathing training can serve as a safe and effective non-pharmacological treatment option for GERD. Participants will: * Be randomly assigned to VIS training, DBE training, or usual care * Perform their assigned breathing training (if in the intervention group) twice daily for 6 weeks * Attend study visits at baseline and at week 7 for questionnaires and esophageal function tests * Keep a diary of their symptoms and breathing practice

The study was done to: 1. Investigate the effect of respiratory training on functional lung capacity and 2. To detect the effect of respiratory training on pulmonary functions in children with β-thalassemia major. 3. To detect the level of oxygen saturation and heart rate during and after blood transfusion in children with β-thalassemia major.