Effects of Breathing and Core Stabilization Exercises in Gastroesophageal Reflux Disease

No exercise intervention will be applied to the control group.

Diaphragmatic breathing exercises will be performed 5 days per week.

Diaphragmatic breathing exercises will be designed to facilitate conscious activation of the diaphragm and to support the function of the lower esophageal sphincter and crural diaphragm.

The exercise programs will last 8 weeks. Core stabilization exercises will be performed 3 days per week, while diaphragmatic breathing exercises will be performed 5 days per week.

Diaphragmatic breathing exercises will be designed to facilitate conscious activation of the diaphragm and to support the function of the lower esophageal sphincter and crural diaphragm.

Core stabilization exercises will target the transversus abdominis, multifidus, pelvic floor, and diaphragm muscles, aiming to optimize trunk posture, abdominal-diaphragmatic coordination, and intra-abdominal pressure regulation.

The Gastroesophageal Reflux Disease Questionnaire (GERD-Q) is a six-item Likert-type questionnaire that assesses the frequency of GERD-related symptoms over the past week. The first four items evaluate the frequency of typical symptoms and are used for the diagnosis of the disease and monitoring response to treatment. The remaining two items assess the frequency of the disease's impact on daily life, including over-the-counter medication use and sleep disturbance. Each item is scored on a four-point scale ranging from 0 to 3 according to symptom frequency. In items 1, 2, 5, and 6, higher scores indicate increased symptom frequency, whereas in items 3 and 4, scoring is reversed, with higher symptom frequency corresponding to lower scores.

The PROMIS GERD scale consists of 13 items. The questionnaire includes a total of 13 questions, each scored on a scale ranging from 0 to 4 points. The total score is obtained by summing the scores of all items.

According to the scoring system of the original questionnaire, a score of 0 indicates no symptoms, scores of 1-3 indicate minimal symptoms, scores of 4-7 indicate mild symptoms, scores of 8-15 indicate moderate symptoms, and scores of 16 and above indicate severe symptoms.

The Gastroesophageal Reflux Disease Quality of Life Questionnaire (GERD-QOL) aims to assess how regurgitation and heartburn symptoms affect patients' daily life over the past 7 days. It consists of 16 items under four main domains: daily activities, treatment effect, diet, and psychological well-being. The questionnaire is rated using a five-point Likert scale. Lower total scores indicate poorer quality of life.

The Posture Screen Lite application is a posture analysis, body composition, and movement assessment software designed for use on iOS and Android devices with integrated camera systems. In this study, posture will be assessed using the iPad-based Posture Screen Lite application.

Participants will be assessed wearing appropriate clothing that leaves the upper trunk and lower legs exposed. Photographs will be taken from anterior, posterior, and right and left lateral views using a smartphone, without placing reference markers on the participant beforehand. The captured images will then be analyzed using the Posture Screen Lite software by identifying anatomical reference points on the photographs.

Based on these marked points, postural deviation values and the degree of postural imbalance will be calculated by the software and reported for each participant in centimeters (cm).

The Visual Analog Scale (VAS) will be used to assess participants' pain intensity. The VAS is a valid and reliable method that is sensitive to small changes in clinical pain and treatment-related pain intensity.

Participants will be asked to indicate their pain level on a 10-cm horizontal line, where "0" represents "no pain" and "10" represents "the worst imaginable pain." In addition, participants will be asked to mark the location(s) of their pain on a body diagram to identify pain distribution and localization.

The Pittsburgh Sleep Quality Index (PSQI) is a scale that evaluates sleep quality and sleep disturbances over a one-month period. The PSQI was developed by Buysse et al. (1989) and has been shown to have adequate internal consistency, test-retest reliability, and validity. The Turkish validity and reliability study was conducted by Ağargün et al. (1996), and the scale was found to be appropriate for the Turkish population. The Cronbach's alpha internal consistency coefficient is 0.80. The PSQI consists of 18 items used for scoring. It includes seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. Some components are derived from a single item, while others are calculated by grouping multiple items. Each item is scored on a scale of 0 to 3, and the sum of the seven component scores yields the total PSQI score.