The Effect of Autonomic Modulation on Symptoms in Patients With Reflux Hypersensitivity

This is a randomized single-blinded parallel study and the investigators aim to recruit 40 participants. Patients will be enrolled for a period of 4 weeks and don't have to attend our institution. A video chat on day 1 will consist of confirming eligibility, after which the patient will be randomised to follow either the slow deep breathing protocol or the sham breathing protocol in a single blinded fashion. That is, the patient will be unaware of which the active breathing exercise is. Once randomised during a video chat, they will undergo baseline heart rate variability (HRV) measurements using a smartphone app, answer the questionnaires on Research Electronic Data Capture (REDCap), and then practice the relevant breathing exercise with an instruction video. The patient will then be trained to self-administer the breathing exercise during a video chat, which will be used twice a day for 10 minutes over the next 4 weeks with a standardized instruction video. This study finishes when participants answer the online questionnaire and record HRV on day 29. The investigators will set up this questionnaire on our electronic data capture system (Research Electronic Data Capture: REDCap). Participants will answer questionnaires using this online system on day 1, day 8, day15, day 22, and day 29 (end of the study). Therefore, participants will also be trained on how to use REDCap and answer questionnaires under supervision on day 1 during a video chat. Questionnaires on day 8, 15, 22, and 29 will be answered at home. The investigators will send a reminder message to participants using a REDCap system the day before they answer the questionnaire. Participants will be asked to record their HRV using a smartphone app on day 1, 8, 15, 22, and 29.