This study aims to understand why patients have predominantly upright gastroesophageal reflux disease by comparing such patients to healthy persons AND whether a behavioral intervention (diaphragmatic breathing) will impact this disease

There are two major patterns of gastroesophageal reflux disease (GERD), predominantly daytime and upright reflux and predominantly nocturnal and supine reflux.

Traditionally, upright reflux has been attributed to more frequent or wider opening with transient lower esophageal sphincter relaxations (TLESRs) while supine reflux results from a consistently reduced lower esophageal sphincter (LES) pressure. This may further be accounted for by the finding of larger hiatal hernias and greater pressure gradients between the crura and LES when comparing supine to upright refluxers. These findings may help explain supine reflux, but they offer little insight into the mechanisms of upright reflux.

In this study the investigators will be recruiting twenty healthy persons and up to 60 patients with GERD will be recruited from the clinical practice at Mayo Clinic Rochester. The investigators aim to study the intervention on 40 patients with GERD. However, recognizing that up to 33% of patients with typical symptoms of GERD will not have reflux by ambulatory pH monitoring (pH power of hydration), the investigators provide for enrolling up to a maximum of 60 patients which should be sufficient to yield 40 patients with upright GERD by pH monitoring. In addition, up to 10 additional healthy persons may be recruited.

Subjects with upright reflux and healthy controls will be randomized into one of two groups:

Experimental: Diaphragmatic breathing or Sham comparator: (listening to music/watching Television (TV) for 30 minutes after each meal to see how this impacts the disease.

Inclusion Criteria for Healthy Persons:

-Patients 18 years of age or older with no symptoms of GERD

Inclusion Criteria for Patients:

• Patients 18 years of age or older with symptoms of GERD
• Upper gastrointestinal endoscopy within the past 6 months and a prior diagnostic pH impedance study showing predominantly upright reflux

Exclusion Criteria for Patients; Items indicated with an asterisk (*) are also exclusion criteria for healthy persons

• Patient who fulfil ROME IV Criteria for rumination disorder20
• Clinical evidence of significant cardiovascular, respiratory, renal, hepatic, gastrointestinal, hematological, neurological (e.g., spinal cord injuries, dementia, multiple sclerosis, Parkinson's disease), psychiatric or other disease that may interfere with the objectives of the study and/or pose safety concerns.*
• Any prior gastric or esophageal surgery and significant intestinal or colonic resection*
• Hiatal hernia measuring 3 cm or larger as assessed by endoscopic or radiological studies
• Prior history of Los Angeles Grade C or D esophagitis, or esophageal stricture.
• Current use opioid analgesics or anticholinergic drugs.* We will permit low doses of tricyclic antidepressants, nortriptyline (up to 50 mg/day) or amitriptyline (up to 25 mg/day) provided they were commenced 3 months prior to the screening period, calcium channel or adrenergic1 antagonists
• Current use of proton pump inhibitors
• Known significant esophageal motor disorder (ie achalasia, aperistalsis, functional obstruction, jackhammer, distal esophageal spasm)*
• Inability to read due to: blindness, cognitive dysfunction, or English language illiteracy *
• Pregnant and lactating females *

Exclusion Criteria for Healthy Persons in addition to those marked with an Asterisk (*) above

• Ongoing use of Proton Pump Inhibitors ( PPIs) or a history consistent with GE reflux for 3 months or longer duration in past.
• Prior history of Los Angeles Grade B-D esophagitis
• Prior history of GERD on the basis of pH testing