A 26-year-old business executive complained of a dull pain (heartburn) behind the sternum. The painwas postprandial (occurred after meals) and disappeared within a few minutes to an hour. It was oftenassociated with belching and often was worse on lying down or on exertion after heavy meals.Sometimes it radiated to the back, jaws, shoulders, and down the inner aspects of the arms, simulatingangina pectoris. X-rays revealed a small portion of the stomach above the diaphragm, and anendoscopic biopsy revealed mucosal inflammation. Esophageal manometry (determining pressures atthe lower esophageal sphincter, LES) revealed decreased LES pressure. Esophageal pH monitoringshowed reflux of gastric contents into the esophagus and provided direct evidence of gastroesophagealreflux. Recommended treatment for this individual is avoidance of strong stimulants of gastric acidsecretion (e.g., coffee, alcohol) and avoidance of certain drugs (e.g., anticholinergics), and specific foods(fats, chocolates, whole milk, and orange juice), and smoking, all of which reduce LES competence.Elevation of the head of the bed by about six inches is also recommended. Suggested treatments alsoinclude the use of cholinergic agonists (e.g., bethanechol) and the use of histamine (H2) antagonists(cimetidine).

5. Why is elevation of the head of the bed recommended?