The purpose of this study is to determine the effects of proton pump inhibitors (PPIs) on the total number of reflux episodes in the distal esophagus measured by impedance in patients with and without gastroesophageal reflux disease (GERD) based on 24-hour pH testing. In addition to changing the acidity of the refluxate, the investigators hypothesize that PPIs also reduce the total number of reflux episodes due to its anti-secretory effects.