How standard is a standard day during a standard ambulatory 24-hour esophageal pH monitoring?

Background: Ambulatory 24-h esophageal pH monitoring is the gold standard method for measuring esophageal exposure to gastric acid. The method has gained acceptability because of its sensitivity, specificity, and accuracy and also because it is easy to perform, well tolerated, and quite physiologic. However: whether ambulatory esophageal pH-metry affects normal lifestyle has not been specifically evaluated. Methods: We investigated 114 consecutive patients admitted to our Unit because of heartburn, acid regurgitation, or non-cardiac chest pain. Patients filled in a diary chart on 2 different days: 1 day while the pH-metry was performed and another normal day, to record the following variables: number, amount, and composition of the meals; time in supine position. number of cigarettes smoked; alcohol intake; degree of physical activity; and number and type of symptomatic episodes. Patients were encouraged to carry out normal activity. Results: When the 2 days were compared, none of the registered variables appeared to differ, with the exception of subjective evaluation of physical activity: 65% of the patients said their physical activity was diminished during the test day relative to their usual standard. Conclusions: Normal habits are not significantly modified by 24-h esophageal pH-metry, with the exception of physical activity, which decreases, possibly owing more to aesthetic than to physical problems.