Gastroesophageal reflux and esophageal motility were studied for 24 hr in 32 ambulatory healthy volunteers (20–73 years old), using a newly developed system, consisting of a microprocessorbased data recorder and algorithms for fully automated data analysis. Physiological reflux was more extensive than expected on the basis of widely used normal values. The percentage of time with pH<4 and="" the="" duration="" of="" the="" reflux="" episodes="" increased="" with="" age.="" of="" the="" more="" than="" 2000="" esophageal="" contractions="" occurring="" per="" day,="" peristaltic="" contractions="" constituted="" 50.9±2.0%.="" their="" amplitude="" was="" significantly="" lower="" between="" meals="" than="" during="" meals="" and="" during="" the="" night.="" the="" duration="" of="" the="" peristaltic="" contractions="" increased="" with="" age.="" simultaneous="" contractions="" constituted="" 10.4±1.2%="" of="" the="" esophageal="" contractions.="" their="" incidence="" increased="" with="" age.="" we="" conclude="" that="" continuous="" ambulatory="" 24-="" hr="" recording="" with="" automated="" analysis="" of="" esophageal="" motility="" and="" ph="" profile="" is="" feasible,="" that="" the="" upper="" limits="" of="" normal="" in="" ambulatory="" esophageal="" ph="" recording="" are="" higher="" than="" previously="" accepted,="" and="" that="" age,="" meals,="" and="" body="" position="" must="" be="" taken="" into="" account="" in="" the="" interpretation="" of="" both="" 24-hr="" esophageal="" ph="" and="" pressure="">.
Key words ambulatory recording - computer analysis - esophageal motor activity - esophageal pH - gastroesophageal reflux