Nocturnal Gastroesophageal Reflux and Sleep Depth in Healthy Adults, as Measured by Portable High-Resolution Manometry, Esophageal pH, and Electroencephalography

Background: The primary mechanism of diurnal gastroesophageal reflux (GER) is transient lower esophageal sphincter relaxation (TLESR) in both healthy persons and patients with gastroesophageal reflux disease (GERD). However, few studies have examined nocturnal GER. Using portable high-resolution manometry (HRM), esophageal pH, and electroencephalography (EEG), we investigated the association of onset of nocturnal GER with sleep depth in healthy Japanese adults. Methods: We recruited ten healthy men (mean age 33.5 ± 4.2 years) with no reflux symptoms, no history of surgery, and no current medication use. HRM and an esophageal pH catheter were inserted in the evening. The participants returned home after consuming a test meal, and EEG was placed at home before bedtime to measure sleep depth. Results: The main mechanism underlying nocturnal GER was TLESR (15/17 episodes: 88.2%). The rate of TLESR with nocturnal GER during sleep was high (51.9%, 27/52 episodes). Sleep depth during TLESR was 44.2% (23/52 times) awake and 34.6% (18/52 times) shallow sleep (N1-2). Sleep depth during TLESR with nocturnal GER was 74.0% (20/27 time) awake and 18.5% (5/27 times) shallow sleep (N1-2). Conclusion: The primary mechanism underlying nocturnal GER was TLESR in healthy Japanese men. TLESR and TLESR with nocturnal GER were more frequent during awakenings and shallow sleep.