title: Increased oesophageal acid exposure at the beginning of the recumbent period is primarily a recumbent-awake phenomenon.
abstract: BACKGROUND
  A significant increase in oesophageal acid exposure during early recumbent period has been demonstrated.
  
  
  OBJECTIVE
  To determine if acid reflux during the early recumbent period occurs in the recumbent-asleep or recumbent-awake period using a novel integrative actigraphy and pH programme.
  
  
  METHODS
  Thirty-nine subjects with heartburn at least three times a week were included. Subjects underwent pH testing concomitantly with actigraphy. Simultaneously recorded actigraphy and pH data were incorporated using a novel integrative technique to determine sleep and awake periods. Characteristics of acid reflux were compared between the recumbent-awake and recumbent-asleep periods.
  
  
  RESULTS
  Seventeen (44.7%) subjects had acid reflux events during recumbent-awake period as compared to seven (18.4%) in the corresponding recumbent-asleep period (P = 0.046). The mean number of acid reflux events in recumbent-awake period was significantly higher than in the corresponding recumbent-asleep period (8.1 +/- 4.4 vs. 3.2 +/- 1.5, P < 0.001). In the recumbent-awake period, 38.4% of acid reflux events were associated with GERD-related symptoms as compared with 3.7% of acid reflux events during the corresponding recumbent-asleep period (P = 0.01).
  
  
  CONCLUSIONS
  Increased acid reflux in the early recumbent period occurs primarily during the recumbent-awake and not during the recumbent-asleep period.
authors.affiliation: The Neuroenteric Clinical Research Group, Southern Arizona VA Health Care System, Tucson, AZ 85723-0001, USA.
authors.forename: L
authors.initials: L
authors.lastname: Allen
authors.forename: C H
authors.initials: CH
authors.lastname: Poh
authors.forename: A
authors.initials: A
authors.lastname: Gasiorowska
authors.forename: I
authors.initials: I
authors.lastname: Malagon
authors.forename: T
authors.initials: T
authors.lastname: Navarro-Rodriguez
authors.forename: H
authors.initials: H
authors.lastname: Cui
authors.forename: J
authors.initials: J
authors.lastname: Powers
authors.forename: B
authors.initials: B
authors.lastname: Moty
authors.forename: M R
authors.initials: MR
authors.lastname: Willis
authors.forename: N
authors.initials: N
authors.lastname: Ashpole
authors.forename: S F
authors.initials: SF
authors.lastname: Quan
authors.forename: R
authors.initials: R
authors.lastname: Fass
mesh_terms: D056044:Actigraphy / Q000379:methods*; D002940:Circadian Rhythm; D050782:Esophageal pH Monitoring; D005260:Female; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012890:Sleep; D011795:Surveys and Questionnaires