Increased oesophageal acid exposure at the beginning of the recumbent period is primarily a recumbent-awake phenomenon.

Background: A significant increase in oesophageal acid exposure during early recumbent period has been demonstrated.

Aim: 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.

Method: 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).

Conclusion: Increased acid reflux in the early recumbent period occurs primarily during the recumbent-awake and not during the recumbent-asleep period.