Effect of Abdominal Wall Activity on the Responses to Meal Ingestion

Meal ingestion induces sensations that are influenced by a series of conditioning factors. Aim: to determine the effect of abdominal wall activity on the responses to a standard probe meal. Study in healthy subjects comparing postprandial digestive sensations (abdominal bloating and digestive well-being) during consecutive maneuvers of diaphragmatic contraction (i.e. descent) versus diaphragmatic relaxation (i.e. ascent) in a cross-over randomized design. Primary outcome: effect of somatic maneuvers on abdominal bloating sensation; secondary aim: effect on digestive well-being.

Participants (16 women) will be instructed to eat a standard dinner the day before, to consume a standard breakfast at home after overnight fast, and to report to the laboratory, where the test meal will be administered 4 h after breakfast. Studies will be conducted in a quiet, isolated room. Participants will be taught to produce diaphragmatic contraction and visible abdominal distention. A probe meal up to maximal satiation will be administered to induce abdominal fullness/bloating sensation; immediately after ingestion, bloating sensation (from 0 to 10) and digestive well-being (from -5 to +5) will be scored during 8 alternating episodes (30 s each) in random sequence of diaphragmatic contraction (abdominal distension) versus diaphragmatic relaxation.