Effect of public speaking on gastric myoelectrical reactivity and parasympathetic cardiac control

Gastrointestinal reactivity is a central concept in several psychosomatic approaches to peptic ulcer disease and irritable bowel disease. One potential limitation of many laboratory studies of gastrointestinal reactivity is their reliance on non-ecological tasks lacking components of social stressors which may better relate to day to day stress. Otherwise, the public speaking task is a well known stressful procedure and has a high degree of ecological validity. Stress reactions induced by preparation for public speaking are the result of both the cognitive demand of preparing a speech and social anxiety. The aim of this study was to observe the effect of the public speaking test on the electrogastric activity and the relationship between gastric myoelectrical activity and cardiac activity prior to and after the task. In particular, we hypothesized that public speaking would reduce the amplitude of the normal 3 c.p.m. band and that this decrease would be positively correlated with a reduction in respiratory sinus arrhythmia. As expected, the anticipation of public speaking triggered a decrease in respiratory sinus arrhythmia, an increase in heart rate, and higher skin conductance level compared to baseline. On the other band, our measure of gastric myoelectrical activity was not affected by the public speaking task. Copyright (C) 2001 John Wiley & Sons, Ltd.