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

Gastrointestinal reactivity is a central concept in several psychosomatic a pproaches to peptic ulcer disease and irritable bowel disease. One potentia l limitation of many laboratory studies of gastrointestinal reactivity is t heir reliance on non-ecological tasks lacking components of social stressor s which may better relate to day to day stress. Otherwise, the public speak ing task is a well known stressful procedure and has a high degree of ecolo gical validity. Stress reactions induced by preparation for public speaking are the result of both the cognitive demand of preparing a speech and soci al anxiety. The aim of this study was to observe the effect of the public s peaking test on the electrogastric activity and the relationship between ga stric myoelectrical activity and cardiac activity prior to and after the ta sk. In particular, we hypothesized that public speaking would reduce the am plitude of the normal 3 c.p.m. band and that this decrease would be positiv ely correlated with a reduction in respiratory sinus arrhythmia. As expecte d, the anticipation of public speaking triggered a decrease in respiratory sinus arrhythmia, an increase in heart rate, and higher skin conductance le vel compared to baseline. On the other band, our measure of gastric myoelec trical activity was not affected by the public speaking task. Copyright (C) 2001 John Wiley & Sons, Ltd.