A ONE-HOUR ACTIVE COPING STRESSOR REDUCES SMALL-BOWEL TRANSIT-TIME INHEALTHY-YOUNG ADULTS

To examine the effect of a prolonged active coping stressor on the tra nsit of a substance from the mouth through small intestine in normal h uman volunteers. Method: Twelve healthy undergraduate males were admin istered 10 g of the nonabsorbable carbohydrate lactulose in two experi mental sessions. In normal individuals, lactulose produces hydrogen ga s upon exposure to bacteria residing in the colon. Repeated measuremen ts of breath hydrogen were obtained for 2 hours. In one session, subje cts rested quietly for the 2-hour period. In the other counterbalanced session, subjects avoided mild electric shocks by playing videogames for the first hour. Results: Stress produced a statistically and clini cally significant reduction in mean transit time, from 79 to 55 minute s. The magnitude of stress-induced reduction in small bowel transit ti me was significantly correlated with change in an index of cardiac sym pathetic activity, pulse transit time. Conclusions: A prolonged active coping stressor with minimal motor requirements produced a decrease i n small bowel transit time comparable with that observed in several st udies of the effects of physical exercise and in comparisons between n ormal controls and patients with diarrhea-predominant irritable bowel syndrome.