Objective: Stress modulates gut function, but whether the type of stressor influences colonic motor activity is unclear. The motor patterns and regional variations are also poorly understood. Our aim was to determine the effects of psychological and physical stress on colonic motility. Methods: Ambulatory colonic manometry was performed by placing a six-sensor probe up to the midtransverse colon, without sedation, in 12 healthy subjects. Five hours later, a dichotomous listening test (psychological stress) was performed, which was preceded by listening to a narrative passage (control); recovery entailed listening to relaxing music (1 h each). Subsequently, intermittent hand immersion in cold (4°C) water (physical stress) was performed, preceded by hand immersion in warm (37°C) water ( 1/2 -h each). Colonic pressure activity and cardiovascular responses were measured throughout the study. Results: When compared with the control period, both stressors induced a greater number of pressure waves (p < 0.05), and the area under the curve (p < 0.01), but only physical stress increased (p < 0.05) pulse rate and blood pressure. There were no regional differences in colonic motility. During recovery, the motor activity returned to baseline after physical stress, but remained high after psychological stress. Psychological stress induced more (p < 0.05) propagated contractions, whereas physical stress induced more (p < 0.05) simultaneous contractions. Conclusions: Both stressors enhanced colonic motor activity, but psychological stress induced a prolonged response with propagated activity and without appreciable autonomic response. Thus, colonic motor responses may vary depending on the stressor.
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