EFFECT OF ACUTE STRESS ON ANORECTAL PHYSIOLOGY IN NORMAL HEALTHY-VOLUNTEERS

Objective: Visceral hypersensitivity occurs in many patients with irri table bowel syndrome; however, it is more common in those with high an xiety levels, raising the possibility that it is merely a reflection o f underlying anxiety. The aim of this study was to assess the effect o f acute stress on anorectal motility and sensitivity in normal healthy volunteers. Design and methods: Anorectal responses to balloon disten sion were assessed in 14 healthy volunteers (aged from 24-52 years; 11 women) on three separate occasions in random order during exposure to either cold pain, mental stress or control conditions. Results: Both subjective and objective measures of stress increased significantly du ring both stress studies [subjective stress level (mean+/-SEM): contro l 23+/-2.9, cold pain 56+/-5.4, mental stress 61+/-6.5, P<0.002; pulse rate: control 71+/-0.5, cold pain 82+/-0.9, mental stress 84+/-1.2, P <0.01]. However, there were no changes in rectal sensitivity [volume t o discomfort (ml): control 190+/-14.5, cold pain 198+/-16.9, mental st ress 180+/-14.9]; rectal compliance (ml/cmH2O; control 6.4+/-0.56, col d pain 7.3+/-0.86, mental stress 6.3+/-0.6), or distension-induced mot ility (control 1405+/-376, cold pain 1389+/-387, mental stress 1021+/- 289). Conclusion: Acute stress does not effect the anorectal response to balloon distension in normal volunteers. Further studies are requir ed to assess whether patients with irritable bowel syndrome respond in a similar or different way to acute stressful stimuli.