# Different Autonomic Responses to Experimental Pain in IBS Patients



## eric (Jul 8, 1999)

1: J Clin Gastroenterol. 2006 Oct;40(9):814-20. Links Different Autonomic Responses to Experimental Pain in IBS Patients and Healthy Controls.Tousignant-Laflamme Y, Goffaux P, Bourgault P, Marchand S. Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada.BACKGROUND: Pain perception ratings in irritable bowel syndrome (IBS) patients suggest that they present either hypoalgesia or hyperalgesia. However, little is known about the physiologic responses these patients present to a somatic painful stimulus. GOALS: The main goal of this project was to study autonomic nervous system responses and the cardiac response to experimental pain in IBS patients. STUDY: This was addressed by exposing 27 women, 14 IBS, and 13 healthy controls (HCs), to a cold water (7 degrees C) immersion test of the forefoot for 2 minutes. Pain perception, galvanic skin responses (GSR), and heart rate (HR) were monitored during and after the immersion. RESULTS: For comparable pain perception, a significant group difference (P<0.02) in the cardiac response was observed during the immersion where the peak rise in HR was much higher for HCs, reaching 22%, whereas it only reached 8% for IBS patients. Moreover, HR variability analysis demonstrated that IBS and HCs had opposite autonomic cardiac reactivity to pain, where IBS had increased parasympathetic/decreased sympathetic reactivity. CONCLUSIONS: For comparable pain perception, IBS subject demonstrated different autonomic nervous system response to pain, which supports the view of autonomic dysregulation in IBS.PMID: 17016138


----------



## SteveE (Jan 7, 1999)

This is really fascinating. It may explain something I've been trying to understand for years. I'm not a big treadmill fan for exercise, but occasionally I go to the YMCA and walk on one next to my spouse just to be with her for awhile. I tried different treadmills in the room and I astound my spouse each time by not registering a significant heart rate increase on it no matter how intense I make the incline or speed. This is not true, however with my exercise bike...but still, perhaps this is a part of an explanation for my lack of HR increase on the treadmill.But wait...I'm confused. Wouldn't we expect this to be the other way around? Aren't we supposed to be the "irritable" ones who would have a greater sympathetic NS reaction? Although the wiki page about the ANS does say that the parasympathetic NS is the "rest and digest" mode. Does this mean we're short-changed on adrenaline or need a little more pull from the sympathetic side? Uh-oh...Steve's in over-analysis mode...what part of the nervous system regulates that???


----------



## eric (Jul 8, 1999)

First steve, did you see the info for your wife I posted in the CBT/HT forum?You know Steve, its confusing for me also and one would expect like you have said overactivation of the sympathetic and not the parasympathetic.I will have to ask about this one.


----------



## SteveE (Jan 7, 1999)

> quote:u see the info for your wife I posted in the CBT/HT forum?


Yes, thanks. We'll weed through it shortly. One thing that doesn't help her condition is very limited free time. She has a 45 minute oneway commute to work each day and occasionally has to stay late. I've been previewing the sites, but they always seem to lead me to questions that I start trying to answer on other sites. Like I said: overly analytical right now.


----------

