In my experience, I believe that mental stress has a significant impact on the colon.
I found this to be especially true when my ulcerative colitis symptoms were worsening. When I experienced emotional stress from work or personal life, the affected area (in my case, the rectum area (lower left abdomen)) would tingle and shiggle. And I often had severe lower bleeding.
Until I developed ulcerative colitis, I underestimated the impact of mental stress on my body, but now I know firsthand its power.
If you are not currently experiencing good symptoms of ulcerative colitis, I urge you to maintain mental rest.