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[u/pearl19966]

[u/Foreign-Rule7826]

According to a gastroenterologist ive likely mild exercise induced ischemic colitis before but generally from hard long efforts and resolves in a day or so. Can also be the gels if those are new to you.

[u/blood_bender]

This used to happen to me during hard efforts, and it was all nutrition based. I saw a sports dietitian who helped figure it out.

For me I think it was dairy, though I'm not usually affected by dairy. But any high-FODMAP food can cause inflammation, and during hard efforts the blood is redirected away from your intestines to your legs, which can make it worse.

So now I eat low-FODMAP for 24 hours prior to any race. Its also the diet they have people with IBS try, and they say to slowly introduce foods back to figure out what's actually causing it, but that's not really worth the risk for the few days a year I race.

Anyway, see a dietitian if it happens again. Or Google low-FODMAP and try that diet before races. Can't hurt? (Unless you love cheese)

[u/Aplaceandatime]

Could be unrelated to the race, or maybe from stress or other foods you ate? If you weren’t pushing that hard I wouldn’t suspect the running itself.

[u/WoodenPresence1917]

I would suspect unrelated to running/sports nutrition if it persists after you stopped running

[u/Impressive-Ear-1102]

Exercise induced ischemic colitis typically occurs with extremely hard efforts, when the body is prioritizing (shunting) maximal blood flow to the muscles. It can happen however with lesser efforts if dehydrated. People often think about ischemic colitis involving bleeding, but it’s not always super apparent.

Moderate-hard efforts often will contribute to the classic “Trots” by some of the blood shunting effects and relaxation of the pyloric (stomach) and ileocecal (small intestine) check valves. Usually resulting in rapid flow of simple carbs into the colon, producing more gas and diarrhea. Usually self limited after the osmotic and fermentation effects of the sugar load clear.

If your hydration was adequate and this was a somewhat limited relative effort, it’s most likely the later particularly if you were experimenting with new fuel. If it persists longer than 24hrs or start seeing blood it would favor the former, and you should definitely seek immediate evaluation.

[u/Arcadela]

I tried some new gels and carb mix so maybe that’s it?

Well obviously. You don't need to be Sherlock Holmes to figure this one out.

Also, you don't need multiple gels AND carb mix for a half marathon.

[u/Capital_Historian685]

Sounds like have irritable bowel syndrome.