How dehydration can be causing your GI problems while running

Runners get thirsty: drink. Runners get hungry: eat. But, as with most things that seem idiot-proof, the most basic of basics, two of the most rudimentary bodily functions can often turn into a runner’s nightmare. I just finished an article for Competitor providing the perfect example of this: “Got Stomach Issues? You’re Probably Dehydrated”.

What’s interesting, and as you will learn from reading the article, it’s often not FOOD wrecking havoc on your stomach and intestines during your hard or long runs. It’s the (not) DRINKING thing that’s giving you a GI nightmare! Talk about a whodathunkit moment, right? 😉
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I’ve been a runner for years and years and still, learning that dehydration is the culprit to most GI problems, both the upward and the downward, came as a bit of a surprise. But if you think about it, it really shouldn’t be; let’s look at what happens when you run:

* Muscles working: Brain and body prioritize the hard-working muscles as the top-tier function at the moment.
* Body delegates: In moving the muscles to priority number one, the stomach, intestines, and anything digestive related gets bumped down.
* Blood to muscles: All the major blood-flow gets shunted to the muscles, leaving the stomach and delicate intestinal tissues simultaneously deprived of blood-flow. This lapse in blood causes slight damage. Aww, poor, intestines. 😉
* Dehydration: Now water is INSANELY important to the body, it makes up darn near most of it, so NOT having enough water content in the blood stream exacerbates the damage caused to the already weakened stomach and intestines.
* The Backlash: Need I say more?

Runners experience those GI disasters, up and down, because the stomach and intestines are already deprived of blood-flow while you’re running and then on top of that if there isn’t enough water content in the body to begin with, they stage a major revolt.

Bottom line: It doesn’t matter what kind of food you’ve got in your stomach or intestines, if a runner isn’t hydrated, that food can’t be digested so it’s coming out…pick a direction.

Solution: Duh, Runners, stay HYDRATED! 😉 I jest, I jest, kind of…but the reality is, many times runners underestimate just how much fluids they need. What’s more, when I say fluids that includes more than just water: also electrolytes.
burrito pooping beans
The tricky thing with hydration is, once you’re dehydrated and experiencing the effects of it you’re already on a sinking ship. Kind of like it’s too late at that point; that’s why it’s IMPERATIVE you stay in a constantly hydrated state and remain that way through the duration of your hard workout or long run.

Staying hydrated during long runs, and marathon geared workouts, means taking in fluids and replenishing those stores at a steady rate. Read the article for some awesome tips from Molly Pritz and Krista Austin, Ph.D., on how to come up with a personal hydration regimen.

See, you think relying on those little “I’m thirsty” cues is enough to keep you hydrated. But the truth is, especially for runners, by the time you FEEL thirsty you are already in a state of dehydration. So go chew, err sip, on that. 😉

1) Had you been aware dehydration could be the culprit of you GI problems?

2) Especially in the heat GI problems become more common, how do you make sure to stay even more conscious of fluid consumption when it’s hot or humid?

3) An upset stomach after a hard or long run can be common too, and traced back to dehydration. What are some of your go-to ‘safe’ foods for restoring and repairing those muscles AFTER your runs?
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23 thoughts on “How dehydration can be causing your GI problems while running

  1. OK – I’m going to really put this to the test this weekend – I have a 5 hour run scheduled and any time I run much longer than an hour I always have issues. I’m going to focus on drinking more than I normally do and see if it helps.

      • Well, I stayed hydrated better than normal (I never stopped sweating and I have during past long runs!) but my stomach was still unhappy by the time I finished. I guess 31 miles of bouncing around is going to cause some upset!

        • great to hear u hydrated like a fiend! but i’d venture to agree 31 miles will always lead to some upset, but u prolly avoided a real nightmare. 🙂

  2. Thank you for the great information! I have been having “bathroom issues” on most of my runs since it got hotter outside, and not drinking enough during the day while I’m at work may very well be the culprit. Unfortunately I’m not sure how to fix this. I can’t full explain without disclosing my job, but I work out of my car and the majority of my day is involved walking around doing stuff when I can’t carry fluids with me. My only opportunities to hydrate are when I’m in the car typing my report, and I do, but I think I need to consume even more.

    My safe post-long run food is eggs!

    • shoots, let’s get creative with how u can stay hydrated…is there any way u can have a watterbottle SOMEWHERE stashed in ur car? could u even slip some kind of camel pack on under a loose shirt?? i dunno, we’ve got to come up with something for u!

  3. I absolutely agree with you! Hydration is so important and once you are thirsty, you are simply too late. I have been working extra hard at staying hydrating especially during these hot and humid months where I am sweating beyond my own belief. I definitely feel the effects if I am not hydrating properly. Lately water doesn’t cut it so I find that watermelon or really any fruit added into my diet does the trick – but watermelon works the best.

    • i honestly have no IDEA how you who live in states with ‘real’ weather survive! and watermelon is a great double-duty food…got your water, some electrolytes, and antioxidants…dang, win win! 😉

  4. I knew it could be a hindrance, but I never thought about it being the cause. Thanks Wizard Cait!!

    Safe foods after exercise – carbs and protein. Hand me some eggs and toast please :-). My nutritionist swears by a smoothie when I don’feel like eating after a long run. Yogurt and berries for the win.

  5. I honestly had no idea. Whenever I had er… stomach issues during a run I assumed it was because of something I had eaten, not that I was dehydrated. I feel like I already drink a lot of water but you can bet I’ll be drinking more with this info!!

  6. I feel like I should call you Dr Cait now. It certainly has a lovely ring to it!
    I am a little ashamed to admit that I let myself get dehydrated way too often, and when I stumbled on your article just after my half marathon (while experiencing some GI issues) I jumped straight on the water train, and I am certainly getting better at making sure I don’t reach the ‘too far’ point again.
    Thanks Cait!

    • awww shucks, u are too kind! 🙂 tho maybe doc klutz is more fitting…hehe. but i’m bummed i couldn’t have caught u BEFORE ur half…buuuuut, at least now u’re making sure to double up on those fluids!

  7. I’m with the girls… You are a wizard/doctor. I’ve been lucky to have only had GI issues a couple of times and I think they were all in the heat when hydration could have been better.

    Being hydrated is the base for good functioning of everything. An IV would be so convenient on those “too busy to remember” days!

    • u’re so sweet! haha. we should invent a nice little hydrator shot for runners…kinda like an epi-pen that would work ASAP mid-run or mid-race…but let’s find a better way than with needles. #needlephobic 😉

  8. Wish I had found this years ago…I did finally figure it out on my own, but I suffered from horrible stomach cramps for a long time! I don’t remember exactly how I discovered that they were caused by dehydration, but I have been very careful to hydrate all day every day ever since I figured it out. It might have been because I was running first thing in the morning when my stomach was empty, so that’s how I knew food wasn’t the culprit. I also was getting awful leg cramps for awhile (more recently), and they turned out to be caused by too much salt in my diet; no matter how much water I drank, it wasn’t enough to counteract all the salty food I was eating.

    • while i’m sorry it didn’t come soon enough to spare you of all your problems, i’m glad NOW you know how to beat those nasty GI disaster runs!! and make sure to get some of those fluids packed full with the electrolytes, that salt/sodium one definitely makes a difference with the cramps. let me know how it goes!

  9. Pingback: Hydrate Like a Champ: Running, fluids, electrolytes, and Nuun Energy |

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