How to Recover Your Gut After a Marathon: 7 Things to Do After Race Day

You did it! That feeling of seeing the finish line and crossing it is incredible.

26.2 miles is no joke.

Months of training.

Early mornings.

Long runs on the weekends.

Sore legs.

Figuring out your fueling.

And now....?

Your legs aren't the only thing that needs to recover.

Your gut just ran a marathon, too.

I remember finishing my first 70.3 half-ironman. In fact, I call it the race of stupid because not only was my nutrition all off, I ended up getting heat exhaustion. My second 70.3 left me feeling super sick with flu-like symptoms.

Your GI tract, nervous system, and even your hormonal system can take a beating after a physically grueling activity.

If you're experiencing nausea, diarrhea, bloating, stomach cramps, loss of appetite, or just feel like your digestive system is completely "off" after your marathon, your body may simply be asking for a little recovery time.

So, what should you do?

1. Rehydrate—But Don't Go Crazy

Yes, you need fluids, but chugging tons of plain water isn't the best.

You just spent hours sweating, losing fluids and electrolytes, and asking your digestive system to keep working while you ran 26.2 miles.

Try sipping on black cherry juice, pickle juice, and normal sodium broth. Clear pedialyte is also a good choice.

Your gut needs very easy, electrolyte rich, fluids. Take smaller, frequent sips throughout the next few days to replenish and restore what you've lost.

2. Start With Foods Your Gut Already Knows

This is probably not the time to challenge your digestive system with something completely new.

If your stomach feels sensitive, start with familiar, easy-to-tolerate foods. You might even need the B.R.A.T. diet for a few days. That's bananas, rice, apples, and toast to keep things easy.

Think carbohydrates + protein to begin replenishing what you just used and remember, keep it simple.

3. If You're Nauseous, Don't Force a Giant Meal

You cross the finish line and everyone wants to celebrate with burgers, pizza, beer, and a massive meal.

Meanwhile, your stomach is saying...Absolutely not!

Listen to it.

If solid food sounds terrible, then take to fluids and softer, cooked foods. This is much easier on the digestive tract.

Start small. Refuel gradually.

Your appetite will likely return as your body settles down. It might take a few days, but I promise, it'll get back to normal.

4. Give the Celebration Drinks a Minute

I know, I know... You just ran a marathon and a beer sounds amazing!

You've earned it!

But if you're already dehydrated, nauseated, having diarrhea, or your stomach feels irritated, alcohol may not be what your gut needs right away.

Give your body a moment to catch up.

5. Keep Moving—Gently

Recovery doesn't necessarily mean lying completely still for two days.

A gentle walk can help get your body moving again without adding another major training stress.

Notice the word gentle.

Do NOT "run it out" with crazy sprints and hill repeats.

Your body just ran a marathon.

Give it some grace.

6. Sleep and Let Your Body Recover

Your muscles, nervous system, and digestive system are all recovering.

In fact, your entire body just experienced a major physiological stressor.

So, if you feel more tired than usual, give yourself permission to take your active recovery week seriously.

*Don't be surprised if your sleep feels a little strange the first night or two, either. The nervous system is coming down from an endorphin and adrenaline high. It might take a moment for it all to settle back down.

7. Before You Forget—Do a Gut-Nutrition Debrief

This may be the most important thing you do after your race.

Write down what happened.

Did you get diarrhea at mile 16?

Did your stomach start cramping after your third gel?

Did nausea make it impossible to continue fueling?

Whatever happened, Write. It. Down.

Because two months from now, when you start training for your next race, you probably won't remember all those details.

And those details matter.

Your Race Just Gave You Data

Here's what I DON'T want you to do:

Finish the race, have terrible GI symptoms and say:

"Well...I guess that's just marathon running."

Well, maybe not.

Your race just gave you a lot of information about how your body responds to distance, intensity, fueling, hydration, and physical stress.

Use it.

If nausea, diarrhea, bloating, vomiting, or stomach cramps repeatedly interfere with your long runs or races, it's worth investigating the pattern rather than simply switching to another gel.

And please don't wait until two weeks before your next marathon.

Your gut needs to time to repair and heal, just like your muscles. Then when training kicks back into gear, you've got to focus on gut training, too.

Your off-season is about assessment, recovery, and rebuilding.

Learn from this race.

Then prepare your gut for the next one.

Dr. Lexi Lain

Naturopathic Doctor | 4x Half-Ironman Finisher

Fix Runner's Gut