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Stomach Pain After Running? How To Help Running Stomach

Do you suffer from stomach pain when running or stomach pain after running? You may be suffering from running stomach and these tips can help!

As many of my fellow runners may know, running can knock things loose. It’s not a gentle sport in that the swish and the swosh of things in our stomach when we run can impact how we feel. 

Girl running around a track | Bucket List Tummy

Can Running Cause Stomach Pain?

While running is a high impact exercise, it can cause symptoms of stomach pain, or “running stomach,” among certain people.

This may be a result of diet, dehydration, weather, or a combination of other things as well. 

Training For a Race? You need this resource!

What is Running Stomach?

Running stomach refers to unpleasant feelings and cramping in the stomach, likely due to the nature and impact of running. This GI distress during running causes adverse symptoms for many. 

woman bent on knees suffering from stomach pain after running | Bucket List Tummy

Runners belly, as it is sometimes known, may show up as cramping in some runners, and runners diarrhea in others.

As you may guess, it is not a pleasant experience and can certainly affect one’s intensity and performance while running. 

It may also affect child and teenage athletes differently. Here’s a post all about nutrition needs for teenage athletes

Why Do I Get Stomach Cramps After Running? What Causes Stomach Pain When Running?

Along with the question, “Why is my stomach sore after running?,” these are common questions likely related to nutrition or timing.

There can be a variety of things that may be related to an upset stomach while running but many of the common ones I see are related to:

  • dehydration
  • eating the wrong pre-run snack
  • eating at the wrong times
  • stress

Let’s review each briefly.


If you go into exercise dehydrated, it’s unlikely that you will be able to “catch up” on your hydration.

Therefore, I always recommend my clients to review hydration tips especially in the summer months (and that includes water + why electrolytes matter) before starting exercise. 

When you’re dehydrated, symptoms like cramping, headaches, dizziness and bloating are very common. In essence, your body is working harder on everything. 

I love mixing Skratch hydration into some water so I’m getting water and electrolytes before exercise. 

hydration drink mix to stay hydrated

Eating The Wrong Pre-Run Snack

If your stomach hurts after running, you may be choosing the wrong pre-run snack.

I typically tell clients to avoid high fat and high fiber foods before exercise. It may also be prudent to avoid high protein meals/snacks 1-2 hours before exercise. 

While we each have different sensitivity levels in terms of what our digestive systems can handle, fiber and fat tend to stick around longer in our stomach. Therefore, it takes time for them to be digested.

Here are more pre workout snack ideas – love these pb&J energy bites!

whole wheat toast with peanut butter, yogurt and jelly as pre exercise snack

Once we start exercising, our body diverts the blood that we usually have in our GI system for digestion and absorption to our extremities to power our run.

In other words, things that are in the stomach tend to just “sit” there rather than move through. This can lead to uncomfortable bloating and cramping. 

This post about nutrition tips for runners stomach offers nutrition recommendations to help solve these problems.

In summary, you’re probably better off eating higher glycemic index foods with less fiber, like white rice, white bread or bananas before exercise. 

green graphic for intuitive eating for athletes guide

Eating At The Wrong Times

Eating too close to exercise can be problematic for some. While I can eat 30 minutes before a run and feel okay, many need upwards of 1-2 hours to digest what’s in their stomach. 

Orange Protein Smoothie, great for a post workout meal

Therefore, depending on when you’re exercising, I recommend allowing 1-2 hours for snacks to digest and 2-4 hours for meals to digest. Smoothies can be great for quick digestion (especially this tropical smoothie)!

The closer you are to exercise, the smaller you want your meal to be. We talk about this a lot in our Fueling for Exercise course, which reviews everything you need to have in place for your fueling and hydration plan. 


Stress in and of itself can cause unpleasant digestive symptoms for some, manifesting as cramping, a slowed metabolism, bloating, diarrhea, inflammation, and decreased oxygen flow to your gut. 

stressed man sitting and thinking

Feeling stressed will also affect the absorption of nutrients, so if you’re feeling stress, anxious or nervous about something, that could manifest during your running as well. 

What Causes Stomach Pain After Running?

Do you suffer from gi issues after a long run? Some people are more sensitive to an upset stomach after running, another common form of runners gut.

If you don’t suffer from stomach pain during running, but instead, it’s after running, there could be a few different reasons for this.

girl suffering from stomach pain when running Detroit marathon | Bucket List Tummy


While dehydration can still play into adverse symptoms after a run, there are also other weather and water-related conditions to take in, such as overheating or heat stroke, hyponatremia (low salt levels) or overhydration. 

When the salt levels in our blood are dangerously low, either due to low salt intake, or extremely high water intake, this can be dangerous.

Symptoms, like nausea, vomiting, drowsiness, restlessness, headaches and dizziness are common, and some can even be life-threatening, like coma or death. 

glass of water with kiwi for hydration before exercise

Nausea and vomiting are probably some of the more mild symptoms but should signal to you the importance of staying hydrated and taking in proper electrolytes during longer bouts of exercise.

Eating Before Exercise (Or Not Eating Before Exercise)

More often than not, it could again be related to what someone ate before a run (or what he/she did not eat), or even something he/she took in during a run. Running and digestion problems tend to go hand in hand. 

Maybe you didn’t eat before exercise and your empty stomach is what’s uncomfortable. Sometimes, hunger or a gnawing stomach can cause unpleasant runners gut symptoms. 

date with peanut butter as snack before exercise may cause stomach pain for some

Alternatively, maybe you ate something too heavy during exercise and your body is just getting started on digesting it after exercise. Since blood flow shunts away from the stomach during exercise, it just sits there while you’re running.

After exercise when your body has the resources to digest it, you may feel uncomfortable. This is likely due to feeling tired, dehydrated and more. 

Check What You’re Taking in During Long Exercise

Is it too much glucose and/or fructose? Too concentrated? Ideally, you want a 6% carbohydrate solution product for the best intestinal fluid absorption during exercise

Generation UCan is a great product made with superstarch, that slowly releases during exercise and avoid blood sugar spikes. It is easy on the stomach and helpful for many people. You may want to try it. 

tub of generation ucan for fueling during exercise

Running Knocks Stuff Lose

Runners’ bowel problems are common topics of jokes among runners, but in all honestly, running is a high-impact form of exercise and can jiggle things in our digestive system.

Some typical symptoms of runners belly include:

  • diarrhea
  • nausea
  • vomiting
  • constipation 
  • cramping
  • bloating
  • GI distress 

These are some reasons why you may have stomach pain after running. 

How To Solve Running and Stomach Problems

If none of the above apply to your stomach aches when running, it may be time to see a doctor. You want to rule out chronic conditions, like ulcerative colitis and irritable bowel syndrome. 

Nutrient timing, or the food you consume and when, around exercise sessions can make a big difference. 

Sweet potato energy bites on striped napkin | Bucket List Tummy

You may want to do some trial and error around the times you eat and run. If you typically get up and run on an empty stomach and still experience runners bowel problems, try eating something first and letting it digest before you run. 

Try Running on an Empty Stomach – Alternatively, if you typically run right after a meal and feel uncomfortable, try running before the meal or on more of an empty stomach. 

Avoid Artificial Sweeteners – If you eat many foods high in artificial sweeteners (like sorbitol, xylitol, aspartame, sucralose), know that those can be unpleasant for many people

spoonfuls of artificial sweeteners | Bucket List Tummy

Mess Around With Your Pace and Time of Day You Run – Maybe you’re just not someone who can stomach running fast in hot weather. Can you run earlier in the day when it’s cooler? Or take speed runs on a treadmill?

There is no one-size-fits-all approach, and many of us will have to do some troubleshooting to figure out what the triggers are for each of us. 

If you need more help with your personalized fueling plan, sign up for our endurance fueling course!

Save it For Later

woman with hands on knees suffering from stomach pain after running with pinterest text overlay | Bucket List Tummy


  1. Stress and Health: Psychological, Behavioral and Biological Determinants
  2. Carbohydrates for Training and Competition
  3. Artificial Sweeteners: A Systematic Review and Primer for Gastroenterologists

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Have you ever suffered from stomach pain when running? What helped?

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