Stomach Cramps While Running

Causes, Prevention, and Coping

There is nothing worse than a rumbling stomach while you are out on a run. Whether you have a side stitch or feel the need to rush to the nearest porta-potty, stomach issues can really cramp your running style. Learn the cause of stomach cramps while running and how to avoid them with these 15 tips.

illustration of woman stretching on track with text "how to avoid stomach cramps while running"
Illustration by Jessica Olah, Verywell

Warm Up

A cramp in your side (side stitch) is—just like it sounds—a severe pain in your side body. It typically occurs right below the rib cage. It is not actually related to your stomach or digestive system. While the exact cause of side stitches is unknown, some theories suggest that it could be related to blood flow to the liver, spasms in the diaphragm, or stretching of the ligaments.

To prevent side stitches, warm up properly. This gives your body time to accommodate to faster breathing and adjust to stretching ligaments.

If you experience a side stitch, try slowing your pace, taking deep breaths, and stopping to stretch for a few minutes.


Do you skip drinking fluids during a run because you worry they will cause sloshing and cramping? It is time to adjust your strategy. Dehydration actually exacerbates stomach issues.

When you are exercising at an intense level, your body diverts blood away from the stomach in order to supply your muscles with much needed oxygenated blood. This can negatively affect digestion.

However, if you couple this reduced blood flow with dehydration, it is a recipe for digestive disaster. Blood volume decreases, which means even less blood flows through the digestive system to help process fuel. This can lead to cramping, vomiting, and diarrhea.

By the time you hit this point, it is very difficult to correct. Instead, aim to stay hydrated from the start. Drink adequate fluids in the days leading up to your training session or race, and drink throughout your run. 

If you struggle to pay attention to thirst signals or often forget to drink, set a periodic alarm on your watch to remind you.

Practice Fueling

When you train for a long-distance race, you put in hours of running each week to gradually build your muscular and cardiorespiratory endurance. And just like you are training your legs for those long runs, you also need to train your gut.

Often, newer athletes skip fueling during training but attempt to use a sports drink or gel during their first long race. The result? Stomach cramps while running, thanks to a belly that has never practiced processing fuel under such circumstances.

Luckily, the fix for this is easy: Practice your fueling strategy during training. This will help teach your stomach how to process fuel under conditions of decreased digestive blood flow along with the jostling motion of running. 

Since sports nutrition is so individualized, you will also quickly learn what your body tolerates best—whether that is gels, blocks, sports drinks, bars, or any of the other products on the market.

Avoid Over-Fueling

It can be tricky to nail down the correct amount of fuel to take in during a long run. But one thing is certain: Trying to replace every calorie you burn is a recipe for disaster. Instead, aim to take in around 30 to 60 grams of carbohydrates (about 120 to 240 calories) per hour on runs lasting longer than one hour and 15 minutes. 

If you are training for a long-course triathlon or ultra-marathon, you might bump that range up to 30 to 90 grams of carbohydrates per hour. As you start experimenting with fueling, start at the lower end of this range. If you feel like you need more energy, you can gradually work your way up to the higher end of the range on subsequent runs and see how your stomach tolerates this.

Check Ingredients

A few decades ago, there were very few sports nutrition products on the market. Gatorade or flat Coca-Cola were basically the runner’s go-to options. Today, running stores offer a massive array of fueling products with different nutrition breakdowns.

The issue: Some products have ingredients which may cause stomach cramps in certain athletes. For example, some gels contain protein as well as carbohydrates.

While protein is key for recovery, it can cause gastrointestinal upset if used during a run due to its ability to slow down digestion.

For those participating in events like a half or full marathon, this kind of protein is unnecessary and increases the risk of cramping. The best choice is a high-carbohydrate fuel during the run, and then a protein-rich snack post-run for recovery.

That said, ultra-endurance athletes may find some choices that contain a little protein (or fat) useful. These can help with hunger, and protein may also help prevent muscular breakdown. 

The important difference to note is that ultra-athletes usually run at a slower pace (but over a much longer period of time) than other athletes, so they may have better blood flow through the digestive tract. This offers a bit more flexibility with food choices, which is important during long events. Twelve hours of gel could get old very quickly.

Skip Sugar-Free Foods and Gum

Sugar-free foods are a less common cause of stomach cramps when running, but if you are a die-hard gum-chewer, listen up: Most sugar-free gums contain sugar alcohols to create a sweet flavor without sugar. You can spot these on the label.

Common Sugar Alcohols

  • Erythritol
  • Maltitol
  • Mannitol
  • Sorbitol
  • Xylitol (most common in gums)

When sugar alcohols reach the digestive tract, they can cause an osmotic effect, pulling water in. When you're sedentary, your body can usually handle limited amounts of these sugar alcohols. Most people can chew a few sticks of gum without any issues.

However, when you couple this osmotic effect with the jostling that happens during a run, sugar alcohols may cause cramping and diarrhea. It is best to skip the gum altogether, but if you need it during your run, stick with regular sugar-based gum.

In addition, if you eat a lot of sugar-free products as part of your daily diet, it is worthwhile to cut down on these the night before and the morning of a long run. For example, sugar-free cakes, ice creams, and cookies typically have sugar alcohols in them as well.

Minimize Fiber

Fiber is key to digestive health on an everyday basis, helping to bulk up stool and prevent constipation. However, before a run, the last thing you want is a belly full of fiber that can cause cramping and an urgent need to find a bathroom.

Different people can tolerate different amounts of fiber in a pre-exercise meal. And if you're used to it, a moderate-fiber meal can help keep you regular before a race.

For example, if you have a bowl of oatmeal every morning and you know that it will help empty your bowels, then do what works for you. But if you deal with stomach cramps or diarrhea during training, take a look at that pre-run meal and consider cutting down on the fiber. High-fiber ingredients include:

  • Beans and lentils
  • Berries
  • Bran
  • Broccoli
  • Chia seeds and flax seed
  • Leafy greens
  • Peas
  • Whole grain breads and cereals

Minimize Fat

Fat is a satiating nutrient. It slows down digestion and helps us feel full longer. While this is great for everyday life, it is not ideal before a training session. You do not want to start running with a belly that is still feeling full and risk cramping. Low-fat, low-fiber breakfast ideas include:

  • Cereal with milk and a banana
  • Toaster waffle topped with peaches
  • Bagel with a small amount of cream cheese
  • Rice with a poached egg
  • Sandwich with a small amount of peanut butter, banana, and honey

The exception to this tip is if you are a fat-adapted athlete who is practicing the keto diet. In that case, you should follow your normal routine, as foods outside of that could cause stomach cramping. For most athletes, however, a standard moderate carbohydrate diet will lead to the best performance.

Know Your Lactose Tolerance

Lactose is a sugar that is found in dairy products. Some people lack enough of the digestive enzyme known as lactase to properly break down this sugar. This is what is commonly known as lactose intolerance. If you have this condition, eating dairy foods can cause stomach cramping and diarrhea.

Interestingly, you can develop lactose intolerance later in life, even if you previously were able to tolerate dairy. Lactase production decreases over time for certain people based on genetic factors. For others, a gastrointestinal infection or inflammatory bowel disease may cause secondary lactose intolerance.

If you are experiencing stomach cramps when running, try taking a closer look at the ingredients in your usual pre-run meal. Is you tend to consume a lot of dairy, try nixing it for a few weeks and see if you notice any improvements.

If the cramps disappear when you cut dairy, you may have lactose intolerance or a dairy sensitivity, and it is worth discussing with your doctor. If there is no improvement, dairy likely was not the issue.

Assess New Fueling Products

If you are experimenting with different fueling products to find what works best for you during training, odds are that you will encounter a product that does not agree with your body.

For example, solid products like energy bars generally increase the sensation of stomach fullness, so athletes with sensitive stomachs may want to avoid these. Your body may not react well to other fuel choices for no particular reason (other than that sports nutrition is very individualized).

Try keeping a log for your long runs, noting your fuel choice, how much you consumed, and any cramping or other gastrointestinal symptoms that you experienced. This will help you rule out certain foods and beverages that do not settle well in your stomach.

Mix Powdered Drinks Properly

Sports drinks are designed to have a particular concentration of carbohydrates in them—ideally, this is around 5% to 8%. Most prepared commercial drinks fall nicely within this range. Adding powdered drink mix to the proper amount of water per the instructions will also result in a drink that falls into this range.

Doubling up on the powder, or even adding just a little extra, is not a good idea. By much tougher time processing it. This causes your stomach to empty more slowly, increasing the risk of stomach cramps.

Stick with the correct powder-to-water ratio for the best gastrointestinal outcomes.

Digest Before Running

Most experts recommend eating a meal about one to four hours prior to running, though this is very individualized. Some runners have iron stomachs that allow them to eat a burger 30 minutes before a jog, while others might need two hours to process a small sandwich and some fruit.

If you often experience stomach cramps when running, try eating about three to four hours prior to your training session or event. Allowing more time between eating and running gives you more flexibility for the type and amount of food you can eat, as your body has ample time to digest.

Avoid NSAIDs

Ibuprofen and naproxen are NSAIDs (non-steroidal anti-inflammatory drugs). While some athletes might take these medications prior to or during a run to stave off muscle soreness, this practice increases the risk of stomach upset and cramping.

In addition, overusing NSAIDs on long runs has been shown to increase the risk of hyponatremia (a dangerous diluting of blood sodium levels) and kidney damage, and could impair muscle recovery. It is wise to avoid these medications before or during a run unless a doctor has advised you to take them.

Cut the Caffeine

Your morning cup of coffee is not only good for waking you up, but research has shown that it improves performance in endurance athletes as well. However, if you have ruled out other causes of stomach cramps, it might be worthwhile to cut caffeine and see if this helps. 

For some people, caffeine intake can cause stomach upset. This can become exacerbated with the nerves and motion that accompany a long run.

Rule Out Medical Conditions

In some cases, stomach cramps could indicate a food sensitivity or intolerance, irritable bowel syndrome, celiac disease, or another digestive complication. It is best to consult with a healthcare professional.

If you find that nothing seems to work to relieve your stomach cramps when running—especially if they are quite painful—visit a doctor to rule out anything serious.

A Word From Verywell

While it is true that most runners' cramps are related to nutrition, hydration, and training intensity, it is always a good idea to visit your doctor if any kind of pain persists. In some cases, the pain could be related to another health condition.

Keep a record of when you experience pain, where on your body you feel it, what you have eaten that day, and what kind of physical activities you have completed. This can be helpful to share with your doctor as you troubleshoot the issue together.

14 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Morton D, Callister R. Exercise-related transient abdominal pain (ETAP). Sports Med. 2015;45(1):23-35. doi:10.1007/s40279-014-0245-z

  2. Ter Steege RWF, Kolkman JJ. Review article: The pathophysiology and management of gastrointestinal symptoms during physical exercise, and the role of splanchnic blood flow. Aliment Pharmacol Ther. 2012;(35)5:516-28. doi:10.1111/j.1365-2036.2011.04980.x

  3. De Oliveira EP, Burini RC. Food-dependent, exercise-induced gastrointestinal distress. J Int Soc Sports Nutr. 2011;8:12. doi:10.1186/1550-2783-8-12

  4. Fitzgerald M. The New Rules of Marathon and Half-Marathon Nutrition: A Cutting-Edge Plan to Fuel Your Body Beyond "the Wall". Hachette Books.

  5. Williamson E. Nutritional implications for ultra-endurance walking and running events. Extrem Physiol Med. 2016;5:13.  doi:10.1186/s13728-016-0054-0

  6. Gupta M. Sugar substitutes: Mechanism, availability, current use and safety concerns--an update. Open Access Maced J Med Sci. 2018;6(10):1888-1894. doi:10.3889/oamjms.2018.336

  7. Kanter M. High-quality carbohydrates and physical performance: Expert panel report. Nutr Today. 2018;53(1):35-39. doi:10.1097/NT.0000000000000238

  8. Deng Y, Misselwitz B, Dai N, Fox M. Lactose intolerance in adults: Biological mechanism and dietary management. Nutrients. 2015;7(9):8020-35. doi:10.3390/nu7095380

  9. Orrù S, Imperlini E, Nigro E, et al. Role of functional beverages on sport performance and recovery. Nutrients. 2018;10(10). doi:10.3390/nu10101470

  10. Academy of Nutrition and Dietetics. Timing your pre- and post-workout nutrition.

  11. U.S. Food and Drug Administration. The benefits and risks of pain relievers.

  12. Lipman GS, Shea K, Christensen M, et al. Ibuprofen versus placebo effect on acute kidney injury in ultramarathons: A randomised controlled trial. Emerg Med J 2017;34:637-642. doi:10.1136/emermed-2016-206353

  13. Pickering C, Grgic J. Caffeine and exercise: What next?. Sports Med. 2019;49(7):1007-1030. doi:10.1007/s40279-019-01101-0

  14. National Institutes of Health. Irritable bowel syndrome.

By Chrissy Carroll, RD, MPH
Chrissy Carroll is a registered dietitian and USAT Level I Triathlon Coach, and the author of "Eat to Peak: Sports Nutrition for Runners and Triathletes."