Exercise-Induced GI Distress vs. IBS: What’s the Difference?

If you’ve been experiencing gastrointestinal (GI) symptoms such as bloating, cramping, nausea, vomiting, or diarrhea during your training sessions or workouts, it’s natural to wonder why. A few Google searches later, you may be wondering: do I have Irritable Bowel Syndrome (IBS)? If your symptoms are impacting you during exercise only, then there’s a good chance the answer is no. It’s important to understand the difference between IBS versus exercise-induced GI distress in order to determine the best strategies to cope with your symptoms. In this post, I’ll explain why GI symptoms are common with intense exercise, the telltale signs of IBS, and approaches to symptom management.

What is exercise-induced GI distress?

It’s common for high intensity exercise to cause GI symptoms such as bloating, cramping, nausea, vomiting, or diarrhea, particularly in endurance athletes. In fact, exercise-induced GI distress is so common in distance athletes that  it is often coined “runner’s stomach”, but it can affect any type of athlete.

While the symptoms described above are similar to those experienced by individuals with IBS, they are usually temporary, directly tied to the workout, and do not have detrimental effects on your long-term health. There are several possible physiological explanations for these unpleasant symptoms, including reduced blood flow to the intestines and delayed gastric emptying, as blood flow to your muscles is prioritized during intense exercise. Additionally, physical jostling and specific postures during exercise may further exacerbate GI distress.

We can all agree that GI symptoms are an unpleasant, unwelcome nuisance, especially when you’re trying to push your body to the limit during a workout. But, the good news is that if these issues are only coming up for you during exercise, there may be some simple changes you can make to your pre-workout (and mid-workout, for endurance athletes) nutrition routine to minimize them or avoid them altogether.

What is IBS?

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder, meaning the gastrointestinal tract functions abnormally due to receiving mixed signals from your brain. Your brain-gut axis serves as the link between the emotional and cognitive centers of your brain and intestinal function (i.e. digestion). If you’ve ever felt your stomach churn in a stressful situation, this is an example of your brain-gut axis in action and is a normal part of your stress response. However, in individuals with IBS, brain signaling may become erratic and intestinal function is altered in the absence of a serious stressor.

Symptoms of IBS include abdominal pain and changes in bowel movements (constipation, diarrhea, or both), often accompanied by bloating and gas. IBS is usually chronic, interferes with day-to-day life, and worsens with stress. Symptoms of IBS may improve with low to moderate exercise but may worsen during high-intensity exercise.

While there is no “cure” for IBS, there are a variety of options for symptom management including stress reduction techniques, gut-directed hypnotherapy, biofeedback therapy, various supplements and medications, and dietary changes. You can learn more about these strategies in our guide to exercising with IBS. Because IBS is a chronic condition that can affect intestinal function even in the absence of a stressor, if your symptoms only present during exercise, IBS is likely not the root cause.

How To Cope With GI Symptoms

Whether your GI symptoms are confined to your workouts or you suspect you have IBS, there are several steps you can take to help get your symptoms under control.

1. Work With A Healthcare Professional

If your GI distress is linked to your workouts, consider consulting with a sports dietitian to discuss pre-workout nutrition, meal timing, and how to best tolerate fuel during a workout. Research indicates that you can “train your gut” to better tolerate nutrients during high-intensity exercise. In one study, athletes who had practiced fueling during exercise were half as likely to experience GI symptoms related to fluid and food ingestion than athletes who were unaccustomed to fueling during a workout. This indicates that their bodies had adapted through training, and numerous other studies suggest that practicing nutrition and hydration strategies can improve tolerance of them. Learn more in this post on training your gut for performance!

If your symptoms are persistently interfering with your day-to-day life independent of your workout schedule, talk to your doctor. You may have IBS, but self-diagnosing is never a good idea. Depending on your symptoms, your doctor will likely want to run tests to rule out other possibilities. Several serious diseases can present with some similar symptoms to IBS including Celiac disease, Inflammatory Bowel Disease (IBD), and colon cancer, making comprehensive diagnostics important. For those of you who do struggle with IBS, check out this post on coping with IBS as an athlete.

2. Don’t Cut Out Foods Unnecessarily

Regardless of the root cause of your GI symptoms, it is never a good idea to cut out foods without talking to a Registered Dietitian. There is a lot of misinformation out there about food sensitivities, and it can be tempting to believe that taking more foods out of your diet will be a miracle cure. However, while there is a place for dietary changes under the guidance of a dietitian to help manage GI disorders, it is unlikely that you need to be on a dairy-free, gluten-free, sugar-free, or {insert other type of food}-free diet.

Even in circumstances where dietary modifications are appropriate, it usually does not need to be black and white, and in cases where a particular food truly needs to be entirely eliminated from your diet, dietitians play an important role in ensuring you are getting adequate nutrition from alternative foods. Getting the nutrients you need as an athlete is already a challenge, and restricting your intake of certain foods unnecessarily can be detrimental to your physical and mental health

3. Nourish Your Gut

Research has shown that the bacteria and microbes residing in our guts greatly influence digestion as well as many other aspects of our health. To keep your gut healthy, it’s important to feed those microbes with prebiotic foods like whole grains, legumes, fruits, and veggies daily and to colonize your gut with the live bacteria found in probiotic foods.

For more detail, check out this post on prebiotics and probiotics for fitness and health. Just be sure to space probiotic and prebiotic foods out throughout the day and avoid them immediately before or after exercise. Following these general tips for gut health will support a healthy microbiome and may help you lower the incidence of future GI symptoms.

4. Make Sure You Are Eating Enough

The worst thing you can do in response to GI symptoms is to stop eating enough to support your energy needs. Athletes are commonly under-fueled, which is counterproductive for performance and health. Relative Energy Deficiency in Sport (RED-S) is now being more widely identified, showing how low energy intake impacts all areas of health negatively, including gastrointestinal health.

Restrictive eating patterns can delay the digestive process which may cause GI distress. So if you’ve been struggling with GI symptoms or runner’s stomach, remember: your body still needs fuel. Work with a dietitian to modify what and when you eat while ensuring that you continue to take in adequate energy.