Staying Comfortable on the Run: Reducing GI Issues When Running

Article written by Kelsey Martin, CNS, LDN

As an avid runner, and once a competitive racer, I’ve had my share of poorly timed pit stops due to gastrointestinal upset. Over the years, through trial and error and an extensive nutrition education, I’ve developed strategies to keep those uncomfortable moments at bay.

I’m excited to share some practical tips so you can run more comfortably on the trails and roads. Whether you’re training for your first race or aiming for a new personal best, these insights can help you avoid those frustrating interruptions and stay focused on your stride.

The Impact of Running on the GI Tract

Research indicates that running is one of the most strenuous forms of exercise on the GI tract, with over 80% of runners experiencing symptoms of discomfort.

When you start exercising, your body redirects blood flow from the digestive system to your muscles and other systems that help regulate body temperature. This can cause a reduced blood supply to the gut, known as splanchnic ischemia.

Additionally, exercise activates your body’s stress response, releasing hormones that affect digestion. This slows the movement of food through your gut and reduces your body’s ability to absorb nutrients properly.

The response may manifest as lower GI issues, such as stomach cramps, bloating, the urge to go to the bathroom, and diarrhea. Upper GI issues include nausea, vomiting, acid reflux, chest pain, heartburn, and burping. These problems can impact an athlete’s performance and may even prevent them from finishing a race.

How to Reduce GI Issues When Running

When working with athletes experiencing GI distress, I like to begin with a three-day food journal. This gives me a more in-depth window into their typical eating patterns to evaluate likely contributors.

Often, I find that small changes can lead to big improvements. And it may not only be the food an athlete eats before a run that impacts their GI response.

While working one-on-one with a licensed nutrition expert is always recommended for individualized nutrition guidance, here are a few tips for reducing GI issues when running.

1. Adjust Your Nutrition

Nutrition plays a crucial role in managing GI issues for runners. Here’s some advice on making food choices to help reduce symptoms such as bloating, cramping, and nausea:

Choose Easily Digestible Foods: Before a run, focus on simple carbohydrates that are easier on the stomach and less likely to cause digestive issues during exercise. Foods such as fruit, oatmeal, toast/bagels, applesauce, and fresh fruit pouches can be great pre-run options, especially for early-morning runners who run before having a full breakfast. Some research suggests that low-FODMAP foods, gluten-free grains, and avoiding personal food triggers can reduce GI distress before a run.

Train Your Gut: Repetitive and consistent exposure to similar foods before running may help minimize gut discomfort and improve carbohydrate digestion. Experimenting with new foods before shorter runs can help you determine your tolerance of these foods.

Avoid High Protein, Fiber, and Fat Before a Run: Foods high in protein, fat, or fiber take longer to digest and may lead to stomach cramps or bloating while running.

Stay Hydrated: Hydration needs vary depending on run duration, race conditions, and sweat loss. However, aiming for at least 64 ounces of water and other hydrating fluids throughout the day can help maintain adequate hydration levels, support daily motility, and reduce the risk of mid-run discomfort.

2. Use Strategies to Calm Your Mind

Relaxation techniques such as deep breathing, gentle yoga, and meditation can support a calm nervous system, allowing the body to function more efficiently and support your GI system.

Depending on the relaxation technique, the timing can be flexible. If you’re feeling a bit anxious before a long run or speed workout, deep breathing with the 4-7-8 method or Box Breathing are great ways to calm and relax your system before you begin your run.

If you have a challenging time falling asleep at night, an evening deep breathing session or short meditation session may be more beneficial.

3. Personalize Your Approach

Time of Day Matters: If you’re an early-morning runner, a simple carbohydrate pre-run snack may be your best bet. A midday or evening run 2-3 hours after a meal may allow for more flexibility, but be mindful of your protein, fat, and fiber intake to help reduce GI distress.

Trial and Error: What works for one runner may not work for another. Give yourself time to practice varying your techniques with timing and different foods such as low-FODMAP options, gluten-free grains, and easily digestible carbohydrates. I recommend experimenting with a new food before a shorter run to allow your body to adapt and evaluate without the added pressure of a long run.

Keep a Journal: Track your body’s response to foods and new changes with some form of journaling or note-taking. For instance, what did you have for dinner the night before your run? How long before your run did you have a snack? Were there any GI issues on your run?

GI issues when running are challenging to evaluate on memory recall alone. Knowing these variables can help connect the dots, especially when working with a licensed expert to customize a plan.

Disclaimer: This article is not intended to provide personalized medical guidance. Before choosing to follow the advice provided in this article, be sure to consult with a licensed health expert about your health and medical concerns. Running and exercising are done at your own risk, including any injuries or health issues you may encounter.