Supplements for Runners Diarrhea

You’re 2 miles into your long run, and suddenly you’re hit with a familiar yet unpleasant sensation and you need to find a bathroom, stat. You can feel the cramping and the urgency and you start to get nervous. How many times has this happened to you? Too many to count? 

Runner’s diarrhea, also known as runner’s colitis or runner’s trots, are loose, urgent bowel movements occurring during or shortly after running. Long-distance runners who run longer than 3 miles most commonly experience this phenomenon.

According to one study 47% of participants experienced diarrhea after racing or during hard runs and 62% of participants had to stop for a bowel movement during training runs. With the prevalence so high, it’s important to address this issue to improve performance, safety, and quality of life.  

Why Runner’s Diarrhea Happens

So, why does runner’s diarrhea happen? Runner’s diarrhea is a multifaceted issue that has several mechanisms of action, although the direct cause is still unclear. 

One factor driving runner’s diarrhea is certainly related to the mechanical jostling of the intestines that happens during running as well as the reduced blood flow to the GI tract that happens with endurance exercise.

Because blood flow is shunted away from the gut and toward the working muscle combined with the jostling, motility can easily be affected. 

Other factors that contribute are stress hormones like cortisol and adrenaline as well as anxiety and nerves related to training and competition. Hormonal shifts like this pull water into the bowels and can cause runner’s diarrhea effects. 

We can’t forget about nutritional triggers that contribute to runner’s diarrhea as well. Stimulants like caffeine speed up transit time in the bowels, high fat and fiber foods before a run take a long time to digest and alter transit time, as well as commonly harder-to-digest foods like sugar alcohols and higher FODMAP foods that may contribute to diarrhea.  

Nutrition Strategies to Manage Runner’s Diarrhea

So, what can you do to help mitigate these effects? First we will break down dietary strategies and then lifestyle and training adjustments that make the biggest impact. 

Timing and Type of Pre-Run Meals

As alluded to above, the timing and type of your pre-run meals is very important in reducing GI distress on your runs. Eating a low-fiber, low-fat, carbohydrate-rich meal or snack is imperative the closer you get to training or competition. 

You may choose a normal dietary approach 3-4 hours prior to training and then eat a carbohydrate-rich snack in the 2 hours prior that are easily digestible and low in fat and fiber. 

Soluble Fiber: Your Gut’s Best Friend

Another strategy to manage GI distress in running is to incorporate more soluble fibers in small amounts at your meals throughout the day, rather than just prior to a run. 

Soluble fiber absorbs excess water in the bowels, slows digestion, and improves stool consistency making it a great help in managing runner’s diarrhea. Top soluble fiber options include: 

• Bananas, especially green 
• Chia seeds 
• Oats 
• Back to Balance Plus

Hydration and Electrolytes

Maintaining optimal hydration is a runner’s best friend when it comes to protecting the gut against excess damage in training. Fluids help protect the gut from heat stress and excess rubbing that can degrade the lining of the GI tract and cause or contribute to distress. 

Electrolytes like sodium combined with glucose allow for optimal hydration of the cell and play important roles in providing energy and replacing fluid losses. Long-distance runners should work with a sports dietitian to personalize fluid, electrolyte, and carbohydrate recommendations specific to their fueling needs. 

Avoid Common Gut-Offenders

As previously mentioned, adjusting and/or avoiding common gut-offenders around training and competition can significantly improve gut tolerance. Caffeine and sugar alcohols may need to be avoided before and during long-runs. 

High fat and spicy foods slow digestion and may irritate the gut so should be avoided prior to runs as well. It’s recommended to identify specific food triggers with a professional, however some may benefit from reducing high FODMAP foods like apples, onions, and garlic in the meal prior to a long-run or in the days prior to an important competition. 

Carbohydrate Type and Intake

Because the gut is a muscle it is also trainable. With gradual training of the gut you can acclimate to tolerate more and better nutrition. 

This takes time and consistency, but taking in fuel and fluids during all runs, even shorter ones, your gut will adapt. Opting for glucose-based or glucose-fructose blends are most easily tolerated. A sample day of eating might look something like this. 

Sample Day-Before and Race-Day Meal Plan 

Day Before:

• • Breakfast: Oatmeal with blueberries and chia seeds
  • Pre-run snack (shakeout run): Banana + fig bar  
  • Lunch: White rice with grilled chicken, steamed carrots and peas 
  • Dinner: Baked potato with sautéed spinach and firm tofu + BBQ sauce 
  • Snack: Yogurt bowl with granola and berries 

Race Day (Half-Marathon):

• • 3 hrs before: Sprouted grain toast with peanut butter and banana sprinkled with hemp hearts 
  • 30 mins before: 2-4 graham crackers 
  • During run: 30-60 g/hr using gels, dates, or chews (tested in training!) and water 
  • Post-race snack: OWYN drink + a banana 
  • Recovery meal: Pasta with grilled chicken and a side of steamed broccoli 
  • Snack: Edamame and whole grain crackers
    

Lifestyle & Training Adjustments

Consistent Bathroom Habits

Outside of nutrition strategies, there are a few lifestyle and training adjustments that can easily be made to help manage GI distress.

Incorporating a consistent bathroom habit to train the gut with a routine can be a very helpful strategy. 

Our bowels thrive on consistency and a dependable routine, so starting the day with a warm liquid, some light movement, and then sitting on the toilet about the same time each day to create a routine for the bowels to completely empty prior to runs is recommended.

Try to use the timing on training days for race days if possible as well. 

Warm-Up and Nerve Management

It’s almost impossible to replicate the nerves and stress that comes with competition and races, but trying to recreate that same environment to build stress resiliency is a great strategy for managing runner’s diarrhea. 

Many athletes enjoy strategies like practicing mindfulness, deep breathing, and other calming routines before training and races to reduce nerves and reduce GI distress. Be sure to give yourself enough time to properly warm up and practice calming routines next time you lace up! 

Strengthen the Gut Through Gradual Exposure

Again, gradually increasing carbohydrates and volume of fluids during training helps your gut adapt to what you are asking it to do. This will strengthen the gut and allow for maximum adaptation. 

Tracking foods and symptoms can also help you identify triggers or specific timing that works best for you. 

When to See a Specialist

We must discuss red flags that should always be addressed and referred out to a specialist.

We recommend seeing a doctor when: 

• Symptoms persist despite all modifications 
• Blood in the stool 
• Unintentional weight loss 
• Anemia
• Bowel movements occurring overnight 

There are many other diagnoses that can be happening with runner’s diarrhea such as IBS, IBD, or Celiac Disease. It’s important to identify exactly what is being experienced so that proper interventions can be initiated and diagnosis is not delayed.  

Final Thoughts

Every runner is different in how they respond to training, nutrition, and environment so it’s best to test, track, and tailor your intervention to what works for you. 

With the suggestions offered in this article you can make important changes and be empowered to manage your run effectively! We would love to hear your experience with runner’s diarrhea and what has worked for you, comment below.