How to Prevent GI Distress in Endurance Athletes

GI distress doesn’t have to ruin your race—or your training. In this episode of the Find Your Edge Podcast, Coach Chris dives into the real reasons endurance athletes struggle with nausea, bloating, cramping, and emergency bathroom breaks… and what to do about it.

Whether you’re training for a triathlon, marathon, or long ride, this guide offers key strategies to manage and prevent gastrointestinal issues during exercise—plus long-term gut health tips to support your performance.

Know someone who can benefit from this episode? Please share it!

What Is GI Distress?

GI distress (short for gastrointestinal distress) refers to uncomfortable symptoms that can appear before, during, or after exercise. These may include:

Nausea
Cramping or bloating (upper or lower abdomen)
Reflux or vomiting
Diarrhea or urgent bowel movements

These issues are particularly common in long-course endurance events like Ironman triathlons or ultra-distance races, where blood is diverted from the digestive system to working muscles—making digestion more difficult.

Top Causes of GI Distress in Endurance Athletes

1. Overeating or Chugging Fluids

Taking in too much food or drink at once can overwhelm the gut, especially during high-intensity training or long-duration events. Instead of guzzling or gulping, aim to sip steadily and consume smaller bites or portions throughout the workout or race.

2. Race-Day Anxiety

The gut-brain connection is real. Pre-race nerves can trigger an overactive or sluggish digestive system, resulting in either diarrhea or constipation. Breathwork, meditation, and visualization techniques can help regulate your nervous system and reduce symptoms.

3. Unfamiliar Products on Race Day

Trying a new gel, drink, or bar for the first time during a race? That could backfire. Your digestive system needs training too. Use your workouts to test what works and what doesn’t.

4. Excess Sugar or Sugar Alcohols

Many endurance fueling products contain free fructose or sugar alcohols like xylitol and sorbitol, which can cause bloating, gas, and diarrhea. Stick to products with a balanced ratio of glucose and fructose, and limit your intake of poorly absorbed sweeteners.

It’s Not Just Race Day—It’s Your Gut Health

Underlying issues like leaky gut, microbial imbalances (dysbiosis), and inflammation can make athletes more susceptible to GI distress. Stress, poor diet diversity, and lack of recovery nutrition all play a role.

Be sure to read and listen to our podcast on Gut Health here.

Improving your gut health can positively affect your performance, motivation, and even sleep. This is why we developed our Longevity Nutrition Coaching Program—to help athletes optimize their gut and overall health year-round.

Simple Strategies to Reduce GI Distress

Before Training

Keep meals predictable and lower in fat, fiber, and protein
Track symptoms to identify triggers
Incorporate 1 minute of breathwork to reduce stress

During Training

Use a tested fueling strategy, spaced out over time
Record food, fluids, and how you felt using a tool like our Sweat Log from our Fueling Bootcamp
Avoid new products and experiment with different ratios of fructose (we dive into this deeper in our Fueling & Hydration Bootcamp too)

Daily Gut Health Habits

Drink plenty of water (don’t rely solely on electrolyte beverages, sodas, etc)
Eat a variety of fruits and vegetables
Include fermented foods if tolerated
Limit processed foods

When to Test (Not Guess)

If symptoms persist, you may benefit from deeper testing to rule out food sensitivities, infections, parasites, or gut inflammation. We offer comprehensive gut and nutrition testing to help you get to the root of the issue. Go here for more info.

Start Your Gut Healing Journey

GI distress doesn’t have to be part of your sport story. With the right plan and a little gut love, you can go from porta-potty panic to podium confidence. Keep in mind, there are MORE strategies, so grab them in the Fueling & Hydration Bootcamp.

Next Steps:

We’ve helped hundreds of athletes just like you—and we’d love to help you too.