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If you’ve ever been out for a run and suddenly felt the urgent need to find a bathroom, you’re not alone. Runner’s gut, also known as exercise-induced gastrointestinal (GI) distress, is a common issue among runners. It can range from mild bloating and discomfort to severe cramping and diarrhea, making training and racing a stressful experience.

What Causes Runner’s Gut?

Runner’s gut occurs when the digestive system struggles to keep up with the demands of running. Several factors contribute to this, including:

• Reduced Blood Flow to the Gut: During exercise, blood is diverted away from the digestive tract to supply working muscles, making digestion less efficient.
• Jostling of the Stomach and Intestines: The repetitive motion of running can irritate the GI tract.
• Increased Stress and Anxiety: Pre-race nerves or general anxiety about symptoms can worsen digestive issues.
• Dehydration: A lack of fluids can lead to constipation or exacerbate diarrhea.
• High-FODMAP or High-Fiber Foods: Certain foods can be difficult to digest before a run, increasing the risk of gut issues.

How to Prevent Runner’s Gut

While runner’s gut can be frustrating, there are strategies to reduce its impact and help you run comfortably.

1. Train Your Gut

Just as you train your muscles, you can train your gut to tolerate food and fluids during a run. Start with small amounts of carbohydrates and fluids during training and gradually increase intake.

2. Adjust Your Pre-Run Nutrition

What you eat before a run can make a huge difference. Avoid high-fat, high-fiber, and if needed, high-FODMAP foods within a few hours of running.

3. Hydrate Strategically

Dehydration can slow digestion, leading to discomfort. Ensure you’re properly hydrated before your run, and sip fluids during longer training sessions, especially in hot weather.

4. Time Your Meals Properly

Give your body enough time to digest by eating at least 2–3 hours before running. If you need a pre-run snack, keep it small and low in fiber.

5. Manage Stress and Anxiety

Anxiety can make gut symptoms worse. Incorporate relaxation techniques such as deep breathing, mindfulness, or visualization before a run to help keep nerves in check.

6. Identify Trigger Foods

Keep a food and symptom journal to track what foods or drinks may be triggering symptoms. This can help you refine your diet and avoid potential gut issues.

What to Do if You Experience Runner’s Gut During a Race

If symptoms strike mid-run, slowing your pace, deep breathing, and taking small sips of water may help. Knowing where restrooms are on your route can also provide peace of mind.

Final Thoughts

Runner’s gut can be frustrating, but with the right nutrition and training strategies, you can reduce its impact and fuel your performance confidently. If you struggle with persistent symptoms, working with a sports dietitian can help you personalize a plan to support both your gut health and running goals.

P.S. Need guidance on fuelling for performance without the gut distress? Check out my Free to Perform Academy, where I help runners like you optimize nutrition while keeping IBS symptoms in check!