IBS and Physical Activity: Managing Symptoms in Active Individuals and Athletes

Irritable Bowel Syndrome (IBS), Exercise and Sports

By a clinical dietitian

Regular physical activity is widely recognized as a cornerstone of good health. Yet for people living with irritable bowel syndrome (IBS), exercise can feel like a double-edged sword: some may get relief of symptoms, while it triggers gastrointestinal (GI) distress for others. Understanding how IBS, gut physiology, and different forms of exercise interact is essential for athletes and active individuals.

This article explores the relationship between IBS and exercise from an evidence-based nutrition perspective, with practical considerations for managing symptoms.

What is IBS

BS is a chronic disorder of gut–brain interaction characterized by recurrent abdominal pain associated with changes in bowel habits, such as stool frequency or form¹. Clinically, IBS can be categorized into subtypes:

Although IBS does not involve structural damage to the intestine, research points to several underlying pathophysiological disturbances. These include altered GI motility, visceral hypersensitivity, immune activation, changes in the gut microbiota, and impaired intestinal barrier function.

IBS affects people worldwide and is diagnosed more frequently in women. Anxiety and depression are also common among individuals with IBS, highlighting another factor, the gut–brain axis in IBS symptom expression¹.

The Gut Barrier

The human digestive tract can have surface area of up to 40 m², designed to efficiently absorb nutrients while simultaneously acting as a protective barrier¹. This barrier consists of multiple integrated layers:

1. Secreted products and GI tract microbes
2. A mucus layer covering the intestinal lining
3. Epithelial cells connected by tight junctions
4. Immune cells

Normal gut motility provides an additional defensive mechanism while also ensuring proper mixing and absorption of nutrients.

In IBS, particularly IBS-D, disruption of this barrier has been linked to increased intestinal permeability (popularized term “leaky gut”, in research ‘increased permeability’). Systematic reviews suggest that approximately 37–62% of individuals with IBS-D show increased permeability¹. Post-infectious IBS (PI-IBS) is another subtype, developing after enteric infections, and can trigger long-lasting changes in immune function and barrier integrity².

IBS and Exercise

Potential Benefits

For many individuals with IBS, moderate physical activity has beneficial effects³. Walking, jogging, yoga, cycling, and other low- to moderate-intensity activities have been associated with improved bowel regularity, and reduced stress. Exercise may also support a more diverse and metabolically favorable gut microbiota, which is considered beneficial for IBS symptom management.

Mind–body activities, such as yoga, appear particularly helpful. They avoid repetitive impact and may positively influence the gut–brain axis by reducing stress and autonomic nervous system activation³.

When Exercise Triggers Symptoms

In contrast, prolonged or high-intensity endurance exercise, especially running, can provoke GI symptoms even in people without IBS³. Up to 70% of long-distance runners experience exercise-associated GI complaints.

During intense exercise, blood flow is redistributed away from the gut toward working muscles and skin. This reduction in splanchnic circulation, combined with potential dehydration, may create a transient ischemic state. As a result, intestinal permeability can increase, potentially allowing leak of bacterial components into circulation and triggering inflammatory responses. For individuals with IBS, whose barrier function may already be compromised, this effect can worsen the symptoms³.

Female Athletes and Hormonal Considerations

IBS is more prevalent in women, and symptoms can fluctuate across the menstrual cycle. Hormonal changes play an important role:

Female athletes are also at greater risk of low energy availability (LEA) due to restrictive eating patterns or high training loads. Inadequate energy intake can negatively affect gut motility, microbiota composition, nutrient absorption, and menstrual function, further exacerbating IBS symptoms³.

Nutritional Strategies to Manage IBS Symptoms in Sport

From a nutrition standpoint, symptom management focuses on minimizing GI stress while supporting performance and recovery³.

Before Exercise

• Consume meals 3–4 hours before training emphasizing easily digestible carbohydrates and lean protein.
• Limit large amounts of fat and insoluble fiber, which can slow gastric emptying.
• A small snack 30–60 minutes before exercise, if needed, should be low in fiber and fat.
• Liquid or semi-solid options (e.g., smoothies, yogurt alternatives) may be better tolerated.

Hydration and Electrolytes

• Begin exercise well hydrated.
• Dehydration worsens gut hypoperfusion and GI symptoms.
• Replace fluids after exercise, approximately 1.5 liters per kilogram of body weight lost is commonly recommended.
• Ensure adequate sodium and potassium intake, particularly during prolonged sessions.

Training Considerations

• Increase training load and intensity gradually to allow physiological adaptation.
• “Training the gut” with planned, individualized fueling strategies may improve tolerance.
• Incorporate stress-reduction techniques to support the gut–brain axis.

Some individuals may benefit from specific probiotic strains, although effects are strain-specific and not universal. Professional guidance is recommended before use³. Some might benefit from glutamine supplementation, especially if they have PI-IBS subtype².

In a randomized placebo‑controlled trial, glutamine supplementation improved IBS symptoms and intestinal permeability markers in individuals with PI‑IBS. However, evidence is currently limited to specific subgroups, and glutamine supplementation should be considered on an individual basis under professional guidance².

Key Takeaways

IBS and sports are not mutually exclusive. While certain types of exercise, particularly endurance running, may exacerbate symptoms, appropriately selected physical activity can be an important part of IBS management. Nutrition, hydration, training structure, and stress management all play central roles in maintaining gut comfort.

With individualized strategies and evidence-based guidance, many people with IBS can remain active and enjoy the physical and mental benefits of exercise.

References

1.         Hanning, N. et al. Intestinal barrier dysfunction in irritable bowel syndrome: a systematic review. Ther. Adv. Gastroenterol. 14, 1756284821993586 (2021).

2.         Zhou, Q. et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut 68, 996–1002 (2019).

3.         Al-Beltagi, M. et al. Exploring the gut-exercise link: A systematic review of gastrointestinal disorders in physical activity. World J. Gastroenterol. 31, (2025).

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