Research

Mixed

Intense exercise (>70% VO2max) can increase intestinal permeability and endotoxemia, leading to temporary systemic inflammation and gastrointestinal distress.

High-intensity or prolonged endurance exercise can temporarily compromise your gut barrier, leading to inflammation and GI issues. This is common in ultrarunning or intense military training. While the long-term benefits of training outweigh these acute stresses, managing hydration, nutrition, and recovery is crucial to mitigate these temporary negative effects.

GoodQualifiesHIGH confidence
Conversely, intense exercise can increase gastrointestinal epithelial wall permeability and diminish gut mucus thickness, potentially enabling pathogens to enter the bloodstream. This, in turn, may contribute to the increase in inflammation levels.
Matthieu Clauss et al. · Frontiers in Nutrition · 2021

Why this rating

Supported by studies on ultramarathoners, triathletes, and military training (refs 45, 46, 49, 50).

Source

Interplay Between Exercise and Gut Microbiome in the Context of Human Health and Performance

Matthieu Clauss et al. · Frontiers in Nutrition · 2021

DOI 10.3389/fnut.2021.637010

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DOI resolved against Crossref · corpus check 2026-06-10

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