The Effects of Exercise on Indirect Markers of Gut Damage and Permeability: A Systematic Review and Meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of interventional studies
PubMed 33201454 · doi:10.1007/s40279-020-01348-y
What was done
A systematic review and random-effects meta-analysis was conducted across PubMed, The Cochrane Library, MEDLINE, SPORTDiscus, and CINAHL through February 2019. The authors evaluated the effect of a single bout of exercise in healthy populations on indirect markers of gut cell damage (plasma intestinal fatty acid binding protein, i-FABP) and gut permeability (urinary disaccharide-to-monosaccharide excretion ratio). A total of 34 studies were included.
What was found
An acute bout of exercise resulted in a large increase in gut damage markers (i-FABP: effect size [ES] 0.81, 95% CI 0.63–0.98; n = 26; p < 0.001) and a moderate increase in gut permeability (sugar ratio: ES 0.70, 95% CI 0.29–1.11; n = 17; p < 0.001). Exercising in hot conditions (> 23 °C) significantly exacerbated markers of gut damage compared with thermoneutral conditions (ES 1.06, 95% CI 0.88–1.23 vs. ES 0.66, 95% CI 0.43–0.89; p < 0.001). Exercise duration had no significant effect on gut damage or permeability outcomes.
Why it matters
This review confirms that acute physical exertion consistently induces transient gastrointestinal epithelial damage and barrier disruption, with environmental heat identified as a significant aggravating factor.
Limits
The abstract does not state the total number of human participants across the 34 included studies. Outcomes were limited to indirect surrogate biomarkers rather than direct tissue histology or clinical GI symptoms, and the abstract does not report analyses by exercise intensity, modality, or participant fitness level.
Cited by
- supports Marathon runners are well described to have high amounts of intestinal permeability.