Changes in gastrointestinal cell integrity after marathon running and exercise-associated collapse.
Level 3 - non-randomized controlled study
Non-randomized cohort study with an observational clinical comparison group
PubMed 33512586 · doi:10.1007/s00421-021-04603-w
What was done
Researchers measured systemic intestinal fatty acid-binding protein (I-FABP), a marker of intestinal epithelial cell damage, in marathon runners. Twenty-four healthy controls were sampled pre-race, immediately upon completion (T0), and at 4 and 24 hours post-race. Eight runners with exercise-associated collapse (EAC) and hyperthermia had I-FABP measured at the time of collapse (T0) and 1 hour later.
What was found
In controls, I-FABP increased from baseline (1129 ± 493 ng·l⁻¹) to race completion (2593 ± 1373 ng·l⁻¹; p < 0.01), with no significant difference from baseline at 4 hours (1419 ± 1124 ng·l⁻¹; p = 0.7) or 24 hours (1086 ± 302 ng·l⁻¹; p = 0.5). At T0, EAC cases had significantly higher I-FABP concentrations (15,389 ± 8547 ng·l⁻¹) than controls at T0 (p < 0.01), which remained elevated at 1 hour post-collapse (13,951 ± 10,476 ng·l⁻¹ vs. pre-race control baseline; p < 0.05).
Why it matters
This study shows that uncomplicated marathon running causes transient gut wall stress, whereas hyperthermic exercise-associated collapse involves acute and substantial enterocyte damage.
Limits
The total sample size was small (24 controls, 8 collapse cases). EAC cases had no baseline pre-race measurements, and follow-up in the collapsed group ended at 1 hour post-collapse, leaving longer-term recovery unmeasured.
Cited by
- supports Marathon runners are well described to have high amounts of intestinal permeability.