Changes in the gastrointestinal mucosa after long-distance running.
Level 4 - case-series / case-control
Small observational before-and-after case series in runners without parallel non-running control groups.
PubMed 1589703 · doi:10.3109/00365529209000073
What was done
Two groups of long-distance runners were evaluated to investigate the effect of marathon running on the gastrointestinal mucosa. In one group (n = 9), upper endoscopy and endoscopic laser Doppler flowmetry were used to inspect the mucosa and measure relative regional gastric blood flow. In a second group (n = 8), intestinal permeability was assessed by measuring the urinary excretion of orally administered 51Cr-labeled ethylenediaminetetraacetic acid (51Cr-EDTA).
What was found
In the endoscopic group, gastric erosions with bleeding were present in 5 of 9 subjects, predominantly in the corpus. Relative gastric blood flow decreased in the cardia region from 7.0 to 5.8 (p < 0.05) but showed no significant change in other gastric regions or within erosive lesions. In the second group, all 8 subjects showed an increase in urinary excretion of 51Cr-EDTA; exact quantitative values were not reported in the abstract.
Why it matters
This study provides direct endoscopic and tracer-based evidence that strenuous endurance running can compromise both gastric mucosal integrity and intestinal barrier permeability.
Limits
The total sample size was very small (n = 17 split into two distinct sub-studies). There was no non-running control group. Baseline pre-run endoscopic status, participant demographic details, and quantitative values for permeability changes were not reported in the abstract.
Cited by
- supports Marathon runners are well described to have high amounts of intestinal permeability.