title: Occult gastrointestinal blood loss in marathon runners.
mesh_terms: D000328:Adult; D000367:Age Factors; D001241:Aspirin / Q000009:adverse effects; D005243:Feces / Q000032:analysis; D006471:Gastrointestinal Hemorrhage / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D010865:Pilot Projects; D012420:Running; D013647:Task Performance and Analysis
chemical_list: D001241:Aspirin