How Common is Lower Gastrointestinal Bleeding in Athletes?

Patient Presentation
A 17-year-old female came to clinic for her health supervision visit. She was a cross-country runner and denied any injuries since her last visit. She did complain of increased stooling that was more liquid in consistency. Occasionally she noticed a small amount of blood after long runs or increases in mileage, but never any clots or frank hematochezia. She did complain of some bloating and gas during training and races, but denied gastroesophageal reflux. She ate a varied diet and took a multivitamin with iron. She denied changes in menstruation or more than 2-3 pounds weight change. The past medical history was non-contributory. The family history showed a paternal great uncle with colon cancer in his 80s. The review of systems was negative.

The pertinent physical exam showed a well developed female with her weight at the 10%, and height at the 75%. Abdominal examination was negative including a rectal examination. Stool hemoccult was negative. The laboratory evaluation showed a hemoglobin of 12.8 gm/dl, platelets of 240 x 1000/mm2 and a smear that was normal. Iron studies were also normal. The diagnosis of intermittent gastrointestinal bleeding due to exercise was made. She was instructed to increase the time between eating and training, limit gas-forming foods and fiber-rich foods in addition to keeping well hydrated. She was also told to increase her training more steadily. She said that she could do the first parts, but that the training schedule during the season was up to her coach. The patient’s clinical course showed stool hemoccults to be positive after her long runs, but were negative during less intensive training. During the off-season when she reduced her mileage she had no positive hemoccults.

Sports are a healthy recreational and social activity. However, various changes to the body inherent with the activity or because of increased intensity or volume of training and/or competition may cause problems for recreational and competitive athletes.

Gastrointestinal (GI) symptoms occur in 30-65% of long distance runners. Upper gastrointestinal problems include nausea, emesis, gastroesohpageal reflux, and ulcers. Upper GI problems are more common in cyclists than runners though. Treatment includes avoiding eating within 3 hours of running, antacids and H2-blockers.

Lower GI tract problems include cramping, increased defecation urge, increased bowel frequency and diarrhea. One well-documented serious problem is ischemic colitis. Potential causes include dehydration, decreased splanchnic blood flow, changes in sympathetic/parasympathetic tone, hormonal changes and mechanical effects. Treatment includes decreasing gas-forming foods, caffeine, and fiber-rich foods, maintaining hydration, and changing training and competition volume and intensity (i.e. working up to a higher level slowly). Oral contraceptives and non-steroidal anti-inflammatory medications may also contribute to gastrointestinal bleeding and therefore modification in their use may also help.

A differential diagnosis of GI bleeding can be found here.

Learning Point

Most studies of GI bleeding are in highly competitive athletes such as marathon runners and therefore there is less information about recreational runners. Studies of marathoners and ultramarathoners found occult blood in the stool after a race occurs in 8-85% of athletes. One study of adult recreational triathletes (averaging 11 hours training/week of 2 miles of swimming, 16 miles of running and 46 miles of biking) found that 50% reported bloating and abdominal gas and 27% had positive hemoccult stools.

GI bleeding occur in others sports also but again is less well documented. A case study of a rugby player had exercise-induced occult bleeding after 20 minutes of playing time in an international qualifying match.

Questions for Further Discussion
1. What evaluation should be considered for lower gastrointestinal bleeding?
2. What are the indications for endoscopy?
3. What is the differential diagnosis for anemia in an athlete?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Gastrointestinal Bleeding

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Worme JD, Doubt TJ, Singh A, Dietary patterns, gastrointestinal complaints, and nutrition knowledge of recreational triathletes. Am J Clin Nutr. 1990:51;690-7.

Babic Z, Papa B, Sikirika-Boxnjakovic M, Occult gastrointestinal bleeding in rugby player. J Sports Med Phys Fitness. 2001;41;399-402.

Simons SM, Kennedy RG. Gastrointestinal problems in runners. Curr Sports Med Reports. 2004:3;112-116.

Sanchez LD, Tracy JA, Berkoff D, Pedrosa I. Ishcemic colitis in marathon runners: A case-based review. J. Emer Med. 2006:30;321-326.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Systems Based Practice
    24. Cost-effective health care and resource allocation that does not compromise quality of care is practiced.


    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital