Your rectum lies at the bottom of your digestive tract and opens into the anus. Rectal bleeding is frightening, but it's actually quite common after exercise, according to Dr. Cathy Fieseler, writing for the "Running Times" website. In fact, 6 percent of marathon runners report bloody stools after the race, while 17 percent report rectal bleeding while training. Rectal bleeding can be a symptom of a more serious condition though, so always get it checked out by a health professional.
Ischemia
Prolonged exercise, such as running, may decrease blood flow to the colon, causing damage which sloughs off as you open your bowel. This can cause further complications if not treated, but most ischemic episodes are reversible, according to Dr. Frank Moses, writing for "Current Sports Medicine Reports" in April 2005. Seek medical advice if you think this applies to you, as you may need medicine to correct your bowel. Avoid ischemia by keeping well hydrated when exercising, to enable adequate blood flow.
Hemorrhoids
About 50 percent of all Americans suffer from hemorrhoids by the age of 50, according to the American College of Gastroenterology. Hemorrhoids are swollen veins that lie either under the skin around your rectum, or protrude through your anal canal, and when aggravated, they produce bright red blood.
They are not caused by exercise, but by strenuous bowel movements, and by eating a high fiber diet and keeping well-hydrated, you should be able to ward them off. Sometimes exercising in tight pants may irritate your hemorrhoids, so treat them by eliminating constipation, using an over-the-counter cream and washing regularly in warm water and patting the area dry.
Anal Abscess
An anal abscess is a pus-filled fissure outside the anus, usually resulting from a gland blockage. When left untreated, it may cause a fistula, which connects the anal gland to an area close to the anus, producing drainage from the anal canal. An abscess aggravated by exercise may burst, causing blood in the stool which is not a result of rectal bleeding. Seek medical advice if you have an abscess, as medication can help.
Warning
While rectal bleeding is caused by many nonserious conditions, it can also be a symptom of colorectal cancer, so always seek medical advice if you are unsure of the underlying cause. Your evaluation will involve a colonoscopy--the insertion of a camera into your anus to search for abnormalities--and your doctor will help you understand your diagnosis. Other symptoms include abdominal and rectal pain, weight loss, altered stools, and fatigue.
References
- "Running Times"; Ask the Coaches: Rectal Bleeding; Dr. Cathy Fieseler: April 2005
- "Current Sports Medicine Reports"; Exercise-associated Intestinal Ischemia; Frank M. Moses, MD: 2005
- The American College of Gastroenterology: Rectal Problems
- "BMC Medicine": The diagnosis of colorectal cancer in patients with symptoms: finding a needle in a haystack; Robert H. Fletcher: 2009
