Red Alert

Blood in the urine is cause for concern

Q: In three instances during the last six months I have had slightly bloody urine immediately after runs of eight to 16 miles. Is it connected with running?

Could it be connected with the fact that I prefer running on empty and take in very little fluid while running? Could this result in permanent damage?

J.A.
Kensington, MD

A: Blood in the urine (hematuria) has been recognized in athletes since the 1700s. It is most common in runners, but has been reported in sports as diverse as field hockey, cross-country skiing, boxing, and bicycling.

Studies have shown that anywhere from 20 to 90 percent of marathoners will have some blood in the urine after a race. The blood can either be visible (gross hematuria) or invisible (microscopic hematuria). Microscopic hematuria is by far the more common type, appearing equally in men and women. Gross hematuria is more common in men.

If the hematuria is exercise related, it usually clears up within two or three days after abstaining from exercise. Most often the blood comes from the bladder. The jarring of an empty bladder during running causes bruises and bleeding from the bladder wall.

The bleeding is occasionally accompanied by lower abdominal pain and the passage of clots of blood in the urine. Bicyclists can also experience hematuria from the impact of the bicycle seat during bumpy rides.

Sometimes the blood can come from the kidney. While the exact mechanism is not known, shunting of blood away from the kidney during intense exercise is thought to cause a temporary, reversible leak of blood cells. Dehydration will worsen the shunting and also the bleeding. If the dehydration is severe enough, serious damage to the kidney can occur.

Most cases of exercise-associated hematuria do not cause permanent damage. Because it is a diagnosis of exclusion, doctors often order a medical evaluation if the bleeding does not resolve itself within two to three days after stopping exercise. Bladder infections, kidney stones, cancer of the bladder or kidney, or other kidney diseases are some of the problems that need to be excluded by tests such as cystoscopy and an x-ray or scan of the kidneys.

In your case, I am very suspicious that "running on empty" is the cause of your problem. Try drinking plenty of liquids the night before a run. Have your physician run a urinalysis after a well-hydrated run. If the hematuria persists, you may require a full work-up.

About the authors: Carol L. Otis, M.D., is Chief Medical Advisor to the Sanex WTA and a UCLA student health physician. Roger Goldingay is a former professional soccer player. They are married and the co-authors of The Athletic Woman's Survival Guide.

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