blood in urine after brief exercise

  I just started walking for fitness again, walking for 45 minutes and running for 5 minutes.  On those occasions when I run for even just 5 minutes, it results in gross hematuria immediatly thereafter.  If I just walk, there's no appearance of any blood in my urine.  At one time, I ran 25 miles a week, with no problems.  However, this started approximately 7 years ago.  There is absolutely no occurrence of this unless I run, but even a brief run of a half mile causes substantial blood to appear.  I'm only 25, but my father developed kidney cancer.  A complete exam (IVP, cytoscopy, and urine analysis) seven years ago yielded no answers, and it was dismissed as due to the running.  Should I have another complete exam?  
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Dear Tina,
Hematuria is the medical term for your condition.  It is important to have a microscopic cell count done to determine if this amount of hematuria needs to have a full work-up.  Above 3 RBC/HPF is suggestive of significant hematuria that needs work-up.  You state that you have gross blood in the urine and this would necessitate a full work-up unless you have an infection or some other medical condition that would explain it.  Are you taking anticoagulation meds?  Are you sickle cell trait positive?  Have you have any recent bacterial infections?
A full work -up consists of a history and physical to direct the studies, an IVP, a cystoscopy which should be done by a urologist, and a cytology looking for cancerous cells in the urine. Performing a cystoscopy immediately following running would be useful to help localize the site of bleeding. Given the amount of bleeding, I might consider an arteriogram (x-ray study of the blood vessels in your kidneys) if everything else is negative
You may well have idiopathic hematuria, simply meaning, we don