I took a medical exam for my job today, part of the procedure is to do a urinalysis.. . Checking for sugar. When the doctor came into the exam room he told me that blood was detected in the urine. This is not visible to the human eye. He said I might wish to check it out with my GP sometime.
He did mention seeing if there were any red blood cell present?

Would any of these changes have caused this? Running 3 miles per day, 4 days per week for the last 4 weeks (bicycled all summer but not much running until recent). Taking mineral supplements a few days prior to the exam (magnisium, zinc, calcium, garlic) Use of Amoxicillian for a sinus infection last dose 2 days prior to exam) Sudifed 2 days prior.
I do have signs of a hernia developing lower left side.
I have no pain what so ever and in reasonably good shape. Thanks for the advice.

I am not sure about the exercise, it should not cause blood in the urine. However, blood in the urine is usually a sign of a urinary tract infection. You should get this checked out before other very painful symptoms present themselves.

I agree with J__9.

Kaptain, I would not delay in checking this out. Hematuria - blood in the urine - has many possible causes - some are harmless while others are serious. Since yours is not visible to the naked eye, it is referred to as 'microscopic' hematuria. Yes, it is feasible that your exercise routine could be a source - but you wouldn't want to risk your health on that assumption. As J 9 has stated, it could be due to an infection - but your lack of other symptoms (abdomen or pelvic pain, burning or pain on urination, cloudy or odd-smelling urine) makes me think it probably isn't. Undetected kidney stones or a bladder stone could be a cause - if you don't stay well-hydrated during your running you are likely at an increased risk for urinary tract stones. Sometimes hematuria is labelled idiopathic - meaning that they don't know what caused it. Lastly, cancer of the kidneys / bladder / or any of the plumbing that hooks them all up - can cause hematuria - and many times hematuria is the only symptom. Of course, a false positive test is always a concern - and serial tests may be needed to confirm actual hematuria. See your doctor... soon...