Dark urine after intense work out

Patient: Recently I began lifting weights after taking 2 months off of my normal workout schedule, cycling and running, that didn’t include weight lifting . My second day of lifting I drank a protein shake after my workout and my urine later was a brownish color so I went to see my doctor and was given a urinalysis which said my urine had a small amount of blood and had an above average amount of protein in it. My doctor told me to stop taking the protein shakes and stay hydrated so I have and my urine is a normal color (clear). I would like a doctors input on this and was wondering if I might have rhabdomyolysis, DOMS, or if it was just the protein shakes causing the discolored urine.

Doctor: I agree with your doctor about stop taking the shakes and stay hidrated. Exercise may stimulate the production of red bl ood cells to carry oxygen throughout the body to active muscles. Sometimes strenuous exercise can lead to blood in the urine, or hematuria. Also, blood in the urine, may be caused by infections, kidney or bladder stones or an enlarged prostate gland for men over the age of 50. Exercise or activity resulting in proteinuria, or protein in the urine, if it episodic, may be normal for younger people. Exercise changes the flow of blood inside the kidneys. According to a rat study published in the June 1, 2010 issue of the “Journal of Sports Science and Medicine”, acute exercise increases urinary protein excretion. In the July 18, 2003 issue of “Journal of Applied Physiology,” researchers at Akdeniz University in Turkey found that exercise-induced increases in nitric oxide decreases blood flow in the kidney, leading to temporary proteinuria after exercise.