I had this problem on Saturday after a run in very warm conditions. When I went for a pee after the run it was pure blood. I went to the doctor who is sending me for tests on my bladder and kidneys. It happened again after my run on Monday morning but not this morning. As the weather is cooler today, could that be a factor? I have also read somewhere that this can happen to runners from time to time.
Has anyone else experienced this?