It was a startling sight. The plastic specimen jar containing several ounces of tea-coloured urine — MY tea-coloured urine — placed in a row with other containers of impossibly dark liquid in the medical tent at the finish of the 2011 Western States 100-mile Endurance Run in Auburn, California.
I had given the sample as part of a study being conducted on the effects of ultrarunning on the human body and was surprised by how dark mine was since I had been peeing clear all day. My friend Tim, a veteran ultrarunner and a former lab technician who had seen more than his share of other people’s pee, assured me my sample looked fine –unlike the other ones on the table which ranged in appearance from espresso to motor oil — and by morning I was peeing normally again. I had expected to see a lot of things running 100 miles for the first time so whether it was dehydration, damaged muscle tissue, slight kidney damage or something else which had darkened my urine, it had passed and I didn’t think much more about what had caused it… until Sunday.
This past Sunday morning a handful of us hit the North Shore trails, spending most of our time on the challenging and often technical Baden Powell trail. The total distance was only about 16k but we ran a fairly aggressive pace, especially on the descents. The weather was warm but comfortable. I drank throughout the run, though maybe a little less than usual, and being in my mid-40s, I stopped to pee a few times along the way. My friend Michael expressed some surprise after the run that I still had something left in my lone, handheld bottle, but we weren’t out that long so it didn’t seem that strange to me. We changed, drank some water, went for coffee and I generally felt pretty good about the run.
After an hour or two at home I took a leak and was horrified by what I saw: I was spewing a steady stream of dark brown into the bowl. Whoa, whoa, whoa… WE ONLY RAN 16k!! Sure, it was the gnarly Baden Powell, BUT IT WAS ONLY 16K!!! This wasn’t in the range of dark golden colours that signal dehydration. This was a deep, dark, perhaps reddish brown. It had to be blood. Blood? After 16k?
At work the next day, my non-runner buddy Steve told me about a condition he’d coincidentally just heard about the night before which results in blood present in the urine of runners. He couldn’t recall the name but it often occurred in runners who were dehydrated and had no urine in their bladders. We Googled it and discovered it goes by a few different names: March Hemoglobinuria or March Hematuria (both so named because doctors observed that soldiers often got it after marching long distances) and our favourite, Bladder Slap.
Although the name and concept of Bladder Slap seemed a little ridiculous at first, the more I thought about it the more it explained what had happened to me both on Sunday and during Western States. I may have been a little dehydrated but the main culprit was that I had been peeing too efficiently. This is my understanding of Bladder Slap:
The bladder is a flexible, hollow organ which collects and temporarily stores urine. The presence of urine in the bladder normally provides as a cushion, but when the bladder is empty — completely empty — the walls of the bladder can slap together. During vigorous, prolonged activity the slapping can be significant enough to cause irritation and bleeding as red blood cells in the bladder walls rupture. The blood then mixes with urine and bingo! Bloody urine!
The key to preventing Bladder Slap and saving yourself the shock of peeing brown? Be kind to your bladder. Stay hydrated and don’t be in such a hurry to completely empty your bladder while out on a run. Keep a little in the tank to give your bladder walls a little extra protection.