What’s That Pain?
Several years ago, I ran my first ultra and I fell in love with the race. I am not an elite runner, so my goal has never been to win an ultra. I compete against my last performance, and with each new race, I am trying to push myself a little farther. I have been fascinated with the problem-solving aspect of ultras. You have to figure out how to fuel, hydrate, what to wear, how to avoid injury, and when you have reached your limit. Each race I learn a little more, but I am always faced with a nagging pain in my kidneys after about mile 32. The pain lasts a few days and then disappears. I want to discover why this happens, and how I can prevent it.
When I told a friend about what I was feeling, she said, “I have another friend who does ultras, and he complained of the same thing. He researched it, and discovered that the pain was coming from his kidneys, and running long distance can cause temporary kidney damage that clears up in several days.” My first reaction was to panic and think, “What? , I damaged my kidneys?!!” Then I wanted to know more about the situation, so here is what I discovered.
- 40% of our body mass is skeletal muscle. Excessive running can damage muscle cells causing them to be disrupted, and release potentially toxic substances into the bloodstream. The term rhabdomyolysis means dissolution of skeletal muscle. It is actually very common.
- Taking ibuprofen when running long distances doubles the risk of injury to the kidneys. It decreases the blood flow to the kidneys.
- Blood in your urine is somewhat normal after extreme distances, but brown or black urine is a sign of kidney failure, and requires immediate care.
- Renal failure is rare unless there are a combination of factors such as dehydration, ibuprofen use, low fitness, or bacterial infection.
- Dehydration can lead to the pain in the kidneys.
- The pain will usually subside in 48 hours.
- There may be trouble if you no longer have to urinate.
Now that we know the why for the pain, here are the dos and don’ts to make sure it doesn’t happen in the first place.
- Do not take Advil, Motrin, Alieve, Celebrex, or analgesics before or during distance running.
- If you are on antibiotics do not run extreme distances.
- Do not race if you have recently had a viral or bacterial infection.
- Do not over or under hydrate.
- Monitor your urine output and color.
- Train well. A well-trained body can better support the stress being put on it.
- Listen to your body.
- Eat a good breakfast the morning of the race.
- Rest the day before a race.
My doctor treats me like a member of his family, so he was the first person whom I thought to ask about the kidney pain. He does not really understand why I would want to run an ultra, but he understands my passion for running in general. Last year, an x-ray revealed I had sprained my neck in karate. My doctor scheduled a visit for me with a neurosurgeon and told me that until I had that visit, I would have to stop running because it was too dangerous. I said, “Dr. Elsbree, you know I can’t do that.” He made a lot of calculations, and then said, “O.k. two miles a day.” This time I just gave him an incredulous look, and he said, “O.k. promise me you’ll run soft like an Indian.” Here is what Dr. Elsbree said about avoiding kidney pain. “The pain has to do with musculoskeletal stress, particularly because of bending from fatigue further in the race. My advice is to stay as well hydrated as possible.
A study links marathon running to acute kidney injury, but it’s temporary. Dr. Martin Hoffman, a health sciences clinical professor at the University of California, Davis, and a founding member of the Ultra Sports Science Foundation says,
“It’s also important to keep this all in perspective,” he said. “While there may be some risks with marathon running, the lack of regular exercise among most of our population is far more dangerous and costly to society than the overall risks from participation in marathon running.”





