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Not Just Your Average 100 Miler: My experience with Hyponatremia

by Michele Burr, Sept ’02

After running the Vermont 100 Miler, I had a seizure then went into a coma. I was suffering from a severe case of hyponatremia. I don’t remember much from the experience, but I have pieced together the basic facts from talking with people who saw me at the race, and from talking with my husband who fortunately was waiting for me at the finish line and remained with me during my five-day stay in two hospitals (in Vermont and New Hampshire.)

What Is Hyponatremia?

Hyponatremia is a condition in which there is a very low concentration of sodium in your blood. It is usually seen in conjunction with weight gain (not weight loss) and most often occurs during endurance exercise lasting more than five to seven hours. More specifically, hyponatremia develops as sodium and free water are lost and replaced by fluids such as plain tap water, half-normal saline, or dextrose in water. Basically, the condition occurs when a person takes in too much water and not enough salt.

Readers may wonder whether I was taking Succeed! capsules or drinking electrolyte fluids. Yes, but obviously I wasn’t taking enough of either. I was also eating potato chips, peanut butter and jelly sandwiches, Fig Newtons, and potatoes-but still I wasn’t getting enough salt and I was taking in too much water. The normal level of sodium is about 140-145 mEq/L (the standard measure of blood sodium content) but I had 113 mEq/L, which is extremely low. This is a problem because you need sodium in your blood for your brain to function.

What Are the Symptoms?

Many of the symptoms are neurological. In extreme cases like mine, the level of alertness can range from agitation to disorientation to a coma. There are variable degrees of cognitive impairment (e.g., difficulty with short-term recall; loss of orientation to persons, place, or time; and confusion or depression). Other symptoms include seizures and irrational and inappropriate behavior. In people with acute, severe hyponatremia, there will be signs of brainstem herniation (brain damage), coma, and respiratory arrest. Coma and seizure usually occur only with acute reduction of the sodium concentration to less than 120 mEq/L (remember, my sodium level was at 113 mEq/L).

When the neurosurgeons asked me to guess the month, I said, I think it’s Vermont.

I have received reports from spectators that during the last part of the race, my speech was slurred and I was staggering, unable to walk in a straight line. During the last few miles I didn’t recognize my friends that were running by me (although they identified themselves). I walked the last five to ten miles, which is very unusual for me. People said I didn’t even seem to know I was in a race. At the finish line I didn’t recognize anyone, including my husband. Shortly after I crossed the finish line I started to vomit uncontrollably, had a seizure, and then went into a coma for three days. At some point before I came out of the coma, I began to exhibit irrational and inappropriate behavior. I pulled out all my IVs and ripped off my EKG patches and struck out at the nurses and neurosurgeons. I was very combative whenever someone tried to touch me, so they gave me anti-psychotic medication.

When I woke up I didn’t know where I was, what had happened, the month, or year. When the neurosurgeons asked me to guess the month, I said, I think it’s Vermont. I couldn’t read and couldn’t add numbers. Three days after the race, I started to feel much, much better. I could read again, and by watching a car commercial I managed to figure out what year it was.

What Are the Long-Term Effects?

At the moment of writing, I feel about 95 percent back to where I was neurologically before the race. (Physically, I’ve lost ten pounds.) When I got to my office, I couldn’t remember my password so I couldn’t log into my computer. I also forgot a combination lock number that I often used. I forgot the names of a few people. I had a little trouble typing and signing my name, but that seems to be gone now. The last clear memory I have of the race is the mile 18-aid station. Sometimes I find it a bit difficult to concentrate, feel lethargic and just simply wiped out.

I intend to avoid such problems in the future by drinking less water during long races and eating more salt. My doctor has also given me permission to get a blood test after very long training runs and before future 50 and 100 milers. The doctors at the Dartmouth-Hitchcock Hospital thought that the causal factors were my low-sodium diet, a high volume of running (sometimes as much as 100 miles a week) which means a lot of sweating in the hot, humid climate of the Washington, DC area, and the low volume of electrolytes relative to the amount of water I was taking in.

For More Information

Here are several websites for those who want to know more about hyponatremia:

Michele A. Burr, Ph.D., is a senior study director at Westat in Rockville and an associate adjunct professor at Gallaudet University.