When Too Much Water Can Cause Problems for Runners

By , SparkPeople Blogger
For many runners, our biggest concern after injury, is becoming dehydrated, especially when temperatures start to sore and our mileage begins to creep up. While dehydration can be an issue, overhydration can be an even more dangerous issue, particularly in endurance athletes, such as marathon runners and tri-athletes.

Overhydration occurs when we drink too much water hence flooding our bloodstream with excess fluid. In doing so, we throw our electrolytes out of balance which can lead to deadly consequences if we do not recognize the warning signs early. And this issue does not just affect new runners. In an April 2005 report published in the New England Journal of Medicine, 13% of all runners who ran the Boston Marathon in 2002, had hyponatremia, or low blood sodium, due to overhydration.

The word is slowly getting around to runners of all levels to pay special attention to hydration. Even race directors are stressing awareness of overhydration and the need to monitor fluid intake with output, especially in the longer races.

Oddly enough slow, female runners are most susceptible to falling prey to overhydration. Some experts believe this is due to the longer time it takes them to run the course, therefore it allows them ample time to hit the water stations. And because the symptoms of overhydration, such as muscle cramps, lethargy, and confusion, can mimic those of dehydration, it isn't uncommon for runners to mistake the two causing the runner to take in even more fluid.

So what are the signs of overhydration?
  • Swelling of the fingers and wrist (tight watch) can be one of the first tell-tale signs that you are flooding your body with too much water.
  • Nausea, vomiting and bloating of the stomach.
  • Progressively worsening headache-this is due in part to the brain swelling due to the excess fluid.
  • Confusion, 'not feeling right' and irritability
  • Muscle cramps
  • Seizures and ultimately death if the symptoms of overhydration are not recognized early enough.

As a runner it is very important to monitor your fluid intake and output. Measuring your sweat rate is a great way to do so. To measure your sweat rate you should weigh yourself without clothing before your run, then run for an hour and then immediately after your run, weigh yourself again without your clothing and without drinking. For every pound you lose, you will want to consume 16 ounces of fluid over the course of the day. See the following link for a more in depth means of determining your sweat rate.

Many race directors of long distance races recommend writing your pre-run weight on the back of your bib. Should you become disoriented or confused during your race having this number can help determine whether this is a dehydration issue or an overhydration issue.

Because many of us have been indoctrinated to drink, drink, drink to avoid dehydration, the new trend being touted by running coaches, running experts, and organizations such as the United States Track and Field, is to have runners drink to thirst in other words DO NOT FORCE YOURSELF TO DRINK. And if you can choose a sports drink over water, however note that these will not prevent one from developing overhydration if you drink more fluid than your body needs.

According to Dr. Tim Noakes, author of the Lore of Running "Everyone becomes dehydrated in a race. But I have not found one death of a runner from dehydration in a competitive race in the entire history of running. Not one. Not even a case of illness." But the same cannot be said about overhydration which is why awareness and educating runners is essential to keeping us all safe.

Have you heard of overhydration or water intoxication? Were you aware of the dangers drinking too water much can cause? Are you surprised that this issue is not more on the forefront?