Ask the Expert – Can athletes drink too much water?

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Q:  I recently ran in the CAF national running championships, where the temperature was 32 °C. A more experienced competitor advised me to drink a lot of water before and during my race to avoid becoming dehydrated. I took this advice seriously and drank quite a bit of fluid before and during my event. When the race was over, I did not feel well and someone suggested I may have drank too much water. Can drinking too much water be dangerous?

—A novice runner

 

A: Dear novice runner:

I covered the finish line at that race and it was extremely hot. You were wise to be well-hydrated for your race. This may sound strange, but drinking too much of something as good for you as water can be potentially dangerous. People who over-hydrate can develop a medical condition known as dilutional hyponatremia and some people are more vulnerable than others. People who develop this condition basically drink so much water that the concentration of sodium in their blood becomes significantly reduced.

Sodium is an electrolyte that is extremely important for the effective functioning of many things in the body. Your body carefully controls the level of sodium in your blood and when the level gets too low a number of bad things can happen, including: fatigue, muscle weakness, headache, irritability, reduced appetite, muscle spasms/cramps, nausea, vomiting, mental confusion, reduced consciousness, hallucinations, convulsions, coma, and death. Fortunately, death from dilutional hyponatremia is quite rare.

It is very important to keep in mind that while dilutional hyponatremia can be life threatening, it is quite uncommon. What is not uncommon is athletes becoming ill because of dehydration at sports events held in hot weather. This is why sport medicine physicians continue to urge athletes training and competing in hot climates to make sure they drink adequate amounts of fluid before, during, and after their practices and events. As a general rule, if you are competing for less than one hour you really only need to drink water. However, if you are competing for more than an hour you will benefit from consuming an electrolyte replacement drink.

The bottom line is, when you train and compete in hot weather you need to ensure you remain well-hydrated. While water may be absolutely essential to life, please keep in mind that too much of a good thing could put your life at risk. Exercise is medicine!

-Dr. Darrell Menard, MD Dip Sport Med

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