In a previous workout tip about proper hydration, I mentioned that hyponatremia is a topic I would revisit later. Hyponatremia is something to be aware of but not something to be worried about. It is something that is all the rage in the media these days as something to warn people about, and yes, it can be dangerous. It is just such an easy thing to avoid that a little knowledge and a smattering of common sense can make it a non-issue.

I was reminded I needed to write about this topic after reading another scary article about hyponatremia over at the Health and Fitness blog that comments on a New York Times article about it.

This excellent NYT article recaps this very real threat to athletes, primarily marathoners. The article sagely notes that there are no recorded deaths from dehydratrion in world running but deaths from hyponatremia have occurred. The articles quotes the a rule of thumb that eight ounces of fluid every 20 minutes is plenty.

Making broad statements like that is more dangerous to a marathoner, especially an inexperienced marathoner, than the condition itself. While it is possible they somebody may overhydrate themselves, it is far more likely that they will underhydrate themselves. While I am sure that a 0.5% chance of dying is bad, is it really worse than bad advice causing a 50-70% chance of heat exhaustion*?

There are two things to bear in mind when hydrating for any sort of endurance event.

  • Be sure to consume plenty of water and to eat plenty of food.
  • Do not do anything on marathon/race day (or the day/s preceding it) that you have not already done in training.

Being properly hydrated involves drinking plenty of fluids, especially water, and especially for the day or three preceding your event. As I mentioned in my previous tip, you want to make sure that your urine is a very pale yellow or almost clear color. If it is completely clear, you may be slightly overhydrated, but probably not at a dangerous level. Which means, rather than not drinking anything else, which would be a mistake, you should drink a sports drink or fruit juice and eat some food. Eating is just as important as drinking for any sort of endurance event. In the case of a marathon, where you will be performing for 3 or 4 hours, you will have used up all of your body’s readily available fuel that has been stored up by the time you are ½ to ¾ of the way through the race. You should be sure to top your tanks off before you begin, and you should replenish your tank as you go along so that at no point are you running on empty. Following that one simple concept will make it next to impossible for you to suffer from hyponatremia.

Do not do anything on race day that you have not practiced in training. That includes what you decide to eat, how you decide to fuel yourself and hydrate yourself, and what you consume on the race course while you are out there. Gel packs are easily carried, and most major races include at least one or two water stations that have gel packs, and many have water stations that serve sports drinks. Buy some gel packs ahead of time, and practice consuming them every 20 minutes to half an hour during your long runs. They will replenish the vitamins, minerals, and salts in your system that water will not, which will not only make sure you do not hit the wall as hard as you otherwise might, but will keep you going strong your entire race and will make it so that you do not have to worry about having a drink water for fears of hyponatremia. When you take gel packs, however, make sure you wash them down with water. Your stomach will not be able to process them correctly without it. When in doubt, read the package labels.

*Note: I made those numbers up off the top of my head to illustrate a point; they are not based on any scientific data.