Yes, I bonked at the Run, Row, Rock and Roll at Fairbury, June 14, 2008. Physically, I felt good but I just didn’t do a good job hydrating myself, even though I knew how important it was with the high heat and humidity levels. By the time I hit checkpoint #29 at the lime kiln, I knew I was in trouble due to dehydration.

So, this brings me to the topic of hydration. What to drink and how much to drink are often an adventure racer’s most frequent questions. The best way to know how much to drink is to determine how much water you lose at a certain temperature over a certain period of time. So, if you find that you lose two lbs of weight over a two hour training bout, then you can determine that you need to rehydrate at approximately 4 ounces per 15 minute interval (or 16 ounces over a one hour interval at that temperature and at that pace). Obviously, the warmer and more humid the conditions are, the more hydration you will need. This way of determining proper fluid intake takes some effort and diligence but is an excellent way to take out some of the guesswork involved.

What to drink? Water is easily found and absorbed by the body and is also inexpensive. However, water does not replace electrolytes which muscle needs to work properly (and not cramp!). According the Innovative Endurance website, sweat contains between 2.225 and 3.4 grams of salt per liter. An endurance athlete can easily lose around one liter of sweat per hour in a longer race. The authors postulated that a competitor can lose roughly 27 to 41 grams of salt in a 12 hour Ironman race. This makes it that much more important to supplement electrolytes in an adventure race if you decide to drink water as the mode of hydration. Also, it is important to limit drinks that contain most of their calories in the form of simple sugars. Drinks that contain long-chain maltodextrin and electrolytes (i.e. Hammer Nutrition Perpetuem, et.al) do slow the insulin release from the kidneys thus avoiding a rebound effect of low blood glucose that are caused when using drinks that rely on simple sugars.

Finally, it is a good idea to pre-hydrate before an adventure race so you do not begin the race dehydrated. Just make sure not to overdo it!

Hopefully you all had a better finish than I did at Fairbury. Maybe I will practice what I just preached next time………

Matt Bornschlegl, PT, CSCS
www.proformancetherapy.com