Nutrition and Hydration for the Long Haul

Nutrition and Hydration for the Long Haul

By Beth Shutt

Who gets excited when talking about race nutrition and hydration?  No one?  As a registered dietitian (and coach!), I will say, nutrition and hydration actually “excite” me.  They are two variables that you have 100% control over.  You cannot say this about many things on race day!  You can’t control the weather, you can’t control the competition, you can’t even control (to some extent) how your body will feel.  But you CAN control what you put in your mouth to fuel you for 100 miles or 100km.  So, let me share a little of my excitement with you!

First, a little story.  A friend of mine made her first attempt at the 100 mile distance in Vermont several years back.  She was well trained and ready for the day.  But by mile 60 she was feeling pretty dizzy.  By mile 70, when she picked up her pacer, she added some confusion to the dizziness.  At one point, her pacer kindly asked “you know you are only talking to me in a whisper, right?”  I laughed when she was telling me this story, envisioning my friend suspiciously whispering so the trees couldn’t hear her…. But by mile 83 she was sitting at an aid station, and then laying down and then, she woke up in the hospital.  And just like that, her day was over and her goal not met.  Classic signs of hyponatremia (abnormally low sodium concentrations in your blood caused, in this case, by drinking too much water).  My friend had eaten well and drank fluid, but she only drank water and a “little electrolyte here and there.”  And that mistake cost her the day.

Below are some tips to helping you manage your hydration to avoid making these same mistakes, and successfully cross that VT100 finish line with a smile on your face and a loud WOO-HOO!  (although if you’d like to whisper, that’s okay too, it just won’t be because you are hyponatremic though :).

The difference in weight #1 and #2 is what we are looking for.  Each pound lost is equal to roughly 16 oz of fluid.  That then converts to your fluid needs per hour.  For example: weight #1 = 146.3 lbs, weight #2 = 144.8 lbs ——> the difference in weights = 1.5 lbs x 16 (number of ounces in fluid/lb) = 24 ounces/hour.

 (file photo-our race is now cup-less)


It is important to note that we do not need to replace 100% of our needs and SOME level of dehydration is acceptable in training and racing.  However, even being dehydrated by 2% affects performance and, in addition, the nature of ultra running (ie: running for 24 hours straight!) doesn’t leave much room for error.

(file photo-our race is now cup-less)

It should be noted that “water” is not on the list above.  I simply do not recommend using it as a source of fluid in ultra distance events (or really any endurance events, for that matter), as it only serves as a “blank”, washing away critical electrolytes that you’ve already taken in and putting you at risk for hyponatremia.  Sports drink, on the other hand, provides the fluid simple sugars AND electrolytes that you DO need, all in one shot.  Seems like a no-brainer to me!  And my friend from the opening story would agree.  She uses sports drink now and has since seen multiple 100 mile finish lines.

I hope these tips help you think about and prepare your hydration strategy well for race day!  If you are interested in delving further into your fluid AND calories needs (we didn’t even discuss what to eat!) and coming up with an entire fueling strategy, check out the fueling plans offered by The Core Diet.  As a VT100 athlete, you can get a 15% discount on a fueling plan with the code ‘VT100’!

Beth Shutt is a registered dietitian and the Operations Director at The Run Formula.  She’s been an endurance athlete for over 25 years, including racing professional triathlon for 6 years.  She has made every nutrition mistake in the book (including drinking water!) and loves to help people NOT make the same mistakes.  She can be reached at

The Run Formula

VT Adaptive Ski & Sport Headquarters
Attention: Amy Rusiecki
PO Box 139 Killington, VT 05751
Call: 1-802-786-4991

Directions to Silver Hill Meadow, Site of the VT100 Endurance Race Start/Finish