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Managing Your Hydration Plan for Race Day with Hillary Allen

October 24, 2022
Managing Your Hydration Plan for Race Day with Hillary Allen

Hydration is important any day of the week but when it comes to running a race, hydrating correctly is essential for a successful race. We partnered with Hillary Allen, an elite trail runner and endurance athlete, to find out how she planned out her race day hydration at the Ultra Trail du Mont Blanc, an incredibly challenging, world renowned trail race in Chamonix, France. 

Managing Your Hydration Plan for Race Day with Hillary Allen

For running ultra-marathons, many people focus on nutrition during long efforts to practice for the big day, but in my experience, a well-dialed hydration plan can make or break your race experience! I’m going to walk you through my hydration plan from UTMB.

How do you start planning? 

During my latest race, at UTMB, I started by looking at the course map to see where the aid stations were and planned my fuel accordingly. This helped me determine how much water and how many gels I had to bring with me at the start of the race and how many I would need to pick up at key aid stations along the way.

Water vs. Electrolyte Drink? What do you use?

I calculate my nutrition needs based on consuming 200-300 calories an hour - this calculation includes my hydration needs, since drinks with electrolytes in them typically have some sort of caloric content. The main electrolyte drink mix I use is Skratch Labs. Not only do I like the taste (which is important), their electrolyte profile is spot on. I always use a combination of water and electrolyte drink mix, during UTMB, I had two 500mL SpeedFlasks with straws for easy drinking. One flask was always filled with water, and the other with a scoop of my Skratch Labs Drink mix. During the later hours of the race, when it got hotter and I got a little tired, I added 1.5 scoops of my Skratch mix to my flask (premeasured in little bags I took with me) with some added caffeine (my favorite is the Matcha Skratch drink mix). 

How do you make sure you stay hydrated throughout the race?

100 miles is a long way. It took me 29 hours to run UTMB while drinking roughly 500mL of fluids an hour. The important thing for a hydration plan is to make sure you are drinking to thirst – it’s the body’s cue that you are drinking enough. I always drink to thirst with plain water and then supplement the sips with my electrolyte mix. I also listen to my body’s salt cravings. This is an indication that I might need more electrolytes. It’s not uncommon to crave salty things, especially later in a race or when it gets really hot. I try to pay attention to those cravings, so when I come to an aid station, I can grab some salty chips, or potatoes to nibble on throughout the race and drink plain water after eating. In the later hours of the race, I planned to increase my electrolyte consumption – by adding 1.5 scoops of Skratch to my SpeedFlasks. 

What HydraPak Products did you use for UTMB? 

I’m a big fan of soft flasks, and if a race has enough aid stations to get by with flasks, I prefer to use those as opposed to a hydration reservoir. Flasks are a bit lighter and much easier to fill up during a race setting. My favorite HydraPak products for racing are the 500mL UltraFlasks. The pop-cap top makes it so easy to refill bottles in aid stations, without having to worry about screwing on and off the top. I also changed the drinking attachment to straws. This made it easier for me to keep drinking as the flasks collapsed in my vest, the straws kept the access to my hydration easier. Usually in long races I bring a filter flask with me, but in a race like UTMB, there are many refill stations for water, so I did just fine with my 2 flasks.

Overall, I was very satisfied with my HydraPak gear choices for UTMB, and my hydration plan went very well, thanks to the ease of my gear choices and products I put in them. The only addition to my hydration plan, was later in the race, I mixed coca-cola with water to get an extra energy and caffeine boost, but that’s pretty much standard with an ultra these days!