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Training and Race Nutrition

By Lionel Sanders

I had a traumatizing experience at Ironman Texas in 2015. It was very hot and humid and I was coming from a long Canadian winter. In all of my training and racing leading up to this race I never really gave much thought to hydration and nutrition. It was the norm to go for a 20 kilometer run in the middle of summer and not bring anything to eat or drink. On the bike in Texas I consumed less than one Gatorade bottle per hour. The bike took me over four hours, and I also probably sweat a bit in the hour long swim. By the time I got off the bike my vision was beginning to get blurry, and my muscles were not functioning very well. I felt like a concrete block. These symptoms only got worse during the marathon, to the point where I was swerving all over the path. It was by far and away the most painful experience I have ever endured. I remember having the feeling that I was pushing myself very close to death. For a long while after that race I feared the next time I would have to do an Ironman.

Lionel Sanders Swims

In the days and weeks after that race I did a lot of searching for the answer as to why I felt so terrible. Eventually I went to a laboratory and had my sweat rate measured under similar conditions to those in Texas at the time of year of the race; I also had my sweat sodium concentration measured. In heat and humidity very similar to that of the race in Texas, my sweat rate on the bike was over 2L per hour. My sweat rate on the run was closer to 2.5L per hour. Keep in mind, the actual sweat rate during the race was likely higher because there was no sun heating the surface of my skin in the laboratory.

So, let’s assume I lost 0.5L in the swim. I was on the bike for a little over four hours, and sweat a minimum of 2L per hour, which means I lost a minimum of 8L on the bike. Thus, in the first five hours of the race, I lost 8.5L. I consumed four bottles of Gatorade in that time, each of which were 710mL, for a total of 2.84L. Therefore, coming off the bike, it is safe to say I was in a minimum deficit of 5.66L. In terms of percentage of body weight, 5.66L is equal to 12.45 pounds, and before the race I weighed about 165lbs, so I had lost a minimum of 7.5% of my body weight. Running a marathon being 7.5% dehydrated is a very painful experience that I do not wish anyone to endure.

Lionel Sanders

Long story short, this whole experience lead me to a company based right in the city that I live, called Infinit Nutrition Canada. They create fully customizable nutrition products that allow you to control every aspect of your sports drink. For example, you can decide exactly how much carbohydrate, sodium and electrolytes, protein, caffeine, flavour intensity, etc. you want in each serving.

Over the next year or so, I continued to measure my sweat rate under various conditions, as well as started to log how I felt under various degrees of dehydration. I came to the conclusion, that at 3% dehydration I was starting to notice subtle cognitive impairment, and by 5% dehydration I was beginning to have significant cognitive and physical impairment. This lead me to conclude that ideally, I would be finishing the race around 5% dehydrated i.e. just as I was starting to have significant impairment. Knowing this, I can then work backwards and formulate both my race hydration plan, as well as my custom nutrition blend. I will give you an example:

Let’s say I am doing a hot 70.3, in Texas for instance. Under those conditions, I will likely sweat about 2L per hour on the bike, and 2.5L per hour on the run. The bike usually takes me about 2 hours, and then the run takes me about 1.25 hours. That means I will lose about 4L on the bike, and another 3L on the run, for a total deficit of 7L. When I first learned about this stuff, I wanted to keep pace 100% with my sweat rate, which lead me to rationalize committing this aerodynamic and weight atrocity, which I believe added a significant amount of time to my Kona bike time.

But, keep in mind, all I really have to do is get to the finish line not too much greater than 5% dehydrated, because this is just when I am starting to experience serious impairment. So, 5% of 165lbs is 8.25lbs, which is equal to 3.75L. We calculated above that my total sweat deficit would be about 7L, but I have 3.75L to give away, therefore I really only need to consume 3.25L of liquids during the bike and run. Keep in mind, it is much more difficult to consume liquids while running than while biking, so it is best to consume as much of this as possible on the bike.

Lionel on Bike


Of course, things always look different in the real world, and in reality I have no problem consuming four 750mL bottles on the bike. Therefore, in a hot race like Galveston 70.3, I was able to come off the bike having consumed around 3L of liquids. This means I would only have to consume 250mL during the run to reach the finish line right around 5% dehydrated. In reality, I usually take two cups of water per aid station, and it is safe to say I consume 50mL or so out of each of those cups, so I likely consumed a liter or more on the run. This puts me at the finish line having consumed around 4L and having lost 7L, which means I was around 4% dehydrated. This makes total sense because I didn’t have much cognitive deficit at the finish line, nor were my muscles functioning poorly, nor was my perceived exertion very high.

Lionel Sanders

That is the process that I go through when determining my actual fluid consumption plan for a race. Armed with this, I am then able to customize my nutrition blend that is in my bottles, with the help of Infinit Nutrition. First things first, I am exercising at a very high intensity in a 70.3, so a lot of my energy will come from carbohydrate. Therefore, I need to be sure I am consuming as much carbohydrate as possible so I do not begin to run out of energy before the end of the race. Through lots of trial and error, I have come to find I can safely consume around 400 calories per hour, without much gastrointestinal issues. Each serving of Infinit Nutrition needs to be consumed with a mimimum of 600mL of water, so on the bike, I will consume four servings along with 3L of water. This means, I need each one of my Infinit Nutrition servings to contain 200 calories, so that after hour one on the bike, I will have consumed two servings and a total of 400 calories, and the same is true for hour two. The math works pretty well on the run too, but I will likely consume slightly less.

Once the carbohydrate is added I can then add my electrolytes. I learned in the laboratory that I lose about 900mg of sodium per liter of sweat. This means I will need to consume as close to this much sodium as possible per liter of fluid consumed. During the bike, I am consuming each of my servings with about 750mL of liquid, this means that I need about 675mg of sodium per serving (because 900mg of sodium is needed per liter, which is 90mg per 100mL; and each serving is 750mL, so 90×7.5=675mg of sodium). But, this is where the expertise of Infinit Nutrition really comes in.

I actually have a bit of advantage when it comes to creating a custom blend because my sweat rate is so high and therefore I am both able and required to consume very large quantities of water. Most sweat rates are nowhere near this level, and so most people are not consuming nearly as much water. Therefore, once the required carbohydrate is added to the blend, adding electrolytes can make the concentration of the blend very high. So high that after while, the concentration in the stomach can get so high that the stomach stops emptying itself. If you have ever been in a race and felt nauseous, or heard liquids swishing around in your stomach, it is likely that the concentration of the liquids in your stomach was too high. Infinit will work with you to find a good balance between carbohydrate, electrolyte, protein and flavouring, so that your stomach concentration never gets too high, so that you continue to process your nutrition properly right to the end of the race.

The final part of the process is to decide what flavour you want your blend to be, as well as how strong you want the flavouring to be. You can also add a small amount of protein to curb hunger, or a small amount of caffeine to fight off fatigue. Once I have my custom blend, I will practice my race strategy in training. At the race, I will mix all four of my servings of Infinit Nutrition into my frame bottle on the bike, as well as 2.25 servings of Infinit Nutrition into my hand bottle on the run. For the entire race the only thing I will use from the on-course aid stations is water.