Fueling IM Events in 2024 in a Mortal Hydration World

ICYMI: Mortal Hydration products are soon going to be replacing Gatorade Endurance at an IRONMAN race near you. Gatorade (regular formula) will be available on North American courses, alongside Mortal Hydration samples, until the end of June. Starting in July, it's all Mortal Hydration, all the time. If you’re considering making changes to your nutrition plan because you intend on “living off the course” on race day, and you’ve heard that on-course nutrition is changing, I recommend keeping a troubleshooting guide handy. It pays to know how to adapt when things go sideways.

Before we dive into how to think about living off the course on race day depending on what’s on your course, we need to define a couple things. First “living off the course” means to me: getting all or most of your nutrition and hydration needs from products available at feed zones on the side of the course. Quick refresher: there are three primary constituents of solid endurance sport fueling: Carbs, sodium, and water. Carbs for energy. Sodium and water for hydration. One without the other does not lead to better hydration. You need to have both. And you need to have adequate hydration to be able to absorb your carbs. And, finally, you need to be consuming carbs to sustain your energy. These things all become increasingly true the longer the race goes beyond about two hours. Usually, feed zones have these things in abundance. Usually. And usually, they don’t have much else.

Here, I’ll hit you with the summary up front: if you’re living off the course with Mortal Hydration only, you’ll be disastrously under-carbed. Hypoglycemic. Hungry, shaky, and under-performing on the bike. Things will go from bad to worse on the run. But at least you’ll be hydrated! There is a fair amount of sodium, and if you’re trying to get a meaningful amount of carbs (energy) from Mortal, you’re going to be taking in plenty of sodium with even their low sodium mix (just over 400 mg sodium per 10 grams of carbs). Friendly reminder: you probably need a whole lot more than 30-40 g of carbs per hour for activities lasting longer than 3-4 hours. Try 80-120g per hour. Consuming less than half of what is needed for optimal energy maintenance is usually catastrophic. You’ve been warned.

If you opt instead to bring your own fuel concentrate or drink mixture on course, you’ll be able to custom blend it to whatever energetic hydration perfection you need. Home brew comes with the need to either carry powder with you, or concentrate one or more of your bottles with powder beforehand with your preferred ratio of carbs and sodium.

How many carbs? Well, there's a video for that.

And sodium.

When your gut is on the brink, the devil is in the details. And guts are usually on the brink, on race day. If you care about race performance, you’ll care about the details. So, let’s dive into strategy. Hang with me here. To do performance nutrition well, you’re going to need your calculator -- or an app or coach that does all the math for you.

Our Race Day Scenario and Math

Let’s assume a 6-hour 70.3 goal. And it’s warm-but-not-hot. Call it 77°F for those of us in the northern hemispheres. I mention the duration of your race because exercise duration is the first thing that you should consider when you think about how much carbohydrate you need per hour. And your estimated thermal stress (how hot you’ll be) should be your next consideration because it informs you about how much fluid and sodium you’ll need to consume.

For math simplicity’s sake, I’m going to say we’re targeting 90g carbs per hour, 900 mg sodium per hour, and 900 mL fluid consumption per hour. Maybe it’s 700 mL in the first hour of the bike because it’s cooler then, but then it shifts to 1000-1100 mL in the final hour of three hours on the bike because the sun is starting to beat down. Then, your gut will only tolerate, say, 900 mL/hr on the run. That all adds up to a tidy 900 mL per hour. The rest of the consideration surrounds two golden questions:

How do I get my 90 grams of carbs per hour?
How do I get my 900 milligrams of sodium per hour?

Let’s be generous, and say in the real world, it’s your “A” race and you’ve got an estimated ±15% variance in what you can actually consume and get away with, without causing serious performance trouble. Higher consumption than that upper bound than that - ~105g/hr carbs or ~1100mg/hr sodium - and you get debilitating gut distress. Lower and you get either hypotensive from dehydration or low-energy and shaky from neurogenic hypoglycemia. That’s the scientific name for “I’m irritable, low-energy, possibly-crying, definitely shaky and maybe cold-sweating, probably starting to get ravenous” which comes from insufficient energy consumption. (In reality, you can probably overshoot sodium by as much as 30-50% and be okay. Do that with carbs, and you may be looking for the nearest restroom.)

And one more FYI before we get to the exactly how-to section: whether you’re targeting a 5-hour 70.3 or a 7-hour 70.3, your intake rates - per hour - might still be the same, so this example should hold for most folks. So, how do we get the necessary sodium and carbs by living off the course at our favorite long course triathlons? Let’s find out.

Hitting Performance Targets

For our scenarios, we are going to do a series of evaluation steps: first, we’re going to figure out how many servings of each product would need to be consumed to hit our carb target. Then figure out how many servings would be needed to hit our sodium target. Then calculate if that’s feasible at manufacturer prescribed - or bottled - concentrations. As in, how much fluid would that need to be with, if you listen to the manufacturer. Then, see what it would take to modify with any other on-course-available products or strategies. And finally, figure out what else we’d need to carry to compensate for any shortcomings in the aid station-stocked products.

I discuss primarily the bike leg, but this all applies to the run leg at the same hourly rates. Except that your wiggle room for error gets tighter, and your carb needs might have to shift down about 20% per hour. Maybe. Some folks can keep right on slamming carbs during the run, too.

Racing with Mortal Hydration

I’m just going to hit you with this up front. Mortal Hydration is a hydration product. Not a fuel product. Read: not for energy! Yes, there are a few carbs in it. (10g to be exact). But they are so limited that our example here is quickly going to turn into a “must-add-carbs-or-else!” optimization problem. The alternative is that you don’t finish your race, probably cry at least once, and maybe swear more than you usually do. The second alternative would be to WAY overdose sodium and have a really funky stevia-tweaked flavor trying to get carbs from what is not meant to be a meaningful fuel source.

To get to 90g/hr, we’ll need to divide 90 grams per hour by 10 grams per serving, which comes out to 9 servings. That’s 9 servings of Mortal Hydration to hit 90g/hr carb consumption. I highly recommend NOT doing that. Your sodium intake and flavor intensity will be insane. (Or you’ll drink an egregious amount if mixing at manufacturer recommended doses).

To hit 900 mg/hr sodium you’ll take 900 mg sodium per hour, and divide by either around 450 or 900 mg sodium per serving, which yields: 2, or 1, serving(s) of Mortal Hydration, to hit target sodium consumption, depending on if you’re using Mortal’s “normal” or “Salty” blends. There are three flavors of each. The dark-mode colored packaging are the “salty” ones, FYI!

Just for fun, let’s assess how much fluid we need to be consuming to hit our carb and sodium targets with Mortal Hydration.

For carbs: 9 * 22 oz per serving (derived from the adequate carbs scenario) gives a whopping - and totally impossible - 198 oz per hour.

For sodium: 1 serving (salty) or 2 servings (normal) * 22 oz per serving gives us either 22 or 44 oz of fluid per hour, if mixing at recommended strengths, which Mortal recommends more strongly than just about any other company. They mention “athletes are making a fatal mistake: over scooping their hydration.” Turns out, you’ll actually want to over-scoop Mortal’s “normal” mix if you’re needing 900 mg/hr (which is a pretty modest need for a 6-hour event.

If you’re trying to get carbs from Mortal, you are out of luck. If you are trying to get sodium, you’ll probably need to over-scoop their normal mix beyond what they recommend, but their “salty” mix might do the trick mixed in whatever fluid amount you like or at manufacturer-recommended mixing instructions.

Let’s say we decide to use the Mortal “Salty” mix. Pomegranate flavor because that’s Michelle’s favorite. (We have no affiliation with Mortal, although TheFeed.com did send us a big package of every version to try. It’s okay-ish. We’ll get through it eventually.)

Let’s put that 900mg Mortal Hydration “Salty” single serving in a 22 oz bottle because that’s what they say to do. (Let’s assume that’s what they’re doing on the side of the Ironman courses, where it is now a standard mix.) We’ve now met our sodium needs.

We’ll also need to make sure we’ve got another 8 oz of water onboard somewhere for this hour, and another 8 for each subsequent hour. (8 oz + 22 oz = 30 oz, which is roughly 900 mL, our hourly fluid target.)

That leaves us approximately - no, exactly - 80 whopping grams (which are the same as regular grams) of carbs short, per hour. We’re going to need to source an additional 80 grams per hour times 3 hours on the bike. That’s 240 grams of carbs over three hours. 8-10 bananas from aid stations should do the trick! Or 10 Maurten Gel 100s, or 12 Quantum Energy Squares. I don’t recommend you use bananas. I also probably wouldn't use that many Energy Squares, with their caffeine. But if you’re going to live off the course, using Mortal, you’re also going to have to use the other carb options -- and grab a lot of them.

If you don’t the result will be catastrophe. Please tell your friends.

Now, let's optimize this solution by bringing something with us.

Since the carb need is so high, the most straightforward would be to carry your own bottle of concentrated fuel mix. 80 grams per hour worth, to be exact. That’s a serving of most beverage products plus 1 cup of table sugar, or half cup of maltodextrin, half cup of fructose.

Alternatively, there are many other gel sources you can bring for your on course nutrition. Just make sure you bring a lot if you plan of supplying your own -- 240g of carbs worth.

Building Your Own Fuel to Avoid Mortal

Alright. So perhaps you have a stevia sensitivity. Or you just don't like what I described above, and you want to be more self-reliant out of the gate. Let's home-brew a solution that solves for this problem. To start with carb needs, I usually do one serving of any product I like the flavor of, and then sugar for the rest. It might look like 1 rounded scoop of Gatorade (which is a little over 60g carbs, call it 70g) plus a cup of sugar (200g carbs). That’s 270 grams of carbs. Perfect. You can also do any ratio of maltodextrin to fructose you like or dextrose to fructose. Somewhere between 2:1 and 1:1 is probably a good idea. Flavor and experience are the only driving factors.

On sodium: Two teaspoons of sodium citrate or one teaspoon of table salt gets you about 2000 mg sodium. Use sodium citrate for all or part of it if you want it to be as easy on your gut as possible. Chloride ions in excess are sometimes gut-offensive. I might shake a little more table salt in there just for fun and flavor and to bump me up to the needed 2700 mg (900 mg per hour times three hours!) sodium in the concentrated bottle.

Getting all the fluid: Drink a third of the concentrate bottle per hour, for three hours straight. Call it a 1000 mL reservoir. You consume an additional two 900-mL bottles of water, splitting each over 1.5 hours. You’ve hit your 2700 mL fluid intake goal perfectly. There is no need to modify with anything on-course. Fill up fresh water as needed.

If this is something you're interested in doing -- or just figuring out the optimal way to use your preferred beverage / gel / food of choice -- that's why this app exists. I frequent the Triathlon Forum here on slowtwitch and am happy to answer questions.


Ironman has moved from a fuel source that does it all - mostly kind of okay, even if I have a worse taste in my mouth for Gatorade than I do Mortal… no pun intended - to a hydration beverage that requires people to either do one of two things: (1) stuff their pockets full of everything they can get their hands on at each aid station, or (2) purchase high-carb gels, chews, bars, or other portable single serve options (“sachets”). Be prepared.