How to prepare water bottles and gels for elite marathon racing

Getting your personal water bottles placed at aid stations in a road race is one of the perks offered to people fast enough for elite or sub-elite status at major marathons. It’s amazingly convenient to be able to place your own nutrition and hydration along the course, but since this perk is such a rarity among the broader running population, there’s very little information out there about how to change your nutrition strategy if this is an option for you.

The advantages of personal nutrition are manifold: you’re free to choose the form and flavor of the nutrition you consume, you don’t have to physically carry the gels and fluids with you, and you can drink out of an actual water bottle, which is much easier than drinking out of a paper cup.

Additionally, marathons sometimes make questionable decisions about the official hydration sponsor; I know of more than one major race that has historically offered a low-carb or calorie-free hydration mix as their official fluid at the general public aid stations! Using your own nutrition frees you from worrying about this problem.

A few of the athletes I’ve worked with over the years have been fast enough to get “bottle service” at major city races, and I’ve learned a few tricks from other coaches and athletes for how to optimize a nutrition plan for this scenario. Let’s say you’ve just qualified for the elite field at a big race, and you find out you get to supply your own nutrition–what do you do? In this post, I’ll walk you through how to design your fueling plan and how to prepare the bottles themselves, using an example from a real athlete and a real marathon.

The remainder of this article is focused on bottle service for the marathon, but in rare cases you might get the same perk for a half marathon. Much of the same info applies, though the actual fueling considerations (how much, and when) differ a bit. I’ll defer thoughts on fueling (or not fueling) for the half marathon for another day, though.

The following advice is written primarily for elite marathoners planning out how to situate and prepare their personal fluids, but much of the information below also applies to people who don’t get personal water bottles in a marathon, so even if you’re not a top runner, you might learn a few things from how they prepare their nutrition.

Designing your fueling plan for an elite marathon

The science on fueling for the marathon is pretty straightforward: for carbs, you want to aim for about 60 grams of carbs per hour [1], and for fluids, you want to drink when you are thirsty, and not drink when you aren’t thirsty. In ultramarathons, you can fuel at higher rates (up to 90 grams per hour), but in the marathon you can get to the finish without running out of fuel at a relatively moderate carb intake rate of 60 grams per hour.

Physiologically speaking, the specific form of fuel you choose is not particularly important–sports drinks and gels both work fine. For fluids, there is no need to worry about electrolyte content or lack thereof: there’s no good evidence that electrolytes provide any benefit over water (or sugar water) when it comes to hydration during marathons.

Choosing the right fuel: are energy gels or sports drinks better for elite marathoners?

For most athletes, energy gels are a better choice for the primary form of fuel for most of the race, for a few practical reasons. First, you can decouple your fluid intake and your carb intake. If you are relying on a sports drink, you need to drink a constant amount of fluid to hit your target carb intake.

A traditional sports drink, like Gatorade or Powerade, is diluted enough that the fluid intake required to sustain 60 grams of carbs per hour can be too high if you’re racing in cool weather. To hit that level of carb intake you’d need around 36 fluid ounces of Gatorade Endurance, if mixed per the standard instructions. This is nearly double than the average fluid ingestion rate of top marathoners when running in ideal conditions [2].

The specifics of what fuel you choose are not that important, as long as your fuel of choice contains both glucose and fructose (two different forms of sugar). A combination of maltodextrin (which is just a long chain of glucose molecules) and fructose also works.

Pretty much all sports drinks and gels you will find feature both of these compounds, so this detail is only important if you’re trying to hack together a custom sports drink. Maurten gels, for example, feature glucose and fructose; GU gels feature maltodextrin and fructose.

Why do you need two forms of sugars? Glucose and fructose are absorbed through different pathways, which means that your carbohydrate absorption rate can increase by up to 50% when consuming glucose + fructose, versus glucose alone [3].

If you’re gunning for a fast time at Cal International, Indy Monumental, Chicago, Houston, or any of the other popular elite and sub-elite marathons, chances are good it’s going to be in the mid-40s or low 50s–perfect for fast marathoning. In these conditions, your fluid needs will be surprisingly low. Conversely, if it’s very hot, you might be drinking a lot of fluids, which can sometimes cause stomach issues if all the liquid you’re drinking is a sugary sports drink. If you separate fluids from fuel, you can drink as much or as little water as needed, while still hitting your carb intake target.

Energy gels are also easier to work with in training, and are easier to carry on your body if you don’t have bottle service at a marathon. They also contain a set amount of carbs (usually 25 grams, or 100 calories of carbohydrates) which makes planning fueling for most of the race dead-easy: take a gel as close to every 25 minutes as possible. That way you’re hitting a carb intake rate of 60 g/hr (i.e. one gram per minute).

However, energy gels are not for everyone: some runners have trouble stomaching energy gels; for these athletes a liquid sports drink mixed to about 5-6% carbohydrates by weight is a better option (most commercially-available sports drinks fall in this range if mixed as directed).

Sports drinks are also useful late in the race, when you want to take advantage of the “mouth rinse effect” to sustain your performance, but are too close to the finish line for consuming more carbs. So you’ll want to find a sports drink that you like, even if you’re going to use gels for most of your fuel. More on this mouth rinse technique later!

Identifying your arrival time at each aid station in the race

After selecting your fuel and fluids of choice, you need to plan out where and when you’ll consume them. In practice, you usually have to deviate from the theoretically-optimal fueling strategy because your fueling is constrained by where the aid stations are on the course. This is the case even if you don’t have bottle service, but is doubly true when you’re relying on nutrition placed at aid station tables for most or all of your fuel.

So, to prepare our fueling plan, we need to know two things: first, where the aid stations are at, and second, an approximate pace plan so we know when how long into the race (in minutes) we’ll be arriving. An additional consideration is which of the aid stations are eligible for personal nutrition–at some races, you can only place your own nutrition at a limited number of aid stations (e.g. 10k, 20k, and 30k, even though the race may have general public aid stations every 5k).

As an example, we’ll be looking at aid station locations from a marathon in the Midwest United States. The athlete preparing for the race is a low-2:30s marathoner (observe: at many races you do not need to be world-class to get personal nutrition!). For the race in question, aid stations with personal nutrition were located at the following mile markers: 3, 5, 6.8, 10, 14.5, 18, 20, and 22mi.

We want to plan out nutrition according to time, not distance. To do so, we’ll consult our pace plan for the race to find out roughly when we’ll arrive at each aid station—you do make pace plans for your marathons…right? If you don’t, we’ll have to table that discussion for another day.

Here’s what the arrival times look like for each aid station:

Aid stationApprox. arrival time

Keeping in mind our fueling guidelines from above, we can start to formulate a plan. Remember, we want to aim for one gel every 25 min or so. If we take gels at 3mi, 6.8mi, 10mi, 14.5mi, 18mi, we’ll hew pretty close to the theoretically-optimal rate of carbohydrate ingestion.

The 20mi and 22mi aid stations are a bit too late in the race for gels to be worth it, so these would be good locations for a sports drink instead, possibly leveraging the mouth rinse effect.

The benefits of a sports drink mouth rinse late in the marathon

There is a delay between when carbohydrates are ingested and when they actually make their way to the bloodstream. However, sports scientists have noticed an interesting phenomenon: the benefits of ingesting carbohydrates seem to materialize earlier than that, and carbohydrates seem to improve performance even in events that shouldn’t be carbohydrate-limited, like the half marathon (which lasts ~60-70min for elites).

In fact, some clever experimentation has revealed a small benefit even to a “mouth rinse” with a sugar-containing sports drink (mixed to a standard concentration of ~6% carbs by weight), where you swish a sports drink in your mouth for about 10 seconds [4], then spit it out.

The proposed explanation for why this trick works is as follows: the brain regulates your subjective feelings of fatigue based on anticipation of physiological distress, and your perception of fatigue ramps up in proportion to how soon and how severe your central nervous system is expecting a “crash.”

Some good evidence for this model of fatigue comes from data on time trial performance in the heat–traditional exercise physiology textbooks will say that endurance performance in the heat is worse because the body’s core temperature rises above the level that is optimal for performance.

This is true to some degree, but what’s interesting about time trial performance in the heat is that runners slow down far before their core temperature has risen above the typical temperature levels you’d experience during a time trial in cool conditions [5]. This suggests the initial feelings of fatigue you feel during a race, time trial, or hard workout in the heat are not a reaction to dangerous core temperatures, but are generated in anticipation of the heat, based on the body’s perception of heat generation versus heat loss.

The same explanation can be proffered for the fatigue that leads up to “bonking,” or glycogen depletion. The usual experience runners have when they run out of carbs is not that they go from cruising along without issues to immediately being reduced to a jog; rather, their sense of fatigue and tiredness builds over the course of a few miles, ultimately culminating in exhaustion and dead legs.

Similarly to how the brain is generating feelings of fatigue as a consequence of anticipating dangerous rates of heat accumulation, the brain is also likely generating feelings of fatigue as a consequence of anticipating an unsustainable rate of carbohydrate usage versus intake. A carbohydrate mouth rinse, which stimulates receptors in the mouth that can sense the presence of sugar, sends a signal to your brain that carbohydrates are continuing to be supplied to the body, tamping down on fatigue related to glycogen depletion (or so the hypothesis goes).

This mouth rinse trick is useful in two contexts for distance running: moderate-distance races of ~45-80 minutes, and late in the marathon.

For example, in this race, the 20 and 22mi aid stations are within about half an hour of the finish for our athlete, meaning any carbohydrates you’d ingest won’t make their way to the leg muscles until you’re practically at the finish line. However, these are excellent spots for a sports drink mouth rinse.

Another (optional) one at 24mi would be ideal, but that wasn’t an option in this race because the 22mi aid station was the final one before the finish.

Now, in practice, it’s difficult to actually swish a drink around in your mouth while running since that tends to require closing your mouth. Instead you can hold the sports drink under your tongue, and in your cheeks, for the requisite ten seconds. You’ll spill a bit, but having some sports drink on your singlet is going to be the least of your concerns when you’ve finished a marathon.

You might wonder: why not actually swallow the sports drink? Indeed, if you are feeling up to it, there’s no harm. Sometimes, though, your stomach can be fairly sensitive late in the race, and trying to force down a sports drink can induce nausea or vomiting.

So, the ability to just do a mouth rinse is a bit safer for the stomach, especially if the weather is fairly cool and you aren’t particularly thirsty. Sports drinks are also a good option for late in the race because if you are feeling like you’re on the verge of crashing because of low glycogen availability, you can aggressively consume them (e.g. grab two cups and drink both in quick succession) with the hopes of being able to hang on a bit longer.

Finalizing the fueling plan for the marathon

Based on the principles above, here’s the fueling plan that I developed for this athlete:

Aid stationItem at table
3miGEL #1 + water or electrolyte mix
5miGEL + water backup
~6.8miGEL #2 + water or electrolytes mix
10miGEL #3 + water or electrolytes mix
~14.5miGEL #4 + water or electrolytes mix
18miGEL #5 + water or electrolytes mix
20miSports drink (consume or swish)
22miSports drink (consume or swish)
BackupsExtra gel in shorts pocket, general public gel at mile 19

The plan allows for five gels (125 grams of carbohydrates) consumed over the first ~103 minutes of the race, which should come into full effect at just over two hours into the race. I’d have preferred to bump the third gel and beyond back a bit later (to 11mi or 12mi for #3), but based on the layout of the aid stations that wasn’t an option. In situations like this, I prefer to front-load energy gels, then rely on sports drinks late in the race if needed.

Backup fuel plans: what if there’s a problem with the marathon fueling strategy?

You’ll notice a few backup options baked into the plan above. There’s always a chance something can go wrong with your fueling plan in the marathon, but when you’re relying on your own water bottles placed at an elite athlete table there are some additional risks involved.

First, the water bottles might not be laid out correctly, or the first aid station might have them set up in a non-obvious place. So, you might run right by the elite-only aid station without seeing it!

Second, you could miss or drop your own bottle. Grabbing a water bottle at sub-6:00 mile pace with sweaty hands is not always easy.

Third, another athlete could knock your bottle off the table when trying to grab his or her own bottle. Or they might grab yours instead!

Worst of all (though least likely), there could be a catastrophic mix-up and none of your bottles make it out onto the course.

I’ve seen or heard of all of these circumstances happening in elite marathons. High-level marathoning does involve cultivating an ability to “roll with the punches” of unexpected problems during the race, but having some backup options ready is useful.

At this race, the 5mi aid station is a nice spot for an extra water bottle. We wouldn’t be taking a bottle at all at that aid station if everything goes okay, but if there’s an issue with the first aid station, you’ve got another bottle with a gel only two miles later. On top of that, I advised this athlete to tuck another gel into his shorts pocket in case there was an issue with one of the aid stations in the middle of the race.

Lastly, the race offered energy gels to the general public at a special station at 19mi. So, we have three backup options for gels. This is probably overkill, but the downside (carrying an extra 25 grams in your shorts pocket, and being out a few dollars more for one more water bottle) is pretty small, and having backup plans also helps tamp down some of the “what-if” anxiety that can be generated by having a fueling plan with no backups.

For this race, we didn’t actually have to prepare water bottles for the 20 and 22mi aid stations–we knew that the general public aid stations would have an acceptable sports drink available. If this athlete had a particularly sensitive stomach, or strongly preferred a specific sports drink, we would’ve placed water bottles with their sports drink of choice at these aid stations as well.

Preparing water bottles before the marathon

Now for the most exciting part: how do you actually prep your bottles for an elite marathon? Each bottle needs fluids (usually water, but a mildly-flavored electrolyte drink or sports drink is fine if you prefer that instead) and it needs to have a gel attached to it, externally (remember, one advantage of gels is that we can decouple carb intake from fluid intake).

The first question to address is what kind of bottle to use. I prefer simple cycling-style water bottles, since they are cheap and semi-disposable. You want to choose bottles that are not too big, have a squeeze-top that you can “bite” open without using your hands, and that don’t leak when laid on their side. The classic green Gatorade bottles are much too big. Smaller trail-running style water bottles are a better choice, since most of the time you aren’t going to be consuming more than eight or twelve ounces of fluid per bottle (except for races in very hot weather).

Once you’ve selected your water bottles, you should decorate them in a way that is distinctive and easily-recognized. If you don’t, your water bottle will be just one of possibly dozens at an aid station (and think how many of your competitors also bought the same cheap water bottle on Amazon!).

There are plenty of creative ways to decorate water bottles, but I prefer brightly-colored duct tape. Maybe you want to use a BeDazzler–fine. Colors like fluorescent yellow and fluorescent green are particularly easy for the human eye to spot (which is why safety vests are these colors, by the way). These colors are especially easy to spot when they are opposed against a black background. Decorate all your bottles with a similar pattern so you know what to look for as you approach each aid station.

Next, you’ll need to attach the energy gels to the outside of each bottle. Early on in my coaching career, when I was captaining an “aid station” for a few of my athletes doing a marathon-specific workout, I tried taping energy gels to the side of a water bottle with trainer’s tape. This doesn’t work–the tape sticks too well, and you can’t get the gel to come off the bottle when you’re running!

This is the wrong way to do it!

I learned a much better technique from Matt Gabrielson, who ran at the 2009 World Championships in the marathon: get some strips of adhesive-backed Velcro, then attach one side to the gel, and the other to the water bottle. It doesn’t matter whether the bottle or the gel gets the “hook” or “loop” side. Then, wrap a rubber band around the gel to secure it. Now your energy gel is securely attached to the water bottle, and won’t fall off in transit, but can be easily detached and consumed during the race.

Much better! You can't see it from this angle, but adhesive-backed velcro secures the gel to the water bottle

Lastly, you’ll want to fill your bottles with your fluid of choice. You’ll want to err on the side of slightly more fluids than you need. Don’t completely fill the bottle, and even if you plan on drinking barely any fluids at that particular aid station, still fill the bottle roughly halfway to give it some weight (empty bottles are easily toppled!).

The gear you need to prepare marathon fuel bottles

If I was tasked with putting together personal nutrition for an elite athlete on short notice, here’s the gear I would use:

Water bottles: Elite Fly Bottle (550 mL) or Maurten Bottle (500 mL)

Why: Both options are inexpensive, come in a manageable size, and can be “bitten” open without using your free hand. The Maurten bottle is often out of stock, though, and you can bet that tons of your fellow competitors are going to have the same bottle (hence our decoration strategy).

Velcro strips: Velcro 6′ x 3/4″ adhesive-backed hook and loop fastener

Velcro adhesive-backed roll

Why: I find brand-name adhesives perform more reliably than generic knock-offs. A strong adhesive is useful because the bottle might get condensation on the outside, which could wash away cheap adhesives.

Rubber bands: Generic brand assorted-size rubber bands

BAZIC Multicolor Rubber Bands

Why: Thick, springy, and comes in different sizes to fit different water bottles. Don’t need to get overcomplicated on this one.

Tape for decorating bottles: Craftzilla Rainbow Duct Tape & 3M Black Duct Tape

Why: Fluorescent stripes on a black background stand out nicely from a long ways away.

Energy gel: Maurten Gel 100 or GU Energy Gel

Why: Athletes I’ve worked with are more or less evenly divided on preferring an intentionally bland, unflavored gel (Maurten) or something with sweet or savory flavors (GU). From a performance standpoint, either are fine: you get 25 grams of a dual-carbohydrate mix.

Sports drink: Maurten 160 Drink Mix or Tailwind Endurance Fuel or Skratch Labs Hydration Mix

Why: As discussed above, the only thing that matters with a sports drink is the carbohydrate content: it should contain both a glucose-based and a fructose-based sugar. Maurten, Tailwind, and Skratch all fit the bill, and taste a bit less acidic than Gatorade or Powerade (though if those are your preference, go for it). As above, choose Maurten if you want a bland unflavored drink, and Skratch or Tailwind if you prefer something with a mild flavor. All three have electrolytes but as discussed above those do not matter for our purposes.

An aside: Should you drink warm or cold fluids during a marathon?

This is very much obsessing about the details, but it’s worth spending a moment on whether you should aim to have your water bottles ice-cold. The temperature of a sports drink does not affect how fast you absorb the fluids [6], though ice-cold fluids (especially if you actually consume the ice) can boost performance in very hot conditions [7]. That’s the academic side, but as usual, practical considerations end up dominating whether or not you’ll have any control over what temperature your fluids are.

You’ll get specific info from the elite coordinator on when to turn your water bottles in. If it’s the morning of the race, and you prefer cold fluids, you can add ice, though it’d be a waste if you added the ice the night before–it’d melt by morning anyways, diluting any carefully-prepared sports drink mix.

It’s worth some experimentation in training to figure out how well you can stomach ice-cold fluids, and how well you can stomach ambient-temperature fluids. Some people are sensitive to this, and others are not. It’s also worth adding that fluid temperature is often outside of your control, both in training and in racing.

Unless you have a coach, friend, or partner biking support for you in training, your water bottles are going to be whatever the ambient temperature is by the end of a long workout. So it’s best to prepare for anything on this front.

Practicing your marathon fueling plan in training

In the final six weeks or so of marathon training, I always try to design the fueling during marathon-specific workouts to mirror our fueling plan on race day. If you are getting personal fluid placement at a marathon, it’s worth practicing at least a few times with the actual water bottles you’ll be using on race day–even doing a few workouts this way goes a long ways towards learning the right way to grab a water bottle, consume your gel, and drink some fluids, all without slowing down. Just do me a favor and don’t leave your gel wrapper and rubber band on the ground, ok?

In closing: Expect the unexpected in elite marathoning

One piece of advice that I always give to athletes before a marathon is that something is bound to go wrong. They should expect the unexpected and be ready to roll with the punches and adapt to the circumstances. I take a principled approach to fueling for the marathon, and try to optimize every step (some might say to an excessive degree!) but I also expect things to go awry during the chaos inherent in a 26.2mi race.

Many of the details in the plan are ‘fault-tolerant’ – if you drop a gel, for example, it’s not a big deal–you’ve got a backup in your pocket. Likewise, if water bottles aren’t where you expect them to be, or if you drop a bottle, you can always fall back to using general public fluids. A good fueling plan combined with a readiness to adapt to changing circumstances is the best way to increase your odds of success when racing a high-level marathon.

How did the fueling plan we prepared here work out? Two days before the race, major flooding forced a change in the course, and the race organizers scrapped the elite aid stations completely! We reverted to a carry-your-own-gels strategy with similar gel timings, and that was good enough for a podium finish. How’s that for expecting the unexpected!

About the Author

John J Davis, PhD

I have been coaching runners and writing about training and injuries for over ten years. I've helped total novices, NXN-qualifying high schoolers, elite-field competitors at major marathons, and runners everywhere in between. I have a Ph.D. in Human Performance, and I do scientific research focused on the biomechanics of overuse injuries in runners. I published my first book, Modern Training and Physiology for Middle and Long-Distance Runners, in 2013.

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