Ruck Marathon Fueling & Hydration: Exactly What To Take Per Hour (26.2-50 miles)

Fueling for a race feels high stakes…because it is. Get it right and your pace stays steady and your head stays clear. Miss it and everything gets harder mentally and physically. At PATHFINDER, my job is to remove the guesswork with a plan you can trust. Below, you'll find exact hourly targets, a calm pre-race meal, and a short gut-training routine you can practice in training. Use it as written for a few sessions, take some notes, and adjust until your stomach and pacing stay consistent from mile one to the finish. Let us know how it goes!

About PATHFINDER Horizon

Horizon, fully updated for 2025, is our marathon-to-50-mile program with two distance tracks so you can choose 26.2 or 50 and train with intention. It includes clear long-ruck progressions, supportive strength, purposeful mobility, and four required Challenges. You'll practice fueling and pacing in training and finish with a simple post-race reset. If you want the full program details, you can learn more here: PATHFINDER Horizon.

Your hourly targets

Carbohydrates: You'll want to consume between 30-60 g per hour for events up to ~2.5 hours. For longer events, you may want to increase your carbs to 90 g per hour by using a glucose plus fructose mix. You can practice with liquids, gels, chews, or soft, simple-carb foods, like an PBJ or Rice Krispy Treat. Practice until you find what your stomach tolerates, and don't use something you haven't tested in training on the event day.
Fluids: Drink to thirst inside a typical range of 0.4-0.8 L per hour. Your needs will rise, though, in hot weather, or if you have a high body mass, or faster pacing. Very small athletes in cool conditions will need less. Avoid trying to replace every drop of sweat.
Sodium: Include sodium in your fluids or use small capsules. A practical starting point is to aim for 300-600 mg sodium per hour, but if you sweat a lot, or it's really hot, you may need more. Most sports drinks sit around 230-690 mg per liter, which covers light to moderate needs. This is also something you can personalize in training to make sure you have your plan down before the event day.
Caffeine (optional): If you use caffeine, take 1-3 mg per pound of body weight spread before or during the event. (This would equal around a single 12oz cup of coffee.) Do not take this all at once. Start on the low end if you're sensitive, or skip altogether. The jitters may not be worth it to you. Don't experiment for the first time on race day.

*Hourly targets for carbs, fluids, sodium, and caffeine.*

Some calm pre-race meal ideas

On race morning, you’ll want to top off your energy and keep your stomach quiet. It's best to keep the meal familiar, and important to keep fiber and fat low. Sipping water (not gulping it all down) is important to top off your hydration, and include a little salt so you start steady. If you use caffeine, take a small dose 45 to 60 minutes before the start only if you practiced it.

If you have 3 to 4 hours, eat a full but simple meal and then chill out. Think plain bagel with honey, a banana, and a cup of yogurt or milk. A small rice bowl with a side of scrambled eggs and applesauce also works. You should feel comfortably full, not heavy.

If you have 1 to 2 hours, keep it lighter and easy to digest. A bagel or English muffin with some jam plus an applesauce pouch and a sports drink is enough. Instant potatoes or white rice are a good alternative to the bagel. You want simple carbs, here.

If you have 60 to 90 minutes, drink most of your calories. A 300 to 500-calorie carb drink or smoothie that you tolerate, plus a banana or a few chews, gets the job done.

If nerves are high, drink liquids, eat soft carbs, and very low fiber. Skip spicy or rich foods.

The night before, keep dinner low fiber and low fat. Choose white rice or pasta, a small portion of lean protein, a little oil, and salt. Avoid large salads, or anything else fibrous or hard to digest.

If you'd like a personalized version of this routine, PATHFINDER Nutrition offers it as an add-on coaching package.

Simple pacing and fueling rules

Set a repeating timer for every 10-15 minutes to sip from your water bladder or your electrolyte water bottle.
Eat 100-150 calories every 30 minutes until the finish.
Add sodium according to conditions and what you tested.

These rules align with endurance guidelines on carbohydrate delivery and gut comfort for long-duration efforts.

What to carry between stops

Plan by the time you expect to take on the course, not only miles. If the longest gap between refills is 90 minutes and your comfortable intake is 600 ml per hour and 60 g carbs per hour:

Carry ~900 ml fluids for that gap, plus a small buffer.
Carry ~90 g carbs, which is three 30 g servings.

This time-based approach reduces surprises at aid stations that may not have what you need and the additional benefit of keeping your stops short. The formula matches general hydration and sodium guidance while supporting some steady carbohydrate delivery for your hard-rucking body.

Example setups

Marathon ruck (26.2):

Fluids: 400-600 ml per hour with electrolytes.
Carbs: 40-60 g per hour from gels or bottles with glucose/fructose.
Sodium: 300-600 mg per hour, matched to sweat rate and heat.
Optional caffeine: 2-3 mg/kg early, then small top-ups if you tolerate it.
These numbers align with ACSM carbohydrate guidance and practical hydration ranges.

50-mile ruck:

Fluids: 500-800 ml per hour with electrolytes, adjusted for heat.
Carbs: 60-90 g per hour using mixed sources and multiple easy-to-carry carbs (as long as they have glucose plus fructose).
Sodium: Start at 300-600 mg per hour and increase it if your training tests and/or conditions demand it.
Caffeine: 1-3 mg/kg in smaller doses later if it keeps you steady without GI issues or jitters.
This approach reflects research on higher carbohydrate delivery during ultra events and individualized hydration and sodium strategies.

Train your gut like you train your legs

"What if I have to poop?"

No one wants to talk about GI issues, but it's a common cause of pre-race anxiety. GI comfort can actually improve with a little practice eating while out on your ruck. Two to four weeks of eating during training can reduce symptoms and improve tolerance to higher carbohydrate intakes. Schedule one or two long sessions each week where you practice your exact race intake and record what worked. Of course, start low and slow, using our micro-plan below.

2-week gut-training micro-plan

Week 1: Target 40-50 g/h carbs with your normal drink.
Week 2: Move to 60-70 g/h using glucose plus fructose.
If aiming for 80-90 g/h, increase your numbers gradually and keep your total fluid volume comfortable.
Evidence suggests gut training lowers GI symptoms and may improve performance when you fuel at higher rates.

Stay Smart

Start hydrated. Drink enough water so your urine is pale-yellow, not colorless.
Drink to thirst. Avoid forced drinking, which increases hyponatremia risk.
Adjust for heat. In hot conditions you will need more fluid and may need more sodium per hour.
Keep a small emergency carb and extra electrolytes.
Log what mattered: intake totals, how your stomach felt on which foods, and any fixes that helped.

Where PATHFINDER Nutrition coaching fits

If you're building toward 50 miles or you have a sensitive stomach, coaching can save you trial-and-error miles. Over three months of coaching, we can help you:

Find the right mix that works best for your training.
Translate the hourly ranges into a personal plan that your gut tolerates.
Choose glucose-fructose mixes that reach higher carbohydrate targets without discomfort.
Set up heat plans with practical sodium and fluid ranges for your sweat rate.
Rehearse and refine your aid-gap items and routine.
Use caffeine conservatively and effectively if you choose to include it.
Foundation and habits, layering in performance needs, as well as guided nutrition for your race prep, taper, and reset.

Ready to train with intention? Choose your track and start Horizon 2025 here: PATHFINDER Horizon.

FAQs

How many carbs per hour should I plan for a ruck marathon?

Plan 30 to 60 grams of carbohydrate per hour for most marathon-length efforts. Use gels, chews, or drink mix. Practice until your stomach feels stable.

Do I really need up to 90 g per hour for 50 miles?

Many ultra-distance athletes perform well at 60 to 90 grams per hour when they use a glucose plus fructose mix. Build up during training and keep GI comfort first.

How much should I drink per hour?

Drink to thirst within a typical range of 0.4 to 0.8 liters per hour. Warmer weather, higher body mass, and faster pacing increase needs. Very small athletes in cool conditions may need less.

How much sodium should I take?

A practical starting point is 300 to 600 milligrams of sodium per hour. Adjust based on sweat rate, heat, and how you felt in training.

What should I eat before the start?

Eat 1 to 4 grams of carbohydrate per kilogram of body weight in the 1 to 4 hours before your start. Keep fat and fiber low, and use familiar foods.

Can I use caffeine?

Yes, if you tolerate it. A conservative plan is 3 to 6 milligrams per kilogram of body weight, split before and during. Do not try this for the first time on race day.