Energy plan hour by hour for a marathon

When you stand on the start line of a marathon, the training is in your legs. What can make the difference between having a smooth experience and hitting a significant energy dip along the way is your fueling plan—especially how you plan your carbohydrate and fluid intake hour by hour throughout the race.

In this guide, you’ll get a concrete, time-based template so you can create your own fueling strategy, test it in training, and show up on race day with a plan you already have experience with.

What is an hour-by-hour fueling plan?

An hour-by-hour fueling plan means you plan your energy intake by time—for example every 30 minutes—instead of only going by kilometers and aid stations. This can provide structure throughout the race and make it easier to maintain a more consistent intake.

With a time-based plan you get, among other things:

A more even distribution of carbohydrate intake across the entire distance
Less likelihood of long periods without planned energy intake
A plan that’s easy to adapt to your expected finish time

In big races you can still use the aid stations as reference points. The challenge can arise if you only think “I’ll take something at 10 km, 20 km and 30 km.” Then you may end up going a long time without planned intake, or the aid stations may be placed less conveniently in relation to your stomach and your pace. With an hour-by-hour approach you use the aid stations as support, but you take in energy when your plan says so.

If you want to go even deeper into the strategy before, during and after a marathon, you can find inspiration here: marathon energy and hydration strategy.

Set your goals for carbohydrates, fluids and salt

Before you create your fueling plan, it can be an advantage to have three clear goals: how much carbohydrate you’re aiming for per hour, how much you want to drink, and whether you want to supplement with electrolytes or salt based on your needs and the conditions on the day. If you want to explore your options, you can browse the full energy range for endurance training and race day.

Carbohydrates per hour

As a starting point, many runners can aim for a carbohydrate intake within these ranges:

Around 30–60 grams of carbohydrate per hour for most people
Up to about 90 grams per hour at high intensity if you’ve trained it and your stomach can keep up

A typical energy gel contains about 20–23 grams of carbohydrate. That can, for example, translate like this:

One gel and a bit of sports drink can together provide about 30–40 grams of carbohydrate per hour
Two gels and water can provide a high carbohydrate intake in a short time, which often requires getting used to it in training

If you want to see how the number of gels can relate to pace and finish time, you can read more in the guide on gels for marathon: how many gels should you take in a marathon?. If you want to keep your fueling easy to execute, you can also check out PurePower’s energy gels and plan your intake in 30-minute blocks.

Fluids per hour

Fluid intake is important in an overall endurance plan. A practical rule of thumb can be:

Around 0.5–0.8 liters of fluid per hour, split into small intakes
The body can usually absorb a maximum of about 1 liter of fluid per hour

In bigger races it might, for example, look like this:

Drink about 150–200 ml at each aid station
Stop at most aid stations rather than only every third or fourth

If you want to combine carbohydrates and electrolytes in the same drink, an energy powder can be part of your fueling plan. For example, you can use Carbo Race Electrolyte Orange 1 kg as a base for your planned carbohydrate intake per hour.

Electrolytes and salt

When you sweat a lot—especially in warm or humid weather—you lose both fluids and electrolytes. This can affect how you feel along the way, and some people experience fatigue or cramp sensations in connection with it.

It may be relevant to consider extra electrolytes if:

You sweat a lot during training and races
You run in warm or humid conditions
You have previously experienced cramps on long runs

Many choose to supplement with a salt or electrolyte capsule about every hour, or every other time they take a gel, depending on the product and needs. If you want to see more options for supporting fluid balance during long races, you can read more here: electrolytes for hot races and high sweat rate.

Build your plan from theory to practice

It’s often easier to get an overview if you see your plan as a set of building blocks. They can typically consist of:

Sports drink, for example Carbo Race, as a source of carbohydrates and electrolytes
Energy gels as a practical way to plan carbohydrate intake
Energy chews, if you prefer small bites instead of a whole gel at once

An example of a simple structure that can provide about 45 grams of carbohydrate per hour could be:

About 250 ml Carbo Race with around 20–25 grams of carbohydrate
One gel with about 20–23 grams of carbohydrate, for example every other time you hit a 30-minute interval

If you want to keep it as simple as possible, you can let most of the energy come from gels and combine them with water at the aid stations. You can see the selection of gels here: energy gels for your hour-by-hour plan.

If you’d rather have small bites, you can replace some of the gels with gummies. Here you can see the alternatives: energy chews as an alternative to gels.

Example fueling plan for a four-hour marathon

Below is a template you can use as a starting point. You should always adapt it to your body, your pace and your training experience. The example is based on:

Expected finish time around four hours
A target of about 40–50 grams of carbohydrate per hour
Fluid intake of about 0.5–0.7 liters per hour
Optional extra electrolytes if it’s hot

Preparation before the start

What you do before the start can influence how you experience the first hours.

Three to four hours before the start: Eat a light, carbohydrate-rich meal, for example rice or pasta with a little protein and low in fat and fiber
30–60 minutes before the start: Have a small snack, for example an energy bar, a roll with honey or a banana, and possibly a gel if you know you tolerate it close to the start

Fueling template during the race

During the race itself, it can help to think in 30-minute blocks. Here’s an example of what that can look like.

0:00–0:30: Start easy, find your rhythm, and take small sips of water, especially if it’s hot
0:30–1:00: After about 30–45 minutes, take your first gel and drink about 150–200 ml of water at the next aid station
1:00–1:30: Drink at each aid station and possibly a little sports drink at one of them
1:30–2:00: Around 90 minutes, take your second gel and top up with water at the aid station
2:00–3:00: Repeat the pattern and take a gel about every 30–45 minutes, for example around 2:15 and 3:00, and drink at each aid station
3:00–4:00: In the final part of the race, continue with a gel about every 30–40 minutes as long as your stomach feels good, and take small, frequent sips of fluids without drinking too much at once

A runner finishing in around four hours will typically end up with:

About five to seven gels in total, depending on how much sports drink is also used
Two to three electrolyte intakes if it’s hot
About two to two and a half liters of fluid spread throughout the race

Remember, this is only a template. You can adjust both the intervals between gels and the distribution between gels, chews and drink to suit your stomach and your experience.

Adapt the plan to your finish time

The basic principle of the fueling plan is the same, no matter how fast you run. You follow the plan for a longer or shorter time and adjust the amounts based on duration, intensity and what you have trained.

If you run under three hours, you have a shorter duration and often higher intensity. Here a higher carbohydrate intake, for example around 60–70 grams per hour, may be relevant if you’ve trained it and tolerate it well. The total number of gels will typically be lower, but the intervals can be a bit shorter
If you run around four and a half to five hours, the duration is longer and the intensity is often slightly lower. Here 30–50 grams of carbohydrate per hour may be appropriate, especially if your stomach is sensitive. The focus can be on a steady intake of fluids and possibly electrolytes in hot conditions

If you want to nerd out even more on the relationship between finish time, pace and number of gels, you can read more in this guide: how many gels should you take in a marathon?.

Train your stomach and your fueling plan

A fueling plan typically works best when you’ve tested it in training. Use your long runs to test and adjust your strategy so you know what works for you on race day.

Especially these training sessions are often well suited for testing your plan:

Long, easy runs of about 25–30 kilometers
Marathon-pace workouts, for example three times five kilometers at planned race pace

During these sessions you can, among other things, test:

How early you can take the first gel without getting stomach issues
Whether you do best with gels and water, gels and Carbo Race as a base, or more chews and fewer gels

If you experience discomfort, you can adjust the plan step by step:

Lower the carbohydrate intake slightly per hour, for example from 50 to 40 grams
Spread the energy across more small intakes, for example chews and smaller amounts of drink
Try a different flavor or texture if that’s where the challenge lies

After the finish line and your recovery

When you cross the finish line, it may be relevant to focus on replenishing your energy and fluid balance. A simple plan can help you structure intake in the hours after the race.

Within 30 minutes: Get some carbohydrates you can easily eat or drink, for example an energy bar, a banana or a sports drink, and top up with fluids with electrolytes or a light sports drink
One to two hours after: Eat a larger meal with both carbohydrates and protein, and continue drinking water and possibly electrolytes in small sips for the rest of the day

If you’d like to make it easy to plan both before, during and after the race, you can find inspiration in PurePower’s complete range for energy during endurance. See the selection here: energy for your training and your races.

Make the fueling plan part of your preparation

An hour-by-hour fueling plan isn’t about making things more complex, but about creating calm and predictability on the day. Once you’ve set your goals for carbohydrates, fluids and electrolytes, you can build a simple schedule and test it on at least two to three long training runs.

That way, you’ll stand on the start line with a strategy your body already knows—and one that can help you hold a planned pace more easily and have a more even experience all the way to the finish line.