The long run
Training 9 minutes

The long run

August 3, 2020

One of the most important types of runs in the training plan of a marathoner is the long run. What is the (marathon) long run and why is it so important?

The long run is just that: a run where you go longer than your normal workouts or easy runs. It can be time or distance based, depending on your plan and needs. There are some variations of the long run, one of which we will discuss below, but it is typically ran at your easy run pace or slightly slower, especially if you are not an elite-level athlete.

To get some of the training benefits discussed below, your run should be longer than 90-120 minutes, but if your easy runs are currently around 30 minutes then 45-60 minutes could count as a long run for you.


You should include a long run at least once every microcycle, meaning typically every week, throughout your training cycle. The day before and after should not contain a (hard) workout, but instead only easy running.

At the beginning of your training cycle you can slot your long runs based on time or distance, but as you get closer to your goal marathon race you should start planning them by distance. If you are (re)building fitness, gradually build up the long run. Don't go from running 30 minutes on your easy runs straight to hitting the roads for 2+ hours for long runs. The only thing that will bring is injury.


The purpose of the long run is to train you both physically as well as mentally. Mental strength is such a crucial aspect in running, but that's a topic for a different article. For now it's enough to say that it allows you to power through the rough parts and stay focused when your body gets tired. By running long during training your mind will be trained to deal with the fatigue when the race comes.

“A long is crucial for me. It tells my mind and my body that you need to run that long.”

Eliud Kipchoge

Physically the long run trains your ability to burn more fat instead of precious glycogen (refered to as "glycogen sparing"). Glycogen is the preferred fuel of the body when going faster, over burning fat, but storage is limited. Your body can store around 2,000-2,400 kcal of the stuff. Look at your energy expenditure on recent runs and you can see how long you would last on just glycogen, while keeping in mind that only part of the stored amount can be used as there are other systems that will require glycogen.

Fat on the other hand is stored in amounts that would allow you to run for days on end, if you could use that as your only fuel source. In practice your body burns both at given aerobic speeds, preferring fat over glycogen for lower speeds and using more glycogen when running faster.

The human body also allows only limited uptake of carbs per hour. Depending on the specific substances it can be 60-100 grams per hour (240-400 kcal). From the fact that we have limited amounts of glycogen, and replenishing it during the race being hard, we can conclude that it is useful to be able to burn more fat at any given speed.

Note though that this training adaptation is caused by lower amounts of glycogen in the body because you are depleting your stores. That is why it is useful to not take carbohydrate supplements during the run for a period of time in training. Do however bring something, especially if you are out alone, for emergency use. If you get wonky and you really need some food, or if your intentions for the long run do not include training the fat adaptation, you should definitely take it.

Besides the fat adaptation the long run also trains your muscle's resistance to fatique and builds leg strength, which obviously is crucial for long distance running. Additionally it gives you the ability to try your race-day routine, practice your gear and nutrition strategies every now and then. How does your body respond to different types of hydration and fueling during your long run? Your gear might be fine during a 1 hour run, but when you are out there for 3+ hours how is it going to hold up then?

On a side note, the NN Running Team released an interesting and motivational short documentary a while ago about the long run:

Fast-finish long run

As your fitness improves and as race day comes closer there are variations of the common long run. One such an example is the fast-finish long run, where you run the first portion just like normal but at the end pick up the pace. You should finish the final part (the last ten minutes) by really picking up the pace even more, emptying the tank.

This teaches the body and mind how it feels to run fast in an already exhausted state. How long you maintain the faster pace is increased over time. Assuming a long run in the range of 25 to 40 kilometers, perhaps start out with the last 5 to 8 kilometers, building up to 12-20 kilometers of faster paced running.

The fast-finish long run can best be run on a bi-weekly basis in the last few weeks leading up to the marathon.

Finishing up

As you get home from your long run, make sure to refuel and rehydrate as soon as you can to start the recovery process.

So, are you including long runs in your training plans? Most runners do them during the weekends, simply because there is more time there. Whatever your week looks like, I highly encourage you to slot it in somewhere where you are highly unlikely to skip it!

Koen van Urk