Splitting Long Runs: Is It OK To Split Up My Long Runs?

Our expert coach gives us her top tips.

Almost all marathon runners have the same anxiety when they look at their marathon training plan: the long run.

The notion of running several hours or upwards of a 20 mile run can be extremely daunting. For this reason, splitting up long runs for marathon training in two can be an appealing alternative.

But, is it OK to split up long runs for marathon training? Will splitting long runs into two shorter marathon training runs offer you the same benefits as a marathon long run?

The short answer is yes—you can occasionally break up long runs in your training plan.

In this guide, we will discuss the pros and cons of splitting long runs and provide tips for splitting marathon long runs to minimize the consequences and maximize the benefits of dividing longer run mileage into separate runs.

A runner running their long run.

What Does It Mean to Split Up Long Runs In Marathon Training?

Splitting up marathon training long runs means that instead of following your marathon training schedule and running the full long run distance in one single run without stopping, you do two shorter runs that total the same long run mileage.

For example, imagine that your marathon training plan calls for 18 miles on Sunday, and you have to take your kids to soccer practice early in the morning, so you can’t get in those 18 miles all in one shot.

Instead, you might split up an 18-mile long run by running 10 miles in the morning before your family obligations and then 8 miles before dinner once you are home from soccer practice and the various activities of the day.

There are different ways to split long runs.

Some people run half or part of the long run distance in the morning as their first run and then run the remaining mileage in the afternoon or evening as their second run, as just described.

Other runners split up long runs over two days by actually doing part of it on one day and then the remaining mileage the next day.

Let’s sift through the pros and cons of breaking up your long run total mileage either in one day, or back to back days.

A person running their long run on the beach.

Is It OK To Split Up My Long Runs?

Even runners training for shorter distances like the 10K and half marathon often ask if splitting up the long runs on the training program is OK.

After all, particularly with marathon training, once the long runs start to get up to 18 or 20 miles, you may run for 3 to 4 hours, depending on your marathon training pace and ability level.

With busy lives, family commitments, and even just the struggle of mustering the motivation to push through a 3 to 4 hour run, it becomes all the more appealing to split up a long run into two separate runs.

There are various reasons why runners may split long runs up into multiple workouts. The most common include the following:

  • Logistics of fitting in long runs based on your schedule
  • Inclement weather
  • Lack of motivation
  • Traveling or inability to find a suitable long run route
  • Illness, muscle cramps, chafing, possible injury, blisters, or other discomfort when you start out a long run, so you truncate and then hope to finish the long run distance in a separate workout
A person running.

The short answer to “Can I split up my marathon long runs?” is yes—you certainly can break up long runs on your training schedule.

There are no rules or “marathon training police “ that will force you to run your long runs in one continuous run or follow your marathon training plan to a T.

However, as a running coach, I suggest not splitting up your long runs, especially not frequently.

Occasionally, splitting long runs into two distinct workouts is fine and may even have some benefits, but relying on split long runs as a standard practice instead of following your training plan long run distance as written is going to shortchange your potential.

Splitting a long run negates the benefits of long runs and the entire purpose of long runs for marathon training or preparing for any longer distance races.

A person running their long run.

Pros and Cons of Splitting Long Runs

Splitting long runs has various pros and cons. Understanding the benefits and the downsides will help you determine whether to follow your marathon training plan long runs as written or split them into two separate workouts.

Benefits of Splitting Up Marathon Long Runs

#1: Cuts Back Overuse Injuries Risk

Injury-prone runners often find that splitting up long runs reduces the risk of injuries because you build in more recovery time and accumulate less fatigue and microscopic damage to your bones, muscles, joints, and connective tissues.

(But strength training can also help this cause!)

#2: More Motivating

When there is bad weather, and you have to do a long run on a treadmill, splitting up a long run can be more appealing from a motivational standpoint.

A person running their long run

#3: More Feasible

Splitting up long runs is often more logistically feasible if you have a tight schedule, are traveling, or are trying to avoid running in the dark.

Even though it’s not ideal, it’s better to get all of your weekly mileage in by spitting up long runs instead of not doing them at all.

#4: Potential to Run Faster

Splitting up long runs may allow you to run your long runs at a faster pace because you are not running as far without stopping.

However, if your long runs are planned as easy runs, running them at a faster pace may stray from your objective.

#5: Decreased Recovery Time

The main benefit of splitting long runs is decreasing recovery time relative to long runs completed in one continuous nonstop run.

This means you can bounce back faster after your weekly long run and recover quickly for your next hard speed work session if you run two medium-long runs rather than one super long run.

A group of people running in the road.

Downsides of Splitting Up Long Runs

Understanding why you shouldn’t split up long runs centers around understanding the benefits of long runs on a marathon training plan.

The primary objectives of long runs in your training cycle are to increase physical and mental endurance, increase blood volume, strengthen the cardiovascular system, help your body adapt to higher mileage and a longer time on your feet, and develop your aerobic base.

Essentially, marathon training long runs are the closest replication to running the marathon race that you will experience in training and, therefore, serve a key role in preparing your body and mind for running 26.2 miles on race day.

Long distance running strengthen and improve the efficiency of the cardiovascular system1Hellsten, Y., & Nyberg, M. (2015). Cardiovascular Adaptations to Exercise Training. Comprehensive Physiology6(1), 1–32. https://doi.org/10.1002/cphy.c140080 and strengthen the heart muscle, which then increases stroke volume.

This enables the heart to pump more blood—and thus oxygen—out to the body every time it beats. This can effectively lower heart rate because the heart becomes more efficient.

Two people running their long run

Capillary density increases, allowing for better perfusion of working muscles, and blood volume increases over time. 

These adaptations, in turn, also increase stroke volume, cardiac output, oxygen transport and delivery, and, ultimately, VO2 max

Long runs also increase the mitochondrial density in skeletal muscles, particularly in Type I muscle fibers, and improve your ability to burn fat for fuel (rather than glycogen stores) at higher intensities.

Additionally, long runs are your “dress rehearsal“ for your marathon race in that they are a great opportunity to practice your fueling, work on your race pace, hone your mental strength to stay focused and tough when you start to get tired, and try out different running shoes and outfits to make sure that you do not experience any chafing or pain.

Splitting up long runs robs you of this opportunity, particularly in practicing your fueling and hydration strategies for your marathons.

Your second session will also be run on tired legs, so unless you are an ultrarunner or used to following a triathlon training plan with back-to-back sessions, this may take a toll on your body as you’ll be using up precious rest time.

Tips for Splitting Long Runs

If you decide that you do want to split up marathon training long runs into two different shorter runs, here are some tips:

  • Only split up long runs occasionally rather than all of your marathon training plan long runs so that you still get some of the benefits of doing long runs without stopping.
  • Split up shorter long runs rather than your 20 milers.

If you are looking for a marathon training plan, check out our database:


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Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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