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Go the Distance with Your Ultimate Guide to the Long Run

Taren Gesell

Whether you’re a beginner runner training for your first 5k, or an advanced runner training to for a personal best to qualify for the Boston Marathon, running requires a great deal of endurance and stamina. 

One of the key components to building up run endurance is the long run, also known as the LSD run (long slow distance). In any run training plan from 5k races all the way up to ultramarathons, the long run is literally the single most important workout of the week.

A long run is a run that lasts for anywhere from 60 minutes to three hours (or sometimes even longer). The pace of a long run is typically very slow and the goal is to build your endurance for running. 

The long run is the answer to the question "how to run longer?" By gradually building up the distance and duration of your long runs, you will be able to increase your endurance and make the distance of your goal races completely attainable.

In this article you’ll learn:

  • How long should long runs be
  • How fast should the pace of long runs be
  • How many long runs you should do each week
  • What to eat and drink on long runs
  • How to recover from long runs
  • Long run mistakes to avoid
  • What example long run workouts are
Go the distance with your ultimate guide to the long run

4 Primary Benefits of the Long Run

There are four primary benefits of the long run.

  1. Benefit #1 Increased endurance and stamina: A study published in the Journal of Strength and Conditioning Research identified that long easy runs were one of the primary contributors to success in long distance running races. The long run allows runners to gradually build up their endurance and stamina over time, so that they are able to run for longer periods of time without getting tired.
  2. Benefit #2 Improved cardiovascular health: Another benefit of the long run is improved cardiovascular health. Low intensity zone 2 running, which most of the long runs should be, is one of the absolute best ways to improve the health of your heart and lungs, improving your quality of life and your lifespan.
  3. Benefit #3 Improved race performance: More fat burning is for better race day performance. When athletes are able to burn fat as a fuel during exercise they will have a nearly limitless supply of energy. However, when they are unable to burn fat (as many people on a carbohydrate-rich Western diet have a hard time doing) they are almost guaranteed to run out of energy and experience the dreaded"bonk" during a race.
  4. Benefit #4 Mental preparation for your race: Many runners have a hard time fathoming the distances of the races they want to complete. A well-designed training plan, with a purposeful weekly long run, will make the distance of your goal race seem insignificant. By gradually building up the distance and duration of your long runs, you will be able to conquer the distance of your goal race with confidence and ease.

Science of the Long Run

The long run is not just based around running culture, there’s a tremendous amount of science supporting the physiological effects that occur as a result of completing one weekly long run.

As a study published in the Journal of Applied Physiology confirms, low intensity long duration exercise increases mitochondrial density while high intensity exercises really teach that mitochondria how to function. Mitochondria are the cells that produce all of the energy you put out, more mitochondria = more energy to run.

As we’ve mentioned, long runs improve your ability to access fat as fuel. The reason for this is because when we exercise at a low intensity we use a higher amount of fat as fuel as opposed to carbohydrates.

You can see from the image below (Romijn et al. (1993)) that long duration exercise at a low intensity burns the most fat of any type of exercise. Form follows function, and if we perform exercise that burns a lot of fat our body will adapt to that exercise and get better and better at burning fat. 

Burning more fat will have a significant impact on energy availability and your success on race day. This study found that it was as important as VO2 Max for Ironman athletes. 

An athlete who is unable to burn fat well, at a common rate of 0.4g of fat per minute, will start to run out of energy in races of 3-4 hours or longer. On the other hand, an athlete who has followed a good training plan with a long run that is designed to improve the ability to access fat as fuel will burn 1.2-1.6g of fat per minute and have a nearly limitless supply of energy. 

How to Incorporate the Long Run into Your Training

In order to get the most out of your long runs it's important to train in the right heart rate zones and run the correct distance. In this section, we'll walk you through the steps you need to take to properly plan and execute your long runs.

Step 1: Calculate Your Heart Rate Training Zones

We prefer to use heart rate to dictate long runs as opposed to pace. Heart rate automatically adjusts to changes in your life or training stress level to get you into the right intensity each and every run, while pace is a static number so you may be going too fast and overreaching some days then going to slow and underperforming on other training days.

For calculating your heart rate training zones we prefer the Karvonen method because it tends to be almost as accurate as lab testing. It also works for every athlete, while other methods tend to be inaccurate 30-40% of the time.

The first step in determining your Karvonen heart rate zones is to determine your maximum and resting heart rate. To perform a maximum heart rate test, we recommend the workout below from our training app.

Instructions for how to do a maximum heart rate run test

Once you have your maximum heart rate, you can then collect your resting heart rate by wearing a wrist-based heart rate monitor to bed for a few nights. If you don’t have a wrist based heart rate monitor you can take your resting heart rate while lying down first thing in the morning, then use a number that’s 5-10 beats per minute lower than the reading you collected.

Finally, to determine your heart rate zones using the Karvonen method, you will need to use the formula: ((Maximum Heart Rate – Resting Heart Rate) x Intensity Percentage) + Resting Heart Rate. Or you can simply enter your maximum heart rate and resting heart rate into the calculator below.

It’s important to note that monitoring heart rate using a chest-based heart rate strap is the most accurate method. Women can use an arm band if they cannot use chest straps, but watch-based heart rate monitors can be inaccurate by as much as 40 beats per minute.

Step 2: How Long Should Your Long Runs Be

You can use the guidelines below for to determine roughly how long your long runs should be based on the distance of race you’re training for:

Base season:

  • Athletes in running races and triathlons where the run is 80 minutes or less: 30-75 minutes long
  • Athletes in running races and triathlons where the run is longer than 80 minutes: 75 minutes - 2 hours long

Race preparation season. Build up to the following distances or durations:

  • 5k running race and Sprint triathlon: 5 miles (8 kilometers)
  • 10k running race and Olympic distance triathlon: 10 miles (16 kilometers)
  • Half marathon and Half-IRONMAN: 15 miles (24.5 kilometers)
  • Marathon and IRONMAN athletes: 4 hours
  • Ultramarathon runners: 5 hours

Step 3: Schedule Long Runs in Your Training Plan. 

The long run should ideally be towards the end of a training week after you’ve done most of your key workouts. The idea is to actually perform this workout in a pre-fatigue state. A study found that running on legs that are slightly tired has an excellent training effect. For most people this means performing the long run on a Saturday or Sunday, but you really can do it on any day

Step 4: Gradually Increase the Distance of the Long Run

It's important to gradually increase the distance of your long runs. While it may be tempting to jump right into running the distances listed in your plan, it's important to start by running just 8-10% longer than a currently comfortable distance for you and then building up by 8-10% each week. This will help your body adjust to the increased distance and prevent injury.

Step 5: Take a Rest Week Every Third or Fourth Week

Many runners don't train hard enough on hard days, or easy enough on easy days. This can lead to burnout or injury. 

In order to give your body the rest it needs, every third or fourth week you should take a rest week where the total time or distance you train is reduced by 40-50%. This will help your body recover from the previous weeks' training and prepare for the next phase of your training plan.

For example, let's say you're training for a half marathon. In a work week, you may have a long run of 10 miles. But on a rest week, your long run would be reduced to 6 miles. This allows your body to recover and adapt without overworking it.

3 Tricks to Making the Long Run Even More Impactful

Simply logging miles isn't enough to make the most of your long runs. Here are three keys to making your long runs even more impactful:

  1. Perform a lot of long runs on trails and hills. Running on trails has been shown to reduce the likelihood of injury, and athletes who train primarily on trails run less while performing relatively better than comparable runners who run primarily on roads. Not only that, but running on trails and hills can help to improve your overall strength, endurance, and agility.
  2. Fuelling and hydration during the run. Keeping your muscle glycogen levels low during your long run is critical for teaching your body to access fat as fuel. Consuming refined carbohydrates raises blood sugar levels and releases insulin, which can blunt fat oxidation. To avoid this, eat protein and fat-based meals like omelets, protein bars, nut butters, meats, and perhaps a small amount of berries before your long runs. Then, stick to protein bars, but butters, and unripe bananas or something like a Ucan bar during the run. Long run nutrition is a complex topic, and we discuss it in more depth here.
  3. Incorporating strength and flexibility training. Strength training is second only to sleep for how significant a performance enhancer it is with endurance athletes, this is particularly important when it comes to athletes and their long runs because the purpose of a long run is to run a little bit pre-fatigued and run long enough to have to withstand fatigue. Your body needs to be strong enough to still run with good run technique while being fatigued to avoid injury. We discuss more about strength training for running here.

Example Long Run Workouts

Here are some example long run workouts from the training plans in our app. You can see how the pace is dictated by heart rate and not pace most of the time, but as the season gets closer and closer to races the runs get longer and they feature some intervals to build resilience to fatigue.

Details of a long run workout from a triathlon or run training plan
Long run workout from Baseline training in the MOTTIV training app

Details of a long run as part of a run or triathlon training plan
Split Run from the MOTTIV training app (sometimes called a "Back to Back Run")


As you can see, the long run is a critical part of a well designed training plan. It isn’t as simple as just going and running a randomly long distance, with the right structure and scheduling the long run will be the key to you reaching your running race goals.

If you want a training plan for any running race you want to train for, from 5k races, to half-marathons and marathons, or even ultramarathons, check out our app where we provide personalized training plans designed for ordinary people who want to accomplish something extraordinary in endurance sports.

Written on:


Table of contents

4 Primary Benefits of the Long Run
Science of the Long Run
How To Incorporate the Long Run Into Your Training
3 Tricks to Making the Long Run Even More Impactful
Example Long Run Workouts

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Taren Gesell
Taren Gesell

"Triathlon Taren" Gesell is founder of MOTTIV and one of the world's top experts on helping adults become endurance athletes later in life. Best known for his YouTube channel and podcast, Taren is the author of the Triathlon Foundations series of books and has been published featured in endurance publications around the world.

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