Go the Distance with Your Ultimate Guide to Long Runs

by Taren Gesell

Blog ▸ Go the Distance with Your Ultimate Guide to Long Runs

Whether you’re a beginner runner training for your first 5k, or advanced distance runner training for a personal best marathon to qualify for the Boston Marathon, running requires a great deal of endurance and stamina, and long runs will be the key to achieving your goals. 

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 — this is the single most important workout of the week.

A long run is a run that lasts 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 the pace of your long runs should 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

4 Primary Benefits of Long Runs

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 can run for longer periods of time, at a nice steady race pace, 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, and increase your aerobic capacity, to improve 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 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 the confidence and ease you see in other experienced runners.

The Science Showing Long Run Benefits

The long run is more than just a well-known part of 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 exercise teaches that mitochondria how to function. Mitochondria are the cells that produce all of the energy you put out, so more mitochondria = more energy to run.

As we’ve mentioned, long runs improve your ability to access fat as fuel. 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 this image (Romijn et al. (1993)) that long-duration exercise at a low intensity burns the most fat of any exercise. Form follows function, and if we perform exercise that burns a lot of fat, our body will adapt to that exercise and continually get better at burning fat. 

Burning more fat will significantly impact energy availability and your success on race day. This study found that it was as crucial as VO2 Max for IRONMAN-distance 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 which includes a long run 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 a Runner Can Incorporate the Long Slow Run into Their Training

To get the most out of your long runs, it’s essential to train in the correct heart rate zones and run the proper distance. In this section, we’ll walk you through the steps you need to take to plan and execute your long runs properly and include them in your training cycle.

Step 1: Calculate Your Heart Rate Training Zones

We prefer heart rate to dictate long runs instead of pace. Heart rate automatically adjusts to changes in your life and your training stress level to get you to the right intensity during each and every run. On the flip side, pace is a static number so if you use pace to guide you, you may be running too fast and overreaching some days, then going too slow and underperforming on other training days.

We prefer the Karvonen method for calculating your heart rate training zones because it is 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. We recommend the workout below from our training app to perform a maximum heart rate test.

Once you have your maximum heart rate, you can then figure out 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 enter your maximum and resting heart rates 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 armband if they cannot use a chest strap, 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 to determine roughly how long you need to run 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 and Sprint distance triathlon: 5 miles (8 kilometers)
    • 10k and Olympic distance triathlon: 10 miles (16 kilometers)
    • Half-marathon and half-IRONMAN (70.3 distance): 15 miles (24.5 kilometers)
    • Marathon and IRONMAN athletes: 4 hours
    • Ultra marathoners: 5 hours

Step 3: Schedule Long Runs in Your Training Plan. 

The long run should ideally be done towards the end of a training week after you’ve already done most of your key workouts. The idea is actually to perform this workout in a pre-fatigue state. A study found that running on slightly tired legs has an excellent training effect. For most people, this means doing the long run every week 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 increase the distance of your long runs gradually. While it may be tempting to jump right into running the distances listed in your plan, it’s important to start by running only 8-10% longer than a currently comfortable distance for you, 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. 

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 doing half marathon training. 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 Distance Run As Impactful As Possible

Simply logging miles isn’t enough to see the real benefits of long sessions. Here are three keys to making them even more impactful:

  1. Run your long runs on trails and hills as often as possible. Running on trails has been shown to reduce the likelihood of injury, and athletes who train primarily on trails end up running less while performing relatively better than comparable runners who run mostly on roads. Not only that, but running on trails and hills can help to improve your overall strength, endurance, and agility.
  2. Be intentional with your fuelling and hydration during your training runs. Keeping your muscle glycogen levels low while going at your long-run pace (as determined by your HR) 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, before you want to run, eat protein and fat-based foods like eggs/omelets, protein bars, nut butters, meats, and perhaps a small amount of berries. Then, during the session, stick to protein bars, nut butters, unripe bananas, or something like a Ucan bar. Long run nutrition is a complex topic, and we discuss it more in-depth in other posts here on our blog.
  3. Incorporating strength and flexibility training. Strength training is second only to sleep for how significant a performance enhancer it is for 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 while also running long enough to withstand more tiredness. To avoid injury, your body needs to be strong enough to run with good technique despite fatigue. We discuss more about strength training for running in other posts here on our blog.

Example Long Run Workouts In Your Weekly Training

Here are some example long run workouts from the training plans in our app. You can see how the easy pace is actually dictated by heart rate and not a numerical pace most of the time. As the season moves along, getting closer to your races, the runs get longer and they feature some intervals where you run fast, which will help you build resilience to fatigue.

This is a long run from baseline training (from December to March, before race season begins) workout in our app.

This is a long run workout in the later stages of a marathon training plan in our app; note the speed-work toward the end of the workout.

This is a long run workout from a full IRONMAN workout in our app. It’s a split run, which means you run part of the workout early in the day, and the second part later in the day.

Wrap-Up on the Benefits of The Long Run Pace

As you can see, a regular 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 reaching your running race goals.

If you want a training tool to help you get ready for any running race you want to train for (anything 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.

About the Author

Taren Gesell is the world’s leading authority on helping adults take up endurance sports successfully. Taren is an accomplished age group athlete and a respected amateur endurance sports and running coach. Taren wants to help you become the best version of yourself.