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The Purpose of the Long Run (21 Long Run Benefits)

Regardless of whether you’re preparing for a 5K or a marathon, long runs are a part of every training plan.

In this article, you will find out what is the purpose of the long run and why is it important, along with 21 long run benefits.

Long runs increase aerobic endurance, strengthen the musculoskeletal system, and increase the ability to use fat as fuel. Likewise, they increase your pain tolerance and build self-confidence, and are a great opportunity to test your diet and hydration the day before a race.

Below I will explain in detail each benefit of long runs and why they are an important part of a training plan for almost every runner.

1. They increase the number and size of mitochondria

Longer activities increase the number and size of mitochondria.

In the presence of oxygen, mitochondria break down carbohydrates, fats, and proteins into energy that we use for all sorts of activities, including running.

Therefore, the more mitochondria you have and the bigger they are, the more energy you can generate, allowing you to run faster and longer.

Two key studies help determine the optimal distance and pace required for the development of mitochondria.

A study from 1967 showed that the maximum development of mitochondria occurs after around two hours of exertion at 50-75% VO2 max.

A subsequent study from 1982 showed that the maximum development of mitochondria occurs after 90 minutes of exertion at 70-75% VO2 max.

Therefore, long runs are ideal for the development of mitochondria.

The Purpose of the Long Run

2. They develop capillaries

Long runs boost capillary development in muscles.

Capillaries are the smallest blood vessels in the body that help deliver oxygen and nutrients to muscle tissue and remove waste products.

The greater the number of capillaries that surround each muscle fiber, the faster the oxygen and carbohydrate transmission to the muscles, which also means faster energy production.

3. They increase aerobic endurance

By increasing the number and size of mitochondria, developing capillary networks, and strengthening the heart, long runs also increase aerobic endurance.

That way, your body will no longer have to work at the same intensity to achieve the same performance level.

4. They are important in a base-building phase

Long runs are especially important in the preparation phase (base) when you do longer and less intense workouts.

The better you build your base, the more you will be able to progress and the closer you will be to your maximum potential.

5. They increase your VO2 max

Long runs increase your maximal oxygen uptake (VO2 max), that is, the maximum amount of oxygen that your heart can send to the muscles that use it for energy production.

That way, your muscles will have more oxygen and will be able to produce more energy.

6. They strengthen your heart

The heart is a muscle that sends oxygen-rich blood and nutrients to your cells while returning the blood that contains waste products.

By strengthening the heart, long runs increase the amount of blood that the heart can pump in one heartbeat.

That way, your heart becomes a lot more efficient and doesn’t have to work that fast.

All professional long-distance runners have athlete’s heart, which allows them to have an extremely low resting heart rate.

I experienced the same thing when I was in my best shape, having a resting heart rate of only 35 beats per minute.


The resting heart rate is a great metric for daily tracking of your current form. It is important to measure your heart rate right after you wake up. Measure it daily and record the results. As your fitness level rises, your resting heart rate will get lower. On the other hand, if you notice an increase in heart rate, it might be a sign of overtraining. In that case, take a rest and lower your training intensity.

7. They strengthen the muscles used in running

Long runs, aside from strengthening your heart, strengthen your leg and core muscles, as well as the entire respiratory system, including your diaphragm.

With the number of miles run, these tissues become stronger and less susceptible to injury.

Read more: Key Muscles Used in Running (8 Main Muscle Groups)

8. They adapt your ligaments, tendons, bones, and joints to forces in running

Long runs help adapt your ligaments, tendons, bones, and joints to physical stress in running.

The stronger they are, the easier it will be to do workouts specified for a race, such as tempo runs and interval training.

long run benefits

9. They increase myoglobin concentration in muscle fibers

Myoglobin is a special protein in muscles that binds the oxygen that enters the muscle fibers through the blood.

When oxygen becomes limited during exercise, myoglobin releases oxygen into mitochondria.

Simply put, the more myoglobin you have in your muscle fibers, the more oxygen the muscle will be able to get under aerobic conditions, that is, under race conditions.

10. They boost the ability to burn fat

Long runs teach the body to use fat as an energy source instead of carbohydrates.

Due to that, stored glycogen stores last longer, helping you avoid “hitting the wall” during a race.

The infamous “hitting the wall” happens when all glycogen stores are depleted, making your body use fat as a source of energy.


When you start running, your body uses only glycogen as a source of energy. After about an hour, the body consumes about the same amount of fat as it uses glycogen. After about two hours, your body primarily uses fat as a source of energy. For this process to be as painless as possible, training is necessary.

By running slower and longer, such as when doing long runs, you train your body to use fats for energy.

By combining long runs with a diet plan that lowers or eliminates carbohydrates, you could burn fats more efficiently and avoid the infamous “hitting the wall” during a race.

11. They increase your glycogen stores

Although this is not important for races that last less than 90 minutes, during races like marathons, the more glycogens your body can store, the later you’ll “hit the wall”.

The goal of long runs is to use all glycogen stored in your muscles. Your body reacts to this by learning to store even more glycogen to prevent future exhaustion.


The faster you run, the higher the percentage of energy that comes from carbohydrates. Although there is no scientific research concerning the optimal pace required for burning significant amounts of carbohydrates, the experience and study of elite runners has shown that the optimal pace is 65-75% of the 5K pace.

12. They make you faster

Long runs boost endurance and thus allow you to maintain a certain pace for a longer period of time.

After a certain level of fatigue, your slow-twitch muscle fibers get tired.

Therefore, the body activates fast-twitch muscle fibers that act fast to help maintain pace.

At that moment, it is necessary to check your running technique to avoid injury.

That way, the increase in endurance will allow you to run for a longer period of time at a faster pace.

13. They allow you to test your diet and hydration

During longer races, such as marathons, you should know how your body will react to certain dietary supplements and beverages.

In order to know this, it is necessary to find dietary supplements and beverages that suit your body during training.

Likewise, a meal before and on the day of a race is important to avoid indigestion and the appearance of premature fatigue. Long runs are a great form of pre-race rehearsal.


While trying out diet and hydration during long runs, introduce one change at a time. Otherwise, you will find it hard to accurately attribute the results to the changes you have introduced.

14. They allow you to try on equipment and clothes

Have you heard of the rule “nothing new on race day ”?

In addition to diet and hydration, this rule also applies to your running shoes, clothes, and equipment.

Use long runs to find out which equipment suits you best and to avoid unnecessary inconveniences and surprises during a race.

Pay attention to every detail, from your running socks to your caps.


Never run with new running shoes, even if they are the same model. They need to be properly broken in beforehand to fit your foot. That way, you will reduce the possibility of blisters.

15. They increase your pain tolerance

For many runners, long runs are the closest they feel to their body dealing with the physical pain of running.

By this, I am not thinking of pain during injury, but of fatigue, that will arise in the muscles used in running.

The more times you test your body, the easier you will be able to deal with muscle fatigue.

why should you do long runs

16. They build self-confidence

Long runs build your self-confidence as you learn to overcome fatigue and cope with discomfort.

This will make it easier for you to cope with the difficult parts of longer races, such as half marathons and marathons, especially when you “hit the wall”, which is when you deplete your glycogen stores.

17. They are great for mental preparation

Long runs are the most specific form of mental preparation for long races.

It is very hard to run a long race without doing long runs since long races require mental preparation along with physical preparation.

In addition to building base endurance and providing physical preparation for long races, long runs prepare you to stay focused and mentally strong to be able to avoid having your mind tell you when to stop instead of your muscles.

18. They burn more calories compared to other workouts

Shorter running at a high intensity such as interval training will burn more calories per minute.

But ultimately, by running longer distances at a slower pace, that is, by doing long runs, you will burn more calories.

If your end goal is to burn as many calories as possible, long runs are the best way to do it.

19. They teach you patience

Many runners do easier workouts at a faster pace than the one that is set.

Every workout has its purpose, and there is a reason why some workouts are planned at a certain pace.

Long runs take longer and due to that, you should not start running too fast or at a pace faster than the one that is set.

Sometimes, the pace will seem very slow, but as I mentioned above, each workout has its purpose, and not every workout is supposed to get the most out of you.

Instead, you will gradually progress by accumulating workouts and recoveries.

That way, long runs make you a more patient and disciplined runner.

20. They help you achieve your target weekly mileage

Since long runs are the longest workout of the week, they help you achieve your target weekly mileage.

It is important to gradually adjust your weekly mileage to avoid the risk of injury.

Regardless of whether you’re preparing for a 5K or a marathon, it is important to run a certain weekly mileage.

It will allow you to achieve your racing goals by preparing your body for stress and physical and mental effort.

21. They allow you to explore places

Since long runs take longer, you will run longer distances.

That way long runs push you to find different running routes that you were previously unaware of.

To learn all about the long run read this article: What is Considered a Long Run? (5 Long Run Examples).


Matea Matošević

Hi, I’m Matea! I’m an Olympic Marathon Runner, founder, and writer behind OLYRUN.com. On this site, I provide help in the form of my knowledge and experience to all who love running and active living. Read more…