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Aerobic vs. Anaerobic Training


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If you are reading this article, chances are you have been bitten by the running bug. It can be hard to explain, as at some point you probably never thought you would end up enjoying running, but yet somehow it happened, and you are now a runner. Part of being a runner is wanting to do the best you can; chase down those PRs, and keep getting better.

Knowing the difference between anaerobic and aerobic training can make all the difference when it comes to running to your potential on race day.

When you learn how to train at the appropriate level, you can change your training for the better, and by understanding what each of these terms mean, you will be able to put that into practice.

In this article, we’re going to break down the difference between the two in-depth so you can better target your training.

To get started, let’s keep it simple:

At the heart of aerobic and anaerobic training is the following science; to exercise, your body needs to break down sugar and convert it to glycogen, so it can be used as energy or fuel.

When the body has an adequate supply of oxygen for this process, we call it aerobic respiration.

When there is not enough oxygen, for example when you are running hard at the end of a 5k, this is called anaerobic respiration.

Each of these have difference effects on the body.

What is Aerobic Running?

Aerobic running or respiration occurs when your body has sufficient oxygen – like when you run easy miles with your friends.(Did you know we found running 80% easy could make you 23% faster?) Each time you breathe in, your body efficiently uses all the oxygen it needs to power the muscles, and you exhale out what your body does not need.

When you are “running aerobically”, your muscles have enough oxygen to produce all the energy they need to perform.

The waste products of aerobic respiration are carbon dioxide and water. These byproducts are easily expelled through the simple act of breathing. This is why your breath is carbon dioxide rich and moist.

Aerobic running is extremely important to your training as a runner, and will allow your body to become stronger, while recovering from harder bouts of exercise.

What is Anaerobic Running?

Anaerobic respiration occurs when there is NOT sufficient oxygen present.

In this instance, the muscles do not have enough oxygen to create the energy you are demanding (usually from an increase in pace that is faster than your body is able to sustain, for example sprinting at the finish).

When running anaerobically, the muscles begin to break down sugar, but instead of producing just CO2 and water, they also produce excessive amounts of lactate.

Unfortunately, lactate is more difficult to reconvert back into energy and has a downside compared to exhaling out water and CO2. In the absence of oxygen, your body can’t clean up the extra hydrogen ion created by lactate and this is what causes that burning feeling in your muscles.

Did you know?

Many runners sabotage their training by allowing their long runs and easy runs to become anaerobic, and this can sacrifice future races, as well as future workouts.

Anaerobic vs. Aerobic Running explained here.

Why Do I Need to Know the Difference?

Here’s the deal:

The importance of understanding these definitions will save your racing.

If you begin to run too hard in the middle of a workout or the start of a race, your body goes into an anaerobic state, producing lactate.

If you “go anaerobic” early in a race, you will fatigue sooner, and your ability to maintain pace will take a nosedive. Lactate pools in your muscles, and you will have to slow dramatically to get your body back into an aerobic state. Your PR is out the window and you will be struggling before the halfway mark of your race.

For those running the marathon, learning the difference between aerobic running and anaerobic running is absolutely critical.

Check this out:

The faster you run, the more energy you burn – just like a car burning fuel on a highway. During the marathon, your body needs to conserve as much fuel as possible; if you run faster than your aerobic threshold (the point at which you switch from running primarily using aerobic respiration to running anaerobically) you will burn through your fuel stores faster, and more than likely bonk before you finish.

Read more about the science behind glycogen depletion and bonking and how to fuel for a marathon to prevent bonking.

Learn the difference between aerobic and anaerobic running and why it matters.

How to Learn to Run Aerobically When You Need To

Learning to establish and feel your anaerobic and aerobic pace is a really important skill if you want to start racing faster.

The secret to keeping yourself in an aerobic state is this:

The easiest way to test whether you’re running aerobically is to perform what is called the “talk test”. While running, try to speak to someone (or yourself if alone) out-loud. If you can get out a short paragraph without too much trouble (i.e. you can convey a detailed thought, but you’re not quoting Shakespeare) you’re running aerobically. If you can only get out one sentence before you start grasping for breath, you’re running too hard – slow down.

Exclusive bonus: For a more scientific assessment, you can download our amazingly helpful calculator. We’ll tell you exactly what pace and heart rate will keep you running aerobically. Download it free here.

If you have questions about what your “aerobic” and “anaerobic” pace is, or how to practice feeling it, please don’t hesitate to leave a comment, we would be happy to help!

If you’re running slower than 12min a mile, you’re still not running slow as this pace still puts you in the second largest majority of average paces.

This article is by Coach Jeff from