Aerobic vs. Anaerobic Conditioning – What’s the Difference and Why It Matters for Runners

Are you a runner looking to improve your performance? If you’ve heard the terms aerobic and anaerobic used but aren’t quite sure the heck that means or why you need to know the difference, you’ve come to the right place. 

Why does knowing the difference matter? Well, when it comes to conditioning, understanding the difference between aerobic and anaerobic training can be one of the keys to reaching your running goals and getting unstuck from a plateau. 

In this article, we’re going to explore the benefits and differences of these two types of conditioning and how knowing how to balance them can help you become a better runner.

First here’s a basic way to understand the difference between aerobic vs. anaerobic exercise:

Aerobic Exercise…

• Builds cardiovascular health. 
• Uses oxygen as a fuel source from fat and carbohydrates. 
• Is lower intensity and sustained over long periods. 
• Engages the heart, lungs and blood vessels.
• Helps build endurance over long distances.

Anaerobic Exercise…

• Builds muscle mass and tone.
• Uses glucose stored in muscles as a fuel source. 
• Is done in rapid bursts at higher intensity.
• Exhausts muscle after which it rebuilds stronger. 
• Helps build strength, speed and power.

Here are some real-world examples of different exercises and intensities and how they can be classified: 

Aerobic Exercise Examples

• Running at an easy pace. 
• Power walking 
• Biking/Cycling (low intensity) 
• Swimming 
• Skiing
• Stair climbing 
• Aerobics 
• Rowing

Anaerobic Exercise Examples

• Sprinting
• Hill sprints
• Swimming (sprints)
• Biking/Cycling (high intensity)
• Working out with free weights
• HIIT exercise (High Intensity Interval Training)
• Body resistance exercise like push ups, chin ups, squats and lunges
• Heavy weight lifting
• Skipping rope

Aerobic vs. Anaerobic: What’s Best for Running?

Which is more important for runners?

For the purposes of your training, use the 80/20 rule. Roughly 80 percent of your training should be in the low intensity category (aerobic) and about 20 percent should be in the high intensity or anaerobic category. 

BOTH aerobic and anaerobic training is important for runners–it’s just a matter of proportion. 

Too much high intensity training can lead to injury and may be at the expense of building your aerobic capacity for those longer runs. However, you do need that extra bit of strength from anaerobic training to push through those hills or when a burst of speed is needed at the right time. 

The key to achieving the best running performance lies in striking a balance between aerobic and anaerobic conditioning. This is why you’ll see the 80/20 rule referred to and used in the majority of training plans. 

While both types of training are essential, for runners–especially distance runners–building your aerobic base to sustain longer distances over time is key. 

If you want to run a marathon for example, the vast majority of your training miles should consist of easier pace runs.

In his book, 80/20 Running: Run Stronger and Race Faster By Training Slower, author Matt Fitzgerald says, “The question is not whether one is ‘better’ than the other and thus ought to be done exclusively. The question, rather, is how high-intensity and low-intensity training should be balanced.”

High vs Low Intensity Running

As a rule, low-intensity runs can be performed while holding a conversation without huffing and puffing and gasping for air. This might be an easy pace 5K run for example.

A high intensity run would be a sprint for 30 seconds or running up a hill at near maximum effort for 90 seconds and then jogging to a stop. High intensity exercise raises your heart rate well above low intensity running.

Benefits of Aerobic Exercise

The biggest benefit to aerobic exercise is to our cardiovascular health. It increases our heart rate and boosts circulation.

Here are other potential benefits of aerobic exercise: 

• Can help with weight loss
• Can help you sleep better
• Can improve your immune system
• Increases stamina
• Lowers blood pressure
• Can improve your mood and help with depression
• Can help slow the loss of bone density. (study)
• Can increase your “good” cholesterol and lower levels of “bad” cholesterol in the blood.
  Sources

Benefits of Anaerobic Exercise

Anaerobic exercise also benefits your cardiovascular system but because anaerobic exercise is done in short bursts it demands a different fuel source from the body–glycogen stored in muscles. This difference means anaerobic activity can help reduce body fat. 

Here are some of the potential benefits of anaerobic exercise:

• Can build muscle density
• Can help reduce body fat
• Can increase bone density
  Sources

These are specific benefits for runners: 

• Improved running form
• Reduces risk of injury
• Builds your running power
• Improves overall running speed
• Improves running economy (running faster while using less energy).

As you can see, knowing the difference between the types of conditioning is important for your overall health but also for anyone who wants to improve their running. 

Balancing your running between low intensity and high intensity can help you run longer but also get stronger. Being aware of the 80/20 rule for runners can also help you know what to look for in a good training plan.