Aerobic vs. Anaerobic – Understanding The Difference

What are your fitness goals? Do you want to improve your cardio, loose weight, increase your long-term endurance or build strength and speed? Should you focus mostly on aerobic or anaerobic, maybe a combination of both, but at what ratio?

Whether you just want to improve your overall fitness, or your goal is to compete at competition level, it’s vital to understand the difference between each type. Both aerobic and anaerobic exercise consists of a distinct style of training resulting in different types of fuel metabolism.

Always consult your physician before engaging in any kind of fitness activity. This is especially important when engaging in new activities or higher intensity levels than your body is accustomed to.

Aerobic Exercise

Aerobic is a term that is used quite often and involves long-duration performance in activities such as jogging, cycling, brisk walking and so on.

Aerobic, often referred to as cardio, is an essential form of fitness that is needed to maintain optimum health. Even though “aerobic” and “cardio” are different by definition, essentially, they are achieved simultaneously.

Aerobic refers to oxygen, or more specifically, the requirement and use of free oxygen. Primarily, our body’s need for energy is reliant on oxygen to fuel metabolism which is known as aerobic metabolism. Surprisingly, our body is reliant on aerobic metabolism even when we are at a state of rest.

As we increase our physical activity, our need for fuel metabolism increases, creating a greater demand for oxygen. Therefore, when we exercise aerobically our muscles require more oxygen causing a faster heart rate and an increased breathing intensity.

Generally, aerobic exercise places the heart rate within an aerobic zone that ranges from 70-80% of your maximum heart rate. This aerobic zone allows you to maintain a consistent exercise intensity for an extended period of time. This provides the benefit of increasing cardiovascular endurance.

Reaching The Metabolic Threshold

Once you exceed 80-85% of your heart rate your body reaches the metabolic threshold. At this point, the heart and lungs can no longer meet the oxygen demand required for this higher increase of fuel metabolism. Once the metabolic threshold is reached the body starts to transition to anaerobic metabolism to compensate.

The body’s metabolism never switches entirely from aerobic to anaerobic. It just increases the anaerobic demand to supplement the aerobic deficiency that occurs during higher levels of performance. This is especially true during many sporting activities that require short bursts of maximum performance such as hockey, basketball and soccer.

Anaerobic Exercise

Weight Lifting, Fitness, Anaerobic - Affluent Vitality

Unlike Aerobic exercise, which promotes long-term endurance, anaerobic exercise involves a high intensity performance within shorter periods of time. It’s a “burst” style of exercise that pushes the body into a zone of maximum or near maximum performance.

When the body is forced into this maximum performance zone, it creates a high and immediate demand for fuel metabolism which exceeds the aerobic supply. As a result, the body starts to rely on anaerobic metabolism.

Unlike aerobic exercise which relies on oxygen, anaerobic exercise relies on glycogen to fuel metabolism. Stored primarily in the liver and skeletal muscles, glycogen can be quickly metabolized to meet an immediate need for extra energy (glucose) requirements.

However, unlike oxygen which is unlimited, glycogen is limited to the amount that is stored in the body at any given time. This limited supply shortens the ability to maintain maximum performance for long periods.

Additionally, during anaerobic metabolism, high levels of lactic acid is produced in the cells of the muscles. It’s this lactic acid buildup that causes the burning sensation in the muscles and further causes muscle fatigue. For this reason, we are forced to take short recovery periods to allow the lactic acid to diffuse out of the cells. It is then processed by the liver into glucose, a usable form of energy.


For those who are just starting out on their fitness journey, it’s recommended to focus mostly on light aerobic training and increase the intensity at a comfortable pace. As the body becomes conditioned aerobically then more focus can be placed on anaerobic training as desired.

Remember, always consult your physician before engaging in new activities or higher intensity levels than your body is accustomed to.

Set your goals, set your pace. Be the best you can be.