fbpx

Pure Endurance Blog

Aerobic vs Anaerobic Training: Why You Need To Be Doing Both

The terms ‘aerobic’ and ‘anaerobic’ are used to describe how our body’s cells within the body produce energy. 

So…what is the difference?

During training our body requires energy and there are three main ways that this is done; one with oxygen (aerobic) and two without oxygen (anaerobic)

Aerobic means ‘with air’ and refers to the body producing energy with the use of oxygen. This typically involves any exercise that lasts longer than two minutes in duration. 

Anaerobic means ‘without air’ and refers to the body producing energy without oxygen. This is typically exercise that is performed at a higher intensity. There are two ways that the body can produce energy anaerobically.

Short burst vs Long and slow

One anaerobic energy system is known as the ATP-CP system and provides immediate energy for an instantaneous burst of exercise such as for a power clean or snatch, sprints or other explosive movements that last between 1 – 10 seconds.

The other anaerobic system, known as the lactic acid system, provides energy for very hard efforts lasting roughly 10 – 120 seconds and is associated with the feeling of burning in your muscles due to the build-up of lactate and other metabolites within your muscles.

The aerobic system, known as aerobic glycolysis, is the most efficient and able to produce energy for long periods of time as long as oxygen is present. 

Aerobic training typically falls in the range of 60 – 80% of your estimated maximum heart rate and can be done continuously for prolonged periods of time while anaerobic training will fall between 80 – 90% of your estimated maximum heart rate. 

Anaerobic and aerobic energy systems do not work in isolation, during a training session or WOD energy will be derived from all three systems, but the emphasis will change depending on the intensity of the exercise relative to your fitness levels.

Why does this matter?


We know that Crossfit is a sport of constant variability. In one training session you may encounter a max lift (anaerobic), a sub three minute metcon (anaerobic + aerobic) and a fifteen minute AMRAP (aerobic).


Each of those workouts will utilize a different metabolic system to produce energy. We believe in a balanced approach to training in order to best prepare our athletes for the demands of their. Through periodization and prescribed intensities we can target each metabolic system so you are prepared for any WOD.