Anaerobic versus Aerobic Exercise

Exercise comes in many forms with ongoing types of exercise being formed every day. No matter the form of exercise, being active is great for your overall health. But what makes different types of exercise so different? As a matter of fact, there are two broad classifications of exercise, and they are known as anaerobic and aerobic exercise. This article will help you better understand the difference between these two classifications by understanding the overall mechanisms, intensities, and types of exercise within anaerobic and aerobic exercise. 

The main difference between the two classifications is that anerobic exercise does not rely on oxygen use whereas aerobic exercise does. This is because anaerobic exercise is seen in medium- to high-intensity exercise (1) and, therefore, needs to make energy fast to keep up with the body’s energy demands. There are two metabolic pathways that the anaerobic system heavily relies on (2), and they are the adenosine triphosphate-phosphocreatine (ATP-PC) pathway and the glycolysis pathway. Both systems result in the formation of adenosine triphosphate (ATP), which is the primary form of energy used within the body. The ATP-PC pathway can provide energy for the first 3 – 15 seconds of anaerobic activity by phosphocreatine donating its inorganic phosphate (Pi) to ADP to produce ATP. Since the ATP/PC pathway only lasts approximately 15 seconds, the body starts to rely on glycolysis, which is the breakdown of glucose, more. This pathway can provide enough energy to last approximately 2 minutes in an all-out exercise bout. Exercise types that fall into this category would be high-intensity interval training (HIIT), strength sports, and sprinting, to name a few. 

The aerobic system, on the other hand, is seen in low- to medium-intensities1 and relies on the metabolic pathways that utilize oxygen (2). These metabolic pathways are known as beta-oxidation, the tricarboxylic acid (TCA) cycle, and the electron transport chain. Fat is the primary fuel source for aerobic exercise as it can produce more ATP per molecule than carbohydrates. However, glucose (a carbohydrate) can be used as well. Overall, the aerobic systems can provide the body with a sufficient supply of energy for a substantially longer time (2) than the anaerobic systems. For example, athletes such as marathon runners and long-distance swimmers primarily rely on their aerobic system for their sport instead of their anaerobic systems. Keep in mind that, when exercising, the body is not only using the anaerobic system or only using the aerobic system. Both systems are working no matter the type of exercise1. However, depending on the exercise intensity, one system will be predominant over the other system. 

A frequent misconception is that one system is more effective than the other (i.e., anaerobic exercise is better than aerobic exercise). However, this is not the case (1). Both types of exercise are beneficial for the body; anaerobic exercise has been shown to increase strength and power and aerobic exercise has been shown to increase mitochondrial and capillary density1 while both types have shown increased enzymatic activity and benefits to the cardiorespiratory system (1). The increased mitochondrial, capillary, and enzymatic activity all improve the efficiency of the body, therefore increasing the strength, power, and endurance of the individual. In summary, both types of exercise provide many benefits to the individual and increase their overall health and well-being. 

Written by: Siri Pederson

Last edited: 05/11/2022