We were recently asked: “Hey, I just heard about catabolic and anabolic exercise. What are the differences, and which is better?”

To address this question, let us first define what is meant by the terms ‘catabolic’ and ‘anabolic’.
The central premise of physiology, is the concept of ‘balance’, or homeostasis. The body is constantly hard at work trying to maintain homeostasis, without which, life cannot exist. All the millions of systems and reactions operating in your cells and organs every second, are in a tight balance with one another. Quite often, the violation of this balance in either direction, leads to the most of problems we experience with human health.

Building on this, ‘catabolic’ then refers to any process or reaction in your body, which causes a net ‘breakdown’ of complex molecules or tissues into simpler pieces. For example, breaking down the food you’ve just eaten into the basic components which are required by your body’s cells, is an example of a catabolic reaction.

Anabolic is defined by a reaction which ‘builds up’ more complex molecules, from simpler constituents. An example of this, is the increased protein synthesis in your muscles following an intense weight session. Here, amino acids (the building blocks of all protein) are taken up from the blood, and joined together into the required proteins, thus restoring any damage which occurred.

How does this relate to exercise?
Stated simply, catabolic exercise is low-intensity, cardio-type movement such as jogging or swimming. Here, muscle protein actually gets broken down to serve as an energy source, alongside glycogen, carbohydrates and fats. Muscle protein degradation only begins after PROLONGED exercise of this type, like a 6km run for example. While this is ultimately beneficial for the muscles, increasing their capacity to perform work, and the efficiency with which they use fuels, it doesn’t necessarily lead to gains in size. Rather, the muscles become more ‘toned’, slender and supple (think long-distance runners or swimmers).

Anabolic exercise, leads to a net synthesis of new muscle proteins (note that resistance exercise does not only cause your muscles to grow, but increases bone density as well as joint and connective tissue strength). The most common type being weightlifting. Keep in mind, that even though DURING the actual exercise, muscle protein is broken down, this is reversed in the hours following the workout, and the body slightly ‘overcompensates’ by synthesizing a little bit more muscle, in preparation for similar subsequent stresses the body may experience in future. This type of work improves the strength of the muscle, but not necessarily its flexibility or speed. In addition, fitness techniques like High-Intensity Interval Training (HIIT), focus on this type of exercise response. Here, very high muscle intensity is employed for shorter times, preventing the muscle protein-loss associated with endurance activities, while still leading to an overall anabolic response in the muscles following the workout. Note that such exercises lead to the large scale breakdown of fat (catabolic) for hours after the exercise, providing the muscle with needed energy to carry out its repair mechanisms. These types of anabolic exercises can improve speed AND strength. Think of 100m sprinters.

Thus, the two exercise approaches should ideally be combined together, with slightly less catabolic vs. anabolic if a gain in size is being sought. The opposite is of course true if toning and slimming is the intention. Whichever way, it is not a good idea to completely exclude either, because violating homeostasis in anyway, is ultimately detrimental.

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