What is FatMax?
In the world of fitness and endurance training, optimising fat metabolism has long been a coveted goal. One key concept in achieving this is the notion of FatMax.In this blog, we'll delve into what FatMax is, how it's calculated, and why it holds significance for athletes seeking to enhance their performance.
Understanding FatMax:
FatMax, short for "maximal fat oxidation," is the exercise intensity level at which your body burns the most fat for energy. This concept is important because, in endurance events, the ability to rely on stored fat as a fuel source can spare precious glycogen (stored glucose) reserves, ultimately leading to enhanced stamina and endurance.
The FatMax Test:
The FatMax test is a specialised assessment that aims to pinpoint the exercise intensity at which your body maximises fat oxidation. This test is typically performed using indirect calorimetry, which measures the volume of oxygen you breathe in and the volume of carbon dioxide you exhale. This data helps determine your respiratory exchange ratio (RER), which is the ratio of carbon dioxide produced to oxygen consumed. It is important to note that this test is only accurate when performed at lower intensities, as there is an assumption that all CO2 produced is from either fat or CHO oxidisation. Whereas at higher intensities when lactic acid needs to be buffered, CO2 is also released as a waste product in this reaction.
Calculating FatMax:
During the FatMax test, different exercise intensities are examined, and the corresponding RER values are recorded. As the intensity of exercise increases, your body begins to rely more on carbohydrates for energy, leading to a higher RER. On the other hand, when exercise intensity is lower, fat oxidation becomes predominant, resulting in a lower RER.
The FatMax Curve:
When graphed, the relationship between exercise intensity and fat oxidation creates a distinct curve. On average, fat oxidation rates rise from low to moderate intensities. This trend begins to reverse as exercise intensity continues to rise from moderate to high levels. At this point, fat oxidation decreases, and carbohydrate utilisation takes precedence.
Significance for Athletes:
Understanding an athletes FatMax holds tremendous value, particularly those engaged in endurance events.
1. FatMax manipulation: Understanding an athletes FatMax can have a significant impact on their nutrition during training. For example if an athlete has a significantly low FatMax, they might decide to adopt a “train low” strategy to increase fat oxidisation, and increase the FatMax value.
2. Extended Endurance: Athletes who have trained their bodies to rely more on fat at sub-maximal intensities can maintain their stamina for prolonged periods without feeling depleted, by preserving valuable glycogen stores.
3. Improved Performance: Enhanced fat oxidation capacity can lead to better overall performance, especially in events that demand a sustained effort over extended periods.
