In this blog we explain what the Aerobic and Anaerobic Thresholds are, and why they are the foundation to plan and control your training.
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As a reminder, all the ideas shared in these videos are the result of my interpretation, approach and practical use of cycling training concepts I have learnt for several years from recognized and reliable sources.
They contain my synthesis of the very complex science of training as I understand and use it being myself a self coached cyclist.
Become a self coached cyclist with the guidance of The Self Coached Cyclist Training with Power, covering everything from training concepts to performance tracking.
Aerobic & Anaerobic Thresholds
When doing any physical activity, the body produces energy that is then transformed to movement.
A by product of this energy creation is the generation of Blood Lactate that increases as the physical activity intensity gets higher.
There are two markers identified in this process.
The first one is known as low metabolic event or aerobic threshold and is defined as “… the intensity where blood lactate levels start raising above resting levels”.
Fat is the major and most efficient fuel source at this level and it is an intensity that can be maintained for a long time.
The second marker is the upper metabolic event or anaerobic threshold.
It is also known as the Maximal Lactate Steady State defined as “… the highest levels at which blood lactate levels can be sustained for 15 to 30 minutes.”
At this point the body uses glucose for fuel for the most part.
These thresholds are used as reference parameters to create, execute and control training plans.
For an in depth look at these concepts search for Dr. Iñigo San Millán, check this link
The True Definition of Threshold
and download our free guide The Self Coached Cyclist Power Training Concepts
Activities done below the Aerobic Threshold are low intensity, known as the Low Aerobic Zone, and used to train endurance.
Activities done between the Aerobic and Anaerobic Thresholds, known as High Aerobic Zone are used to increase performance in endurance events.
Training above the Anaerobic Threshold known as the Anaerobic Zone, develops the ability to do short high intensity efforts.
Finding Thresholds
The only way to get an accurate measurement of the Aerobic and Anaerobic Thresholds is through dedicated laboratory tests, where blood samples are taken at different intensity levels to measure lactate.
As a result, the heart rate and power values at which the Aerobic and Anaerobic Thresholds occur are recorded and used as reference parameters to create training plans.
Though very precise, these laboratory tests are expensive and not a must for the amateur rider as there are other practical and affordable options.
For the self coached cyclist, a better approach is to use an Anaerobic Threshold Estimation Model, also known as Field Tests.
These models allow to get reliable estimates of the heart rate and power at which the Anaerobic Threshold occurs and can confidently be used to create training plans.
There are several methods that we are aware of:
- The FTP/FRC model, explained in detail in the book “Training and Racing with a Power Meter” by Allen, Coggan and McGregor, where the estimated Anaerobic Threshold is known as Functional Threshold Power or FTP. FTP is the most widely used method and is supported by all GPS bike computer brands and training platforms.
- The Critical Power and W Prime model that has a large amount of research and authors, where the estimated Anaerobic Threshold is known as Critical Power.
- The CTS Field Test model from Carmichael Training Systems also known as the 8 minute test where the highest average power and average heart rate are used as the AnaerobicThreshold.
The Aerobic Threshold is calculated based on the results of the field tests.
Each method will result in a value that will not necessarily match those of the others.
So, it is important to always use the same method for all the rider’s tests made as part of a training plan.
This results in consistent reference parameters to measure performance improvements.
Training Zones
They are heart rate or power based ranges used to create training plans targeting specific cycling abilities to develop and improve.
For power, there are several training zone models. The most common, and available in most GPS bike computers and training platforms, is the 7 zones model that has:
- Zones 1 and 2 below the Aerobic Threshold
- Zones 3 and 4 between the Aerobic and Anaerobic thresholds
- Zones 5, 6 and 7 above the Anaerobic Threshold
- The border of Zones 2 and 3 corresponds to the Aerobic Threshold
There is also the 3 zones model with :
- Zone 1 below the Aerobic Threshold
- Zone 2 between the Aerobic and Anaerobic thresholds
- Zone 3 Anaerobic Threshold
But it is not supported by neither Garmin nor Wahoo and maybe neither by other brands.
For heart rate, the most common is the 5 zones model with:
- Zones 1 and 2 below the Aerobic Threshold
- Zones 3 and 4 between the Aerobic and Anaerobic thresholds
- Zone 5 above the Anaerobic Threshold
- The border of Zones 2 and 3 corresponds to the Aerobic Threshold as well.
Your GPS device and training platform will calculate them for you, either power or heart rate based, upon entering the threshold values in the corresponding settings options.
Wahoo
Garmin
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The Self-Coached Cyclist Training with Power: Concepts
Cycling Fitness CTL Planning Worksheet
The 2025 Cycling Fitness TSS & CTL Planning Worksheet
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