In the article 'the basics' we already described that we often work with heart rate or power training zones. In order to better understand these zones, we explain in this article what the zones mean and how you can use them.

Training Zones

Let's start with the main reasons to use training zones. By using a heart rate monitor and/or power meter you can make your training more specific. Specific training makes it easier to meet your training goals and to monitor your workload. Using training zones you can make sure that you are training at the right intensity. Afterwards a training can be analyzed on the basis of the hr zones and you can monitor your progress. A good picture of what you have done in previous training sessions is important to plan future training sessions and training zones can help you with that. There are different ways to classify the training zones, but almost all are based on your heart rate at the threshold power level also known as the functional threshold power (FTP). This point is set at 100% and the other zones are percentages of this threshold heart rate or FTP.

Why use zones?

What are the underlying physiological processes in the different zones? The body basically has three different energy systems to create ATP, which is the energy that is needed for muscle contractions and thus your ability to run or cycle. The systems are the creatine phosphate system, the anaerobic system and the aerobic system. The first is mainly used during a sprint and is exhausted after about 15 seconds of extreme exertion. After those 15 seconds, the anaerobic and aerobic systems take over.

The anaerobic system can generate a lot of energy in a short time but does not last very long and you have to adjust the intensity after that. The aerobic system uses mainly oxygen and fat as energy sources and is therefore the system that will deliver energy for the longest time. So for long efforts, like cycling, it is the most important energy system.

On the other hand, all energy systems will work side by side to release energy. Depending on the intensity of an effort, one system will work harder or less hard. At low intensity, almost all energy can be delivered by the aerobic system, but as the intensity increases, the anaerobic system is used more and more.

How to test it?

During an incremental exercise test (preferably with long blocks), you can clearly see how the different systems are functioning. During this test the lactate value will start increasing at some point, because as the power rises through those blocks, the anaerobic system will be employed more and more. During an exercise test, two important thresholds can be distinguished and linked to the training zones.

The first threshold is the aerobic threshold, at this point the aerobic system (and fat burning) is at its maximum. The second threshold is the anaerobic threshold also known as the FTP. This is the point where the production and decomposition of lactate is just stable, above this point lactate levels will rise sharply.

With this knowledge, 3 basic zones can already be distinguished. Below the aerobic threshold, between the aerobic and anaerobic threshold and above the anaerobic threshold. This is how scientific articles look at training zones. When making training plans, it is useful to identify a few zones more, with heart rate zones there are 5:

Heart rate zones at % of threshold heart rate:

• Recovery - (60-70% of threshold heart rate)

• Zone 2 - (71-80% of threshold heart rate)

• Zone 3 - (81-90% of threshold heart rate)

• Zone 4 - (91-100% of threshold heart rate)

• All out effort - (101-max of threshold heart rate)

Heart rate or Power

Different tools that tell you what you are actually doing on your bike. But on which one to focus when training? In this episode of the Beter Worden Podcast, Laurens te Dam, Stefan Bolt and Jim van den Berg reflect on the history of measuring tools for training, from speed to watts.