Chapter 6: Everything you need to know about Training Zones

In previous chapters, we examined various training adaptations and the time required for them to fully develop. These adaptations include changes to the heart muscle to increase its size, as well as developing certain muscle fibers. Some adaptations take longer to achieve, while others can be improved more quickly. Now, we have a list of potential adaptations that need to be worked on, each with a different time frame and training stimulus. To keep track of progress, it is now useful to look at how we can categorize these training stimuli ‘inputs’ into different categories or ‘zones’.

To me, this is the root purpose of training zones – to help us define valid and practically useful ‘inputs’ that we can later test against an ‘output’.

In this sense, there is nothing especially ‘magical’ in where we set the boundaries and how we categorize the zones. We could just use arbitrary percentages as many do…

Zone 1 = 50-60% Max Heart Rate

Zone 2 = 60-70% Max Heart Rate etc.

However, arbitrary percentages do have one significant problem that makes them inferior to physiologically based methods of defining zones: Arbitrary percentages can mean different things, physiologically – both with respect to different athletes, and with respect to the same athlete at different times of the season or their development…

Figure 6.1: The need for individualized zones

As the tweet above suggests, setting an arbitrary limit of 65% of max as the limit for Zone 2 may not be appropriate for all athletes. Some may find this intensity to be manageable and sustainable for a long time, such as during an Ironman race. However, others may find this intensity to be close to their second threshold, which is challenging to sustain for even 60 minutes. This illustrates that the same percentage zone can result in different feelings of intensity and physiological responses. To properly categorize training according to the desired physiological response, it is important to use a method other than arbitrary percentages.

If we want to talk about the same *physiological* input for different individuals, we need to do some individual *physiological* testing.

So what does a useful “zone setting test” look like?