3 Zone vs 5 Zone vs RPE
I love this quote. It applies to much more than you think in life. All around us are models. We are constantly sizing up situations in our head and how to proceed. This includes running and applying different stimuli to our training.
One thing a lot new runners do not realize is that the highly talked about “zone 2” is actually a part of a physiological model created by Dr. Andrew Coggan in the early 2000s as part of his book “Training and Racing with a Power Meter”, which was originally meant for cyclists but was also applied to the broader endurance community.
The 5 zone physiology model is exactly that—a model. As our good friend George used to say, “all models are wrong, but some are useful”. Well this also applies to our HR zones devised by Dr. Coggan. We can (and should) use pieces of this model to apply to our training, but we should also look for other models that may be of use to us in other ways.
But that brings us back to the point that all models are wrong, including the alternatives to the five zone model. The other two models I am talking about today are three zone model and the RPE scale, although there are others out there as well.
Five Zone Model
Circling back on the infamous “zone 2” many users on X speak of, they are always referring to the zone 2 that sits inside of the FIVE zone model.
“Z” = Zone, so “Z2” = Zone 2.
The point of the five zone model is to be able to become extremely specific with your training and accurately apply different stimuli to your training based on HR. By becoming hyper-specific with their zones, in theory, athletes are able to tailor workouts more effectively to their needs/ability.
Zone 1 (Recovery/Easy):
Purpose: Recovery and active rest. Promotes blood flow and aids recovery without adding significant stress. Also builds aerobic endurance and improves fat metabolism, but at a lower cost than zone 2.
Zone 2 (Aerobic/Base):
Purpose: Builds aerobic endurance and improves fat metabolism. Ideal for long, steady workouts.
Zone 3 (Tempo):
Purpose: Enhances aerobic capacity and muscular endurance. Balances intensity and duration for effective endurance training.
Zone 4 (Threshold):
Purpose: Improves lactate threshold, allowing athletes to sustain higher intensities for longer periods. Key for increasing sustainable power or pace.
Zone 5 (VO2 Max/Above Threshold):
Purpose: Increases maximum aerobic capacity (VO2 max) and enhances anaerobic power. Used for short, high-intensity efforts.
The common application of the five zone model is to take your maximum heart rate and multiple the intensity % you want to train in. Broken down:
Zone 1 = 50-60% of Max HR
Zone 2 = 60-70% of Max HR
Zone 3 = 70-80% of Max HR
Zone 4 = 80-90% of Max HR
Zone 5 = 90-100% of Max HR
There are other models inside of the five zone model to use such as HRR%, which factors in your heart rate reserve, taking your resting heart rate into account which acts as a variable to predict fitness. As two people can have the same max HR, but one is a lifelong runner with a resting heart rate of 40, versus the non-runner with a RHR of 70. These two individuals heart rate zones and RPE will be much different.
If using the HRR% model, the % distributions stay the same for each zone (above). If you want to apply both the three and five zone models, pick either the Max HR formula or the HRR formula.
Three Zone Model
The 3-zone model is more simple and divides exercise intensity into three primary zones based on physiological thresholds:
Zone 1 (Low Intensity):
Intensity: Easy or recovery effort.
Physiological Marker: Below the first lactate threshold (LT1), also called the aerobic threshold.
Description: This zone is often characterized by a comfortable pace where conversation is easy—AKA “conversational pace”. It’s primarily used for easy sessions that build aerobic capacity and promote fat oxidation.
Zone 2 (Moderate Intensity):
Intensity: Moderate but still steady-state effort.
Physiological Marker: Between LT1 and the second lactate threshold (LT2), also known as the anaerobic threshold or lactate threshold.
Description: This zone involves a pace that is harder to maintain a conversation but is still sustainable for extended periods. Training in this zone improves aerobic endurance and increases the body’s ability to clear lactate. This is the smallest of the three zones in this model, with “zone 2” only being characterized as the HR between LT1 and LT2.
Zone 3 (High Intensity):
Intensity: High or intense effort.
Physiological Marker: Above LT2.
Description: This zone is marked by high-intensity efforts that can only be sustained for short periods due to significant lactate accumulation. It’s used for high-intensity interval training (HIIT) and efforts aimed at improving anaerobic capacity and power.
Essentially, the three zone model is just the five zone model condensed to make digesting it easier.
Why this matters is that the average amateur, or someone picking up endurance for the first time may not need or care about all five training zones. Additionally, they many not even be able to train in a few of the zones. For example, someone new to running will most likely *not* be able to run in zone 1 in the five zone model. But does this even matter? Do they have to only stick in zone 2 until they can properly train in other zones?
What if zones were combined, so zone 1 & 2 of the five zone model simply became “zone 1” in the three zone model? The average amateur would actually have a much easier time in training, as their stress would greatly be reduced in not caring about keeping their HR in a 10BPM range only.
Differences Between Three and Five Zone Models
Granularity: The 5-zone model offers more detailed guidance on training intensities, allowing for more precise targeting of physiological adaptations.
Application: The 3-zone model is more simple and will be easier for beginners or runners looking for a straightforward approach. The 5-zone model is often preferred by someone who is more data driven and wants to be as precise in their HR/effort as possible. Note that this can also be a hindrance in training!
Intensity Distribution: When using the five zone model, your intensity is often hyper specific and chosen for a reason within a workout. In the three zone model, the workouts will be more fluid and not as exact in terms of hitting a certain effort level.
Zone 1 & 2 in the five zone Model become Zone 1 in the three zone model.
Zone 3 in the five zone Model become Zone 2 in the three zone model.
Zone 4-5+ in the five zone Model become Zone 3 in the three zone model.
RPE Model
Many nay-sayers of the five and three zone models tend to point that perceived effort is *all* that matters, but disregard the fact that RPE is also a model. And as we know…all models are wrong.
This model my be the most wrong of all them because of the human element variable—which is the most volatile factor in any model created.
As humans we are all vastly different. The way we perceive this world is extremely varied from person to person. Just look at the world today, almost everyone disagrees. So how are we to expect that any runners, beginner to advanced, can agree on what a 3 RPE feels like on the scale? It’s almost impossible. But we can get close enough to where it matters. On specific days you can really feel it. It’s *not* for everyday use, but it does have it’s place, because as we know…some models are useful.
As you can start to imagine, one person’s idea of “light activity” will be vastly different from someone else’s. The worst part is that neither of them are incorrect. RPE model is only validated by the user. That’s why it’s best to compare and translate the models together as best we can:
Translating three zone model, five zone, and RPE:
What This All Means
Essentially, you find that there are certain camps for all different sorts of effort models for training. What you need to do it be open to trying different models and training methods.
If you suddenly find yourself at altitude but live year-round at sea level? Maybe switching to a mix of the three zone model along with an RPE guideline will be better than not being able to run in your traditional effort inside of the five zone model. Same goes if you’re deep into a long run and cardiac drift is affecting you. Maybe by mile 10 you start running off of RPE alone and ditch the zones.
Or maybe you want to keep your easy runs as easy as possible so you stick the zone 1 inside of the five zone model at all costs. It really depends on your training and needs. The model you use is allowed to switch multiple times a week!
Regardless, become nuanced when adding different stimuli to your training! All zones matter, all efforts matter, and staying consistent is what matters *most*.
-BTR