Zones & Perceived Effort

We introduced the concept of HR-based training in an earlier post. Here we continue on this journey.

This table, found on CrossFitForGlory, links together the “Rate of Perceived Exertion (RPE) scale with the more commonly used “Training Zone” scale, which is simply produced by taking a percentage of the maximum heart rate.

This is not correct in most cases, and we’ll see why in detail in the next part of this series, but for now it serves our purpose: getting a general feel of the relationship between Perceived Effort and Heart Rate.

Zone 1

You should be here when warming up and cooling down, or if doing a post-injury walk/run. Not much more to be said.

It needs to feel a bit like a walk. Absolutely easy, conversational. A run spent mainly in this HR zone is usually called a Recovery.

Zone 2

When you read on a training program that a run has to be “conversational”, they usually mean something a little harder than a Recovery run – therefore, Z2. This type of run is also called “Easy”, or “Endurance”, or “General Aerobic”, which adds a lot of confusion – but hopefully by the end of this series, this will all be clear.

That said, a rule of thumb for such a Z2 run is to be able to breathe with your mouth close, only through your nose. Or to be able to hold a conversation, without breaking down into small, “huff and puff” sentences. Z2 is supposed to feel slow. It’s awkward, sometimes, but it does work.

If you follow the 1-2-3 Program, your Long will surely be mostly in Z2. Your Steady will probably cycle through Z2 and Z3 weeks, depending on how you feel. Your Speedy, on bad days, may use Z2 as base, and power up to Z3 and Z4 for short intervals. Your Recovery should start in Z1 but can end in Z2.

Z2 running forms the base, the foundation of all your training – its importance cannot be emphasised enough!

Zone 3

This zone is sometimes called the “grey zone”. Advanced runners who try to squeeze out as much as they can out of every day of the week, may tell you that Z3 is worse at training the aerobic system than Z2, and it’s worse at training the anaerobic system than Z4.

This logic does have a certain solidity, but there’s plenty of things to consider. Beginner or intermediate runners may benefit a lot from Z3, as it’s a moderate, controlled effort that challenges your body without taxing it overmuch.

It’s great to learn to pace yourself, to solidify the previous weeks’ work, to improve your form, to let off steam without compromising your next hard workout. It’s also great for those running just 3-4 times per week, and for them it may be more efficient than running mostly in Z2.

I personally love Z3 training, once per week or biweekly. For those that follow the 1-2-3 Program, your Long may sometimes finish in Z3 (because you pushed a bit more as a “horse smelling the barn”, or because of cardiac drift). And as said before, your Steady might be a fully Z3 run if you feel fresh.

As a rule, if you run more than four times per week you may want to switch your Z3 for a different zone. if you find yourself too tired on hard days because you introduced a Z3 workout, swap it to Z2. If you don’t like speed workouts like Fartlek, Tempo and Intervals, just swap that for a upper-Z3 workout (which is a also called a Slow- or Mid-Tempo).

This might not be optimal, but running has to be, first of all, enjoyable and safe. Performance optimisation can always be done later on.

Zone 4

This is where serious stuff happens. Your anaerobic energy systems get trained, your lactate depletion becomes more efficient, glycogen is consumed more than fat. It’s a great zone for speed workouts and short races, but it’s also going to be very important for longer distances.

You can keep running in this zone for quite a while. It will be uncomfortable. But it will be manageable. Just make sure you arrive to this point incrementally, well warmed-up, and trained.

If you start training a lot at Z4 before having built a proper running base, you are going to get injured. That’s, sadly, a fact.

Zone 5

This is where you push your limits. Some speed workouts touch this zone, but rarely let you keep using it for long. 5K races are usually run for a good chunk at Z5, if are well trained for this. Your last mile of many races will probably bring you there too.

In this zone, your anaerobic system gets finely tuned for maximal efforts, and your VO2Max (your body’s maximal ability to take oxygen in, and use it) will improve. That’s a good (but not great.. we’ll see why) indicator of fitness, as also used by many sport watches.

Don’t use this zone if you don’t know what you are doing. If you are a beginner, give your body time to adapt with Z2 and Z3 workouts.