If your training programme tells you to run at Level II, ride at Level IV, or swim at threshold, there is an important question you need to be able to answer:
Where did your training zones actually come from?
Did you test for them? Did your coach calculate them from a recent performance? Or did your watch or training platform simply generate some numbers that you have been following ever since?
Training zones are only useful when they reflect your current fitness. In my coaching, I use a five-level system — Levels I–V — across swimming, cycling and running. Depending on the discipline, we can establish those levels using pace, power or heart rate.
Here’s how I do it.
What Are Training Zones?
Training zones divide exercise intensity into ranges that allow us to prescribe the appropriate effort for a particular session.
I use five primary levels:
- Level I – Very Easy/Recovery
- Level II – Easy/Aerobic
- Level III – Moderate/Tempo
- Level IV – Hard/Threshold
- Level V – Very Hard/VO₂ Max
The important point is that these aren’t arbitrary numbers.
Your zones need to be calculated from your ability and your current fitness. They will also change as you become fitter, which is why I often reassess athletes approximately every four to six weeks during periods of focused training.
And pace, power and heart rate don’t necessarily tell us the same thing.
Pace tells us how quickly we’re moving. Power provides a more immediate measure of output. Heart rate tells us how our body is responding to the work we’re asking it to perform.
Understanding those differences is important when deciding which training metric to use.
Swimming: Find Your Zones With CSS
For swimming, I primarily prescribe intensity using pace.
In a swimming pool, conditions are relatively consistent. That makes pace a very practical way of controlling training intensity.
To establish an athlete’s swimming threshold, I use a Critical Swim Speed (CSS) test.
After an appropriate warm-up:
- Complete a 400m Time Trial as fast as you can.
- Recover sufficiently.
- Complete a 200m Time Trial as fast as you can.
We then calculate:
CSS pace per 100m = (400m time − 200m time) ÷ 2
For example, if you swim:
400m = 7:00
200m = 3:20
The difference is 3:40.
Divide that by two and your CSS is:
1:50 per 100m
That gives us the reference point from which we can establish your swimming training paces.
Coach Ray’s Swimming Pace Levels
| Level | % of CSS |
|---|---|
| Level I | <84% |
| Level II | 84–91% |
| Level III | 96–100% |
| Level IV | 102–106% |
| Level V | 106–120% |
Remember that swimming pace becomes less reliable in open water, where wind, waves and currents can significantly affect your speed.
Cycling: Finding Your Power Zones
If you’ve got access to reliable power data, power is my preferred method of prescribing cycling intensity.
Functional Threshold Power (FTP) is an approximation of the power you could sustain for approximately an hour.
Of course, riding as hard as possible for an hour isn’t necessarily the most practical way to establish it!
I commonly use one of two alternatives.
One is a hard 20-minute effort following appropriate pre-fatiguing efforts, from which we can use approximately 95% of average 20-minute power.
The other — and one I use regularly — is an FTP Ramp Test. Ride the RAMP on Velocity with me: https://app.vqvelocity.com/vod/3691?s=eapbh1
During the ramp test, the workload progressively increases each minute until you can no longer maintain it.
I then use:
FTP = 75% × your best 60-second power
So, for example, if your best one-minute power during the test is 320 watts:
320 × 0.75 = 240 watts FTP
The athlete’s FTP then becomes our reference point for their cycling power zones.
Coach Ray’s Cycling Power Levels
| Level | % FTP |
|---|---|
| Level I | <55% |
| Level II | 56–76% |
| Level III | 77–90% |
| Level IV | 91–105% |
| Level V | 106–120% |
Power has one particularly useful characteristic: it responds immediately.
Increase the force you’re putting through the pedals and your power changes immediately. Your heart rate doesn’t necessarily do the same.
Cycling: Finding Your Heart Rate Zones
Heart rate can still be an extremely useful tool, particularly if you don’t have a power meter on your bike.
However, I don’t recommend calculating your zones from the old 220 minus age formula.
More importantly, maximum heart rate isn’t what we’re trying to establish anyway. For training prescription, I’m interested in your threshold heart rate — the intensity you can sustain rather than your theoretical maximum.
One method I use is a 20km cycling Time Trial.
Ride the 20km at a hard, sustained effort and calculate your average heart rate over the final 20 minutes.
For example, if your 20km TT takes 36 minutes, we’d analyse your average HR from approximately minute 16 through to minute 36.
This allows the initial rise in HR to occur before we assess the sustained portion of the effort.
Coach Ray’s Cycling Heart Rate Levels
| Level | % Threshold HR |
|---|---|
| Level I | <68% |
| Level II | 69–83% |
| Level III | 84–94% |
| Level IV | 95–105% |
| Level V | 106–116% |
Heart rate does have limitations.
Heat, hydration, caffeine, fatigue and other factors can alter your HR on any given day. That’s one reason I prefer power for cycling when it is available.
Running: Finding Your Pace Zones
For running, both pace and power can be excellent measures of intensity.
For pace, I typically use a recent 5km Time Trial or race performance and Matt Fitzgerald’s Pace Zone Index (PZI) methodology to help establish training paces.
The important thing is to use a performance that represents where your fitness is now.
That 5km PB you ran three years ago isn’t necessarily relevant to the runner you are today.
Coach Ray’s Running Pace Levels
| Level | % Threshold Pace |
|---|---|
| Level I | 75–80% |
| Level II | 81–89% |
| Level III | 90–94% |
| Level IV | 100–103% |
| Level V | 110–120% |
There is another important limitation to pace.
If you run uphill, maintaining the same pace requires considerably more effort. Run downhill and you can move faster for the same effort. Wind, heat and terrain can have similar effects.
Your watch might tell you that you’ve moved outside Level II, but physiologically you may still be producing exactly the effort the session requires.
Running: Finding Your Power Zones
Power can be particularly useful when running over changing terrain because it gives us another way of assessing output when pace is constantly changing.
To establish running threshold power, I can use a 30-minute Running Time Trial.
Run for 30 minutes at the hardest intensity you can sustain evenly.
Ignore the first ten minutes and calculate your:
Average power for the final 20 minutes.
That gives us a practical threshold value from which we can establish your running power zones.
I can also use a Pace Zone Calibration Run to establish and confirm an athlete’s zones.
Coach Ray’s Running Power Levels
| Level | % Threshold Power |
|---|---|
| Level I | 70–80% |
| Level II | 81–88% |
| Level III | 89–95% |
| Level IV | 96–106% |
| Level V | 116–128% |
Running: Finding Your Heart Rate Zones
The same running test can also give us your threshold HR.
For a 30-minute Running Time Trial, discard the first ten minutes and take your:
Average heart rate for the final 20 minutes.
This becomes the reference value for your running HR zones. This approach is particularly useful for faster runners whose 5km performance takes less than 20 minutes.
Coach Ray’s Running Heart Rate Levels
| Level | % Threshold HR |
|---|---|
| Level I | <68% |
| Level II | 69–83% |
| Level III | 84–94% |
| Level IV | 95–105% |
| Level V | 106–116% |
Don’t assume your running and cycling threshold heart rates are the same.
They are discipline-specific, so establish each independently rather than copying your cycling zones across to your running watch settings.
Pace, Power or Heart Rate: Which Is Best?
There isn’t one answer for every sport and every situation.
For swimming, I primarily use pace alongside Rating of Perceived Exertion (RPE).
For cycling, power is the gold standard when it’s available. It’s immediate and measures output, while heart rate provides useful information about the body’s response.
For running, I like power when terrain is variable and pace when conditions are relatively consistent. Heart rate can add further context, particularly during very long-duration events.
The technology should serve the training session — not dictate it.
Don’t Blindly Follow the Numbers on Your Watch
This is probably the most important takeaway.
Before worrying about whether you’re sitting at 82%, 94% or 103%, ask:
What is today’s session actually trying to achieve?
Your prescribed intensity needs to match that purpose.
And don’t blindly accept zones automatically assigned by your watch or training platform. Make sure your zones have been established from your own current fitness.
Then remember that the real world isn’t a laboratory.
Heat, altitude, hills, wind, fatigue and accumulated training load can all influence your numbers.
Use your data to guide you — but listen to your body as well.
How Often Should You Test Your Training Zones?
As your fitness changes, your zones should change with it.
During focused training, I typically look to reassess athletes approximately every four to six weeks across swimming, cycling and running. During an early-season or winter phase, testing may be spaced further apart.
The process is straightforward:
TEST → ESTABLISH YOUR THRESHOLD → CALCULATE YOUR ZONES → TRAIN AT THE RIGHT INTENSITY → REASSESS
Because the better your starting numbers are, the more useful every Level I–V prescription becomes.
Want My Training Zones Cheat Sheet?
I’ve put the percentages and testing methods from this article into a simple Training Zones Cheat Sheet covering:
🏊 Swimming Pace | 🚴 Cycling Power | ❤️ Cycling HR | 🏃 Running Pace | ⚡ Running Power | ❤️ Running HR
Keep it on your phone or print it out so you’ve got a quick reference whenever you’re setting or reviewing your training zones.
Want Help Setting Your Own Training Zones?
If you’re unsure whether your current zones are right, or you’d like some help turning your test results into training that suits your fitness and goals, book a free 40-minute coaching consultation with me.
We can talk through where you’re at, what you’re training for and how I can help.