Calculating training zones from a lactate test: heart rate, pace and watts
Training zones are based on the individual threshold from the step test. The zones are set as percentages of this threshold power. Five zones are common, from recovery to competition-specific endurance. Whether you manage intensity by heart rate, pace or watts determines how sharp the zone boundary actually is in training.
From threshold to zone
The analysis of a step test first provides two points: the aerobic threshold (abbreviated IAS in Plenea reports) and the individual anaerobic threshold (IANS). Training zones are the ranges derived from these points, usually as fixed percentages of the threshold power.
This means all zones depend on a single value. If the threshold shifts, all zones shift with it. That is exactly why the choice of analysis model is not an academic matter. It determines how hard a person’s base zone is for the coming months.
The five-zone diagnostics model in Plenea
Here we describe Plenea’s five-zone diagnostics model. Training planning uses a zone model of its own. The numbers are not a universal physiological classification. The percentages refer to the threshold power. This is how Plenea derives the zones from the test result.
| Zone | Share of threshold power | Training goal |
|---|---|---|
| REG — Recovery | up to about 60 % | Active recovery, deliberately low load, ideally in joint-friendly sports |
| GAT1 — Basic endurance 1 | about 60 to 73 % | Predominantly aerobic, easy base pace, main volume of every phase |
| GAT2 — Basic endurance 2 | about 73 to 93 % | Brisk base zone, use sparingly in the base phase |
| GAT3 — Threshold training | about 93 to 105 % | Around the individual threshold; the threshold lies within the zone, not at its upper limit |
| WSA — Competition-specific endurance | above about 105 % | Above the threshold: intensive intervals, VO₂max and lactate tolerance |
Common misunderstanding: the threshold is not a zone boundary. It lies in the middle of GAT3. How it is classified depends on the explicitly named model.
Heart rate, pace or watts
All three variables can be derived from the same test. But they behave differently. Watts are the most direct variable: they measure the power actually produced and show changes in load immediately. Pace is practical in running, but loses meaning as soon as gradient, surface or wind come into play. There, a grade-adjusted pace can help.
Heart rate is the slowest variable and the most prone to disturbance. Heat, fluid loss and day-to-day form shift it3, without a change in fitness being derivable from that alone. It still remains useful: it is available in every sport and shows long-term changes well.
In practice, the combination works best. You manage the zone mainly with the variable that is most stable in the sport and check it against a second one. If the two persistently diverge, that is a sign: of fatigue, of an outdated test or of an error in the derivation.
Transferring zones between sports
If you were tested running and train on the bike, you cannot adopt the heart rate zones unchanged. Heart rate can differ between cycling and running at a comparable load, partly because of the smaller muscle mass involved and the seated position4.
For this, Plenea uses fixed deductions from the running heart rate, not ranges. This keeps it traceable in the report how the calculation was done: cycling and ergometer minus 12 beats, stepper minus 10, cross trainer and walking minus 8, swimming minus 18. These are fixed rules of thumb in the software, not individually validated conversions. They do not replace a test in the respective sport.
Typical mistakes when deriving zones
A common mistake is calculating zones from maximal heart rate formulas. Actual maximal heart rate varies widely between individuals around any age formula2. The zones derived from it can therefore be off by whole zones in individual cases. A step test replaces exactly this estimate.
Just as common is the silent change of model. The new report was calculated with a different analysis method, the zones shift, and the change is read as training progress.
A third mistake is the outdated test. Zones from an 18-month-old report align training with a state that no longer exists. This applies especially after injury breaks, changes in training or major jumps in form.
- Never derive zones from maximal heart rate formulas when a test is available
- Set the intensity variable per sport and do not mix them
- When changing sport, convert heart rate zones rather than adopting them
- Always state zones together with the model and test date
- If heart rate and power persistently do not match, question the test, not the person
Frequently asked questions
How many training zones are there?
That depends on the model used. Plenea uses a five-zone model: recovery, basic endurance 1, basic endurance 2, threshold training and competition-specific endurance. Other schools work with three zones5. More important than the number is that one model is used consistently.
Does the anaerobic threshold lie at the upper limit of the threshold zone?
Not in the model described here. The threshold lies within zone GAT3, which ranges from about 93 to 105 per cent of the threshold power. Other models set other boundaries.
Can I use heart rate zones from a running test for cycling?
Not across the board. Fixed deductions in the software are rules of thumb and must be checked individually. A test in the sport you train in is better.
How often do training zones need to be redetermined?
As soon as the threshold has changed. Typically this is after a training block, after a longer break or when heart rate and power in the zones persistently no longer match. A uniform time interval does not follow from this.
Why are zones from maximal heart rate formulas problematic?
Because actual maximal heart rate varies widely between individuals around any age formula2, and the threshold also lies at different percentages of it1. Two people of the same age can therefore have very different real zones, even though the formula gives the same values for both.
Sources
- 1
Meyer T, Gabriel HH, Kindermann W. Is determination of exercise intensities as percentages of VO2max or HRmax adequate? Medicine and Science in Sports and Exercise. 1999;31(9):1342–1345.
Original researchDOI 10.1097/00005768-199909000-00017PubMed 10487378
- 2
Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology. 2001;37(1):153–156.
Meta-analysisDOI 10.1016/s0735-1097(00)01054-8PubMed 11153730
- 3
Achten J, Jeukendrup AE. Heart rate monitoring: applications and limitations. Sports Medicine. 2003;33(7):517–538.
- 4
Millet GP, Vleck VE, Bentley DJ. Physiological differences between cycling and running: lessons from triathletes. Sports Medicine. 2009;39(3):179–206.
- 5
Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance. 2010;5(3):276–291.
Specialist information on training management. No medical advice. The percentages stated describe the zone model used in Plenea and do not replace individual training advice.
Further reading
Zones that come from the test.
Plenea derives the zones directly from the approved report and converts heart rates between sports. You see which reference values were used. Before the zones are taken over into training planning, you check them professionally.