How ZoneX measures your true physiological zones on the bike
- PAIRFS
- 3 days ago
- 3 min read
Why measure your true physiological zones?
To progress effectively on a bike, everything depends on your training zones . They determine:
your endurance outings,
your tempo sessions,
your work at the threshold,
your high intensity,
Your pacing strategy in cyclosportive events.
The problem? The majority of cyclists still use estimated zones: heart rate (often inaccurate), FTP (performance, not physiology), or generic formulas.
👉 To precisely target the right intensities, you need to measure your ventilatory thresholds , VT1 and VT2 — the physiological markers that really structure your energy systems.
That's exactly what ZoneX allows, directly on your bike rides.
1. Breathing: the key to understanding your physiology
During progressive exertion, your breathing changes accordingly:
fuel used (lipids vs carbohydrates),
from the production of CO₂,
muscle acidosis,
of the actual metabolic load.
Two key points emerge:
🔹 VT1 – Ventilatory Threshold 1
Transition: lipid aerobic → carbohydrate aerobic
This is the boundary between basic endurance and active endurance.
🔹 VT2 – Ventilatory Threshold 2
Transition: aerobic → anaerobic
This is the point at which the effort becomes costly and difficult to sustain.
It is these two thresholds that allow us to cut out truly individualized zones, adapted to YOUR physiology — not that of a theoretical model.
2. How does ZoneX measure these thresholds on your bike rides?
ZoneX analyzes your breathing in real time using three key measurements:
1) Ventilation (VE)
Inhaled and exhaled airflow → shows how your respiratory system responds to exertion.
2) Concentration of exhaled CO₂ (FEO₂ / FECO₂)
Indicates the metabolic production of CO₂ → direct marker of energy transitions.
3) Respiratory dynamics
Analysis of respiratory rate variations → allows for the detection of ventilatory disruptions.
➡️ ZoneX then uses specific algorithms to automatically detect:
respiratory inflection (VT1),
ventilatory disruption (VT2),
and the stability of your energy sectors.
All this without complex protocols , without laboratories , and in just a few minutes , directly on your bike.
3. How does a measurement with ZoneX take place?
ZoneX was designed to be simple and convenient.
Step 1 – You drive normally
Gradual uphill training, on a home trainer or on a field trip.
Step 2 – ZoneX automatically analyzes your breathing
No need to interpret complicated curves.
Step 3 – VT1 and VT2 are detected
ZoneX accurately identifies both physiological thresholds.
Step 4 – Your training zones appear immediately
Endurance, Zone 2, Tempo, Threshold, VO₂ max: everything is generated automatically.
Step 5 – You sync with your training platform
The areas are exportable and ready to be integrated into your sessions.
Why is this method much more reliable than FTP or heart rate?
🔹 1. Based on actual physiology, not performance
FTP ≠ your energy pathways. Ventilatory thresholds, on the other hand, measure them directly.
🔹 2. Insensitive to factors that disrupt heart rate
Fatigue, stress, heat → your heart rate can vary greatly. Your breathing, much less so.
🔹 3. Applicable in real-world conditions
No need for a lab test or a bulky mask.
🔹 4. Allows you to adjust your zones over time
In just a few minutes, you can repeat the test every week.
5. The benefits for your cycling training
✔ Perfectly calibrated zones
No more areas that are too high or too low.
✔ Precise pacing during the race
Ideal for hilly cyclosportive events, triathlons, and time trials.
✔ Accelerated progress
By working in exactly the right metabolic pathway.
✔ Better controlled fatigue
Less overload, more quality.
✔ Objective monitoring over time
You can clearly see how your thresholds are changing.
Conclusion: measurement is progress
ZoneX allows cyclists to know their true physiological zones simply, quickly and with great precision , directly on their bike.
👉 No need to estimate your zones: ZoneX measures them.
👉 No more guessing your pacing: ZoneX reveals it.
👉 No more heavy testing required: ZoneX works in real-world conditions.
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