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Lactate thresholds vs. ventilatory thresholds: comparison of measurement protocols

Why compare these protocols?

To determine training zones, coaches traditionally use:

  • lactate thresholds (LT1 and LT2), measured via blood tests,

  • ventilatory thresholds (VT1 and VT2), measured via respiration.


Although the two methods provide similar information, their protocols are very different , as are their accuracy, accessibility, and relevance in real-world conditions.


👉 This post compares the protocols point by point to understand their advantages and limitations.


1. Lactate test protocol: biochemical measurement


The lactate test consists of measuring the amount of lactate in the blood at each stage of exertion.


✔ Protocol Procedure

  1. Warm-up 10–15 minutes

  2. Start of the test on an ergocycle or treadmill

  3. Stages of 3 to 4 minutes

  4. At the end of each stage: a drop of blood is taken (ear or finger).

  5. Lactate measurement (mmol/L)

  6. Protocol progression until exhaustion


✔ What the protocol detects

  • LT1 : First point where lactate increases slightly

  • LT2 : 2nd point where acidosis rises rapidly


✔ Advantages

  • Direct physiological measurement

  • Method used in the laboratory for decades

  • Good detection of threshold 2 (LT2)

  • Scientific reference tool


✘ Limits

  • Invasive (multiple blood draws)

  • Long plateaus → less precise dynamics

  • Few measurements (one data point per level)

  • Sensitive to stress, nutrition (carbohydrates), and fatigue

  • Impossible to do outdoors or in real-world conditions

  • Expensive and non-transportable equipment


👉 The lactate test is accurate but cumbersome, invasive and difficult to repeat .


2. Ventilatory test protocol: dynamic measurement of respiration


Ventilatory thresholds are observed by analyzing:

  • ventilation (VE),

  • exhaled CO₂,

  • respiratory dynamics,

  • ventilatory stability.


✔ General procedure

The protocol depends on the hardware, but follows a similar logic:

  1. Gradual warm-up

  2. Start of the test on a home trainer, ergometer or road

  3. Short stages or continuous progression

  4. Continuous breath analysis (no mandatory stages)

  5. Automatic detection of VT1 and VT2 via respiratory ruptures


✔ What the protocol detects

  • VT1 : lipid → carbohydrate switch

  • VT2 : onset of acidosis → hyperventilation


✔ Advantages

  • Non-invasive

  • Continuous and dynamic measurement

  • Huge data density → very high accuracy

  • Suitable for indoor and outdoor use

  • Very good detection of VT1 (sometimes difficult in lactate)

  • Repeatable every week

  • Portable and lightweight equipment (e.g., ZoneX)


✘ Limits

  • Requires a reliable and well-calibrated sensor

  • A poorly executed protocol can disrupt the transitions.

  • More sensitive to intentionally modified breathing (rare)


👉 The ventilatory test is the simplest, most reproducible and most accessible .



3. Comparison of protocols: point by point


Criteria

Lactate test

Ventilatory test

Invasive?

Yes

No

Continuous data?

No (1 measurement / level)

Yes (real-time data)

Field representative?

No

Yes

Test duration

20–35 min

8 to 25 minutes depending on the protocol

VT1/LT1 Accuracy

Average

Excellent

VT2/LT2 Accuracy

Excellent

Very good

Reproducibility

Low (numerous external variables)

High

Test frequency

Every 6–12 weeks

Every week if needed

Cost / Materials

Moderate, portable

Raised, lab-grown... But made accessible with ZoneX

Logistics

Average

Lightweight with ZoneX

👉 To calibrate a training plan or track progress, the breathing protocol is far superior in practice.


4. Why are respiratory tests becoming the modern standard?


✔ 1. Easier to make

No blood, no lab, no complicated protocol.


✔ 2. More precise on metabolic dynamics

CO₂ is an extremely sensitive indicator.


✔ 3. Applicable in real-world conditions

Uphill, on a stationary trainer, on an endurance ride.


✔ 4. Very often reproducible

Ideal for following VT1 / VT2 every 2 weeks.


✔ 5. Scientifically correlated with lactate thresholds

VT1 ≈ LT1

VT2 ≈ LT2


👉 So we have the same information… but obtained more easily and more often.


5. ZoneX's advantage in this comparison


ZoneX allows:

  • a continuous analysis of CO₂

  • automatic detection of respiratory ruptures

  • a measurement in any environment

  • very high reproducibility

  • an automatic update of training zones

  • longitudinal monitoring of thresholds


🎯 Result: You get the same information as a lactate test… but without a lab, without a blood test, without the hassle.




Conclusion: two useful methods, but a clear winner for training


The lactate test

✔ precise

✘ rare

✘ invasive

✘ depending on the conditions

✘ Not very practical for the athlete


The breathing test

✔ precise

✔ Non-invasive

✔ easy

✔ frequent

✔ terrain

✔ dynamic


👉 To calibrate your zones and track your progress, the breathing protocol is the most reliable, modern and suitable method for real training .

👉 With ZoneX, this method becomes accessible to everyone, on every outing.



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