Demo

Lactate Analysis Demo

Try analysis, training zones, VLamax and race planning with sample data. No registration required.

Measurements from your step test.

Test profile & conditions2026-10-05 · Earlobe

Test Date

HRmax

Your maximum heart rate (optional). Only used to show "% HRmax" next to the thresholds. Heart rate zones come from the measured threshold heart rate of your test, not from HRmax.

Resting HR

Your resting heart rate in the morning while lying down. Stored and exported with the test. HR zones come from the measured HR-power curve of the test, not from a formula.

Stage Duration (min)

Duration of each exercise stage in minutes. ≥5 min recommended for lactate steady-state (Heck et al. 1985). Below 4 min, lactate values are systematically underestimated.

Body Weight (kg)

Optional. Used for: relative power (W/kg), VO₂max estimation, and relative carbohydrate consumption (g/kg/h).

Gender

Sample Site

Record the sample site and never switch it: fingertip values tend to be higher than earlobe values (Dassonville 1998; Moran 2012: +9%, not significant). The app does not correct the values but warns when the site changes between tests.

6 Stages active•Step size: +20W

Complete: 6 Stages|5 Stages = Minimum|6 Stages = Best validation

Record mid-stage values

Optional: a second lactate sample within the stage, e.g. after 4 of 8 minutes. Only fill in where you measured. Curve and thresholds use the end-of-stage value.

Power (W)

Power in Watts. After entering the first stage, others will auto-fill with +20W/stage.

Heart Rate (bpm)

Heart rate at the end of the stage (after 3 min effort).

Lactate end of stage (mmol/L)

Lactate value in mmol/L, measured at the end of the stage (e.g. with Lactate Pro).

Mid-stage value (mmol/L)

Stage 1

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

Stage 2

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

Stage 3

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

Stage 4

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

Stage 5

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

Stage 6

Watt

HR (bpm)

Lactate

Mid

bpm

mmol

View analysis

Analysis Results

Test QualityR² = 1.000

100%Excellent

Test Coverage

Complete

⚠️ Stage duration 5 min: longer stages lower both threshold and peak power (Bentley et al. 2007). The validated accuracy applies to 4-minute stages. Only compare tests with the same stage duration.

Aerobic Threshold (LT1)

210 W±15 W

145 bpm(76% HRmax) • 1.8 mmol/L

Accuracy: ±10–15 W (day-to-day biological variation + device error + method scatter)

What does LT1 mean?

Start of the lactate rise. Up to this point metabolism is predominantly aerobic — the basis for long, easy training (zones 1–2). Definition depends on the method: log-log breakpoint (Beaver 1985) for Log-Poly-ModDmax, minimum of the lactate equivalent for Dickhuth, otherwise baseline + 0.5 mmol/L (Jamnick 2018). There is no gold standard for LT1 comparable to MLSS (Faude et al. 2009).

Anaerobic Threshold (LT2)

258 W±8 W

165 bpm(87% HRmax) • 3.7 mmol/L

Accuracy: ±10–15 W (day-to-day biological variation + device error + method scatter)

What does LT2 mean?

An estimate of your individual anaerobic threshold — an approximation of the Maximum Lactate Steady State (MLSS). The true MLSS varies between individuals and does not sit at a fixed lactate value; only an MLSS constant test gives the gold standard. The "threshold" for tempo training.

As a coach or lab you can set LT1 and LT2 yourself when needed – by typing a value or clicking the lactate curve. Zones and PDF follow the value.

Try it in the coach demo →

Lactate Curve

Lactate within the stage

Stage 4 · 240 W2.4 → 2.8 mmol/L (+0.4 to end of stage)
Stage 5 · 270 W3.6 → 4.5 mmol/L (+0.9 to end of stage)

Curve and thresholds use the end-of-stage value. The mid-stage value shows whether lactate is still rising within the stage. MLSS cannot be derived from it; that requires constant-load tests.

Enter body weight to estimate VO₂max.

AI analysis & interpretation

AI Interpretation

🤖 Demo Analysis

Strengths & Weaknesses

The ratio of LT1 to LT2 indicates a solid aerobic base. Your VLamax appears to be in the moderate range.

Training Recommendation

Focus on polarized training. 80% base training (Zone 2), 20% high intensity (Zone 5).

Weekly Schedule Idea

Mon: Rest day

Tue: Intervals (4x8min at threshold)

Wed: Easy run

Thu: Tempo changes

Fri: Swim/Core

Sat: Long run (Zone 2)

Sun: Bike ride or easy run

Training Zones

LT1-anchored zones

Threshold HR from the lactate curve:LT1 145 bpmLT2 165 bpm

Basis: LT1 (upper bound of zone 2) and LT2 as reference are measured. The bounds at 85% of LT1, midway between LT1 and LT2, and at 105% of LT2 are conventions of this app, not study values.

Zones anchored to LT1: your Z2 upper bound sits at 82% of your LT2 — where your step test shows the first lactate rise. San Millán & Brooks 2018 show that fat oxidation falls as lactate rises; a Z2 bound at LT1 keeps Z2 in the range where fat oxidation still dominates.

HR ranges interpolated from the measured HR-power curve of this test — no formula, no age estimate. Outside the measured range no HR is shown.

Zone 1•Recovery

Active recovery, very easy training

< 179 W

< 69% LT2

HR: < 129 bpm

Zone 2•Base 1

Fat metabolism, long duration

179 - 210 W

69%–82% LT2

HR: 129–145 bpm

Zone 3•Base 2

Tempo run, Sweet Spot

210 - 234 W

82%–91% LT2

HR: 145–155 bpm

Zone 4•Threshold

Threshold training, intervals

234 - 271 W

91%–105% LT2

HR: 155–170 bpm

Zone 5•Peak

VO2max, Anaerobic capacity

> 271 W

> 105% LT2

HR: > 170 bpm

Note: Zones are LT2-referenced (not FTP). Coggan's FTP ≈ Critical Power ≈ ~95% VO₂max power, typically 10–15% above LT2. Zone 4 therefore targets the MLSS range, not above it.

Race Prediction

40 km (OD)

258 – 268 W

100–104% LT2

90 km (MD)

206 – 217 W

80–84% LT2

180 km (LD)

180 – 191 W

70–74% LT2

Rules of thumb from coaching practice, not study values: 10 km ≈ 102–108%, half marathon ≈ 90–98%, marathon ≈ 84–92% of LT2 speed; bike 40/90/180 km ≈ 100–104 / 80–84 / 70–74% of LT2 power. Running economy, pacing experience and heat account for a further ±5–10%.

What if: shift the threshold

Drag the threshold up or down and see what it means in race times. This is a conversion, not a forecast — the slider does not claim the shift will happen.

Shift threshold

0.0 %4:18 /km

−5 %today+10 %

10 km

39:47 – 42:08

3:59 – 4:13 /km

Half Marathon

1:32:31 – 1:40:44

4:23 – 4:46 /km

Marathon

3:17:06 – 3:35:52

4:40 – 5:07 /km

Exchange rate: 1 % threshold ≈ 2:02 over the Marathon — 1:57 to 2:08 depending on the factor. The relative gain is exact, the minutes depend on the base time.

Calculated with the same factors as the race prediction (10 km 102–108 %, half marathon 90–98 %, marathon 84–92 % of LT2 speed). Rules of thumb from coaching practice, not study values. Running economy, pacing and heat add another ±5–10 % — so the range is more likely too narrow than too wide.

Work back from a target time

Enter a target time and see which threshold it would take, and how far away you are.

Distance

Target time

HoursMinutesSeconds

The range below the required threshold is the spread of the factors: with favourable pacing and good economy the slower threshold is enough, in the unfavourable case it takes the faster one.

Cross-check from a personal best

Two independent routes to the same number: one through your threshold, one through a race you actually ran. If they disagree, that gap is the information.

Distance raced

Race time

HoursMinutesSeconds

Riegel (1981): T₂ = T₁ · (D₂/D₁)^1.06, derived from race records. The formula knows neither your glycogen stores nor your weekly mileage. If the personal-best prediction sits well below the threshold prediction, base endurance is the likelier gap; above it, race sharpness or pacing.

🎯 🎯 Your Personalized Pacing

Target IF

Intensity Factor: Your target pace relative to your FTP/threshold. 100% = threshold pace, >100% = above threshold.

88%≈ 227 W ±7 W

Carbs/Hour

Theoretical carb consumption at race intensity. For short events (<1h), intake is not needed as glycogen stores suffice. For longer events (>1h), this shows the recommended intake.

30g

IF Range: 85% – 95%

Uncertainty carried over from the LT2 confidence interval (linear via the IF).

IF source (bike): Allen & Coggan 2019, "Training and Racing with a Power Meter" (3rd ed.). Zones are LT2-relative; Coggan's FTP typically sits somewhat above LT2.Carbohydrates: Jeukendrup 2014 (30–75 min: optional bis 30 g/h)

Race Strategies

Zone 4

~1h

Time Trial (40km)

Exactly at FTP. Pure threshold effort.

Training Recommendations

Focus:Pacing & Holding Aero Position

Key Session 1:2x 20min @ 95-100% FTP (Rest: 5 min)

Volume:Lots of "Sweet Spot" training (88-93% FTP)

Lactate Analysis Demo

Analysis Results

Aerobic Threshold (LT1)

Anaerobic Threshold (LT2)

Lactate within the stage

AI Interpretation

🤖 Demo Analysis

Strengths & Weaknesses

Training Recommendation

Weekly Schedule Idea

Training Zones

Race Prediction

What if: shift the threshold

Work back from a target time

Cross-check from a personal best

🎯 🎯 Your Personalized Pacing

Race Strategies

Time Trial (40km)

Training Recommendations

VLamax Metabolic Profile

Sprint VLamax Calculator
All-out sprint of 10–12 s (Quittmann 2025), lactate before the sprint and then every minute for 8–10 minutes. VLamax = Δlactate / (sprint duration − phosphagenic time).

Your saved tests

Progression Tracking

Like the app?

Lactate Analysis Demo

Enter Test Data

Analysis Results

Aerobic Threshold (LT1)

Anaerobic Threshold (LT2)

Lactate within the stage

AI Interpretation

🤖 Demo Analysis

Strengths & Weaknesses

Training Recommendation

Weekly Schedule Idea

Training Zones

Race Prediction

What if: shift the threshold

Work back from a target time

Cross-check from a personal best

🎯 🎯 Your Personalized Pacing

Race Strategies

Time Trial (40km)

Training Recommendations

VLamax Metabolic Profile

Sprint VLamax CalculatorAll-out sprint of 10–12 s (Quittmann 2025), lactate before the sprint and then every minute for 8–10 minutes. VLamax = Δlactate / (sprint duration − phosphagenic time).

Your saved tests

Progression Tracking

Like the app?

Sprint VLamax Calculator
All-out sprint of 10–12 s (Quittmann 2025), lactate before the sprint and then every minute for 8–10 minutes. VLamax = Δlactate / (sprint duration − phosphagenic time).