Why does my watch-derived LT differ from this calculator?

Different devices use different algorithms. Repeat the field test under similar conditions, average the results, and manually adjust your target heart rate if needed.

How should I recover after an LT workout?

Follow the session with Zone 1–2 jogging or rest the next day, refuel with carbs and protein, stretch, and prioritise quality sleep.

Can I run an LT test on a treadmill?

Yes. Maintain steady pace and incline in a well-ventilated room, then use the treadmill pace converter to align indoor speed with outdoor effort.

Threshold Planner

Convert a 30-minute test into LT pace, HR, and race-ready tempo workouts.

Feed the calculator with field-test or race data to compute LT pace, speed, and heart rate, then deploy the outputs in tempo runs, cruise intervals, and marathon simulations with confidence.

Calculate LT Tempo workout guide

Precise LT metrics Get pace, speed, and bpm tailored to your latest effort.

Workout integrations Receive tempo, cruise interval, and recovery guidance tied to LT.

Zone alignment Compare LT to Zone 2 and marathon pace for a cohesive training plan.

🔥 Lactate threshold calculator

Enter a 30-minute test or race result to calculate LT pace, speed, heart rate, and recommended workouts.

Distance covered (km)

Use your 30-minute test distance or a recent race (e.g., 10K).

Elapsed time

Default is 30:00. Adjust if the test duration differed.

Average HR (optional)

Wear a chest strap for best results. Otherwise enter max HR to estimate.

Max HR (optional)

Used when average HR is unavailable to estimate LT around 90% of max.

LT pace

— min/km

— /mile

LT heart rate

— bpm

—

LT speed

— km/h

—

Recommended workouts

Tempo run (20–30 min): —
Cruise intervals (6–10 min reps): —

Limit LT work to once per week and keep easy days at least 15% slower than LT pace.

Training notes

Tempo progression

Alternate steady LT runs with cruise intervals (e.g., 4×8 minutes) to raise threshold while preserving recovery.

Marathon specificity

Compare the LT pace with marathon goal pace to decide whether more threshold work or aerobic volume is needed.

Cross-check with HR

Use the Zone 2 calculator to monitor recovery days. If LT HR drifts upward, reduce intensity for a few sessions.

Data hygiene

Disable wrist-based optical HR during the test if using a chest strap, and calibrate treadmills before indoor attempts.

Calculate LT now →

Core terms

Lactate threshold (LT): The tipping point where blood lactate rises sharply; roughly the fastest pace you can hold for about an hour.
Tempo run: A continuous effort just below LT for 20–40 minutes that improves stamina and race-day efficiency.
Cruise intervals: Multiple LT-level repeats (5–10 minutes) with short recoveries to raise how long you can sustain threshold pace.

Workout ideas

LT tempo — 20–30 minutes continuous at LT pace followed by an easy cooldown.
Cruise intervals — 6–10 minutes × 4 repeats at LT ±5 seconds with 90-second jog recoveries.
Progression long run — Finish the final 4 km at LT pace to rehearse race-day fatigue.

Companion tools

Align LT with HR zones Rehearse tempos indoors Recovery & strength essentials