LT1 and LT2 calculator for cycling

The terms LT1 and LT2 in cycling refer to two specific Lactate Thresholds, which are critical physiological markers used to define training intensity zones and maximize endurance performance.

The cycling calculator will use your LT1 and LT2 values (usually determined through field tests or laboratory testing) to calculate and set your personalized heart rate or power training zones.

What LT1 and LT2 Mean

These thresholds mark points during increasing exercise intensity where the concentration of lactate (a byproduct of metabolism) in your blood changes significantly.

1. LT1 (Lactate Threshold 1)

• Also Known As: Aerobic Threshold (AeT).
• What it is: The exercise intensity (heart rate or power) where blood lactate begins to rise slightly above resting levels. At this point, your body is still able to clear the lactate as fast as it produces it, establishing an aerobic steady state.
• Training Focus: Training below or at LT1 focuses on building your aerobic base, improving fat-burning efficiency, and enhancing long-term endurance. These are your long, easy, conversational rides (often corresponding to training Zone 2).
• Intensity: A comfortable pace you can sustain for many hours.

2. LT2 (Lactate Threshold 2)

• Also Known As: Anaerobic Threshold (AnT), Maximum Lactate Steady State (MLSS), or Functional Threshold Power (FTP) in cycling.
• What it is: The highest intensity you can sustain where lactate production and clearance are still balanced. Any effort above this point causes lactate to accumulate rapidly, leading to muscular fatigue and a sharp decline in performance.
• Training Focus: Training at or around LT2 improves your ability to sustain higher power outputs for extended periods (critical for time trials and race-pace efforts). These are your sustained hard efforts (often corresponding to training Zone 4).
• Intensity: An uncomfortably hard pace you can typically sustain for about 30 to 60 minutes.

How the Calculator Uses Them

Our cycling calculator uses your LT1 and LT2 values to create highly individualized training zones.

Zone	Intensity Relative to LT	Primary Training Goal
Zone 1 (Recovery)	Below LT1	Active recovery, minimal stress.
Zone 2 (Endurance)	At or just below LT1	Building aerobic base, fat oxidation.
Zone 3 (Tempo)	Between LT1 and LT2	Improving stamina, moderate effort.
Zone 4 (Threshold)	At or just below LT2	Increasing the power/pace you can sustain.
Zone 5+ (Vo2 Max/Anaerobic)	Above LT2	Improving maximum effort capacity.

By knowing these thresholds, the calculator gives you specific Heart Rate (BPM) or Power (Watts) targets for each training zone, ensuring your workouts achieve the desired physiological adaptation.