Calculate Your Lactate Threshold
Your Lactate Threshold Results
Your Training Zones
Training Recommendations
Pro Athlete LTHR Examples
LTHR % by Sport
Which Test to Use?
Most accurate field test. Best for experienced athletes.
Good balance of accuracy and difficulty. Standard for cycling FTP.
Shortest test. Good for beginners but less accurate.
Use recent race HR data. Most practical for runners.
Complete Guide to Lactate Threshold Testing & Training
What Is Lactate Threshold and Why It Matters
Lactate threshold (LT) represents the exercise intensity at which lactate accumulates in your blood faster than your body can clear it. This physiological marker is one of the best predictors of endurance performance, more so than VO2 max or economy in many cases.
For athletes, knowing your lactate threshold heart rate (LTHR) is crucial because it defines the highest intensity you can sustain for extended periods - typically 30-60 minutes for well-trained athletes. Training at or near this threshold is one of the most effective ways to improve endurance performance.
Key Fact
Your lactate threshold typically occurs at 85-90% of maximum heart rate in trained athletes, but can range from 75-95% depending on fitness level and genetics.
The Science Behind Lactate Threshold
During exercise, your muscles produce lactate as a byproduct of anaerobic glycolysis. At low intensities, your body easily clears this lactate through oxidation in other muscles and organs. However, as intensity increases, lactate production eventually exceeds clearance capacity.
The lactate threshold marks this tipping point. Beyond this intensity, lactate and hydrogen ions accumulate, leading to metabolic acidosis, muscle fatigue, and the familiar "burn" sensation. Understanding this process helps explain why threshold training is so effective.
Two Important Thresholds
- LT1 (Aerobic Threshold): The first lactate threshold occurs at ~2 mmol/L blood lactate, typically 65-75% of max HR. This marks the transition from purely aerobic to mixed energy systems.
- LT2 (Anaerobic Threshold): The second threshold at ~4 mmol/L, typically 85-90% of max HR. This is what athletes commonly refer to as "lactate threshold" or LTHR.
How to Test Your Lactate Threshold
While laboratory testing with blood lactate analysis is the gold standard, several field tests provide accurate LTHR estimates without expensive equipment. Here are the most effective protocols:
1. The 30-Minute Time Trial (Gold Standard Field Test)
- Warm-up: 10-15 minutes easy, include 3-4 x 30-second accelerations
- Main Test: 30 minutes at maximum sustainable effort
- Key Point: Pace yourself to maintain consistent effort throughout
- Calculate: Average HR for final 20 minutes = LTHR
- Cool-down: 10 minutes easy
The 30-minute test is highly accurate because the 10-minute "lead-in" allows your heart rate to stabilize, eliminating the initial cardiac drift that can skew shorter tests.
2. The 20-Minute FTP Test
Popular in cycling, this test estimates LTHR by taking 95% of your average heart rate from a 20-minute all-out effort:
- Warm-up: 20 minutes including 3 x 1-minute fast efforts
- Main Test: 20 minutes at maximum sustainable power/pace
- Calculate: Average HR × 0.95 = LTHR
- Cool-down: 10-15 minutes easy
Important Note
The 95% correction factor works well for most athletes but may overestimate LTHR in beginners (use 92-93%) or underestimate in highly trained athletes (use 96-97%).
3. The Ramp Test Protocol
Ramp tests progressively increase intensity until exhaustion. While primarily used for VO2 max testing, they can estimate LTHR:
Cycling Ramp Test:
- • Start at 100W (or 50% expected FTP)
- • Increase 20-30W every minute
- • Continue until failure
- • LTHR ≈ 85-90% of max HR reached
4. Using Race Data
Recent race performances provide excellent LTHR estimates:
- 10K Run: Average HR ÷ 1.03 = LTHR
- Half Marathon: Average HR ÷ 0.99 = LTHR
- 40K Time Trial: Average HR ÷ 0.98 = LTHR
- Olympic Triathlon: Bike HR ÷ 0.97 = LTHR
Training Zones Based on LTHR
Once you know your LTHR, you can establish precise training zones. The most common system uses five zones:
| Zone | Name | % of LTHR | Purpose | Duration |
|---|---|---|---|---|
| 1 | Recovery | <85% | Active recovery, warm-up | 30-90 min |
| 2 | Aerobic | 85-89% | Base building, fat burning | 1-5 hours |
| 3 | Tempo | 90-94% | Aerobic capacity | 20-60 min |
| 4 | Threshold | 95-105% | Lactate threshold | 8-40 min |
| 5 | VO2 Max | >106% | Maximum aerobic power | 3-8 min |
Effective Threshold Training Workouts
Training at or near lactate threshold provides the greatest improvements in endurance performance. Here are proven workout structures:
Continuous Threshold Runs/Rides
- Tempo Run: 20-40 minutes at 95-100% LTHR
- Progression Run: Start at 85% LTHR, finish at 100%
- Sweet Spot Ride: 45-90 minutes at 90-95% LTHR
Threshold Intervals
- Classic: 3-4 x 10 minutes at LTHR, 2-3 min recovery
- Cruise Intervals: 4-6 x 6-8 minutes at 100-105% LTHR
- Over-Unders: 3 x 12 min alternating 2 min at 105% / 2 min at 95%
Weekly Training Distribution
Follow the 80/20 principle: 80% of training at low intensity (Zones 1-2), 20% at high intensity (Zones 4-5):
Sample Week for Intermediate Athlete:
- • Monday: Rest or Zone 1 recovery
- • Tuesday: Zone 4 threshold intervals
- • Wednesday: Zone 2 aerobic base
- • Thursday: Zone 3 tempo run
- • Friday: Zone 1 recovery
- • Saturday: Long Zone 2 with Zone 3 surges
- • Sunday: Zone 2 aerobic or rest
How to Improve Your Lactate Threshold
Lactate threshold is highly trainable. With consistent, targeted training, improvements of 5-15% are common in the first year:
Physiological Adaptations
- • Increased mitochondrial density
- • Enhanced lactate clearance
- • Improved capillarization
- • Better buffering capacity
- • Increased fat oxidation
Training Strategies
- • Progressive overload
- • Consistent threshold work
- • Strong aerobic base
- • Proper recovery
- • Periodized training
Common Mistakes to Avoid
- Testing too frequently: LTHR changes slowly. Test every 4-6 weeks maximum.
- Poor pacing: Starting too fast in tests leads to inaccurate results.
- Ignoring fatigue: Test only when well-rested for accurate results.
- Too much threshold work: More than 2-3 threshold sessions per week risks overtraining.
- Neglecting base training: Strong aerobic base is essential for threshold improvements.
Sport-Specific Considerations
Running
Runners typically have higher LTHR relative to max HR compared to cyclists. Focus on tempo runs and cruise intervals. Monitor pace alongside HR as running economy affects the relationship.
Cycling
Cyclists often train by power at threshold (FTP). LTHR provides a secondary metric and is useful for long climbs where power may vary. Sweet spot training (88-93% FTP) is particularly effective.
Triathlon
Triathletes need sport-specific LTHR values as they differ between disciplines. Bike LTHR is typically 5-10 bpm lower than run LTHR. Train each discipline at its specific threshold.
Swimming
Heart rate response is blunted in water due to horizontal position and pressure. LTHR is typically 10-15 bpm lower than land-based sports. Use pace and perceived exertion alongside HR.
Recommended: Professional Lactate Testing at Home
Eaglenos Blood Lactate Meter
For athletes serious about optimizing their training zones, the Eaglenos lactate meter provides laboratory-grade accuracy at home. Test your actual blood lactate levels to precisely determine your lactate threshold.
- ✓ Professional-grade accuracy (±0.2 mmol/L)
- ✓ Results in 10 seconds
- ✓ Stores up to 180 test results
- ✓ Includes test strips and lancets
- ✓ Used by professional coaches and athletes
Affiliate Disclosure: As an Amazon Associate, we earn from qualifying purchases at no additional cost to you. This helps support our free calculators and content. We only recommend products we believe will genuinely help athletes improve their training.
Why Test Blood Lactate? While heart rate-based estimates are useful, actual blood lactate testing provides the most accurate threshold determination. This allows you to set precise training zones and track improvements over time with scientific accuracy.
Frequently Asked Questions
What is lactate threshold heart rate (LTHR)?
Lactate threshold heart rate is the heart rate at which lactate begins accumulating in your blood faster than it can be cleared, typically around 85-90% of max HR for trained athletes. It represents the highest sustainable intensity for endurance exercise.
How do I test my lactate threshold?
The most common field test is a 30-minute time trial. After a 10-minute warm-up, run or cycle at the hardest pace you can sustain for 30 minutes. Your average heart rate for the last 20 minutes is approximately your LTHR.
What's the difference between lactate threshold and anaerobic threshold?
While often used interchangeably, lactate threshold (LT1) occurs at ~2 mmol/L blood lactate, while anaerobic threshold (LT2) occurs at ~4 mmol/L. LT2 is typically what athletes refer to as 'threshold' and corresponds to LTHR.
How accurate is the 20-minute FTP test for lactate threshold?
The 20-minute test estimates LTHR by taking 95% of your average heart rate. It's reasonably accurate for most athletes but can overestimate for beginners or underestimate for highly trained athletes. A 30-minute test is more accurate.
What heart rate zone is lactate threshold?
Lactate threshold typically falls in Zone 4 of a 5-zone system, or the upper end of Zone 3 in a 3-zone system. It's usually 85-95% of maximum heart rate or 95-105% of your LTHR when using LTHR-based zones.
How often should I test my lactate threshold?
Test your lactate threshold every 4-6 weeks during training blocks, or at the beginning of each training phase. More frequent testing (every 3-4 weeks) during build phases helps track improvements.
Can I improve my lactate threshold?
Yes! Lactate threshold is highly trainable. Tempo runs, threshold intervals, and sweet spot training can improve LTHR by 5-15% in beginners and 2-5% in trained athletes over a training cycle.
What's a good lactate threshold heart rate by age?
LTHR varies by fitness more than age. Typical ranges: Age 20-30: 165-175 bpm, Age 30-40: 160-170 bpm, Age 40-50: 155-165 bpm, Age 50-60: 150-160 bpm. Trained athletes often exceed these ranges.