🧪 What Is Lactate?
Lactate (lactic acid) is a metabolic product formed during anaerobic glycolysis. For a long time it was thought that lactate is a "fatigue toxin", but modern science has revealed a completely different picture: lactate is an important energy source, signaling molecule and substrate for gluconeogenesis. Accumulation of lactate in the blood is not the cause of fatigue but an indicator that anaerobic energy production exceeds the body's ability to utilize lactate.
📊 Lactate Thresholds
1️⃣ Lactate Threshold 1 (LT1/Aerobic Threshold)
First significant increase in lactate above resting level (2 mmol/L). The boundary between light and moderate intensity. Long endurance training sessions take place at this threshold.
2️⃣ Lactate Threshold 2 (LT2/Anaerobic Threshold)
Maximal lactate steady state (MLSS) — the highest intensity at which lactate production = utilization (4 mmol/L). The classic "threshold" intensity.
3️⃣ VO2max Zone
Above LT2 — lactate rises continuously. Intense interval training. It can be maintained for only a few minutes.
📈 Lactate Curve
Dependence of lactate concentration on exercise intensity. A rightward shift of the curve = improved endurance. The same lactate at a higher power/speed.
🔬 Testing Protocols
| Protocol | Description | Duration | Suitability |
|---|---|---|---|
| Graded Test | Speed/power is increased every 3-5 min., and a blood sample is taken | 30-45 min. | Gold standard — most accurate |
| GXT (Maximal Test) | Continuous increase in load until exhaustion | 8-15 min. | Suitable for measuring VO2max + lactate together |
| Modified Conconi | Shorter graded test with 200m increments every 1-2 min. | 15-20 min. | In field conditions, for runners |
| MLSS (Maximal Lactate Steady State) | Several constant-intensity tests of 30 min. | Several visits | Most accurate determination of LT2, but very time-demanding |
📈 Lactate Interpretation
Lactate measurements provide direct metabolic information that cannot be obtained from heart rate or VO2 alone:
- Endurance progression: a rightward shift of the lactate curve — the same lactate level is reached at a higher speed/power.
- Substrate utilization: With lower lactate at the same intensity — more efficient fat utilization, better mitochondrial function.
- Determination of training zones: LT1 and LT2 allow precise determination of 3-5 training intensity zones individually.
- Overtraining detection: Paradoxically low lactate at high load may indicate glycogen depletion or overtraining.
🏅 Application in Different Sports
🏃 Running / Triathlon
Marathon pace is determined (at LT1), half-marathon pace (between LT1-LT2), 10 km pace (at LT2).
🚴 Cycling
FTP (Functional Threshold Power) — power at LT2. Used for defining training zones and race strategy.
🏊 Swimming
Modified protocols in the pool — earlobe blood samples (more easily accessible than fingers during swimming).
⚽ Team Sports
Lactate is measured during competition to assess exercise intensity — whether the player is working in the desired intensity range.
🙋 Frequently Asked Questions
Yes! Understanding of lactate testing in sport helps train more effectively, avoid injuries and achieve better results even at amateur level.
We recommend PubMed, Google Scholar, and Sports Medicine journals. It is also worth following publications from the Lithuanian Sports University.
It depends on the specific study. Some methods require laboratory equipment, while others can be performed with portable devices.
Coaches who understand lactate testing in sport can individualize training programs, monitor progress and adjust loads in a timely manner.
📚 Additional Resources and Sources
To deepen your knowledge about lactate testing in sport, we recommend:
- Scientific publications and conferences of the Lithuanian Sports University (LSU)
- International journals: Journal of Sports Sciences, Medicine and Science in Sports and Exercise
- Annual congresses of the European College of Sport Science (ECSS)
- Sports science podcasts: Science of Sport, The Real Science of Sport
- Sports science programs of the Lithuanian National Olympic Committee (LTOK)
⚡ Pro Tip
Sports science is constantly evolving. What was considered true 10 years ago may be refuted today by new research. Be curious, read the latest literature, and don't be afraid to experiment — of course, while following safety principles.