Lactate Production and Clearance: Energy System Dynamics in Long-Distance Cycling

Introduction

“Leg soreness is caused by lactate accumulation”—this saying is widely circulated among cyclists in Taiwan, but modern exercise physiology has debunked this oversimplified notion. Lactate is not only not an enemy; it is actually one of the most important energy intermediaries in long-distance riding. Correctly understanding lactate metabolic dynamics can make your pacing strategy more scientific and your training results more significant.

The True Role of Lactate

Old View (Incorrect): Lactate accumulation → Muscle acidification → Fatigue

Modern Understanding (Correct):

1. Lactate is an energy intermediate: When the glycolytic rate exceeds the mitochondrial oxidative phosphorylation rate, pyruvate is converted to lactate—this is not waste, but rather a mechanism to allow glycolysis to continue

2. Lactate can be oxidized and utilized: Nearby Type I slow-twitch fibers, cardiac muscle, and other organs can take up and oxidize lactate, reconverting it into energy

3. Lactate Shuttle: Lactate produced by high-intensity muscles (fast-twitch fibers) can “shuttle” to low-intensity muscles or the heart for utilization

4. The true cause of acidosis: The feeling of muscle fatigue mainly comes from elevated H⁺ (proton) concentration, and the primary source of H⁺ is ATP hydrolysis—lactate itself is not the main cause

Lactate Threshold: The Critical Point in Long-Distance Riding

FTP (Functional Threshold Power) is essentially the riding intensity close to MLSS—at this point, lactate production rate = clearance rate, and blood lactate remains stable.

Training for Lactate Clearance Capacity

Training to Raise LT1 (Aerobic Threshold):

• Long-duration Zone 2 training: 4–5 sessions per week, 60–120 minutes each, promoting increased mitochondrial density and enhancing lactate oxidation capacity
• Goal: Make the power corresponding to LT1 progressively higher, increasing the speed of “easy low-intensity riding”

Training to Raise LT2 (Lactate Turnpoint):

• Threshold Intervals: 3–5 sets × 10–20 minutes, at 95–105% FTP
• Sweet Spot Training (88–95% FTP): Highly efficient threshold training with relatively low fatigue

High-Intensity Lactate Clearance Training:

• Over-Under Training: Alternating between riding above LT2 (Over) and below LT2 (Under) to train rapid lactate clearance capacity
• Example: 3 minutes @ 110% FTP → 3 minutes @ 90% FTP, repeated 6–8 times
• Recommended route in Taiwan: Yangmingshan Tianmu Water Pipeline climb (approximately 3 km) paired with flat recovery sections

Long-Distance Pacing and Lactate Dynamics

Taiwan Round-Island 400 km Pacing Strategy (Analyzed from a Lactate Perspective):

• Early on Day 1: Maintain intensity below LT1 to allow the lactate system to fully rest
• Climbing sections: Allow brief excursions above LT2, but no more than 5 minutes at a time
• Long descents and flat sections: Actively reduce speed to let lactate clearance catch up with accumulation
• Late in each day: If legs feel sore, it means you have exceeded MLSS by too much—reduce speed immediately

Important Practical Knowledge Related to Lactate:

• Carbohydrate fueling can sustain glycolytic rate, but it also means more lactate production—during high-intensity riding, fueling timing and intensity must be considered together
• Post-race cold water immersion can accelerate H⁺ clearance and reduce the feeling of acidosis, but it may slightly inhibit training adaptations

Practical Recommendations

1. Undergo a laboratory lactate test (at least once) to identify your personal LT1 and LT2 corresponding power values as the basis for training zones
2. Follow a “build slowly, peak fast” periodized training approach: first spend several months on substantial Zone 2 to establish the lactate metabolism foundation, then progress to the threshold intensification phase
3. Do not neglect Zone 2—Taiwanese cyclists generally train at excessively high intensities, and insufficient Zone 2 volume is the main reason for sluggish lactate threshold progress
4. Over-Under training is an excellent tool for improving race feel, particularly suited for practicing pace control on climbing sections
5. Avoid high-intensity training 48 hours before a race to allow residual metabolic byproducts in the muscles to be fully cleared

Conclusion

Lactate is not your enemy—how you manage lactate is what matters. When you feel that burning sensation on Wuling or Beihong Highway, that is a signal that your body is operating efficiently. Understanding lactate dynamics allows you to stay on that firing line longer, rather than fleeing from it in fear.

Related Topic Reading

• Lactate Kinetics: An In-Depth Analysis for Cycling
• Lactate Threshold Improvement Training: The Scientific Breakthrough in Cycling Endurance
• Lactate Kinetics and Buffering Capacity: The Lactate You Misunderstood
• The Truth About Lactate: It’s Not Waste, It’s Fuel—From Lactate Shuttle Theory to Threshold Training