Lactate Threshold
Definition

The lactate threshold refers to the point during exercise where blood lactate levels begin to rise sharply. It serves as a critical indicator of an individual's performance limits. A higher lactate threshold allows for sustained exercise at greater intensities over longer periods, making it particularly useful for endurance sports like marathons and cycling.

Measurement and Significance of Lactate Threshold

The lactate threshold is identified by progressively increasing exercise intensity until blood lactate accumulation surpasses the body's ability to clear it. This marks the point where lactate production outpaces removal. Lactate threshold is further categorized into two levels: LT1 and LT2.

  • LT1 (First Lactate Threshold): At this point, blood lactate levels begin to rise gradually in proportion to exercise intensity. For recovery phases, exercising below LT1 intensity is recommended.
  • LT2 (Second Lactate Threshold): This marks the intensity where blood lactate levels increase sharply. Sustaining exercise above LT2 intensity is challenging over extended periods, making it a key indicator for pacing in long-distance running.

How pacer works

A non-invasive and highly reliable method for analyzing lactate thresholds is respiratory analysis. As lactate accumulates and acidifies the blood, it stimulates the respiratory center, causing a rapid increase in breathing rate.
The pacer detects two key inflection points where respiratory patterns change abruptly with increasing exercise intensity, defining these points as LT1 and LT2.

Ways to Improve Lactate Threshold
  • Threshold Training: Exercising for extended periods near the lactate threshold intensity helps enhance the body's ability to clear lactate.
  • Interval Training: Alternating between high-intensity and low-intensity exercise improves the efficiency of lactate processing.
  • Muscular Endurance Training: Increases muscle resistance to fatigue, reducing lactate production and indirectly improving the lactate threshold.
Limitations of Lactate Threshold

There are various ways to express lactate threshold:

  • %VO₂max: This method indicates the intensity at which the lactate threshold occurs relative to an individual's VO₂max. While widely used, it does not clearly reflect incremental improvements from training over time.
  • Lactate Threshold Pace (LTP): A more accurate measure of performance improvement is Lactate Threshold Pace (LTP), which calculates the actual pace corresponding to the lactate threshold. For instance, even if the lactate threshold consistently occurs at 90% of VO₂max, the pace associated with that intensity can improve significantly through training.