While it's true that lactate itself is not the direct cause of muscle fatigue and has even been shown to be a valuable fuel source during exercise, the concept of lactate threshold training remains highly relevant for improving athletic performance. The reason for this lies not in the presence of lactate per se but in the body's response to its accumulation and the associated increase in hydrogen ions (H+) that can lead to a decrease in muscle pH (acidosis), affecting muscle function and contributing to fatigue.
What is Lactate Threshold?
When your body breaks down glucose for energy during exercise, lactate is a byproduct. The lactate threshold is the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed. This threshold is a critical marker of aerobic endurance performance. When exercising below the lactate threshold, muscles produce lactate at a manageable rate and it can be cleared from the blood efficiently. However, as exercise intensity increases beyond this threshold, lactate production exceeds the body's ability to clear it, leading to an increase in blood lactate concentration.
Importance of Lactate Threshold Training
Increases Clearance and Utilization: Training at or near the lactate threshold increases the body's capacity to clear lactate from the blood and utilize it as a fuel source more effectively. This is achieved through physiological adaptations such as increased mitochondrial density and improvements in the efficiency of the lactate shuttle.
Enhances Aerobic Capacity: Training at the LT can increase VO2 max and the percentage of VO2 max that an athlete can sustain during endurance exercise, which is crucial for performance
Delays Fatigue: By increasing the lactate threshold, athletes can perform at higher intensities for longer periods before lactate accumulation leads to fatigue. This is crucial for endurance sports where maintaining a high intensity over time is essential for performance.
Improves Efficiency: Training that elevates the lactate threshold also improves overall metabolic efficiency, allowing athletes to use a greater proportion of fat as fuel at higher intensities, conserving glycogen stores.
How to Train at Your Lactate Threshold
1. Estimate Your Lactate Threshold
Field Test
Field tests are a straightforward way to estimate your LT without needing specialized equipment. These tests can be done by anyone with a basic sports watch or fitness tracker.
Running: Try a 30-minute solo time trial where you run as far as you can at a consistent effort. Your average heart rate during the last 20 minutes is a good proxy for your LT heart rate.
Cycling: A 20 to 30-minute all-out effort on a stationary bike or safe outdoor route works similarly to running. Monitor your average heart rate for the effort, focusing on the latter portion as an indicator of LT.
Perceived Effort: Without any gadgets, simply base it on a scale of perceived exertion. Your LT typically falls into a "comfortably hard" effort, where you can speak short sentences but prefer to focus on the effort.
The Talk Test
The talk test is surprisingly effective and straightforward. During a workout, increase your intensity gradually. You're likely near your LT when you can no longer speak comfortably in full sentences but can still utter short phrases. This method relies on the physiological changes that happen as you transition from aerobic (with oxygen) to anaerobic (without oxygen) exercise, affecting your ability to talk.
While these methods may not be as precise as lab tests, they can still provide a useful starting point for structuring your training and monitoring progress.
2. Establish Training Zones
Zone 1: Recovery or Very Light
HR: Less than 70% of LT HR
Perceived Effort: Very easy, you can hold a conversation with no effort at all.
Objective: Enhance recovery, promote blood flow, and prepare the body for more intense sessions.
Zone 2: Aerobic/Low-Intensity-Steady-State (LISS) Cardio or Light
HR: 70-80% of LT HR
Perceived Effort: Easy, comfortable; can speak in full sentences.
Objective: Build aerobic base, improve fat metabolism, and increase endurance.
Zone 3: Tempo or Moderate
HR: 80-90% of LT HR
Perceived Effort: Moderately hard; speaking in full sentences is possible, but you’d prefer to keep it short.
Objective: Improve aerobic capacity, increase the pace you can sustain without significant lactate accumulation.
Zone 4: Threshold or Lactate Threshold
HR: 90-100% of LT HR
Perceived Effort: Hard; speaking more than a few words is challenging.
Objective: Increase lactate clearing rate, push back the LT, enhancing endurance performance.
Zone 5: VO2 Max
HR: 100-110% of LT HR
Perceived Effort: Very hard; speaking is very difficult and not sustainable.
Objective: Improve maximal oxygen uptake and high-intensity endurance.
Zone 6: Anaerobic Capacity
HR: Cannot be accurately gauged with HR due to delay in HR response. Use perceived effort.
Perceived Effort: All-out effort; no speaking possible.
Objective: Increase anaerobic capacity, power, and speed for short, intense bursts.
3. Incorporate Threshold Workouts
Tempo Runs
Sustained efforts at or near LT, solidifying endurance.
High-Intensity Interval Training
Bursts above LT with recovery periods, enhancing anaerobic capacity and lactate clearance.
Progression Runs
Start moderate, finishing at or above LT, teaching your body to handle increasing intensities.
4. Progress Gradually
Increase the duration and intensity of threshold workouts over time, challenging your body to adapt and extend its limits.
5. Recover and Adapt
Integrate rest days and lighter workouts, allowing your body to recover and strengthen in response to the training stress.
6. Reassess and Adjust
Periodically reassess your LT and adjust your training zones to reflect improvements in your fitness and endurance capabilities.
Does lactate threshold in one exercise (say running) translate to lactate threshold in other exercsies as well (e.g. pushups). Is lactate threshold muscle specific?
Does lactate threshold in one exercise (say running) translate to lactate threshold in other exercsies as well (e.g. pushups). Is lactate threshold muscle specific?