The best lactate threshold training (LT), also known as the anaerobic threshold, is the fastest a person can perform aerobic exercise at a steady state without fatigue. Exercise performed above the LT results in a sudden increase in blood lactate levels. Lactate is a byproduct of metabolism and exercise that the body continuously produces.
Under normal conditions (rest and low-intensity training), blood lactate is typically 1-2 mmol/L. During intense effort, it can rise above 20 mmol/L. Lactate levels are measured using blood draws at various stages of exertion.
Athletes often use their lactate threshold to determine how to train and what pace they can maintain during endurance sports. Because lactate threshold can be greatly increased through training, many athletes and coaches design training plans to increase this value.
What is lactate threshold?
During rest and steady-state exercise, lactate levels in your blood are produced and removed in equilibrium. The muscles, heart, and liver can use lactate as fuel during this time. During moderate exercise at a steady state, lactate can be absorbed quickly, but with high-intensity exercise, it is produced faster than the body can absorb it.
The lactate threshold is the point during full, all-out exercise at which lactate builds up in the bloodstream faster than the body can remove it. Anaerobic metabolism generates energy for short, high-intensity bursts of activity that allow lactate to build up before it reaches a threshold where it can no longer be absorbed and, therefore, accumulates. This point is known as the lactate threshold.2
This lactate threshold is marked by a slight drop in pH (from 7.4 to about 7.2). This drop causes fatigue and reduces the force of muscle contraction, which is thought to lead to a decrease in performance. The maximum workload without continuous lactate accumulation over time is called the Maximal Lactate Steady State (MLSS).
Presumably, having a higher lactate threshold means that an athlete can continue high-intensity efforts for a longer period of time before fatigue sets in. For this reason, many consider LT to be a great way to predict athletic performance in high-intensity endurance sports.
Measuring Lactate Threshold
In the lab, lactate threshold testing is done in a similar way to VO2 max testing, using either a treadmill or a stationary bike. The intensity of the exercise is increased over approximately four to five minutes. Blood samples are taken via fingerstick at the end of each period. Heart rate, power output, and VO2 are often measured along with blood lactate concentration.
This process continues until blood lactate concentration increases significantly. There tends to be a fairly obvious spike in the data. Since lactate threshold occurs before VO2 max is reached, it is often measured as a percentage of VO2 max. Athletes and coaches measure power output (usually in watts/kg) at lactate threshold to design training programs.
Some research suggests that carbohydrate intake may affect lactate threshold. For example, one study found that a low-carb diet can shift the lactate threshold toward higher-intensity workloads. Another review found that eating a low-carb, high-fat diet can increase the lactate threshold in off-road cyclists. However, there is no evidence that this increases performance.
Estimating Lactate Threshold
While many people don’t have access to a lab to measure lactate threshold, a test can provide an estimate. A simple method is a 30-minute time trial at a high, sustained pace. This test is best for experienced athletes and should not be attempted by those who are not in top shape. The goal is to exercise at the highest effort you can sustain and monitor your heart rate throughout the test.
During this test, you can run, bike, swim, or do another endurance sport that you can sustain for 30 minutes. You will need a heart rate monitor and a stopwatch or other method for timing.
- Warm up for 15 minutes.
- Begin exercise and work up to your peak, sustained intensity within the first 10 minutes.
- Record your heart rate each minute for the next 20 minutes.
- Cool down.
Calculate your average heart rate over the 20-minute period. This figure is your estimated heart rate at your lactate threshold.
Other Measures of Exercise Intensity
The lactate threshold isn't the only way to assess how hard you're pushing yourself during exercise. Athletes and trainers can use other methods to get a more complete picture of performance. Some of these require lab testing, but others are easy to administer yourself.
VO2 max
Another way to measure maximal effort is VO2 max. VO2 max is the maximum amount of oxygen your body can take in and use during exercise. Your ability to take in and use oxygen is an indicator of your cardiorespiratory fitness level.
VO2 max is measured in a lab using equipment that tracks the amount of oxygen you breathe in versus the amount of carbon dioxide you exhale. During this test, you'll be pushed to your maximum intensity. Your maximum heart rate can be recorded during this test.
Having a higher VO2 max means that you have a higher cardiovascular capacity than someone with a lower VO2 max. You can increase your VO2 max by becoming more conditioned through training.
Heart Rate
Your maximum heart rate is the fastest rate your heart beats in one minute. Unlike VO2 Max, a high maximum heart rate does not necessarily mean you are in good cardiovascular condition.
However, being aware of your maximum heart rate can help you track your progress and set heart rate goals. Using your maximum heart rate is more complicated (ideally, you need a chest-strap heart-rate monitor, and you must take readings very frequently) and more accurate than using the rate of perceived exertion scale.
Rate of Perceived Exertion
Your perceived exertion rate is another way to check how hard you are working. Perceived exertion measures how hard your body is working by tapping into the physical sensations you feel during exercise, such as your heart beating faster, your breathing faster, increased sweating, and muscle fatigue. The Rate of Perceived Exertion (RPE) scale runs from 6, the lowest level of exertion, to 20, the highest level of exertion.
You determine how hard you are working and tie that perceived effort to a number between 6 and 20 based on the sensations you experience during exercise. While 6 is no exertion, such as at rest, 9 is walking at an easy pace, and 12 to 14 is moderate intensity. Levels of 15 and above are heavy exertion and are considered a vigorous intensity, such as running.
Increasing Lactate Threshold
Through training, athletes can tolerate high-intensity exercise for longer periods of time. 6 Endurance athletes, who participate in mini or full triathlons and duathlons and/or half and full marathons, may want to increase their lactate threshold through training, recovery, and nutrition.
Assessing and tracking your lactate threshold using testing can help you determine if your efforts are paying off. Knowing your baseline and then planning your progression with your training will allow you to adapt and improve.
Training
Lactate threshold training means increasing the intensity of your exercise so that you train at or just above your LT heart rate. This training can be interval training or steady-state training. A combination of interval, high-intensity training, and continuous steady-state training may work best. The duration of your exercise should be based on your current fitness level and goals. For example:
- Interval LT training sample plan: Twice a week, perform three to five 10-minute high-effort intervals at 95% to 105% of your LT heart rate, with three minutes of rest between intervals.
- Continuous LT training sample plan: Twice a week, perform one 20- to 30-minute workout at high-intensity effort (95% to 105% of your LT heart rate).
Increase your training volume by 10% to 20% each week to progress. Remember to track your progress and re-test every few months to see if your training efforts are working. If not, you might need to adjust by adding frequency, time, or intensity.
Recovery
Recovery is vital for optimal performance without overtraining. Rest days or days of light work should be interspersed between your active training days. Recovery work such as mobility, stretching, foam rolling, massage, or other methods might boost recovery as well. Remember to get enough sleep each night, as that will play a critical role in your performance and recovery.
Nutrition
Nutrition is also a big part of recovery and performance. To boost your LT during training and racing, you need to make sure you can exercise at a high intensity without running out of glycogen stores. This requires careful nutritional planning in both the pre-exercise meal and post-exercise meals.
Lactate Threshold Training FAQ
What is lactate threshold?
- The lactate threshold (LT) is the exercise intensity at which lactate begins to accumulate in the blood faster than the body can clear it. It's a critical marker of endurance performance because it indicates the point where the muscles switch from primarily aerobic energy production to a mix of aerobic and anaerobic energy systems.
Why is lactate threshold important?
- Your lactate threshold determines how long you can sustain a high-intensity effort. Improving your LT allows you to perform at higher intensities for longer durations, making it a key factor in endurance sports like running, cycling, swimming, and rowing.
How do you measure lactate threshold?
- Laboratory Testing: Involves blood lactate measurements during incremental exercise tests.
- Field Testing: Estimate LT using:
- A 30-minute time trial to find the pace or power you can sustain (e.g., heart rate, speed, or wattage).
- Threshold heart rate or power zones calculated from structured workouts.
What is lactate threshold training?
- Lactate threshold training involves exercising at or just below your LT to improve your body's ability to clear lactate and delay fatigue. It typically includes sustained efforts at threshold intensity or intervals near LT.
What are common lactate threshold workouts?
1. Steady-State Threshold Runs:
- Run or cycle at your threshold intensity for 20-40 minutes.
2. Tempo Runs:
- Sustained efforts at 80-90% of your maximum effort for 20-60 minutes.
3. Threshold Intervals:
- 3-6 x 5-10 minutes at LT with short recovery periods.
4. Progression Runs:
- Gradually increase your pace to threshold intensity.
How do you calculate your lactate threshold heart rate (LTHR)?
- Warm up thoroughly.
- Perform a 30-minute hard effort, maintaining the highest pace you can sustain.
- Record your heart rate during the last 20 minutes and take the average as your LTHR.
How often should you do lactate threshold training?
- For most athletes, 1-2 threshold workouts per week is sufficient. This ensures adequate recovery while maximizing adaptations.
How long does it take to improve your lactate threshold?
- Improvements can be seen in 6-8 weeks with consistent training. The rate of improvement depends on factors like fitness level, training volume, and adherence.
Introduction to Lactate Threshold Training
Lactate threshold training is a cornerstone of endurance sports performance. It focuses on improving the body's ability to sustain higher intensities by enhancing its efficiency in processing and clearing lactate—a byproduct of anaerobic metabolism. When you exercise at higher intensities, your muscles produce lactate faster than it can be cleared, leading to fatigue. The point at which this occurs is known as the lactate threshold (LT)
Training to raise your lactate threshold allows you to maintain a faster pace or higher power output for extended periods, making it a crucial element for athletes in activities like running, cycling, swimming, and rowing. Unlike maximal efforts, LT training emphasizes sustainable, "comfortably hard" exertion, striking a balance between aerobic endurance and anaerobic capacity.
Whether you're a seasoned athlete aiming for peak performance or a beginner seeking improved stamina, incorporating lactate threshold training into your regimen can lead to significant gains. By working smarter, not harder, LT training helps athletes optimize their training time while reducing the risk of overtraining or burnout.