• Introduction
  • The basics of lactate threshold
  • How to measure your lactate threshold
  • Estimating your lactate threshold
  • How to increase lactate threshold?
  • Final thoughts
  • Sources
  • Aerobic respiration: producing energy (ATP) with the presence of oxygen.
  • Anaerobic respiration: producing energy (ATP) without the presence of oxygen.
  • Lactate: a byproduct of anaerobic respiration. Known to cause fatigue and nausea. 
  • Lactic acidosis: lactic acid production exceeds lactic acid clearance.
  • Maximum oxygen uptake: The maximum amount of oxygen a person can use during intense exercise.


During rest and low-intensity exercise, your body is able to produce most of its energy aerobically (with oxygen). As the intensity of the exercise rises, your cardiorespiratory system (lungs, veins, heart) is unable to deliver enough oxygen to the working muscles. Instead, your muscles must rely on anaerobic respiration to produce energy at a faster rate. The downside of this is that it produces lactate as a side product, which is one of the main contributors of exercise-induced fatigue and nausea.

In low quantities, lactic acid can be used as fuel by your liver, kidneys, muscles, and heart. During prolonged exercises at a higher intensity, lactate is produced faster than your body can absorb it. The exercise intensity where this occurs is known as the lactate threshold. 

This post explains the basics of the lactate threshold, as well as how to measure and improve it. 

The basics of lactate threshold

Lactate threshold (anaerobic threshold) refers to exercise at an intensity when lactate accumulates in the blood at a faster rate than it can be removed. The accumulation of lactate results in lactic acidosis (lactic acid production exceeds lactic acid clearance), which can be seen in your blood as a non-linear rise in lactate during incremental exercise. It is also the main cause of fatigue, nausea, and “burning sensation” in your muscles during intense activities. This essentially makes anaerobic threshold the border between low and high-intensity exercise.

Lactate threshold is usually measured as a percentage of your maximal oxygen uptake (VO₂max). For the average person, this occurs at around 60% of VO₂max, and at 80-85% for highly trained endurance athletes. Anaerobic threshold can also be measured as power output to give a better view of training progress. This method can be used to determine the pace of which endurance performance can be maintained, and while designing new training programs to improve it.

The highest possible workload that you can maintain without disproportionate rise in lactic acid is called maximal lactate steady state (MLSS). A higher MLSS indicates that you can perform longer at a higher intensity before lactic acid becomes intolerable. Because of this, anaerobic threshold is often presumed to be a great predictor of athletic performance in high-intensity endurance sports.

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Lactate Threshold

Exercise intensity where lactate accumulates in the blood at a faster rate than it can be removedA good predictor of performance in high-intensity endurance sports.Can be measured via blood samples during exerciseCan be estimated via 30-minute time trialOften measured as percentage of VO₂max or power outputCan be improved with smart & consistent training

How to measure your lactate threshold

Lactate threshold is measured with treadmill or stationary bike (ergometer) tests. The tests usually last 12-15 minutes while increasing in intensity every 3-5 minutes. This is done by increasing speed, resistance, and/or grade of the treadmill.

During each stage of the test, a blood sample is taken from the ear lobe or finger. The procedure is repeated until the lactate concentration in your blood reaches a 4mmol/L, which is considered the marker for lactic acidosis. At this point the accumulated lactic acid is considered to move from the muscles into the bloodstream. The resulting fatigue means that exercise can no longer be sustained at the same intensity.

One of the most important values obtained from this test is the onset of blood lactate accumulation (OBLA) value. This refers to the point at which lactate begins to accumulate in the blood at an accelerated rate. It is also the point where certain exercise intensity can be sustained for a relatively short amount of time. At this point, heart rate, speed and/or watts are also calculated – all of which provide valuable data that can be used to develop training parameters. 

Lactate threshold tests can also be used to measure maximum oxygen uptake simultaneously. For a more accurate VO₂max estimate, you also need to wear a specialized face mask that measures ventilation by calculating carbon dioxide of exhaled air. These give valuable additional data of your current physical condition.

Estimating your lactate threshold

In addition to laboratory tests, there are also several field tests that are used to estimate your lactate threshold. These methods include;

  • VDOT
  • 3,200-m time trial
  • 30-minute time trial
  • The Conconi test

Studies have indicated that the most accurate method for estimating running velocity and heart rate at the anaerobic threshold is the 30-minute time trial. The test itself consists of a 30-minute run at highest possible velocity. For the first ten minutes, the subject runs at a fast pace (5km/10km) pace. After this, the ‘lap’ button is pressed on their heart rate monitor. The threshold heart rate is the average heart rate for the final 20 minutes of the run.

How to increase lactate threshold?

Lactate threshold can be improved in two main ways: with continuous aerobic training or high-intensity interval training.

Although continuous aerobic training does not directly increase lactate tolerance (because of its lower intensity), studies have shown that prolonged exercises at moderate intensity improve aerobic capacity, especially the function of your mitochondria (powerhouse of the cell). This allows you to better utilize oxygen for energy production, making continuous aerobic training a viable method for increasing your lactate threshold. 

High-intensity interval training specifically focuses on training at or slightly below your lactate threshold (80-95% of VO₂max). In several studies, high-intensity aerobic interval training programs have produced significant improvements in maximal oxygen uptake and lactate threshold regardless of the subjects’ age or background. Furthermore, training slightly above the anaerobic threshold seems to be more effective in this than training at anaerobic threshold level. With this in mind, numerous trainers have begun using heart rate zones to indicate the most effective intensity to train at.

Some of the best interval training methods to improve anaerobic threshold include:

Whether you enjoy longer workouts or more time-efficient intervals, the key to better performance is consistency. For the best results, switch between continuous and high-intensity exercises throughout your training program.

Lactic acid is one of the main contributors to exercise-induced fatigue.

Final thoughts

Lactate threshold is a hugely important component in physical performance. After all, it describes the intensity where performance can no longer be sustained. So, the higher your anaerobic threshold is, the better you can maintain working out at a higher intensity.

Lactate threshold measurements are often only useful for highly trained who participate in competitive sports. This is because blood lactate concentration measurements require expensive equipment and the extraction of blood samples. Both of which are inconvenient for frequent monitoring.

The good thing is that anaerobic threshold can also be estimated with non-invasive methods as well. The additional data provided can also help you create better exercise programs. As a result, you can easily adjust your training and focus on improving it.

Did you learn anything new about anaerobic threshold? Let us know in the comments.


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