In the context of endurance training and high intensity sports performance, the production and clearance of lactate is of the utmost importance. If you’re looking to bring your performance to the next level, these are some points that you should care about. However, it isn’t quite obvious what these terms mean by the look of them.

 

Therefore, the purpose of this article is to explain what these terms mean, why they are important, how to estimate what your specific data points are, and how to improve these aspects of your fitness.

Related: VO2max Explained

 

Definitions

First things first. Let’s first define what we’re talking about before bringing up the more exciting points.

 

Lactate: lactate is a byproduct of an energy system in your body called glycolysis when exercising at high intensities. Glycolysis is a process that is always occurring in your body, but it is ramped up during high intensity exercise.

 

This buildup of lactate can be problematic because it is accompanied by a buildup of acidity in the muscle. This buildup of acidity is part of what contributes to that “burning” feeling when exercising. It can also inhibit the muscle’s ability to contract and produce further energy.

 

Lactate Threshold: your lactate threshold is the percent of your VO2max at which blood lactate concentrations begin to surpass normally physiological levels. Your VO2max is the maximum amount of oxygen that your body can deliver to the working muscles. For a more detailed VO2max description, go here.

 

Maximum Lactate Steady State: Your maximum lactate steady state is the highest intensity of exercise at which your body’s ability to clear lactate equals the production of lactate. In other words, it is the highest intensity of exercise where there is no net change in lactate concentration.

 

Why this is all important

When it comes to endurance training, both high and low intensity, there are a few key physiological variables that are important. It is the improvement of these variables that result in greater endurance performance. VO2max, as mentioned earlier, is one of them. However, lactate threshold seems to be the greatest predictor of one’s endurance.

 

Remember, the buildup of lactate is accompanied by an increased acidity in the muscle. This increased acidity limits your muscle’s ability to produce further energy and to contract. If the buildup continues, then there comes a point where you cannot keep going. If you went out for a run and held a pace of around ~75% of a sprint speed, you’ll notice that you can’t keep this going forever. This buildup of lactate is one of the main reasons why.

 

Your body’s ability to clear out lactate (maximal lactate steady state) and delay its buildup (lactate threshold) are major contributing factors to improving both your high and low intensity endurance. For shorter and more intense races, your lactate threshold and maximal lactate steady state will have the more direct effect on your performance. For longer races and less intense races, these two variables will be the determinant of how hard you can push toward the end of a race. If we’re talking about a field or court athlete (soccer, basketball), then both of these feats of athleticism will need to be deployed in a game.

 

Bottom line: your lactate threshold and maximal lactate steady state are big determinants to your overall athleticism.

Related: 3 Types of Endurance Training Every Athlete Needs

 

How to know what your lactate threshold is

There’s two main ways to go about this. The first is difficult and very accurate. The second is easier and is more of an approximation.

 

The first way would be to go into a lab and periodically have your blood drawn through IV while performing a VO2max test for the purpose of measuring blood lactate levels. Obviously, this isn’t practical. However, it is the only way to get true numerical measurements of your lactate threshold.

 

Now, onto the second method.

 

There’s a field test that can be used in order to approximate your lactate threshold. If you grew up playing sports and were ever subjected to shuttle runs or the beep test, the test I am going to describe is rather similar. You would also likely know that these types of tests aren’t known for being very fun.  

 

The test is the 300-yard shuttle test. In order to perform this with any real accuracy, you’ll need someone to measure when you start and stop. The process goes as follows:

 

1.     Set up two lines or cones 25 yards apart from each other on a flat surface

2.     Position yourself at the start of one of the lines.

3.     At the signal of the measurer, sprint to the other line and make foot contact with it, then immediately sprint back. Complete this for 6 round trips which will give you a total distance completed of 300 yards.

4.     Once you complete the first trial, rest for 5 minutes.

5.     At the end of the 5-minute rest period, repeat steps 2-3.

6.     Once you complete two trials of this drill, take the average of the times it took you to complete.

 

This drill simulates a scenario in which the limiting factor of your performance will be your lactate threshold. Once you have your number, you can use that as a metric to measure how you improve if you perform the test again at a later date. Below is a table of some average tested times in different populations:

How to improve your lactate threshold and maximal lactate steady state

In order to specifically train your lactate threshold, there are two variables you need to pay attention to: duration and intensity.

Our lactate threshold is the limiting factor for work we can sustain for 1-4 minutes. If you are performing work that you can sustain for 8 minutes, then you are not training intensely enough.

Heart rate is one of the easiest ways to know if you are training at the right intensity. With threshold training, you should aim to be in either zone 4 or zone 5; ideally starting in zone 4 and ending in zone 5. Zone 4 refers to 80-90% of your heart rate max, zone 5 refers to 90-100% of your heart rate max. Your heart rate max can be estimated by subtracting your age from 220. So, a 20 year old would have a theoretical max heart rate of 200. It should be noted that this estimate can be off by +/- 10 bpm, however if you use it guide your training consistently through a program then this is no problem.

An example of this type of training would be picking a modality and increasing the maximum amount of work you can complete in a given time period. For instance, you could get on an air bike and complete as many calories as possible in 2 minutes. Or, you can get on a ski erg and complete as many meters as possible in 3 minutes. Or, you can run as far of a distance as possible in 4 minutes. As long as you are fatiguing within 1-4 minutes, you can rest assured you are training your lactate threshold.

References

1. Repeatability and predictive value of lactate threshold concepts in endurance sports

   • PubMed ID: 30427900

2. Haff, Gregory G., Triplett, Travis N., 2016, Essentials of Strength Training & Conditioning, 4th edition.