Lactate Threshold Testing & Training for Endurance Athletes

Lactate threshold testing and training for endurance athletes is often difficult to understand and the discussion can become very scientific, very fast. This post is intended to keep the science just deep enough to understand what lactate is, why lactate threshold testing is valuable and how it can be beneficial to us as we work hard to become better athletes. In short, our lactate threshold is pinpointed through blood lactate threshold testing and when this input is used correctly, we train smarter (and more efficiently) and we become stronger and faster. As an endurance athletes, we become more and more reliant on data to guide our training. We track every swim, bike, or run with computers strapped to our person or bikes. We capture our heart rate, pace or speed, cadence or strokes per length… all sorts of information is available as outputs. We do this to effectively monitor the effectiveness of our training, but what we often miss is that it is important that we gather some data to use as inputs. One of the key inputs is our lactate threshold (LT). In short, lactate threshold tells us what the highest level of intensity we can sustain before we begin to build up that burn that comes from blood lactate in the muscles. I’ll go deeper into what LT is, how we test for it and provide a specific example of how it can be used to make training more effective, making us stronger.

Lactate Threshold… What the heck is it?

Energy is needed to move the body. The body produces energy by breaking down something called adenosine triphosphate (ATP). The body cannot store an endless supply of ATP and what it can store (85 grams) would be consumed very quickly if there wasn’t a way for the body to synthesize it. The body does so using three energy systems:

  1. ATP-PC  which is made up of ATP and phosphocreatine. ATP-PC provides energy for high intensity, short duration exercise because while the energy synthesized by ATP-PC is created quickly, it also burns very quickly.
  2. Anaerobic Glycolytic System produces energy from the breakdown of glucose. This system produces a larger amount of energy and it doesn’t burn as quickly as ATP-PC. The energy created by this system isn’t as powerful as ATP-PC so it is generally used for hard interval exercise.
  3. The Aerobic System makes energy from fat, carbohydrate and some proteins. This system doesn’t produce nearly as powerful energy, but it does provide a large amount of it. An added benefit of this system is that it is a very slow burning fuel source. This is what makes the aerobic system an ideal source of energy for endurance exercise and one that we should attempt to fuel ourselves on for as long as we can before tapping into the other two sources.

In endurance sports, as we increase our effort to go harder or faster, we ask our body for more energy than can be provided by the aerobic system. That is when the anaerobic glycolytic system kicks in. It provides energy faster than the aerobic system can provide it. There is a cost to tapping into this system’s energy though. As it provides this energy, lactate builds up in the blood and the muscles. Your body has to flush or clear the lactate from the blood and muscle to turn it into fuel. Lactate threshold is the point that production of energy overtakes the body’s ability to flush the lactate. At this point lactate begins to accumulate in the blood and we begin to feel that burn. Our lactate threshold is pinpointed through blood lactate threshold testing and when this input is used correctly, we train smarter (and more efficiently) and we become stronger and faster at the same lactate threshold.

That sounds good, but do we really care about what our Lactate Threshold is?

If you don’t think so, you really aren’t paying attention. I’m joking of course, however the answer is an obvious and definitive YES. We do care. Our lactate threshold tells us how hard we can push ourselves for endurance efforts. Once we cross our threshold, we begin tap into our glycolytic system and we start to burn our limited amount of matches, so to speak. We want to train our bodies to increase the lactate threshold so that we can get as far in our races as we can before we reach or surpass our threshold. If we can go harder for longer than our competition can, in short, we win.

How do we get our Lactate Threshold information?

To get our lactate threshold information, we do a couple of tests, one for the bike and one for the run. Both of these tests use the same process. After a 10 minute warm up on the bike trainer or the treadmill, we begin to perform a series of four to five-minute intervals. At the end of each four to five-minute interval, we take a small sample of blood and using a blood lactate meter we measure the amount of lactate in the blood in millimoles per liter (mmol/l). We continue these four to five-minute intervals, increasing the workload for each interval, until lactate surges. In addition to the lactate level, we gather your rate of perceived exertion (RPE), which is how hard you feel as if you are going on a scale of 1-10, and your heart rate (HR) at the end of each interval. For the run, we capture the workload in pace and on the run we capture it in watts of power. Using these values; workload, lactate reading, RPE, and HR, the tester can pinpoint your lactate threshold very specifically. The figure below illustrates the output from a completed blood lactate threshold test for an athlete for their run. Notice that they now understand their lactate threshold in pace and in heart rate as well as their training zones, which will help them in training to become stronger and more efficient. The tests usually take under one hour to complete, are done on different days and on days and ideally the athlete has not trained for 24 hours. Lactate Threshold Testing and Training These tests can take place in the field with or without the blood lactate meter, for example on a track for the run test, but we prefer to use a treadmill because it removes the environmental variables and we prefer to use the meter because it gives us a more accurate result. It is recommended that we repeat the test at the beginning of a training season and then again six months into training to account for any changes in fitness.

So we have our Lactate Threshold Information, what can we do with it?

Now that we have this valuable information we now must incorporate it into our training. We use the associated training zones and lactate threshold information to bolster our base fitness to improve pace on the run and power on the bike at lactate threshold making us faster and more efficient athletes. We must be consistent and dedicated to training using this information. For example, proper execution of workouts like progressive interval workouts, with the appropriate amount of recovery between intervals will improve our performance at threshold as the intervals progress in duration workout to workout. Our coach should prescribe these workouts specific to our lactate threshold data and slightly increase the progressive intensity of the intervals over time. The effort metric for a run workout can be in heart rate or in pace for a set period of time. The effort metric for a bike workout can be in heart rate or in power (watts). All of us have limited time to put toward our endurance goals. Time is a FINITE resource. We can’t make more of it. We want to make the best use of every moment of that time. In order to do so, leverage methods as simple as lactate threshold testing. It just may be the best use of a few dollars and a couple of hours of time that you can spend a couple of times a year. Coupled with a quality coach, these measures produce results. That’s been proven time and time again.

Call to Action…

If you are in the Dallas/Fort Worth Area and are interested in doing this testing, you can book online right here from the blog or you can reach out to me and we can schedule times for both your bike and run tests based on your availability. I have a set testing schedule available for you. I test Monday and Wednesday evenings from 5-8PM at Impact Performance and Fitness in Southlake, TX. Alternatively and for athletes North of Dallas, I can test at TriShop in Plano, TX based upon your availability and the availability of the performance studio. It’s simple and easy and such a valuable use of your time and money. If you live outside the Dallas/Fort Worth Area, you can reach out to me and I can likely network you to a quality practitioner in your area.


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