I (Lauren) was recently a test subject for our blood lactate threshold testing. I was the perfect candidate for this testing for a multitude of reasons: 1. Goal race timing, 2. Trying to get back into race shape after statin medication use destroyed my muscles, and 3. I already had a solid running base.
This will be a two-part blog. In this first part, we will describe what blood lactate testing is, describe how the workout is performed, and present my first results from my three-part test.
In the second blog, we will show you all three results of my testing and see how and why things trended the way they did. PLUS, we will show you how wearing super shoes affects blood lactate vs pace.
What is lactate?
When your body is at rest or performing lower-intensity exercise activities, the levels of lactate being produced are equal to the level of lactate being cleared away. This means that the amount of lactate found in the blood is fairly small and steady.
When your exercise intensity begins to increase, the “slower” aerobic system just can’t keep up with the intense demands placed on it, so more and more lactate increases, as the body draws more on the "faster" anaerobic glycolysis system to provide energy more quickly. (Lactate is a backup process for making energy when cells don't have enough oxygen).
When lactate is produced faster than our body can clear away, our net blood lactate levels increase and it is more than our muscles can handle. When this happens, you’ll have to slow down until the lactate clears away. If you’re familiar with the term “lactic acid burn” that’s what this is referring to.
What is a blood lactate test and why would you want one?
A blood lactate test measures the concentration of lactate in your blood. Typically, blood is drawn by a prick on the end of your finger. It is taken at increasing levels of exercise intensity (roughly 3 minutes each interval). I had a series of 800 meters (2 laps around the track) to run for my testing.
The purpose of the test is to determine two thresholds, your aerobic threshold and lactate threshold. There are different definitions of lactate thresholds but for this particular test protocol, the lactate threshold is defined as 4.0 mmol/L of lactate, which is a measurement of the concentration of lactate in the blood. The lactate threshold is essentially the point above which lactate begins to accumulate exponentially – in other words, lactate is produced much faster than it can be cleared away. The aerobic threshold is defined as 2.0mmol/L of lactate.
After a very slow jog of 1-2 laps around the track, I began my test. Starting at a low intensity, I increased the pace of my 800-meter intervals. At the end of each 800, I had my finger pricked for a blood sample onto the strip of the blood lactate monitor. The test continued for eight 800-meter intervals.
How to time your blood lactate testing
These tests are repeated three times, roughly 4 weeks apart. My testing was 4 weeks into a new marathon build, followed by another test 4 weeks later, and my last test was 5 weeks after my last test and one week before my marathon.
So when and why would you decide to do your blood lactate testing?
Before a new training block
It's best to test before starting a new training block and not work out on the day of the test.
To measure progress
You can use follow-up lactate tests to measure how your body is adjusting to training. Your lactate curve can help identify your strengths and weaknesses, and how they change over time
My first test results are shown in the graph below
What do these results indicate?
Based off of the test done, below are the two thresholds and recommended training ranges.
Approx. Aerobic Threshold (2mmol) : 9:08min/mile
Training Range: 9:08 - 9:56min/mile
Approx. Anaerobic Threshold (4mmol) : 7:42min/mile
Training Range: 7:42 - 7:57min/mile
How does training change to clear lactate acid and get faster?
Training Recommendations: While it is beneficial to know these numbers, remember that they can vary from day to day, depending on stress, sleep, hydration, nutrition, etc, so don't take the exact numbers too seriously. It is better to slightly train a little below these numbers than to go past them. By training near these levels, it will help shift this curve to the right which means that for faster paces, you will have lower blood lactate levels.
Training Aerobic Threshold: When training at or slightly below this, you can see improvement in your overall fitness. This pace can feel difficult especially if the body is under stress, like after a long run, or workout, where you may need to take a recovery run at a very easy pace. Running close to this threshold will help set up your marathon, especially when you are early in your build. It can be beneficial to run a couple of runs a week at this pace, either for a portion or its entirety. It can be beneficial to have a portion of your long run done at this pace. Remember to listen to your body and not push too hard, especially if you are not used to doing this. Gradually increase your duration at this pace during the long run and increase the duration as you feel comfortable. Remember that being at this level for a long amount of time, your lactate level will increase gradually so be sure to not overdo it!
Training Anaerobic Threshold: When training at or slightly below, this can help raise your aerobic levels, lactate capacity, clearance, and buffering. Depending on the duration and intensity of your workouts, lactate levels of 2.5 - 4.0mmol/L can be used to help improve.
Summary
Knowing your lactate threshold lets you train with more precision. Many coaches prescribe some running at the lactate threshold as part of an overall training program. Also, it is a main indicator of how well you are training and how fast you are able to run a marathon or half marathon.
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