You may not consider yourself an expert runner, but that doesn’t mean you shouldn’t learn about things that can help you become a better runner. For example, understanding lactate threshold can help you get your training off to a running start.
What is Lactate Threshold?
Before you understand the term lactate threshold, you need to know what lactate is. Put simply, lactate is a substance your muscles produce when you exercise that gives them energy. The longer and harder you go, the more lactate your muscles produce.
Now let’s define what we mean by threshold. If you run hard enough, your muscles will start producing lactate faster than your muscles can use it. At this point, some lactate is released into your bloodstream to provide fuel for other parts of your body. When you hit the level of intensity in your workout when lactate is being produced faster than it is being used by your muscles, we say you’ve hit your lactate threshold.
How Long Can I Run at my Lactate Threshold?
When you’re running at your lactate threshold heart rate, your run will feel “comfortably hard”. You also wouldn’t be able to sustain it for more than about 30 minutes. Here’s a fun fact: If you typically run a 5K in around 30 minutes, you’re probably running at your lactate threshold.
How is Lactate Threshold Measured?
It’s virtually impossible to measure how much lactate your muscles are producing while you are running. Similarly, it’s tough to measure the amount of lactate that starts circulating around your bloodstream once you hit your threshold. Therefore, it’s a good idea to try to figure out the heart rate that equates to your threshold. Then you’ll be able to gauge whether or not you’re training at the right level of intensity for any given workout.
Three Easy Ways to Find Your Lactate Threshold
Method 1: Use the Talk Test
John Greyson at Oxford University initially proposed this method in 1939. Here’s how it works:
After warming up, start running at a comfortably hard pace. After ten minutes at this pace, try reciting some sentences, or the Pledge of Allegiance out loud and determine how easy or hard it is for you to talk. When you hit what you think is your lactate threshold based on the descriptions below, make a note of your heart rate!
- Below Threshold: You are comfortable and can speak without difficulty.
- At Threshold: You can speak, but your speech is slightly labored.
- Above Threshold: You are uncomfortable and can speak only with extreme difficulty or not at all.
Method 2: Look at Past Data
Another way to determine your lactate threshold is by looking at data from past runs. I use a Garmin watch/Garmin Connect when I run. Here’s the method I use. If you use a different app or watch to track your running data, you can probably do something similar.
- Log into Garmin Connect on a computer and click on Activities/All Activities in the menu on the left.
- Filter your activities to show only “running” by clicking on the running icon on the top-right for Activity Type.
- Then click on the Advanced button under Search.
- Search for running activities that were between 25 and 35 minutes long by entering 0:25 to 0:35 in the time search input boxes and clicking Filter Activities.
- Find your hardest efforts (the ones where your pace was the fastest) and select one by clicking on the name of the activity to see all of the data for that run.
- Look for the Heart Rate chart and make a note of your heart rate at the 10-min mark and the end of the run and take the average. This will give you a good approximation of your lactate threshold heart rate.
Method 3: Calculate it from Your Maximum Heart Rate
If you know what your maximum heart rate is, you can easily approximate your lactate threshold heart rate by taking 85% of it (i.e., multiplying your maximum heart rate by 0.85.).
If you don’t know what your maximum heart rate is, you can use one of these formulas:
- 220 – Age: the most common and widely used maximum heart rate formula
- 207 – (0.7 x Age): a more precise formula, adjusted for people over the age of 40
- 211 – (0.64 x Age): a slightly more precise formula, adjusted for generally active people
After you’ve determined what your lactate threshold heart rate is, you can use it to ensure you are working out at the right level of intensity when training for your next race.
For example, if your training plan calls for a Long Run, then you need to make sure your heart rate is significantly below your lactate threshold heart rate for the duration of the run. If your plan calls for a Threshold Run, make sure you are running at a consistent pace and that your heart rate stays right around your threshold rate. If it drops too far below, for example, then you won’t reap all of the benefits of doing the workout.
Do you know your lactate threshold heart rate? Let me know in the Comments box below.
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Keep running to the beat!