Your lactate threshold, commonly referred to as anaerobic threshold, refers to the intensity of exercise that causes lactate to begin to accumulate in your bloodstream. Your particular lactate threshold can be a predictor of performance during endurance-type athletic events. You can calculate your lactate threshold through an exercise and blood test done in a laboratory setting and through a do-it-yourself fitness test.
A Look at Lactate Threshold
During higher intensity exercise, the muscles must use glucose as fuel and that energy utilization process creates lactate as a byproduct. Lactate's role is to help the continued metabolism of glucose. In the presence of oxygen, it can be converted into pyruvate, which in turn can be converted into glucose for the working muscles to use immediately or to be stored for later use. When you’re at rest or exercising at a steady-state intensity, there's enough oxygen present for lactate production and lactate removal to remain balanced. Once you reach a particular intensity, the body is unable to remove lactate at the necessary rate and it abruptly begins to accumulate. You will feel a burning sensation and experience a weariness and impaired muscle contractions. Finding your lactate threshold allows you to design your workouts so that you’re training at an intensity that increases your lactate threshold and thus allows you to exercise at a higher intensity for a longer period of time.
The most accurate way to calculate your lactate threshold is to perform a graded exercise test within a laboratory setting. University exercise science labs and some fitness centers will administer the test. The test, which is performed on a treadmill, cycle ergometer or a rowing ergometer, consists of short exercise intervals. At each interval, blood samples are taken. The blood is tested for lactate, and the levels are plotted onto a lactate performance curve along with your pace and heart rate. The location on the plotted curve where lactate levels make a sharp rise is your lactate threshold. Often, the test administer will give you both the pace you were running or cycling and your heart rate at your lactate threshold.
DIY Lactate Threshold Test
Unless you’re an elite athlete, you can estimate your lactate threshold closely enough through a do-it-yourself fitness test. When you’re at your lactate threshold, you should feel as though you’re exercising at a comfortably hard intensity, which is associated with heavy breathing and yet not gasping for air. Find this intensity with a heart rate monitor and a 20-minute fitness test performed on a treadmill or a flat terrain.
Begin with an easy three-minute walk, paying attention to the comfort of your breathing. Pick up the pace slightly as you walk for another two minutes, continuing to be conscious of your breathing. At the end of the two minutes, recite the Pledge of Allegiance. Take note of your ability to comfortably speak the words. Bump up your pace to a very easy run for two minutes and then recite the Pledge of Allegiance again. Continue to increase the pace gradually every two minutes and recite the Pledge of Allegiance at the end of each segment until you are no longer able to say the words out loud easily. This signifies that you reached the intensity associated with lactate threshold. Check and take note of your heart rate. Gradually lower your pace to safely return to resting levels.
Using Lactate Threshold in Training
Once you know your lactate threshold, you can incorporate high-intensity workouts to effectively increase how intensely you can exercise before reaching it. Workouts that force you to exercise at your lactate threshold are referred to as tempo runs or maximal steady-state exercise and improve your ability to sustain exercise at a higher intensity. This is particularly beneficial for endurance athletes, like long-distance runners and cyclists. One day per week, after a thorough, dynamic warm-up, perform a 20-minute workout that elevates your heart rate to the level associated with your lactate threshold.