Your lactate threshold in running workouts is the point at which lactate begins to accumulate in your blood. The point at which this occurs varies according to an individual’s level of fitness, but it typically occurs when your heart is beating at close to its maximum rate. The higher your lactate threshold, the longer you can hold a vigorous running pace.
Who Needs a Lab?
Expert runners all include running workouts designed to improve their lactate threshold. Although some professional or Olympic athletes learn their precise lactate threshold in a laboratory where they will run on a treadmill and have blood drawn and analyzed, most runners determine their lactate threshold through simple running tests. Once you know your lactate threshold, you can design workouts that enable you to nudge it higher, allowing you to run faster with less discomfort.
Crossing the Threshold
A running test called the 30-minute exam is one way to informally gauge your lactate threshold. After a thorough warm-up, increase your running speed to the highest level you feel you can maintain for 30 minutes. When you reach this speed, start your watch and measure the distance you cover over the next 30 minutes. You will later calculate your lactate threshold by dividing the distance you ran by 30 minutes to determine your per-mile pace. If you ran four miles in 30 minutes, for instance, your lactate threshold is seven minutes, 30 seconds per mile.
An Alternative Test
Another way to determine your lactate threshold is to use a heart rate monitor and a simple rating of perceived exertion -- known as RPE -- scale of 6 to 20, with 20 being all-out. Start out jogging easily and rate the effort from 6 to 20. Increase your pace every two or three minutes and rate your effort again. When you reach an RPE of 13 to 15 -- considered "somewhat hard" or "hard" -- you have reached your lactate threshold. The heart rate on your monitor will help guide you in future workouts.
Maintain the Tempo
Future lactate threshold running workouts will be based on your per-mile pace or your heart rate. There are two types running workouts to improve your lactate threshold – tempo running and interval running. Tempo running is a continuous run at just below your lactate threshold, and interval workouts typically involve running repeats of a specific distance, from a quarter mile to a full mile or more, at a pace that is slightly faster than your lactate threshold pace. The shorter the distance, the faster you should push the pace.
Recover and Repeat
For example, if you are doing one-mile repeats, you should run a few seconds per mile faster than your lactate threshold and do two to four repeats. If you are doing half-mile repeats, you should run a slightly faster pace per half-mile and perform four to six repeats. Recover for the same amount of time that you are running hard; if you ran a 7:22 mile repeat, jog for 7:22 before doing another mile repeat. If your pace feels too fast, slow down slightly so it feels hard or very hard but not all out.
Work Into It
If you are just starting a running program, don’t jump into lactate threshold training. Researchers at the University of New Mexico recommend you build up your training volume by 10 to 20 percent a week at lighter intensity levels until you have reached the volume of training you’d like to maintain. Then you can start doing tempo runs and interval workouts. Neither of these lactate threshold workouts should ever be more than 10 percent of your total weekly running, nor should you do them on consecutive days.