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How fit are you? There are different ways to measure, but an important one that doesn’t get much buzz is called your lactate threshold. As your body breaks down carbs for exercise energy, it’s also cranking out lactate as a by-product.
"Your lactate threshold is the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed, causing muscle fatigue," says Pamela Peeke, M.D., the author of Body for Life for Women. "Having a high threshold means you can work at a higher intensity for a longer time before lactate levels become intolerable."
The good news: You can train yours upward.
How to Find Your Lactate Threshold
Chances are, you’ll never hit a lab to precisely pin down your tipping point: That requires you to ride a stationary bike while increasing the intensity of exercise every three to five minutes until you reach exhaustion, with pinprick blood tests taken intermittently to find where lactate becomes too much, says Dr. Peeke. (Related: Learn How to Push Through Your Workout from CrossFit Coach Colleen Fotsch)
But you’ll know it when you feel it—a burning sensation in your muscles; that ache or even sudden nausea that causes you to stop. Basically, once you get to the point at which the amounts of lactate being produced and cleared are equal (known as LT2, or your second lactate threshold), you’ve reached your "highest sustainable intensity," and it’s only a matter of time, as lactate rapidly increases shortly thereafter, says researcher Samantha Hoffmann, Ph.D., a lecturer at Deakin University in Australia.
In a recent study from Hoffmann published in the Journal of Strength and Conditioning Research, most female athletes tested were able to last at LT2 for at least 30 minutes, but you could range anywhere from 20 to 60 minutes depending on your fitness level.
How to Train for a Higher Lactate Threshold
Improving your LT2 is a different animal from building your VO2 max—aka your aerobic capacity as measured by the maximum volume of oxygen that you can take in and use during exercise. "You could be really good at running for hours, but if I ask you to do five squats, 10 push-ups, and 20 sit-ups, you might be able to do only one round before your legs feel like lead," says Ben Lauder-Dykes, a trainer at Fhitting Room in New York City.
That’s why lactate threshold is a key part of your fitness, says Dr. Peeke. To improve your LT2 using HIIT workouts, Lauder-Dykes recommends going at 80 percent effort for 80 percent of the time.
"You want to work close to your lactate threshold but not go all out, because when you hit that red line, it takes longer to recover. The workout as a whole should be the challenge, not each interval," he says. "The more often you’re at or close to that lactate threshold, the more your body adapts, and you’ll increase the amount of effort you’re able to give before you start to get fatigued."
Workouts to Improve Your Lactate Threshold
OK, now that you know what your lactate threshold is, and a little about how and why you should improve it, here are some short and simple—but not definitely not easy—workouts created by Lauder-Dykes that can get the job done. Note that how you go about improving your threshold will be different depending on your goals. For example, a long distance runner will have a different objective than a weight lifter. To that, Lauder-Dykes lays out two separate workouts tailored specifically to lactate threshold training for aerobic fitness (endurance) and anaerobic training (strength), respectively. (P.S. Then peep these interval running workouts that will make you even faster.)
Lactate Threshold Training Workout for Endurance
How it works: Perform each of the four exercises below for 1 minute each with NO rest in between. Repeat three times for a total of 12 minutes of work. "The goal here is to find a pace you can keep consistently for each movement," says Lauder-Dykes. "It’s ok to slow down but you CAN'T stop."
- Air Squat
- Plank Shoulder Taps
- Alternating Forward Lunges
- Squat Thrust
How to tell if you're improving your threshold: You recover faster post-workout and you can move faster through the exercises. (Try counting the number of reps you can complete.)
Lactate Threshold Training Workout for Strength
How it works: Choose the compound, multi-joint exercise of your choice (ex: squat, deadlift, bench press, kettlebell swing). Find your 10-rep max for that exercise. This is the maximum amount of weight you can lift with proper form for the number of alotted reps until failure (or you hit your threshold). From there, follow the ladder below, decreasing the number of reps in each set. Meaning, you'll complete 10 reps of the exercise, then 8 reps of the same exercise, another 8 reps, then 7, and so on. The goal is to complete a total of 50 reps within 3 minutes or less. You can rest as you need to throughout, says Lauder-Dykes, but remember you're on the clock.
10 + 8 + 8 + 7 + 5 + 5 + 4 + 3 = 50 reps
"This is tough!" he says. "You're always working with some form of fatigue, as rest can usually only be 10 to 20 seconds max before you have to do more reps so you don't run out of time—creating more urgency."
How to tell if you're improving your threshold: If you fell short of the 50 rep target initially: You inch closer to that goal. If you reached 50 on the first attempt: You can finish in less time. You can finish with fewer reps in the final set. You can increase the load.