- How to Improve Your Lactate Threshold
- What is Lactate Threshold
- What is lactate or lactic acid?
- Concisely stated, what is your lactate threshold?
- But why is this important?
- Seven ways to increase your lactate threshold
- What Pace Should Runners Run Lactate-Threshold Workouts?
- Workouts to Raise the AT
- Lactate Threshold Defined
- Developing a Lactate Threshold Training Program
- Step 1: Gather the background research on lactate threshold training.
- Step 2: Where is the best evidence to answer these four questions?
- What are the F.I.T.T. recommendations for lactate threshold training?
- Do these recommendations differ between untrained and trained individuals?
- What type of workout best modifies the LT (steady-state or interval)?
- How should lactate threshold training be progressed?
- Step 3: Implement the lactate threshold training program.
- Final Thoughts
- Lactate Threshold is Misunderstood
- Lactate & Lactate Threshold Basics
- How to Figure Out Lactate Threshold
- Optimizing Lactate Metabolism
- Lactate, A Misunderstood Villain
- Use Threshold Training to Run Faster, Longer
- What do we mean by threshold?
- Why do we care about lactate threshold?
- How can we improve vLT on trails?
- What are examples of LT workouts?
- When are LT workouts most beneficial?
How to Improve Your Lactate Threshold
Photo: svetikd/Getty Images
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.
- By Alyssa Sparacino @a_sparacino
What is Lactate Threshold
Lactate threshold is a term than is commonly used in training vernacular, but has most runners more confused than a high school kid in calculus class. I’m not going to lie, the complexities of lactate threshold, or lactate and lactic acid, can be a bit daunting for the beginner runner. However, if we break things down very simply and avoid discussion of the more scientific terms, it can be easily understood to the point where you can appreciate its application to your training.
What is lactate or lactic acid?
Lactate, or lactic acid as it is commonly known, gets a bad rap thanks to some faulty science from the 1970’s. While lactic acid contributes to why we hurt at the end of races, lactate is actually a source of energy. Your body breaks down glucose for energy and a by-product of this process is lactate. During easy running, your body reconverts and recycles this lactic acid back into energy and efficiently expels the waste products. Therefore, the production of lactate will remain relatively constant while running at an easy aerobic pace, which doesn’t require a huge demand for energy.
As you continue to run faster and demand more energy, the production of lactic acid will slowly increase. At some point, whether it be too fast a pace or holding a steady pace for too long, the production of lactic acid will soar and your body will no longer be able to convert lactate back into energy and expel the waste products. This point is commonly referred to as your lactate threshold. The lactic acid then floods into system, muscle power is diminished and you begin to slow down (1). Ultimately, lactic acid is one of the largest contributors to why you slow down as the race goes on.
Concisely stated, what is your lactate threshold?
So, in short, your lactate threshold is defined as the fastest pace you can run without generating more lactic acid than your body can utilize and reconvert back into energy. This pace usually corresponds to 10 mile or half marathon race pace. Therefore a tempo run or threshold run is basically a workout that is designed to have you running at just below or at your threshold pace.
But why is this important?
By running just below your lactate threshold you can begin to decrease (or improve, depending on how you look at it) the pace at which you begin to produce too much lactic acid for your body to manage.
For example, at the beginning of a training plan for the marathon, your threshold might be 10 minutes per mile. This would mean you could run a 10 mile or half marathon race at this pace. As you do more tempo runs, your body gets stronger, adapts to the increased production of lactic acid, and decreases this threshold pace to 9:30 per mile. Now, since your threshold is lower, you are able to run faster with less effort, which for the marathon means you can burn fuel more efficiently – saving it for the crucial last 10k.
In my opinion, lactate threshold is usually the most glaring weakness in runners I begin working with. It’s not an easy training term to understand and it takes a lot of control and effort to keep tempo runs in the lactate threshold range. Plus, busting out 400 meter or mile repeats is a lot more fun – that comment is for us sick runner types who love coming home dripping sweat from a tough workout and love nothing more than to sit on the coach eating freeze pops. However, development of your lactate threshold can be one of the easiest ways to improve your running, both short-term and long-term.
(1) The actual cause of the fatigue is caused by the hydrogen ions interfering with energy production. The decreased muscle power occurs because calcium, an electrolyte needed to help muscles contract, is unable to make its way to the muscles. This is more complicated stuff for the science lovers out there, but suffice it to say that excess lactic acid causes the fatigue in a roundabout way.
Seven ways to increase your lactate threshold
Increasing one’s lactate threshold the point where lactic acid begins to accumulate in your body is important for maintaining higher speeds, whether racing up the Alp d’Huez as Lance Armstrong did at his lactate threshold, or trying to maintain a place in a faster paceline during a century ride.
Lactate threshold training is hard, but cyclists who train at or near this intensity (often measured by heart rate and the point where you have a hard time talking, or feel a burning sensation in your muscles) see great improvements in their cycling performance.
Here are seven tips for boosting your power with lactate threshold (L.T.) training.
1. Structure your L.T. rides according to experience, not formulas. Formulas can offer only broad guidelines. Begin by taking a period of time to warm up, and at the end of your workout, take a nearly equal period to cool down. In between is the heart of your L.T. workout, which should probably vary somewhere between 15 and 30 minutes.
2. Ride at a pace that is comfortably hard. Chris Carmichael, coach to Lance Armstrong and others, recommends a pace that is about three to five beats lower than your average heart rate during a 10-mile time trial.
3. Ride solo. Unless you have an identical twin, you may have difficulty finding another cyclist whose lactate threshold matches yours. Even when you can, you should be cautious and try to ride according to your ability, With others, it’s too easy to become competitive and push the pace too hard, even in noncompetitive situations.
4. Don’t measure your level of intensity by time. It’s too easy to fool yourself into thinking you’re improving because you did this week’s ride faster than last week’s. The overload principle works with some forms of training, but not here. It’s too easy to cheat by riding the warm-up and cool-down sections progressively faster, which defeats the purpose of the workout. By riding easily at both the beginning and the end of each lactate threshold workout, you eliminate any danger of comparing one workout with another.
5. Ride an L.T. workout anywhere. The road. The track. The woods. Even on a stationary bike in your basement. The important factor is intensity, not how (or where) that intensity is achieved.
6. Maintain a steady effort, not a steady speed. If you ride out with the wind at your back, then return into the wind. Your actual pace may drop, but not your effort. The same is true on hilly courses, where your heart rate may actually rise or drop, depending whether you are going uphill or downhill.
7. Concentrate. You’ll find you are able to ride more effectively if you focus on what you are doing rather than allowing your mind to drift, as is common among cyclists on more purely aerobic rides. Because of the speed at which you are moving, L.T. rides offer a good opportunity to pay attention to how you can maintain good cycling form. This body awareness will help you improve your racing later.
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Lactate threshold is the glass ceiling of cycling performance—it’s an invisible barrier that keeps you down. When you do crack through, the rewards are sweet.
“For the longest time, everyone focused his or her training around max heart rate,”says USA Cycling expert coach Margaret Kadlick. “Now we know lactate threshold is much more important. When you raise your LT, you can produce more power at a comfortable heart rate, and that makes you a better rider and racer in every situation.” Here’s everything you need to know about lactate threshold-including how to raise yours to be the best rider you can be.
What Is Lactate Threshold?
Lactate, your body’s buffering agent, neutralizes the acid that builds up in your legs and makes them burn during heavy exertion. The harder you turn the cranks, the faster acid accumulates. Eventually, your muscles generate more acid than you can neutralize and your searing muscles force you to ease up. The point at which you begin to accumulate acid more quickly than you can dissipate it is your LT, or, in riding terms, the fastest pace you can maintain for 30 minutes without feeling like your legs are on fire.
RELATED: How to Train with a Heart Rate Monitor
How To Find Your LT
Most likely, you won’t find yourself hangin’ with the pros in a lab, where they pedal against ever-increasing resistance while technicians take blood samples to measure the increasing lactate levels. But you can find your LT with a do-it-yourself time trial.
Map a 3-mile route that you can ride without stopping. Strap on a heart rate monitor, warm up for 20 minutes, then ride the route at the fastest pace you can sustain. Recover for 10-20 minutes (ride back to the start of your route at an easy pace). Repeat the test. Your LT is approximately the average heart rate of the two efforts. (More accurately, it’s 103 percent of that figure.) Jot down your times and average paces; repeat the test in eight weeks to see your progress.
How To Raise Your LT
Like most things body-related, LT is partially genetic. But it’s also quite trainable. By systematically pushing your limits, you can help your body become more efficient at clearing and buffering lactic acid.
The trick is riding that razor-thin edge between the point where you can ride comfortably for hours and where you can sustain only a few minutes before frying. “It’s important that you have plenty of base miles and some speedwork under your belt before you start LT training,”says Kadlick. The bigger your aerobic engine when you begin, the better your results will be. The following drills are designed to raise your LT. Choose one drill per workout, and do LT training no more than two days a week, preferably not on consecutive days.
Steady State Intervals
After a good warm-up, ride 10 minutes at a steady effort, keeping your heart rate three to five beats below your LT heart rate. Recover for 10 minutes, then repeat two more times. “Once you’re comfortable at this level, do two 20-minute steady-state efforts, recovering for 20 minutes between. Eventually, work up to one 30-minute effort,”suggests Kadlick. “This is the most effective way to increase power at LT.”
Up And Down Intervals
These intervals blend LT and VO2 max (your body’s ability to process oxygen) training to simulate the effort you need when racing on a hilly course, where you have to push beyond your lactate threshold for short surges then clear the acid and recover quickly. First, warm up. Then pick up the pace to your LT heart rate and hold that intensity for five minutes. Push it to about three to five beats above LT for one to two minutes, then drop it back down to LT. Continue for a total of three cycles, or about 18 to 20 minutes.
LT Tolerance Intervals
Crit and mountain bike racers need to elevate their ST (suffering threshold) as well as their LT, because those situations demand pushing past LT and holding it there for extended bursts over and over. By training at an intensity where your body can’t clear the lactate, you’ll boost your ability to keep riding hard in the face of high lactate levels. After a thorough warm-up, increase your effort to about five beats above your LT heart rate. Hold it there for two to three minutes. Reduce your effort for 60 to 90 seconds, just long enough so you feel partially recovered, but not quite ready to go again. Repeat three times.
selene yeager “The Fit Chick” Selene Yeager is a top-selling professional health and fitness writer who lives what she writes as a NASM certified personal trainer, USA Cycling certified coach, pro licensed mountain bike racer, and All-American Ironman triathlete.
What Pace Should Runners Run Lactate-Threshold Workouts?
As a coach, I’ve noticed that the most difficult type of workout for runners to run at the correct pace are lactate-threshold workouts. Many runners, especially those who are inexperienced with these workouts, have a difficult time holding back the pace and finding their fastest sustainable aerobic pace.
Lactate-threshold pace is about 10 to 15 seconds per mile slower than 5K race pace (or about 10K race pace) for slower runners (slower than about 40 minutes for 10K). If using a heart-rate (HR) monitor, the pace is about 75 to 80 percent max HR. For highly trained and elite runners, lactate threshold pace is about 25 to 30 seconds per mile slower than 5K race pace (or about 15 to 20 seconds per mile slower than 10K race pace), and corresponds to about 85 to 90 percent max HR. The pace should feel “comfortably hard.”
More: Why Lactate Threshold Is Crucial to Becoming a Better Distance Runner
It seems that many runners and coaches miss the nuances of the lactate threshold when prescribing training paces for workouts. Every time I read a magazine or mainstream book about running, I read that lactate threshold pace is 25 to 30 seconds per mile slower than 5K race pace, 15 to 20 seconds per mile slower than 10K race pace, and between 10-mile and half marathon race pace. However, these guidelines are only true for very good runners.
The better a runner’s endurance, the longer he or she can hold his or her lactate-threshold pace, and the better he or she is at sustaining any fraction of his or her lactate-threshold pace. In other words, if a 15-minute 5K runner can run 30 seconds per mile faster than lactate-threshold pace (which equals 110 percent of lactate-threshold pace) for those 15 minutes, certainly a 25-minute 5K runner is not also going to be able to run 30 seconds per mile faster than lactate-threshold pace (which equals 106 percent of lactate-threshold pace) for 25 minutes, 10 minutes (and 66 percent) longer than the good runner. Someone who runs a 10K in 50 minutes is likely running slower than his or her lactate-threshold pace for a 10K, not 20 seconds per mile faster. And someone who runs a half marathon in 1 hour and 45 minutes is certainly not running anywhere near lactate-threshold pace.
More: What Are Threshold and Tempo Runs?
The anaerobic threshold (AT) is the exertion level between aerobic and anaerobic training. The AT is the point during exercise when your body must switch from aerobic to anaerobic metabolism. The AT is a useful measure for deciding exercise intensity for training and racing in endurance sports.
During aerobic metabolism, your body creates energy by burning carbohydrates and fats in the presence of oxygen and produces carbon dioxide and water as by-products (breathing and sweating). Most of our daily activities are fueled by aerobic metabolism.
Anaerobic metabolism kicks in when exercise intensity is greatly increased, and the aerobic system can no longer keep up with the body’s energy demand. This is the point at which we cross the AT. During anaerobic metabolism, the body burns stored sugars to supply the additional energy needed, and lactic acid is produced faster than it can be metabolized. Muscle pain, burning and fatigue make anaerobic energy expenditure difficult to sustain for longer than a few minutes.
The fitter you are, the longer you can fuel your body with the aerobic system before the anaerobic system needs to take over. You can improve your aerobic efficiency—and thus raise your AT—by doing high-quality aerobic work at a level just below your current AT. Monitoring your heart rate and finding your Training Heart Rate Range (THRR) will help you determine what your current AT is.
Workouts to Raise the AT
Interval workouts are effective for raising the AT. For the best results, vary your workouts between aerobic work (where duration takes priority over high intensity), and higher-intensity intervals (where you will be just under or at your Maximum Heart Rate (MHR)). Aerobic work should comprise the largest percentage of your training. Here are a few interval workouts to try. We recommend long sub-maximal intervals, with roughly equal rest. As always, warm-up well before starting your piece:
- 5 x 750 meters with 3 minutes rest
- 4 x 1000 meters with 3–4 minutes rest
- 4–5 x 5 minutes with 4 minutes rest
- 5 x 4 minutes with 4 minutes rest
Conventional wisdom has long held that lactic acid is a metabolic scourge, bringing hard exercise stints to a screeching halt and causing next-day soreness. Recent research shows how wrong that rap is: Not only does lactate have nothing to do with “the burn,” it’s actually a secret source of fuel that can help anyone turbocharge his workout.
“When athletes are training to push up their lactate threshold (LT), what they’re really doing is training their bodies to use lactate as fuel,” says George Brooks, Ph.D., the study author and a lactate researcher at the University of California at Berkeley. “Improving that threshold is crucial,” says Lance Armstrong. You heard the man. Here’s how.
Fast laps can sabotage form in the water, so the challenge is maintaining efficiency at high intensities, says Terry Laughlin, founder of Total Immersion Swimming (totalimmersion.net).
Find your threshold
Warm up for 5 minutes, then do this 500-meter test: Start off at a pace you can hold for more than 500 meters, but build gradually so that your last 100 is at 90 percent effort. Count your strokes per (pool) length (SPL) in the first and last 100 meters.
Improve your threshold
Swim 100-yard repeats for 20 to 30 minutes, resting after each for one-quarter of your swim time. Swim at the fastest pace that allows you to keep an SPL count one or two strokes below your count in the final 100 yards of your test.
“My philosophy was to push up LT by going just below it,” says Armstrong. Here’s how to follow his lead.
Find your threshold
Using a heart-rate monitor, perform two 3-mile time trials on flat roads, riding as fast as you can. Multiply the higher average heart rate by 0.92 and 0.95 to find the ideal range to boost your lactate threshold. So, if your average heart rate was 185, your LT training range is 170 to 176.
Improve your threshold
LT intervals below 6 minutes have less training benefit, says Jim Rutberg, a coach for Carmichael Training Systems. Start with three 6-minute stints, each followed by 6 minutes of active rest (relax, but keep moving). As you can, tack on 60-second blocks to each interval, eventually adding a fourth block. If you reach 10 minutes, retest.
Go on to the next page for running tips…
A higher lactate threshold increases the pace you can sustain over short to midrange distances, powers you over hills, and adds kick to your sprint.
Find your threshold
Warm up, then run 5 kilometers at race pace. If you finish in 15 to 19 minutes, your threshold pace should be 25 to 30 seconds slower per mile than your 5-K pace; 20- to 24-minute finishes put your LT pace at 20 to 25 seconds slower; and 25 to 30 minutes — or if you’re a beginner — 5 to 10 seconds per mile slower.
Improve your threshold
Run four 1-mile segments at LT training pace with 60 seconds’ rest, suggests running coach Jason Karp, M.S. Perform the 5-K test again after 8 weeks.
START YOUR ENGINES…
Your body draws its fuel, ATP, from three energy systems at any given time. Pictured: the contribution, by percentage of total output, for each system during an 800-meter race.
This slow-burning fuel system is your primary supply during regular exercise. ATP comes from the breakdown of fats, blood glucose, and glycogen, using oxygen as part of a chain reaction to clear waste.
Anaerobic system (ATP-CP)
This short-term, oxygen-free process fuels normal movement and sudden, intense bursts of strength. The boost from ATP and creatine phosphate (cp), which are stored in the muscles, lasts only 7 to 10 seconds.
Anaerobic lactate system
This high-intensity, oxygen-free process breaks down glucose. Lactate is formed from a by-product and can be used inside the mitochondria (the cells’ energy producers) as an additional fuel source.
Many of your clients may now be competing recreationally in endurance events, such as mini-triathlons, triathlons, duathlons (running and cycling), half-marathons and marathons. Some clients will seek your training expertise to help them attain the most positive of outcomes. From the research, it is apparent that lactate threshold training is a well-established system to enhance endurance performance. However, before you start designing individual training programs, a few questions must first be answered, such as (1) What are the frequency, intensity, time and type (F.I.T.T) recommendations for lactate threshold training; and (2) How should lactate threshold training be progressed? Questions such as these encourage fitness professionals to use an evidence-based practice to guide program development. Evidence-based practice is the integration of the best research evidence with professional expertise and client values (Straus et al., 2005). This article uses this approach in designing an exercise program that will optimize lactate threshold training.
Lactate Threshold Defined
The lactate threshold is the fastest a person can continuously run, cycle, swim or aerobically exercise in a steady state bout without fatiguing. Increased intensity of training just above the LT results in an abrupt increase in blood lactate levels. At rest and under steady-state exercise conditions, there is a balance between lactate production and removal, as lactate can be used as substrate (fuel) by the heart, liver and muscles (Brooks, 2000). Thus, the LT represents the point at which a disruption begins in the equilibrium between blood lactate production and blood lactate removal. Although actual measurement of the LT is completed with an incremental exercise test in an exercise physiology laboratory, the sidebar at right, “Assessing and Tracking the LT,” presents a validated field test for estimating and tracking improvement in the LT.
Assessing and Tracking the LT
McGehee, Tanner and Hourmar (2005) have validated a user-friendly LT assessment field method with a 30-minute running (or speed walking) exercise bout. Initially, have the client do a five- to 10-minute low-intensity warm-up. Then, have the client run (or speed walk) as fast he or she can for 30 minutes at a 1% grade. The average running speed is deemed the LT (in speed), while the average heart rate (collected every five minutes) during the 30-minute test is the heart rate at LT. Have the client repeat this field test every few months to track progress. Your expectations are that the client will increase his or her running speed while exercising at the same (or similar) heart-rate intensity, thus confirming improvements in LT.
How is lactate produced?
Through the process of glycolysis (which means the splitting of sugar), blood glucose or muscle glycogen is converted to pyruvate, which will either enter the mitochondria (energy factory of the cell) or be converted to lactate, depending on the intensity of exercise. Pyruvate enters the mitochondria at exercise intensity levels below the LT, while at intensity levels above LT the capacity for mitochondrial respiration (the complete breakdown of carbohydrate) is exceeded and pyruvate is converted to lactate. Lactate production should not be viewed as a negative metabolic event, but as a consequence of high-intensity exercise. Also, with this increasing exercise intensity there is a shift toward the recruitment of more fast-twitch muscle fibers, which have metabolic characteristics that are geared toward glycolysis.
How does training affect lactate production?
Reduced lactate production at the same given workload following endurance training can be attributed to increased mitochondria size and number, as well as to enzymes. Both mitochondria size and number have been reported to increase within endurance-trained individuals by 50 percent to 100 percent, which results in an improved capacity for mitochondrial respiration (Holloszy and Coyle, 1984). Furthermore, there is an increase in several of the key enzymes (catalysts to metabolic reactions) involved in mitochondrial respiration following endurance training (Honig, Connett and Gayeski, 1992). The combined result of these training adaptations enhances the muscle cell’s ability to generate energy through mitochondrial respiration, and thus lowers the amount of lactate production from glycolysis.
How does training effect lactate removal?
Endurance training appears to cause an increase in lactate utilization by muscles, which results in an improved ability to remove lactate from circulation (Gladden, 2000). It has been suggested that part of the reason slow-twitch muscle fibers are more resistant to fatigue is that they contain more lactate and hydrogen ion transporters (into the mitochondria) than fast-twitch muscles (Brooks, 2000). Hydrogen ion accumulation is now considered to be the cause of acidosis (Robergs, Ghiasvand and Parker, 2004). Thus, slow-twitch muscle fibers have a greater capacity for clearing lactate and hydrogen ions than do fast-twitch muscle fibers. Training also has been known to improve capillarization in and around the muscles, especially the slow-twitch muscles. This adaptation functions to improve blood flow to and from exercising muscles, which also enhances the clearance of lactate and hydrogen ions.
Developing a Lactate Threshold Training Program
Now, with the understanding of the lactate threshold and its production and removal, let’s return to the evidence-based approach to designing an exercise program that will optimize lactate threshold training
Step 1: Gather the background research on lactate threshold training.
Although maximal oxygen uptake (VO2max) has been viewed as a key component to success in prolonged exercise activities, most researchers agree that lactate threshold is the best and most consistent predictor of performance in endurance events (Londeree, 1997). When considering the optimal LT training program, the following questions must first be answered:
1. What are the F.I.T.T. recommendations for lactate threshold training?
2. Do these recommendations differ between untrained and trained individuals?
3. What type of workout best modifies lactate threshold (steady state or interval)?
4. How should lactate threshold training be progressed?
Step 2: Where is the best evidence to answer these four questions?
A central pillar of evidence-based practice is to identify and employ the best evidence available to answer the questions pertaining to the optimal LT training program compiled in Step 1. The quality of evidence may range from research findings derived from multiple randomized, controlled studies (the most powerful form of evidence) to those resulting from personal expertise (the least attractive type of evidence). Two review articles published in high-impact factor (highly esteemed via research standards), peer-reviewed publications on the topic of LT training were the primary sources of evidence used to address our questions for this article (Midgley, McNaughton and Jones, 2007; Londeree, 1997). Importantly, review articles summarize findings across a number of scientifically rigorous studies and provide the overall ‘state of knowledge’ on a specific topic.
What are the F.I.T.T. recommendations for lactate threshold training?
The general F.I.T.T. approach to exercise programming used for cardiorespiratory fitness–program design can also be applied to LT programming (American College of Sports Medicine, 2014). Two types of specialized LT workouts identified in the literature include steady-state LT exercise bouts and high-intensity interval training (above the LT) sessions. The F.I.T.T. recommendations for each form of training, along with several modifications, are presented in Tables 1 and 2, respectively.
Do these recommendations differ between untrained and trained individuals?
The training status (along with age, body weight and training time) will suggest individual modifications in all aspects of F.I.T.T. with trained versus untrained clients, but the LT approach is the same. Initially, the best way to improve LT levels is to simply increase the client’s training volume (i.e., distance, time and/or frequency) whether their endurance activity involves cycling, using the elliptical crosstrainer or swimming. The premier benefit of increased training volume will be increased capacity for mitochondrial respiration. Training intensity during this phase should fall within the moderate-intensity range recommended by the ACSM of 40 to 60 percent of heart-rate reserve (HRR).
What type of workout best modifies the LT (steady-state or interval)?
Both are critical for the continued improvement of the LT. Importantly, it is the timing for when these specialized workouts should be implemented into a client’s training program. Research has shown that the addition of steady-state workouts performed at LT to an existing aerobic exercise routine in previously active participants results in improved LT levels (Midgley, McNaughton and Jones 2007). For highly endurance–trained clients, or those who have been performing steady-state workouts for some time, interval training sessions must be integrated into training programs to facilitate continued improvement of LT.
How should lactate threshold training be progressed?
A training program designed to optimize LT consists of three components: (1) base-building aerobic training phase; (2) steady-state LT workouts; and (3) high-intensity interval sessions. The increase in training volume should be approximately 10 to 20 percent per week. For example, if an individual is currently running 10 miles per week, the increase in training volume should be 1 to 2 miles per week. Incorporating multiple training modalities (e.g., cycling, elliptical, rowing) into the aerobic exercise routine may also facilitate program adherence. The maximum training volume an individual attains can be best gauged by determining his or her overall capacity and motivation. The base-building phase may last a minimum of two to three months for some individuals.
Following adequate build-up in training volume, the next training period to be addressed is steady-state, continuous LT training. The RPE scale may be the most accurate way to determine training intensity during this aspect of training (recommendations are listed in Table 1). Research has shown that RPE is strongly related to the blood lactate response to exercise regardless of gender, training status, type of exercise being performed or the intensity of training (Weltman, 1995). This is noteworthy, as other methods of monitoring intensity at LT have been known to have serious flaws in methodology, which result in underestimating or overestimating training intensity. Similar to the timeline increase in training volume, steady-state workout sessions can be increased in duration from a starting point of 10 minutes by 10 to 20 percent per week. Evidence suggests that steady-state sessions of 30 minutes in duration are sufficient for optimizing the improvement in LT of most clients during this phase of training (Midgley, McNaughton and Jones, 2007; Londeree, 1997). The progression from 10- to 30-minute steady-state LT workouts may be accomplished gradually over several weeks.
High-intensity interval sessions are the last piece of the LT training puzzle, although these specialized workouts should only be incorporated after first completing a proper base-building phase and steady-state LT workouts. Interval workouts are high-intensity training sessions performed for short durations at velocities or workloads near or at maximal (90 to 100 percent HRR). Evidence suggests that the proper duration of these interval work bouts ranges from two to three minutes, with similar amounts of time for recovery between bouts. Progress gradually with the total number of repetitions (high-intensity bout followed by low-to-moderate intensity recovery bout) completing between five and 10 interval repetitions depending on training status, type of endurance-activity being performed and distance of the endurance activity. The key to successful steady-state and interval training is careful monitoring of intensity to prevent your client from overtraining.
Step 3: Implement the lactate threshold training program.
Table 3 is a case study that shows how a LT program can be implemented.
The lactate threshold is the most important determinant of success in endurance-related activities and events. Through an understanding of the physiological mechanisms of lactate production (and its utilization and removal in the body), an effective training program incorporating base training, steady-state LT sessions and interval workouts (above the LT) can be properly devised. Furthermore, individualizing the lactate threshold training program to your client’s fitness level, age, goals and training time will result in the most realistic and triumphant outcome.
Is the Ventilatory Threshold the Same as the Lactate Threshold?
Ventilatory threshold refers to the exercise intensity at which there is a rapid increase in ventilation. The abrupt rise in ventilation coincides with the development of metabolic acidosis, which is characterized by elevated hydrogen ion (H+) concentrations. Expectedly, ventilation rises to dispose of the excess carbon dioxide being produced apart from metabolism through the buffering (or neutralizing effect by the compound bicarbonate) of the increasing H+ concentration. Because increased ventilation occurs with increasing blood H+ concentrations and the associated blood lactate values concentrations, it has been suggested that the ventilatory and lactate thresholds occur at comparable exercise intensities. This interpretation is attractive because determining the ventilatory threshold is non-invasive compared to the lactate threshold. Although some studies have shown similarities between the thresholds, other studies have determined that various conditions, including training status and carbohydrate nutritional supplementation, can cause the thresholds to differ substantially (Robergs and Roberts, 1997).
American College of Sports Medicine. (2014). ACSM’s Guidelines for Exercise Testing and Prescription (9th ed.). Baltimore: Wolters Kluwer/Lippincott Williams & Wilkins.
Brooks, G.A. (2000). Intra- and extra-cellular lactate shuttles. Medicine & Science in Sports & Exercise, 32, 4, 790–799.
Gladden, L.B. (2000). Muscle as a consumer of lactate. Medicine & Science in Sports & Exercise, 32, 4, 764–771.
Midgley, A.W., McNaughton, L.R. and Jones, A.M. (2007). Training to enhance the physiological determinants of long-distance running performance: Can valid recommendations be given to runners and coaches based on current scientific knowledge? Sports Medicine, 37, 10, 857–880.
Straus, S.E. et al. (2005). Evidence-based Medicine: How to Practice and Teach EBM (3rd ed.). Edinburgh: Churchill Livingstone.
Weltman, A. (1995). The Blood Lactate Response to Exercise. Champaign, Ill.: Human Kinetics.
Lactate Threshold is Misunderstood
If you want to start a debate in a group of runners, mention lactic acid and lactate threshold. The topics are two of the most confused and misunderstood in the running world. For the last few decades, lactate was presumed to be all bad–causing only muscle soreness and dashing dreams of personal records.
But that’s only half the story.
Lactate threshold is the exercise level at which lactic acid builds up in the blood. This accumulation of lactic acid is associated with fatigue, and most people assume the burning sensation of hard exercise is caused by lactic acid.
Endurance athletes specifically focus on lactate threshold as a measure of efficiency and fitness. For many, the goal of training is to maintain increased power and speed without crossing over this threshold. Most athletes want to stave off blood lactate accumulation, training so they clear it faster and produce less.
That’s why lactate is generally considered a four-letter-word, thought to be a waste product linked to muscle fatigue.
Research on the issue makes muddy waters more clear: producing and burning lactate provide essential fuel for cells throughout the body when oxygen is depleted.1
Lactate & Lactate Threshold Basics
There’s a nuance to lactate responsible for its bad rap.
Lactate: More Protons, More Problems
Lactate can be produced throughout the body naturally.2 It’s a result of rapidly burning carbohydrate when the demand for energy is high, and oxygen availability is low, such as during sprinting or other high-intensity workouts.
Glucose is the body’s most readily available fuel, easily transported around the body and broken down to support short bursts of intense exercise. Glucose gets metabolized by a process called glycolysis, resulting in pyruvate. There are two possible uses for pyruvate: anaerobic or aerobic energy production.
When there is plenty of oxygen, pyruvate is turned into energy in the form of ATP through the aerobic pathway. Without enough oxygen present, pyruvate has another fate: anaerobic conversion to lactate. So all that huffing and puffing during intense exercise is used (among other things) to fuel the metabolic reactions that make our muscles work.
The majority of lactate released into the blood is mopped up in the liver where it can be converted back into glucose via a process called gluconeogenesis, and then released back into circulation.1 For example, the brain can directly use it as fuel (along with other parts of the body).
Lactate itself isn’t at all that bad for the body. The bad part is the acid associated with it.
Lactate caries a proton (an acid) when it’s released, and the build up of protons decreases the pH of the blood. When the body gets more acidic, function becomes compromised because the protons interfere with energy production and muscle contraction.
All this time, athletes have been blaming lactate like it’s a referee. But they should be blaming those protons.
Still, generally, lactate is pretty much always associated with protons, so there is a strong relationship between high lactate and fatigue.
As speed increases, lactate production reaches a point where it increases exponentially
Lactate Threshold: Recycling is the Name of the Game
Blood lactate levels rise gradually as one exercises. The harder the exercise, the higher it climbs; this is an indicator of a shift in our energy production from aerobic (lots of oxygen) to anaerobic (less oxygen).
Before reaching the lactate threshold, blood lactate concentrations increase gradually. But upon arriving at the lactate threshold, the blood concentration of lactate begins to exponentially increase. Usually that intensity hovers around 80% of an athlete’s maximum heart rate, or 75% of their maximum oxygen intake–but you can also link it to speed or power.
Recycling lactate is true north of endurance training, which aims to maintain an intensity below the lactate threshold. When the recycling process can’t keep up, lactate produced by the exercising muscles begins build up in the bloodstream.
Well-designed training programs target both sides of the lactate threshold; there should be some training sessions working at or above LT. These sessions are harder on the body, but this forces adaptations that ultimately increase speed on race day.
Why Does Lactate Build Up Happen During High Intensity Exercise?
Lactate buildup is a result of the rapid anaerobic breakdown of carbohydrate.
Cells break down carbs and fats from our food to produce a molecule called ATP (the body’s energy currency), which is then used as energy by exercising muscles. ATP is produced from carbs through a three-step process: Glycolysis, Krebs Cycle and Electron Transport Chain (ETC). Products from Glycolysis feed Krebs which feeds ETC.
ETC is what generates most of our ATP. Energy generated from ETC is effective enough to sustain moderately-intense exercise…but the process doesn’t happen fast enough to keep up with the energy demand of high-intensity exercise. This means rapid-release energy from glycolysis is required to keep going. Glycolysis increases to supplement the difference but, as we know, this leads to lactate production.
Oxygen delivery rate also becomes limited during high intensity exercise. The ETC absolutely relies on oxygen for its function. We can’t breathe enough, or pump blood fast enough to our muscles when they are in overdrive to keep the ETC going. This necessitates oxygen-free energy production via glycolysis and lactate production.
That extra lactate (along with its acidic proton) ends up in the blood and decreases our pH. Our brains aim to keep a steady state of pH, and sensing this imbalance in pH, cause us feel nauseous. This leads to a feeling of fatigue, then a decrease intensity, then decreasing ATP demand, then glycolysis slows, leading to a better match between oxygen demand and oxygen delivery. Ultimately, this match allows lactate clearance from the blood.
Exercise above the lactate threshold can only be sustained for a limited amount of time: the body runs out of glycogen (stored carbs) to convert into lactate, and the increasing acidity of the blood causes fatigue.
Better athletic performance comes from training with LT in mind, geared to a higher production of speed or power at the lactate threshold.
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How to Figure Out Lactate Threshold
Testing protocols to determine lactate threshold are sport-specific. Many consider the running speed at lactate threshold (RSLT) to be the best indicator of running fitness and the most reliable barometer of endurance performance.
In cycling, step-tests (where power is increased at regular intervals until you are exhausted) are the gold standard for measuring physiological performance markers, such as lactate threshold.
Upon completing the test and finding a personal lactate threshold, one can begin incorporating lactate threshold training to target specific adaptations for the body to make.
There are a few different ways to test for a personal lactate threshold, and factors to consider when doing so. It’s important to remember everyone is different, and lactate threshold changes in response to training (or sadly, de-training).
Lab Testing: Accurate But Expensive
The most concrete way to determine lactate threshold is to take a series of blood samples as exercise is conducted at increasing intensities. This type of lactate testing occurs at an exercise physiology laboratory, and tends to be expensive (but worth it).
In a lactate threshold test, athletes exercise on a treadmill or stationary bike while increasing intensity every few minutes until exhaustion. A blood sample is taken during the each stage of the test–similar to testing for ketones, through the fingertip or earlobe–illustrating blood lactate readings at various running speeds or cycling power outputs. Results are then plotted on a curve to show the speed or power at which the lactate threshold occurs.
However, lactate threshold changes as more training is done to build your aerobic base. So in order to maintain an updated understanding of your lactate threshold, you’d have to visit the lab again after a block of training.
During her time on the Great Britian Rowing Team, H.V.M.N. Research lead, Dr Brianna Stubbs, did lactate threshold testing every 2-3 months. She recounts the collective effort to find lactate threshold.
“The gym even got gory on step-test days, with athletes dripping blood from the testing holes in their earlobes.”Dr. Brianna Stubbs
“Seeing results change over time was interesting,” she said. “I recorded my highest power at lactate threshold toward the end of the winter training block, which made sense because that’s when we did most of our endurance work.”
Do-it-Yourself Field Test: You Have a Few Options
Many endurance athletes choose to estimate their lactate threshold by measuring heart rate and/or VO2 max at different training zones (there’s even a portable lactate blood analyzer some use to further cement results).
There are several different methods to estimate running speed at lactate threshold:
VDOT (or VO2 max) Chart
- A VDOT chart is an adjusted VO2 max chart (created by esteemed running coach Jack Daniels) that uses some of your most recent run times (at max effort) to identify training pace that will maintain your lactate threshold. There are two corresponding chats that work together to illustrate max effort and training paces for different distances (we’ve simplified it above)
- For example, running at a 7:49 mile pace at max effort corresponds to a VDOT number of 36. That VDOT number illustrates the pace at which training should be done to maintain lactate recycling: 8:55. For a more in-depth analysis of interval training and different distances, refer to these charts here
- Using a heart rate monitor set to a five second recording interval
- Begin running and increase speed every 200 meters until exhaustion. The goal isn’t to maintain a steady state of exercise, instead increasing incrementally to test yourself
- Plot heart rate against speed; the deflection point in the graph (where your heart rate goes up much more than your speed) roughly corresponds to speed at lactate threshold
Time-Trial Method / 30-Minute Test
- Research has shown that doing a 30 minute flat out time trial is one of the most accurate ways to find your lactate threshold without using fancy equipment3
- Start by warming up
- Then, on a track or treadmill, run for 30 minutes at the fastest sustainable pace. 10 minutes into the run, obtain and note your heart rate. Then, after the final 20 minutes of the test, obtain and note your heart rate again
- Add your heart rate at the 10-minute mark to heart rate at the 30-minute mark–that’s your lactate threshold heart rate. And your average pace for the entire 30-minute test (assuming it was steady) is your lactate threshold pace
Both elite athletes and weekend warriors can benefit from understanding personal lactate threshold to maximize results. However, lactate threshold is impacted by training and changes over time. So keeping regular on these types of tests will indicate an improving lactate threshold through focused training.
Optimizing Lactate Metabolism
Lactic acid gets blamed for muscle soreness, but the production of lactate is an important metabolic process. The idea that lactate is pure waste and leads to fatigue is somewhat outdated. Nevertheless, a higher speed or power at lactate threshold is still one of the key goals of aerobic training.1
Different strategies can help minimize lactate buildup during exercise.
Warming Up: As Important as Cooling Down
Warming up is important to reducing risk for injury and minimizing potential lactate buildup. During a warm-up, heart rate increases, and blood vessels dilate, meaning there is more blood flow and more oxygen reaching your muscles.
When exercise intensity picks up the pace, there’s less mismatch between oxygen needs of the muscles and blood. Therefore, you don’t need to do as much anaerobic respiration, and you don’t build lactate early in the run.
Equally, cooling down and stretching immediately after a workout is especially important. Gentle exercise (slow jogging or spinning on a bike) or using a foam roller can help clear lactic acid buildup from the muscle by stimulating blood flow and encouraging lymphatic drainage.
Nutrition and Supplements: Replenishment is Key
The key to dealing with high lactate production is dealing with the acid associated with it (that pesky little proton). Two “buffer supplements,” sodium bicarbonate and beta-alanine, work by mopping up that proton. This means lactate levels can go higher than before without triggering fatigue because the proton is taken care of.
Beta-alanine works inside the muscles to clean up protons before they affect muscle contraction. Compounding effects of beta-alanine powder (~5g per day) happen after several weeks, but studies show around a 2-3% performance boost.4
Sodium bicarbonate is better for short-term boosts in proton buffering. Bicarbonate is the main buffer usually binding protons to stop blood from becoming too acidic. About an hour before exercise, taking bicarb powder dissolved in water, at 0.3kg per body weight, has shown to improve performance.5 Be weary of stomach aches when first introducing bicarb. But there are bicarbonate gels that provide the same buffing effect without the side-effects.6
Lactate can only be produced by breaking down carbs. Sustaining an exercise intensity that is producing lactate means the depletion carbohydrate stores (glycogen). When the glycogen gas tank reads empty, we hit a wall.
Exogenous ketones can lower lactate production. By drinking pre-workout exogenous ketones, your body can use the ketones for energy instead of carbohydrates–glycolysis decreases and therefore, so does lactate production.
Having ketones as a whole new source of fuel means the body doesn’t need to dip into its existing carb and protein stores: athletes using exogenous ketones show a decrease in the breakdown of intramuscular glycogen and protein during exercise, compared to carbohydrates alone.7
Exercise: Training Toward Adaptation
Regular training forces the body to adapt; what once felt like an unsustainable pace becomes easy. And adopting a training plan helps accelerate how that adaption will progress.
Looking at the whole body, the heart muscle gets stronger, building more small blood vessels. These small blood vessels mean more oxygen-rich blood can be transported to the muscles, requiring less demand for anaerobic respiration and lactate production.
On a muscular level, cells can produce more mitochondria, which are the site of aerobic respiration. This helps increase reliance on that energy system. Muscle cells also express more of the transport proteins for lactate, so lactate doesn’t build up inside the cells and compromise their function.8
Lactate threshold training switches up workout intensity, optimizing the body’s lactate response.
Peter Broomhall, who has been running ultramarathons for seven years, started incorporating lactate training into his regimen with his coach.
“I’ve trained with lactate threshold in mind this year more than any other year. It takes time to build up that threshold, but things like recovery become quicker. It compliments every aspect of training.”Peter Broomhall
For runners, one way to work on lactate threshold is to breakdown a run into mile sections: the first mile or two should be run at a pace just below lactate threshold, while the proceeding mile section should be slower, thus allowing the body to process the lactate. Active recovery is more effective at clearing lactate than passive recovery.9 This allows a high volume of miles without going overboard.
Lactate, A Misunderstood Villain
Next time your running club gangs up on lactic acid, maybe you can remind everyone of its important role in helping our bodies produce energy quickly when oxygen is short.
We do know the combination of high lactate (and the associated increase in protons in the muscles and blood) can impact our ability to maintain peak athletic performance. But we now have a deeper understanding of blood lactate (and how to optimize it), thanks to monitoring tools outside the lab, structural training regimens and recovery techniques.
We’re altering how the body responds to lactate with nutrition supplements like exogenous ketones and bicarb gels. And in the process, we’re rewriting the old story about lactic acid.
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Lactate Theshold Training
Len Kravitz, Ph.D. and Lance Dalleck, Ph.D.
The terms lactic acid and lactate, despite biochemical differences, are often used interchangeably. Fitness professionals have traditionally linked lactic acid or the burn with an inability to continue an intensive exercise bout at a given intensity. Although the conditions within the exercisers muscle cells have shifted towards acidosis, lactate production itself does not directly create the discomfort (acidosis) experienced at higher intensities of exercise. It is the proton (H+) accumulation, coinciding with, but not caused by lactate production, that results in acidosis, impairing muscle contraction, and ultimately leading to the burn and associated weariness (Robergs, Ghiasvand, Parker 2004). The increased proton accumulation occurs most notably from the splitting of ATP (the bodys energy liberating molecule) by the muscle protein filaments, in order to sustain vigorous muscle contraction. Interestingly, the lactate production is proposed to be a physiological event to neutralize or retard the exercisers muscle acidic environment (Robergs, Ghiasvand, Parker 2004). Thus, lactate accumulation, which for years has been associated with the cause of the burn, is actually a beneficial metabolic event aimed at diminishing the burn. Scientists denote conditioning at this physiological state as lactate threshold training.
Fitness professionals can utilize this knowledge to enhance the cardiovascular endurance performance of their students and clients. All world and Olympic endurance athletes incorporate lactate threshold training into their workouts. This article will explain and discuss how lactate threshold training principles can be incorporated into your clients training program.
Lactate Threshold and Endurance Performance
Traditionally, maximal oxygen uptake (VO2max) has been viewed as the key component to success in prolonged exercise activities (Bassett & Howley 2000). However, more recently scientists have reported that the lactate threshold is the most consistent predictor of performance in endurance events. Studies have repeatedly found high correlations between performance in endurance events such as running, cycling, and race-walking and the maximal steady-state workload at the lactate threshold (McKardle, Katch, & Katch 1996).
What is the Lactate Threshold?
At rest and under steady-state exercise conditions, there is a balance between blood lactate production and blood lactate removal (Brooks 2000). The lactate threshold refers to the intensity of exercise at which there is an abrupt increase in blood lactate levels (Roberts & Robergs 1997). Although the exact physiological factors of the lactate threshold are still being resolved, it is thought to involve the following key mechanisms (Roberts & Robergs 1997):
1) Decreased lactate removal
2) Increased fast-twitch motor unit recruitment
3) Imbalance between glycolysis and mitochondrial respiration
4) Ischemia (low blood flow) or hypoxia (low oxygen content in blood)
1) Lactate Removal
Although once viewed as a negative metabolic event, increased lactate production occurring exclusively during high-intensity exercise is natural (Robergs, Ghiasvand, Parker 2004). Even at rest a small degree of lactate production takes place, which indicates there must also exist lactate removal or else there would be lactate accumulation occurring at rest. The primary means of lactate removal include its uptake by the heart, liver, and kidneys as a metabolic fuel (Brooks 1985). Within the liver, lactate functions as a chemical building block for glucose production (known as gluconeogenesis), which is then released back into the blood stream to be used as fuel (or substrate) elsewhere. Additionally, non-exercising or less active muscles are capable of lactate uptake and consumption. At exercise intensities above the lactate threshold, there is a mismatch between production and uptake, with the rate of lactate removal apparently lagging behind the rate of lactate production (Katz & Sahlin 1988).
2) Increased Fast-Twitch Motor Unit Recruitment
At low levels of intensity, primarily slow-twitch muscles are recruited to support the exercise workload. Slow-twitch muscle is characterized by a high aerobic endurance capacity that enhances mitochondrial respiration, which is the aerobic ATP energy production system. With increasing exercise intensity there is a shift towards the recruitment of fast-twitch muscles, which have metabolic characteristics that are geared towards glycolysis (an anaerobic energy pathway). The recruitment of these muscles will shift energy metabolism from mitochondrial respiration more towards glycolysis, which will eventually lead to increased lactate production (Anderson & Rhodes 1989).
3) Imbalance between Glycolysis and Mitochondrial Respiration
At increasing exercise intensities, there is an increased reliance on the rate in the transfer of glucose to pyruvate through the reactions of glycolysis. This is referred to as glycolytic flux. Pyruvate, which is the final product of glycolysis, can either enter the mitochondria for further biological breakdown (for eventual synthesis of energy) or be converted to lactate. There are some researchers who believe that at high rates of glycolysis, pyruvate is produced faster than it can enter into the mitochondria for mitochondrial respiration (Wasserman, Beaver, & Whipp 1986). Pyruvate that cannot enter the mitochondria will be converted to lactate, which can then be used as fuel elsewhere in the body (such as the liver or other muscles).
4) Ischemia and Hypoxia
For years, one of the primary causes of lactate production was thought to include low levels of blood flow (ischemia) or low levels of blood oxygen content (hypoxia) to exercising muscles (Roberts & Robergs 1997). However, there is no experimental data indicating ischemia or hypoxia in exercising muscles, even at very intense bouts of exercise (Brooks 1985).
What is the Anaerobic Threshold?
The term anaerobic threshold was introduced in the 1960s based on the concept that at high-intensity levels of exercise, low levels of oxygen (or hypoxia) exist in the muscles (Roberts & Robergs 1997). At this point, for exercise to continue, energy supply needed to shift from the aerobic energy system (mitochondrial respiration) to anaerobic energy systems (glycolysis and the phosphagen system).
However, there are many researchers who strongly object to the use of the term anaerobic threshold, believing it is misleading. The main argument against using the term anaerobic threshold is that it suggests oxygen supply to muscles is limited at specific exercise intensities. However, there is no evidence that indicates muscles become deprived of oxygen, even at maximal exercise intensities (Brooks 1985). The second main argument against using anaerobic threshold is that it suggests at this point in exercise intensity, metabolism shifts completely from aerobic to anaerobic energy systems. This interpretation is an overly simplistic view of the regulation of energy metabolism, as anaerobic energy systems (glycolysis and the phosphagen system) do not take over the task of ATP regeneration completely at higher intensities of exercise, but rather augment the energy supply provided from mitochondrial respiration (Robergs, Ghiasvand, Parker, 2004).
Lactate Threshold Training Programs and Workouts
Although the optimal training for lactate threshold improvement has yet to be fully identified by researchers, there are still some excellent guidelines you can follow in generating training programs and workouts in order to optimize the endurance performance of clientele. Research has indicated that training programs that are a combination of high volume, maximal steady-state, and interval workouts have the most pronounced effect on lactate threshold improvement (Roberts & Robergs 1997, Weltman 1995).
High Volume Training
Initially, the best way to improve the lactate threshold levels of your clients is to increase their training volume, regardless of the cardiovascular mode of exercise. Lets create a case study as we discuss lactate threshold training to fully see how to design an effective program. For our case study, lets assume the client is presently doing 100 minutes of cardiovascular exercise a week, with the goal of increasing the total time to 200 minutes per week. Increased training volume should be gradual and in the order of approximately 10-20% per week (Bompa 1999). For our case study, if the client progressed at 20% per week, it would take approximately four weeks to safely progress to the target weekly volume of 200 minutes per week. The Rating of Perceived Exertion (RPE) scale should be used to prescribe cardiorespiratory exercise intensity during this period. For this high volume training, your client should train at an RPE of 11-12, which subjectively is a light exercise intensity level. Mix up the total time per session of cardiovascular exercise throughout the week, however it works best for the client. However, the minimum bout of cardiovascular exercise should be 10 minutes in duration. The major benefit of increased training volume is an increased capacity for mitochondrial respiration, which is imperative to improvements in lactate threshold.
Maximal Steady-State Training
Steady-state training at the lactate threshold is often referred to as maximal steady-state exercise or tempo runs. Research has shown that the lactate threshold occurs at 80-90% of heart rate reserve (HRR) in trained individuals and at 50-60% HRR in untrained individuals (Weltman 1995). Without access to an exercise physiology laboratory to get actual lactate threshold measurements for your clients, the RPE scale will be the most accurate way to determine training intensity for maximal steady-state exercise sessions. Research has shown that RPE is strongly related to the blood lactate response to exercise regardless of gender, training status, type of exercise being performed, or the intensity of training (Weltman 1995). Findings from studies have indicated that the lactate threshold occurs between 13 and 15 on the RPE scale, which corresponds to feelings of somewhat hard and hard (Weltman 1995).
Following the build-up in training volume described above, your client may begin maximal steady-state exercise sessions. Collectively, these sessions should consist of no more than 10% of the total weekly volume (Foran 2001). In our case study, 10% of 200 minutes is 20 minutes, which is the upper limit of total time accumulated during maximal steady-state exercise sessions in one week. While this approach may appear conservative, it will help to prevent over training and injuries and is a wonderful starting place.
Interval Training Above the Lactate Threshold
Interval training workouts are high-intensity training sessions performed for short durations of time at velocities or workloads above the lactate threshold. Although you can design the interval workout however you wish, for our case study lets choose to alternate a 4-minute, high-intensity bout with a 4-minute, low-intensity aerobic recovery bout. During the high-intensity bouts above the lactate threshold, have the client exercise above a 15 RPE (subjectively training at a HARD or VERY HARD intensity), but below an all-out effort (19 or 20 RPE). Encourage the client to workout at a very light intensity (less than 12 RPE) during the recovery bout. Similar to maximal steady-state sessions, the total interval training workout time should not exceed 10% of weekly training volume. With our case study, 10% of 200 would be 20 minutes of interval training sessions per week. Important training prescription recommendation! Avoid scheduling the interval training workouts and maximal steady-state exercise sessions in back-to-back workouts.
Lactate threshold is the most important determinant of success in endurance-related activities and events, and the main goal of endurance training programs should be the improvement of this parameter. Factors such as training status, age, gender, body mass, goals, and training time availability will all help determine the actual training intensities and volumes your client is capable of achieving. Utilization of a lactate threshold training program may add much excitement and interest to you clients cardiorespiratory training program. By performing lactate threshold training, your clients are directly increasing their caloric expenditure during this type of exercise program. Educate them that this type of training is also highly recommended to enhance weight loss and weight management. Progress slowly and be creative with this program. Good luck with your lactate threshold training!
1. Anderson, G.S., & Rhodes, E.C. 1989. A review of blood lactate and ventilatory methods of detecting transition threshold. Sports Medicine, 8 (1), 43-55.
2. Bassett, D.R., Jr., & Howley, E.T. 2000. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Medicine and Science in Sport and Exercise, 32 (1), 70-84.
3. Bompa, T.O. 1999. Periodization: Theory and Methodology of Training, 2nd Ed., Champaign, IL: Human Kinetics.
4. Brooks, G.A. 2000. Intra- and extra-cellular lactate shuttles. Medicine and Science in Sport and Exercise, 32 (4), 790-799.
5. Brooks, G.A. 1985. Anaerobic threshold: review of the concept and directions for future research. Medicine and Science in Sport and Exercise, 17 (1), 22-34.
6. Foran, B. (edited by). 2001. High-Performance Sports Conditioning, Champaign, IL: Human Kinetics.
7. Katz, A. & Sahlin, K. 1988. Regulation of lactic acid production during exercise. Journal of Applied Physiology, 65 (2), 509-518.
8. McArdle, W.D., Katch, F.I., & Katch, V.L. 1996. Exercise Physiology: Energy, Nutrition, and Human Performance. Baltimore, MD: Williams & Wilkins.
9. Robergs, R. A., Ghiasvand, F., Parker, D. (2004). Biochemsitry of exercise-induced metabolic acidosis. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. 287: R502-R516.
10. Robergs, R.A., & Roberts, S. 1997. Exercise Physiology: Exercise, performance, and clinical applications. St Louis, MO: Mosby.
11. Wasserman, K., Beaver, W.L., & Whipp, B.J. 1986. Mechanisms and patterns of blood lactate increase during exercise in man. Medicine and Science in Sport and Exercise, 18 (3), 344-352.
12. Weltman, A. 1995. The Blood Lactate Response to Exercise. Champaign, IL: Human Kinetics.
For years, scientists worked to determine the top physiological factor in distance running success. As they dug deeper and deeper, the answer became clear: the pace at your lactate threshold.
While the term “lactate threshold” is less common among researchers these days, the fact remains that, as you run faster, you produce more lactate. At some point, the lactate begins to accumulate at a faster and faster rate. The graph at the right indicates a typical lactate profile for a runner. The faster you can run at the point where the curve begins to turn upward quickly, the faster you’ll race.
The purpose of “lactate threshold” training, then, is to move your lactate curve to the right so that you can run faster before reaching this “threshold.” Toward that end, the weekly tempo run, done at the pace of your lactate threshold, became popular. While frequent tempo runs can improve your lactate profile, I’ve found that variety in this type of training results in better performance improvement. I call it full-spectrum lactate threshold training.
A CLOSE LOOK AT THE CURVE
If you look closely at the lactate curve in the chart at the right, you’ll see the full spectrum of the lactate threshold training zone. On the low end of the zone, the pace is roughly the pace you can race for 2 to 3 hours. In the middle of the zone is the pace you can race for 1 to 1.5 hours. At the fast end of the zone is the pace you can race for 30 to 45 minutes. I’ve found that, if you break your lactate threshold training into workouts from each zone, your body adapts faster and better. Your lactate curve shifts more quickly to the right and improved racing performance follows. Here are the three lactate threshold (LT) training zones and their associated workouts.
LOW-END LT TRAINING
In looking at the low-end zone, you’ll notice that it’s the pace most of us can run for just shy of the marathon. So, doing some workouts at your marathon pace or slightly faster (even if you aren’t training for a marathon) is very beneficial. These workouts are long, steady runs lasting 45 to 90 minutes. Start with 10 to 30 minutes of easy running, then pick up the pace to around your marathon pace. Hold it there for 45 to 90 minutes, then cool down for 10 to 30 minutes.
MIDDLE ZONE LT TRAINING
Middle zone pace is what most of us can race for a half marathon. These workouts are also continuous runs, but last only 20 to 40 minutes, like a typical tempo run. Run this workout a bit more controlled than most runners run tempo runs. (Most runners push a little too hard on tempo runs.) Like the low-end workout, start with a warm-up and finish with a cool-down. Run continuously at this “comfortably hard” pace. If you start approaching 10K pace on these longer, continuous runs, then you’re doing them too fast.
HIGH-END LT TRAINING
High-end zone pace is roughly 10K pace. Workouts for this zone are what many coaches call “tempo intervals.” They’re repeats with a recovery interval but are much more controlled than traditional track workouts at 5K pace or faster. Because the tendency is to run a bit too fast, the recovery interval is minimal (usually one-fourth or one-fifth of the length of the repeat). For example, if you’re doing mile repeats as tempo intervals and your 10K pace is 6:00 per mile, then you’ll take only 60 to 90 seconds for your recovery jog. This ensures that you don’t run too fast but keep the pace in the correct lactate threshold zone. With tempo intervals, try to get in 3 to 6 miles of running at 10K pace.
As I mention frequently in this column, variety is a key ingredient in successful training. Working the lactate threshold across the full spectrum results in faster and better adaptations. Doing a variety of LT workouts also allows you to learn more about yourself.
Sprinkle in these LT workouts throughout the year but at least twice per year, do a focused training phase where, for four to six weeks, you perform a weekly LT workout.
Lastly, remember to control yourself with LT training. The “tough” of the workout should come from the duration of the workout, not the speed. In this case, it’s more important to go slower and do more volume of running than faster but shorter.
GREG MCMILLAN is an exercise physiologist and USATF-certified coach who helps runners via his website mcmillanrunning.com.
Use Threshold Training to Run Faster, Longer
The primary purpose of training is to enable your body hold a faster pace for a longer time. The first step toward getting faster is building an aerobic base of easy miles and improving running economy through strides and short intervals. After you’ve developed a base, the best way to go faster for longer is through threshold training.
Mention threshold training in a group of coaches, and an Anchorman-like rumble will erupt in a minute or two. If you search threshold-training philosophy online, keywords like “tempo” and “steady state” seem to mean slightly different things to everyone. But there’s no need for things to escalate quickly into a brawl over slight disagreements on terminology, since the basic principles are universal.
What do we mean by threshold?
Contrary to conventional wisdom, lactate is a fuel source, not a boogeyman that forces you to slow down. However, it is associated with waste products that force you to slow down, so for most runners it’s a distinction without a difference. Lactate threshold (LT) is the tipping point when your body produces more lactate than it can use and waste products accumulate without being cleared.
Similar to LT, anaerobic threshold (AnT) measures the point at which your body starts burning glycogen rather than fat as its primary fuel source. AnT and LT are often close to one another, and most athletes can probably get by without differentiating them.
In lieu of lab testing, LT usually corresponds to an effort you could hold for about an hour, though it varies based on physiology, training background and the LT definition you prefer. It should feel somewhat hard, a seven or eight out of 10 on the perceived exertion scale, where you can talk in short sentences, but not sing.
You can calculate your LT heart rate (LTHR) by doing a 30-minute time trial. At 10 minutes, lap out your watch—the average heart rate for the final 20 minutes is your LTHR.
Why do we care about lactate threshold?
Lactate threshold is often the most important element in determining running success in long-distance races, even at races far longer than an hour. The power of LT likely comes from a few factors. First, it is trainable, meaning well-trained athletes will have higher LTs and will run faster in races (whereas VO2 max is less willing to budge). Second, exceeding LT results in relatively rapid onset of fatigue, so improving LT raises the “point of no return.” Finally, LT is usually associated with performance at lower levels of exertion like aerobic threshold and even more intense exertion levels, like VO2 max.
What matters is how fast you can run at your LT, or your velocity at LT (vLT). On trails, vLT gets a bit more complicated, mixing how fast you can run on flat ground with your ability on hills and technical terrain.
How can we improve vLT on trails?
High-volume aerobic training can improve LT the most. So before worrying too much about intricate workouts, build aerobic volume at “Zone two.” Zone two itself is subject to debate, but you can think of it as an aerobic intensity that is a five or six on the perceived exertion scale, or easy to easy-moderate exertion where you can comfortably hold a conversation. For my athletes, we use 81 to 89 percent of LTHR.
For most athletes, at least 80-percent of your training should be aerobic. Add fast strides and short intervals to aerobic training to improve running economy, and you are ready for intervals that directly target LT. The extent of aerobic training depends on your background and goals, but most athletes should spend at least a few weeks doing easy running before jumping into harder workouts.
Now is when “threshold” or “tempo” running comes in. Remember, tempo usually corresponds with the effort you could sustain for about an hour. It’s not a race—by training at LT, rather than going as fast as you can, you can elicit more improvement. The general principle is to run 20 to 45 minutes at LT over the course of a workout, broken up as needed, on terrain that suits your goals.
What are examples of LT workouts?
Within those general constraints—20 to 45 minutes at LT—LT workouts can take any form. You can do the LT workout in one tempo run, or over the course of intervals with half the recovery time or less (Coach Jack Daniels would call these “cruise intervals”). Here are five examples (do 20 minutes of easy running before and after each workout).
The Steady Freddie: Thirty minutes at LT on terrain similar to your race. This workout is hard, but not so taxing that you’ll need to be scraped off the trail with a spatula. You can also take a couple minutes of easy running recovery in the middle. This workout is simple and achievable, good for all levels.
The Cruisey Susie: Six to eight x 4 minutes at LT with two minutes of easy recovery. This “cruise interval” workout is an ideal intro to LT training, since the recovery periods make it comfortable. It has the benefit of making sure you are running fast at LT, since many trail runners will have biomechanical fatigue with sustained efforts that is lessened with shorter intervals. Don’t go too fast, even though you’ll be tempted to.
The Crooked Buzzsaw: Eight to 12 x 3 minutes uphill at LT with one minute of jog down recovery. For this workout, you need a long hill. This workout is relatively low stress, with reduced pounding, so is a great option for low volume runners or runners over 50.
Like Riding a Bike: Two x 20 minutes at LT with five minutes of easy recovery. This workout mimics the classic bike workout designed to improve power. Since the physiological principles are the same, it’s also one of the best run workouts, but comes with additional injury risk since 40 minutes at LT running involves lots of pounding on your legs. Only advanced runners should do the full workout.
Ladder to Heaven: 1/2/3/4/5/4/3/2/1 minutes at LT with one minute easy recovery. This workout is similar to the Cruisey Susie, but with some variation in interval length that keeps it fresh. Ladders are a great option to optimize time at LT while keeping the run interesting.
When are LT workouts most beneficial?
The goal is to train your body to go faster at LT, so it’s essential to do LT workouts rested and ready, providing enough recovery time afterward for adaptation. In general, do no more than two LT workouts each week. For trail runners, a great option is to embed a LT workout within a weekend long run. For example, the Crooked Buzzsaw (30 minutes at LT) can be added in the middle of a two- or three-hour run. Like all training, LT workouts have diminishing returns, so after four to six weeks, mix up your training, emphasizing more intense VO2 max efforts or longer aerobic threshold training.
Smooth is sustainable. Lactate-threshold training helps make your smooth pace faster, which means you’ll be able to sustain faster paces on race day.
David Roche runs for HOKA One One and NATHAN, and works with runners of all abilities through his coaching service, Some Work, All Play.