When was the last time you gave lactate threshold training a second thought?
Chances are, you get frequent notifications about your lactate threshold (LT) on your smartwatch. You also know it’s a bona fide performance benchmark for endurance training — akin to the bench press for a strength athlete. But do you have a sound training strategy to take your LT to the next level? If you are like most runners, you schedule the odd LT workout once a week and leave it at that. And that’s a shame.
Because lactate threshold training is the low-hanging fruit to become a faster runner!
What is the Lactate Threshold?
Lactate is a byproduct of anaerobic metabolism (energy produced outside the mitochondria without oxygen).
The higher the anaerobic contribution, the more lactate is generated. Hence, blood lactate values differ significantly between different training zones and races. The marathon sits at a low 2.5 mmol/L, the 5K around 6.5 mmol/L, and the 400m sprint can easily reach 25 mmol/L. In other words, your blood becomes more acidic if you turn up the intensity.
The aerobic nature of easy and moderate runs doesn’t cause a significant rise in blood lactate, indicating that the body is in equilibrium. But once we enter training intensities above marathon pace, we need to be conscious of the 2 thresholds:
The Aerobic Threshold (LT1)
- ~ 2 mmol/L. The first threshold occurs above which blood lactate levels climb above baseline. This is significantly faster than an easy run but slow enough to hold this pace for 2 – 3 hours in a race. Tempo runs at 30K to marathon pace are in this zone and can help to push your aerobic threshold upwards to narrow the gap to your lactate threshold.
The Anaerobic Threshold (LT2)
- ~ 4 mmol/L. The second threshold is defined as the intensity above which blood lactate is produced faster than it can be cleared. This effort can be held for about an hour, which represents 10K pace for beginners, 15K pace for well-trained amateurs, and half marathon pace for elite runners. This is the intensity when we speak about the “lactate threshold”.
Lactate Threshold vs VO2max
Is VO2 max or the lactate the ultimate arbiter for faster race results?
Generally speaking, a high VO2 max is critical for shorter races such as the 5K and 10K, whereas the lactate threshold gains importance for the half marathon and marathon. But your lactate threshold and VO2 max are tightly linked. If you improve your LT, then you can race at a higher percentage of your VO2 max. And if you enhance your VO2 max, your velocity at lactate threshold is higher even though the lactate threshold per se didn’t change. But VO2 max, however important, doesn’t seem to change much above a certain weekly mileage and training years whereas the lactate threshold continues to improve.
Have a look at the percentage of VO2 max where the lactate threshold occurs at different training levels:
- Beginners 55 – 65% of VO2 max
- Competitors 75 – 85% of VO2 max
- Elite level 90 – 95% of VO2 max
How to Determine Your Lactate Threshold
If you were part of an elite running team, your lactate threshold would be tested frequently in a lab.
While you, too, could get tested in a laboratory, this would incur a hefty bill over time, not to mention the inconvenience associated with it. But it isn’t necessary. Here are the three options that are just fine to get a good approximation of your current lactate threshold, all of which are accurate enough unless you train for the Olympics.
Estimating the Lactate Threshold
The easiest way is simply to ‘guesstimate’ your LT. We know the lactate threshold is at roughly our 1-hour race pace. So you could punch a recent race result into a running calculator and then see where you stand for a fictional race over 1 hour. It’s between 10K and half marathon pace for most runners.
Lactate Threshold Running Test
Another option is a running test. Warm up for 10 – 15 minutes, then run hard for 30 minutes. It’s not an all-out time trial, but it’s not far from it either. Your average pace of that test is a good estimate of your current LT pace and the average heart rate of the last 20 minutes is your LT heart rate. Dismiss the first 10 minutes because of the heart rate lag.
Portable Lactate Analyzer
If you really want to geek out about it, then get a portable lactate analyzer. They will relieve your wallet of about $500, but that’s also the cost of a top-notch running smartwatch. The other question is whether you are comfortable taking blood from your earlobes or fingertips. If you are, by all means, go for it.
How to Monitor Your Lactate Threshold
Once you have determined your lactate threshold, you can monitor it during your training using pace, heart rate, or power. A fourth option is the ‘rate of perceived exertion’ (RPE), but that’s only viable for very experienced runners. Also, why would you forego the technological advancements accessible on your wrist, besides perhaps getting a feel for LT pace occasionally?
Lactate Threshold Pace
Monitoring your threshold runs by pace is fine as long as you run on flat terrain. But once you encounter hills, your pace will not reflect your actual effort. Be conscious of this and keep an eye on your running watch’s heart rate or power reading. I recommend always having pace and HR on display to check for discrepancies.
Lactate Threshold Heart Rate
As mentioned, running on undulating terrain is preferably monitored by heart rate. The same is true for runs on hot summer days when blood is directed away from the working muscles to the skin to keep your body’s core temperature in check. The drawback of heart rate is the delayed response in the first few minutes and the heart rate drift toward the end of a run.
Lactate Threshold Power
Power meters didn’t need to be invented if pace and heart rate monitoring were perfect. For that reason, they are becoming more popular, and their technology is advancing rapidly. Power meters represent an accurate effort regardless of the terrain. But they’re not yet on par with the power meters used in cycling, where power is measured directly on the pedal.
Lactate Threshold Training
So, how can you improve your lactate threshold?
By running at the lactate threshold. At least, that would have been the standard answer not long ago. However, scientific knowledge and empirical experience have evolved in recent years. Today’s elite runners frequently use intensities just above and below their LT to push their lactate turnpoint upwards. Assuming your lactate threshold is at 15K pace, weave 10K and HM pace into your threshold training.
How Long Can You Run at Lactate Threshold?
As a rule of thumb, you can sustain 1/3 to 1/2 of your race distance in training. That means 20 – 30 minutes at a steady pace for the lactate threshold. While the intensity allows for a continuous effort, breaking it down into intervals is not uncommon. But unlike VO2 max intervals, the rest periods must be kept much shorter than the work intervals. The goal is a systemic lactate buildup; otherwise, it blunts the adaptations, such as an increased ability to clear lactate.
How Often Should You Run at Lactate Threshold?
Most runners schedule a lactate threshold workout once a week. Given three key workouts a week, it’s typically a speed/VO2 max session, a threshold run, and a long run. But the emphasis should change depending on your race distance and the training phase you are in. For example, if you are in base training, you may leave out tempo runs altogether or do a minimal amount for maintenance. And if you are in the final weeks of a 5K race preparation, LT training has to give way for the more race-specific VO2 max sessions. For the half marathon, in contrast, two LT workouts a week make sense in the final 6 weeks of race preparation plus an optional fast-finish at LT pace on some of your long runs.
The Norwegian Model of Lactate Threshold Training
The Ingebrigtsen family made headlines in recent years with their lactate-guided training method. They run most of their threshold training not directly at the lactate threshold of 4 mmol/L, but closer to 3 mmol/L. The rationale is that the body can absorb significantly more training slightly below the lactate threshold. With this approach, fewer fast-twitch fibers are called into action while slow-twitch fibers are still maximally recruited.
Consider my online coaching if you want to emphasize this method in your training.
The 5 Best Lactate Threshold Workouts
Here are 5 workouts (+1 non-running method) that increase your LT and, therefore, your time to exhaustion at race pace.
The warm-up for a lactate threshold session is simpler than for a VO2 max workout. Run easy for 10 minutes, followed by a few dynamic stretches and two or three strides. That’s it. After your main set, cool down for 10 minutes with easy running. If you are a high-mileage runner, do a 20-minute warm-up and cool-down.
Classic Tempo
This is a steady-state effort at your lactate threshold. Beginners may only run 15 minutes at this intensity, but advanced runners can go up to 30 minutes. Note that I use the term “tempo” for intensities at the lactate threshold here. It’s common to call efforts at marathon pace tempo runs, too. Due to their lower intensity, these can be 40 – 60 minutes long.
- 15 – 30 min @ 15K pace
Tempo Intervals
LT intervals are run at the same intensity as continuous tempo runs. However, the inclusion of rest intervals makes them more manageable. That means you can accumulate more time at the lactate threshold as you would in a continuous effort.
- 2-3x 10 min @ 15K pace w/2 min easy
- or
- 2x 10-15 min @ 15K pace w/3 min easy
Cruise Intervals
Also known as supra-threshold intervals. With an intensity slightly above the lactate threshold, the work intervals are shorter than during the classic tempo intervals. This is a great workout to increase your lactate buffering capacity.
- 4- 6x 5 min @ 10K pace w/90 sec easy
- or
- 5-8x 4 min @ 10K pace w/60 sec easy
Alternations
Change-of-pace tempo runs are a newer form of lactate threshold work. Here, the pace alternates between work bouts 2.5 – 5% faster/slower than your lactate threshold. That’s about 10 – 20 seconds per mile (6 – 12 sec per km) above/below LT pace. Alternation workouts have no rest interval.
- 2 – 3x (5 min @ HM + 5 min @ 10K pace)
- or
- 2 – 3x (5min @ 15K pace +/-10 sec per mile)
Tempo Progression
Progression runs also combine different paces, but they do so in a linear fashion. As the name implies, the pace progresses from lower to higher intensities. Tempo progressions can also be placed at the end of long runs during the buildup to a HM or marathon. Use that option in moderation, as a long run is a hard workout in itself.
- 15 min moderate (optional)
- 15 min @ marathon pace
- 15 min @ 15K pace
- or
- 10 min @ marathon pace
- 10 min @ HM pace
- 10 min @ 15k pace
Cross Training
Yes, cross-training is an effective means to increase your lactate threshold, and that’s precisely because it’s non-specific to running. Let me explain. Cross-training recruits muscle fibers that aren’t used in running and trains them to gobble up the excess lactate that is produced during running at lactate threshold and above. This process is called lactate shuttling. For me, this means boxing and Muay Thai, but for you, it may be CrossFit classes or swimming intervals at high intensity.
Summary
- Determine your aerobic (LT1) and anaerobic (LT2) thresholds
- Periodize your lactate threshold training progression
- Vary your lactate threshold format (e.g., steady vs intervals)
- Utilize paces close to LT, such as 10K and HM pace
- Adjust LT training to your upcoming race distance
- Cross-train to improve lactate shuttling
