Key takeaways
Lactate threshold is roughly the hardest effort you can hold steadily, close to your one-hour race pace
Speed at lactate threshold is one of the best physiological predictors of distance running performance
Threshold work builds sustainable speed while intervals near VO2max raise the ceiling, and most plans need both
Two runners can have the same VO2max and very different race results. A big reason is the lactate threshold: how close to their maximum they can run for a long time. Here is what it is, how to find yours, and how to train it.
What is lactate threshold?
Blood lactate is always being produced and cleared. As intensity rises, two breakpoints appear. In their review of threshold concepts, Faude, Kindermann and Meyer described them as:
- The first threshold, where blood lactate first rises above resting levels. Below it is genuinely easy.
- The maximal lactate steady state (MLSS), the highest intensity at which lactate production and removal stay in balance. Above it, lactate keeps climbing and fatigue arrives fast.
When people say "lactate threshold", they usually mean the second one. For most trained people it sits around their one-hour race effort. The same review found 25 different threshold definitions in the literature, which is why lab reports and watches often disagree.
Why it matters
Bassett and Howley concluded that the speed at lactate threshold integrates VO2max, running economy and the fraction of VO2max you can sustain, and is the best physiological predictor of distance running performance. VO2max is the ceiling; threshold is how much of that ceiling you can actually use. See VO2max vs lactate threshold and FTP.
How to find your lactate threshold
| Method | How | Notes |
|---|---|---|
| Lab lactate test | Step test with blood samples each stage | Most accurate; see VO2max tests explained |
| 30-minute time trial | Run or ride all-out for 30 minutes; average heart rate of the last 20 minutes | Good field estimate of threshold heart rate |
| Race pace | Pace you could race for about an hour (between 10 km and half-marathon pace for many runners) | Easy to apply from recent results |
| Feel | "Comfortably hard": you can speak a few words, not sentences | Useful daily check |
| Watch estimate | Algorithm from heart rate and pace | Convenient, often off; verify with a field test |
Once you have a threshold heart rate, the heart rate zone calculator builds zones around it, and the VO2max running calculator turns a race result into training paces.
Threshold vs VO2max work
Threshold and VO2max sessions do different jobs:
- Threshold work is done just below or at MLSS. It is hard but repeatable, so you can do more of it each week and recover quickly.
- VO2max work is done at 90 to 95% of maximum heart rate or more, in intervals of a few minutes. It pushes the ceiling but costs more recovery. See VO2max workouts.
A meta-analysis by Londeree found that training near the threshold was enough to improve thresholds in sedentary people, but that conditioned people tended to respond better to higher intensities. So beginners can get a lot from threshold work; trained athletes need both.
Practical threshold sessions
| Session | Structure | Effort | Best for |
|---|---|---|---|
| Tempo run | 20 to 30 min continuous | Just below threshold | Building the habit |
| Cruise intervals | 4 to 5 × 6 to 8 min, 1 min easy jog | At threshold | Most runners and cyclists |
| Long threshold reps | 3 × 10 to 12 min, 2 min easy | At or just under threshold | Half-marathon to marathon |
| Short threshold reps | 8 to 10 × 3 min, 1 min easy | Threshold pace, controlled | Variety, faster legs |
| Over-unders | 3 × 9 min alternating 2 min just under, 1 min just over | Around threshold | Cyclists, advanced |
Start with one session a week, and finish each one feeling you could have done one more repeat. If heart rate keeps drifting up across reps, you are going too hard.
The Norwegian double threshold
Some world-class Norwegian middle- and long-distance runners popularised a different structure. Casado, Foster, Bakken and Tjelta described it as lactate-guided threshold intervals within a high-volume, low-intensity approach: three to four threshold interval sessions plus one VO2max session a week, with easy running making up the rest of 150 to 180 km a week. The pace is set by blood lactate targets, typically between 2 and 4.5 mmol/L, measured every one to three repetitions. Several of those threshold sessions are done as two sessions on the same day, which is where the "double threshold" name comes from.
The authors suggest that the interval format allows fast speeds at a relatively low metabolic cost, so athletes recover quickly enough to repeat it often. For most recreational athletes, the lesson is not to copy the volume but to keep threshold work controlled rather than racing it. This is related to, but different from, the Norwegian 4×4 used in health studies.
Putting it into a week
Seiler's analysis of elite endurance athletes shows roughly 80% of sessions at low intensity and about 20% hard. A typical recreational week might be:
- Three or four easy sessions in your zone 2 range.
- One threshold session from the table.
- One VO2max interval session, or a second threshold session if you are training for longer races.
See 80/20 training for more detail on balancing easy and hard work.
Frequently asked questions
What is lactate threshold?
The usual meaning is the highest intensity at which lactate production and clearance stay in balance, also called maximal lactate steady state. Above it, lactate keeps rising and fatigue comes quickly. It is roughly the pace you could hold for about an hour.
How do I find my lactate threshold?
The most accurate way is a lab or clinic test with blood lactate samples during a step test. Practical field estimates include a 30-minute all-out time trial, where your average heart rate over the last 20 minutes approximates threshold heart rate, or the pace you could race for about an hour.
How do you improve lactate threshold?
By combining plenty of easy aerobic volume with one or two threshold sessions a week, such as 3 to 5 repeats of 8 to 10 minutes at threshold with short recoveries, or a steady 20 to 30 minute tempo. Well-trained athletes also benefit from harder intervals.
What is Norwegian double threshold training?
A method used by some world-class Norwegian runners in which two threshold interval sessions are done on the same day, guided by blood lactate measurements, within a high volume of easy running. It suits highly trained athletes, not beginners.
Sources
- Faude O, Kindermann W, Meyer T. Lactate threshold concepts: how valid are they? Sports Med, 2009.
- Bassett DR, Howley ET. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med Sci Sports Exerc, 2000.
- Londeree BR. Effect of training on lactate/ventilatory thresholds: a meta-analysis. Med Sci Sports Exerc, 1997.
- Casado A, Foster C, Bakken M, Tjelta LI. Does lactate-guided threshold interval training within a high-volume low-intensity approach represent the "next step" in the evolution of distance running training? Int J Environ Res Public Health, 2023.
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform, 2010.