This article is for informational purposes only and does not replace consultation with a running coach or sports physician. Before starting intense training, especially after a long break, consult a specialist.
Lactate threshold (also called the anaerobic threshold) is the intensity of effort at which the body starts producing lactate faster than it can clear it. For runners it's one of the key endurance parameters — it determines how long you can hold a given pace before muscles rapidly acidify and performance drops off.
What happens in the body at lactate threshold
Below the lactate threshold, the body works mainly aerobically, and lactate is efficiently cleared from the blood. Once you cross the threshold, lactate production rises sharply, muscles become acidic, and the effort becomes increasingly hard to sustain. That's why a tempo run "at threshold" is demanding but still sustainable for 20-60 minutes, while running above threshold leads to rapid fatigue.
How to estimate your own lactate threshold
The most accurate method is a lab test measuring blood lactate concentration during progressively increasing effort. In practice, simplified home methods are commonly used:
- Threshold pace test — a 20-30 minute run at the highest pace you can sustain without your muscles "seizing up"; the average heart rate from that run is an approximation of threshold heart rate.
- Percentage of maximum heart rate — in trained runners, lactate threshold typically falls at 85-90% of HRmax, though this figure is highly individual.
- Race pace over 10-21 km — for many runners, threshold pace is close to the pace they hold over a half-marathon distance.
Worked example
If a runner has a maximum heart rate of 190 bpm, their lactate threshold might fall around 85% of that value, i.e. about 162 bpm. Threshold training should be done in a heart-rate zone close to that value, e.g. 155-165 bpm, to effectively stimulate endurance adaptations without excessive fatigue.
How to train to raise your lactate threshold
- Tempo runs — 20-40 minutes of continuous running at threshold intensity, once a week.
- Threshold intervals — e.g. 4-6 × 6-8 minutes at threshold pace with short recoveries.
- High volume of easy running — builds the aerobic base that indirectly pushes the lactate threshold higher.
- Consistency — adaptations at the muscular and vascular level require many weeks of consistent training.
Why it matters for race planning
Knowing your lactate threshold lets you choose race pace deliberately — running just below threshold for most of the distance and only crossing it near the finish is a proven strategy in long-distance races.
Check your heart-rate zones for threshold training: Heart rate zones calculator →
Frequently asked questions about lactate threshold
How is lactate threshold different from maximum heart rate?
Maximum heart rate is the highest value the heart reaches during maximal effort. Lactate threshold is a much lower intensity (usually 80-90% of HRmax) at which muscle acidification begins to rise sharply.
Can lactate threshold be raised through training?
Yes, it's one of the most trainable endurance parameters. Regular tempo and interval training combined with a large aerobic base effectively shifts lactate threshold upward over the course of several months.
How long can you run at lactate threshold?
Usually 20 to 60 minutes, depending on training level. Sustaining that intensity longer leads to mounting fatigue and a drop in pace.
Is lactate threshold the same in running and cycling?
No. Lactate threshold is specific to the muscle group and discipline involved — a runner may have a different threshold on a bike than while running, despite a similar overall fitness level.
How often should you train at lactate threshold?
Usually one session a week is enough. Training at threshold too often increases the risk of overtraining and injury, since it's an intense, demanding effort.
Should recreational runners even bother knowing their lactate threshold?
Yes, knowing your approximate threshold helps you choose the right training pace and avoid running too hard on sessions that should stay easy.
Does diet affect lactate threshold?
Indirectly, yes — adequate carbohydrate intake and hydration affect endurance and the ability to sustain threshold effort, though the threshold itself is shaped mainly by training.
Does lactate threshold change with age?
Yes, as overall fitness declines with age, heart rate at lactate threshold typically drops, though regular training can slow that process.
What's the difference between a lab test and a home estimate of threshold?
A lab test measures actual blood lactate concentration and is the most accurate. Home methods (e.g. a 20-30 minute pace test) only give an approximation, but it's good enough for planning recreational training.
Is lactate threshold the same as aerobic threshold?
Not quite. Aerobic threshold is a lower point at which lactate production starts to rise, while lactate (anaerobic) threshold is the intensity at which the body stops keeping up with clearing it. The two thresholds mark different training zones.