Δέσε.Κορδόνια

What is lactate threshold and why it's the key to endurance

19 June 2026 · Science · 5 min read

Runner tying their laces before a tempo session

If you've heard coaches or experienced runners talk about "threshold", you may have wondered what it actually means. It's one of the most important concepts for endurance — and luckily it's easy to explain.

First: what is lactate?

When you run, your muscles produce energy. At low intensity, the body manages easily. But as the intensity rises, lactate is produced as a by-product. At low paces, the body keeps "clearing" it. There comes a point, though, where lactate starts to accumulate faster than it can be removed.

How the threshold works: lactate production vs clearance

Low intensityBalanced · run for hours
At thresholdProduction = Clearance
Above thresholdBuild-up → fatigue
As intensity rises, lactate production outpaces clearance. The balance point is your threshold.

The threshold

That exact point is the lactate threshold: the maximum intensity you can sustain for a long time without "drowning" in lactate. Just below it, you can run for a long time. Just above it, fatigue comes quickly.

💡 In practice: The threshold is roughly the pace you could hold in a 1-hour race. A "comfortably hard" pace.

The "Talk Test": read your intensity from your speech

Easy "Coffee after this?" Full sentences, no trouble
Threshold "Yeah… later…" Only a few words at a time
Intervals "…" Can't talk at all
No watch needed: at threshold you can say a few words — not a full conversation.

Why does it matter?

The higher your threshold, the faster you can run before tiring. Two runners with the same VO₂ max can have very different performance — and the difference is often exactly here.

Same VO₂max — different threshold

Runner A VO₂max 55 Threshold 80% 4:45 /km ≈ 1 hour
Runner B VO₂max 55 Threshold 90% 4:20 /km ≈ 1 hour
Same "engine", but Runner B holds a faster pace for an hour — thanks to a higher threshold.

Why do top runners care so much about the threshold?

The reason athletes like Jakob Ingebrigtsen and Eliud Kipchoge can run so fast for so long isn't only their large VO₂ max. It's also their ability to sustain high speed without fatigue building up quickly. In simple terms: they've pushed their threshold very high.

📌 Did you know? An amateur runner is at their threshold at roughly 80–90% of their maximum heart rate, while elite athletes can sustain very high intensity for a much longer time.

How do you improve it?

With tempo (threshold) workouts: running at that "comfortably hard" intensity for 20–40 minutes (continuously or in intervals). Over time, the body learns to manage lactate better, and the threshold rises.

Tempo / threshold run20–40 min at that "comfortably hard" intensity
The body adaptsLearns to clear and reuse lactate better
The threshold risesYou clear and use lactate more efficiently at the same pace
Faster racesSame effort · more speed
Tempo workouts push your threshold higher — and that's where the biggest endurance gains hide.

Be careful though: the threshold is only one piece. You also need easy days for your base — remember the 80/20 rule. Balance is the secret.

You don't need a lab to improve. You need consistency, patience and a few targeted tempo workouts. Your body takes care of the rest. 🏃‍♀️

3 things to remember

  • It's the pace you can hold for about an hour.
  • It matters more than VO₂max for real speed.
  • Raise it with 20–40 min tempo runs.
← Back to Blog