Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
The aerobic threshold (LT1) is the first inflection point in blood lactate, typically at 60-70% of VO2 max. Below LT1 is pure aerobic metabolism (Zone 1-2); above it, lactate begins to accumulate slightly but remains manageable. Training at and just below LT1 (Zone 2, conversational pace) builds aerobic base, mitochondrial density and fat oxidation capacity. Long-duration low-intensity training specifically targets the aerobic threshold and is the foundation of most endurance training models.
- First lactate inflection point (~60-70% VO2 max)
- Upper boundary of Zone 2 training
- Below: pure aerobic; above: slight lactate accumulation
- Zone 2 training raises aerobic threshold
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Training just below aerobic threshold (often called 'zone 2') builds the mitochondrial density and fat-burning efficiency that underpins all higher-intensity performance — many elite endurance athletes spend 70-80% of their weekly volume at or below this intensity, using the easy conversational effort as the foundation the rest of their training is built on.
FAQ
How do I know if I'm training at aerobic threshold?
You can typically hold a full conversation without gasping for breath — if you can speak only in short phrases, you've likely exceeded aerobic threshold into a harder zone.
Is training below aerobic threshold a waste of time?
No — this easy-effort zone builds the aerobic base (mitochondrial density, capillary network, fat oxidation) that higher-intensity training depends on; skipping it is a common mistake among time-crunched athletes.