Training by Heart Rate Zones

Max heart rate

The old formula 220 − age is off by 10+ bpm for many people. Better: **211 − 0.64 × age** (Nes et al.).

The five zones

• Z1 50–60% recovery
• Z2 60–70% aerobic base
• Z3 70–80% tempo
• Z4 80–90% threshold
• Z5 90–100% VO₂max

Why zone 2 matters

Long, easy work in Z2 builds mitochondrial density, which powers everything else. 80% of pro endurance training is Z2.

Finding your zones

Use our heart rate calculator to get a starting range, then confirm with a talk test: Z2 lets you talk in full sentences.