Training
Zone 2 Heart Rate Calculator
Zone 2 is the aerobic base-building zone — hard enough to drive adaptation, easy enough to sustain for 30–90 minutes. Enter your age to find your exact range.
Calculator
Find Your Zone 2 Range
Find it in your Oura, WHOOP, or Apple Health app — it shows up in your sleep or recovery summary. Skip if you don't have a wearable.
Why Zone 2 matters
- 🫀Mitochondrial density: Zone 2 training signals your body to build more mitochondria — the cellular engines that burn fat and produce energy. More mitochondria = better aerobic capacity.
- ⚡Fat oxidation: At Zone 2 intensity, fat is your primary fuel. Training in this zone improves your body's ability to use fat efficiently at all intensities.
- 🔁Aerobic base: Elite endurance athletes spend 70–80% of their training in Zone 2. It's not just for endurance — a stronger aerobic base improves recovery between hard efforts.
The Zone 2 Cardio Protocol
How to structure Zone 2 sessions for maximum aerobic adaptation.
