Zone 2 Index

The Zone 2 coach your watch isn't. Six sub-scores, AI insights, and one composite Zone 2 Index that adapts to your goals. Your data stays on your phone.

Apple Watch tells you how many Zone 2 minutes you logged. Whoop tells you how recovered you are. Nobody tells you what your Zone 2 fitness actually looks like across the six dimensions that matter.

Zone 2 Index reads your existing Apple Health data and computes a Zone 2 Index: a single score across Aerobic Efficiency, Recovery, Consistency, Decoupling, Load Ramp, and VO2 Trend. Each sub-score is conditioned on your goal, whether that is Event Prep, Base Builder, Longevity, Fat Loss, or Maintenance.

Then we explain it. Every week an AI-written digest walks you through what moved and why, grounded in your actual data and never invented numbers.

WHAT YOU GET

• A composite Zone 2 Index across six aerobic dimensions, weighted to your goal
• A weekly digest that reads your training back to you in plain language
• A weekly streak built around rest, not a daily grind
• Per-session detail with your heart-rate trace and splits
• A warm coach voice that gives rest permission, never grind-shame

FREE FOREVER

• Aerobic Efficiency sub-score
• Your weekly Zone 2 minutes
• The last 30 days of history
• Full Apple Health sync

PREMIUM (subscription or one-time lifetime)

• The full six-sub-score Zone 2 Index and every drill-in
• The AI coach on every surface
• Your complete training history
• Achievements and the full weekly digest

YOUR DATA STAYS ON YOUR PHONE No account. No data sharing. No ads. Your raw health data never leaves your device. The only thing that ever goes out is a small, anonymous summary used to write your insights.

For serious amateur endurance athletes, longevity-minded trainers, and anyone who has heard about Zone 2 and wants to actually know how their aerobic fitness is evolving.

Zone 2 Index is a training analytics app. It is not a medical device and does not provide medical advice.

Terms of Use: https://zone2-index-legal.pages.dev/terms.html