Heart Rate Zones: Underdog

Zone 2 Training & Leagues

Only for iPhone

Free · In‑App Purchases

iPhone

Underdog turns your Apple Watch heart rate data into a game. Every minute you spend in Zone 2 — the sweet spot for endurance and fat burning — earns you points. Compete in weekly leagues with friends and climb from Bronze to Diamond. No manual logging. No ads. Just open the app once and your workouts sync automatically from Apple Health. WHY ZONE 2? Zone 2 training (60–70% of your max heart rate) is the foundation of every elite endurance program. It builds your aerobic base, improves VO2 max, and burns fat — without burning you out. The catch: most people train too hard to actually be in Zone 2. Underdog shows you exactly when you're in the zone. FEATURES * Automatic Apple Watch sync — workouts appear in seconds * 5 heart rate zones (Z1–Z5) calibrated to your max HR * Weekly leagues: Bronze, Silver, Gold, Platinum, Diamond * Points for every Zone 2+ minute * Achievements, streaks, and personal records * Friend leagues — invite via link * VO2 max tracking from Apple Health * Works with running, cycling, rowing, hiking, and 40+ workout types FREE Underdog is free to use. Optional Underdog Pro unlocks unlimited friend leagues, advanced stats, and custom zones. TERMS & PRIVACY Terms of Use (EULA): https://tryunderdog.com/terms Privacy Policy: https://tryunderdog.com/privacy Subscriptions auto-renew unless cancelled 24 hours before the end of the current period. Manage in Settings → Apple ID → Subscriptions.

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- UX fixes and improvements

Version 1.5

The developer, Ignas Velza, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    • Ignas Velza
    Size
    • 20.2 MB
    Category
    • Health & Fitness
    Compatibility
    Requires iOS 26.0 or later.
    • iPhone
      Requires iOS 26.0 or later.
    Languages
    • English
    Age Rating
    4+
    In-App Purchases
    Yes
    • Premium (Lifetime) $99.99
    • Premium (Weekly) $2.99
    • Premium (Annual) $29.99
    • Learn More
    Copyright
    • © 2026 Ignas Velza
  • Developer Website
  • Privacy Policy

    • More by Ignas Velza

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