Underdog

What is Underdog?

Underdog turns heart rate zones into points so you can compete with friends in weekly leagues. It syncs automatically with Apple Health and Apple Watch, so every workout counts without manual logging. The app tracks your time in zones Z1 to Z5, gives more points for harder effort, and shows where you spent your training time. You can join public leagues or create private ones with invite codes. It’s built around fair competition, where effort matters more than pace, gear, age, or fitness level. Health data stays on your device and is never used for ads.

Key features

• Weekly leagues with promotion and relegation.
• Tracks heart rate zones from Z1 to Z5.
• Syncs automatically with Apple Health and Apple Watch.
• Rewards effort with points for every training minute.
• Creates private leagues with shareable invite codes.
• Keeps health data on device, without ads.