Underdog

Underdog is a heart-rate zone training app built for Apple Watch. It converts every minute you spend in Z1–Z5 into points automatically, so you can compete without manual logging.

To get started, connect Apple Health and wear your Apple Watch. Heart-rate and workout data sync automatically after workouts, and Underdog tracks your training across running, cycling, strength, and HIIT while awarding more points for higher zones.

You’ll earn weekly zone points in Bronze→Diamond leagues that reset each week, with private leagues available via a shareable invite code for friend-only competition. You also get a full Z1–Z5 breakdown and weekly insights like a zone breakdown, step trends, and an intensity timeline.

Do I need to manually log workouts or heart-rate data in Underdog?

No. Underdog connects to Apple Health, then syncs your heart-rate and workout data automatically after workouts, with no manual logging.

Which workouts does Underdog score?

Underdog scores time spent in Z1–Z5 for multiple workout types including running, cycling, strength, and HIIT. Every minute in a zone contributes to your weekly total.

How are points calculated across heart-rate zones?

Every minute spent in Z1–Z5 earns points. Zone 2 builds your aerobic base, while Zone 3 and above score more.

How do weekly leagues and promotions work?

You start in Bronze and climb up through Bronze, Silver, Gold, Platinum, and Diamond based on your zone points. Points reset each week, so consistent performance helps you rise.

Can I compete with friends in a private league?

Yes. Create a private league and share an invite code so friends can join and compete on real-time rankings.

Does Underdog cost money or include ads?

Underdog is free and runs with no ads.