Whistle is very simple application on the surface but offers some great features for the fitness enthusiast.

- Totally integrated with Apple Health
- Clean and simple interface legible during your activities
- Large display of color coded metrics (HR, pace, distance, hr zones, target ...)
- No need to bring your phone on your runs/hikes/walks/rides
- Follow your track back if lost
- Load a GPX route and follow the green track
- Zoom in and out using the Digital Crown
- Create and load structured workouts
- Watch will notify you for every workout phase with haptics/visual/voice
- display of the GPS signal quality
- Control your music from the app