Interval Training Timer for iPhone & Apple Watch
How do I set my max heart rate? Go to Settings and toggle “Manual Override” under Heart Rate Max. If you don’t override it, the app estimates your HRmax from your age using the Tanaka formula (208 - 0.7 × age).
Why isn’t my heart rate showing during the workout? Heart rate data requires an Apple Watch paired and running the companion app. Make sure you’ve granted HealthKit permissions when prompted during onboarding.
Can I change the interval durations? The 4x4 protocol uses fixed 4-minute intervals and 3-minute recoveries. You can adjust warm-up and cool-down durations in Settings.
Where is my workout data stored? Your workout data is saved on your device and to Apple Health. The app keeps your workout history locally on your device so you can review past sessions, and you can delete any workout from the History screen. The app has no server and no analytics, you don’t need an account, and it does not transmit your data off your device. Anything you share with another service is your choice.
The app crashed or something isn’t working. Please contact us using the email below with a description of what happened. Include your iPhone model and iOS version if possible.
For bug reports, feature requests, or questions: alicedevwin@icloud.com