Help with your zones.

Because Alisio is not installed on your Watch yet, and the Train tab says so right under the button: Install Alisio on your Apple Watch to start. Open the Watch app on your iPhone, go to Available Apps and install Alisio. The button turns your zone's colour on its own once it is there. If the button is lit but the session does not start, the Watch is usually asleep or Alisio is closed on it: open Alisio on your Watch and tap the button again.

It means the Watch is not getting readings. The first time you start a session, the Watch asks Apple Health for permission to read your heart rate and active energy and to save the workout. If that was declined, open the Health app on your iPhone, tap your profile picture, then Apps, pick Alisio and turn those on. On the iPhone, No data from your watch. Is Alisio still open there? means the Watch has stopped sending: raise your wrist and check that Alisio is still running.

From two numbers you set once, in Settings: your age and your resting heart rate. Your age estimates your maximum heart rate with the Tanaka formula (208 minus 0.7 times your age). Karvonen then spreads the five zones across the gap between your resting and your maximum, so your fitness counts; Simple takes plain percentages of the maximum and needs only your age. Zone 1 starts at 50% and each zone is ten points wide, up to 100% in Zone 5. Change either number and Your zones recalculates on the spot and is sent to your Watch.

Yes. Open Alisio on your Watch, turn the Digital Crown to pick a zone and tap Start. It remembers the zone you used last. A session started from the Watch has no time goal: the clock runs free and the zone taps work the same. The Watch needs your profile first, so open Alisio on your iPhone once before you head out. When you finish, the session reaches your History as soon as your iPhone is nearby again.

No account, no sign-in, nothing to pay for inside the app. Your profile and your session history live on your iPhone; the Watch gets a copy of your profile directly from it. Nothing goes to iCloud and nothing goes to us. The finished workout is also saved in Apple Health, and stays there as a regular workout.

To remove one session, open it in History, tap the trash icon and confirm. Deleting the app removes your profile and your whole history from your iPhone. The workouts Alisio already saved in Apple Health belong to Health and stay there; delete those from the Health app.