You can learn about the intensity level of your cardio-focused workout by viewing Heart Rate Zone information on your Apple Watch. Heart Rate Zones are a percentage of your maximum heart rate and are automatically calculated and personalized using your health data. On Apple Watch, Heart Rate Zones are presented in five segments—estimated effort levels ranging from easier to harder. By monitoring your Heart Rate Zone, you can make your workout more efficient and challenge yourself to improve your fitness.
Note: Heart Rate Zones are calculated only if you’ve entered your date of birth in the Health app on your iPhone.
Go to the Workout app on your Apple Watch.
Go to Workout > Heart Rate Zones.
Tap Manual, tap zone 2, 3, or 4, then enter lower and upper limits.
You can also open the Apple Watch app on your iPhone, tap My Watch, go to Workout > Heart Rate Zones, tap Manual, tap zone 2, 3, or 4, then enter lower and upper limits.