You need to go to Sports Health app Home > Smart Devices, click on the connected wearable devices, enter the device management interface, and turn on the automatic heart rate measurement switch. When turned on, the heart rate sensor of the wearable device will measure the heart rate in stages.
During rest or low-intensity activities, the heart rate is measured every 30 minutes or 10 minutes.
Your heart rate will be continuously measured when you run or engage in high-intensity activities.
After the automatic heart rate measurement is turned on, you can see the heart rate monitoring curve of the whole day, including the sleep heart rate at night, on the sports health app. If automatic heart rate measurement is turned off, no curve will be generated.