[feature request] heart rate sensor only active while in activity or sleeping

It is already available. Disable the HRM in general settings, and create a Power Mode enabling the HRM. Assign then the power mode to any activity where you want to log the HR. As for the sleep, enable the option Battery Saver @ Sleep, edit the battery saver profile, and enable the HRM there too. 

In GC you cannot enable hrm in battery saver if you have it disable in normal profile.

Have you managed to make it work?

valerhs said:

In GC you cannot enable hrm in battery saver if you have it disable in normal profile.

Ah yes, you are right. In that case you could create an activity profile for the sleep with the Power Mode enabling the HRM, and starting the activity when going to bed.

www.garmin.com/.../

That isnt a solution.

need to be able to turn HR monitor completely off. Only when I click an activity, like a trail run, is when the hr is monitored. Is this possible yet?

7852402 said:

Is this possible yet?

Yes, since the very beginning. As already suggested in this thread earlier, disable the HRM sensor in the general settings, and enable it only in a Power Mode that you activate in the activity profiles you use.

However, please be aware that by disabling the wirst HRM you will lose most of the functionality the watch offers - Body Battery, Stress, Sleep Monitoring, Intensity Minutes, and other features require a functional HRM. Also the Calories calculation, and performance metrics will be influenced, since the watch will not be able to detect your Resting HR. So you will render your smart watch into a simple stupid watch, while you will not gain much battery life.