Setting option "heart rate measurement only together with the start of an activity"?

You can do this a couple of ways (I had the same thought, when I moved to my VA3, from a couple of FBs, which obviously support this, automatically).

1. I created a couple of duplicate activities (unfortunately with the VA3, there's no way to rename them, that I ever found), say called "Walk(2)" and "Bike(2)". These can then be customized to have the GPS disabled. When you choose one of these, the HR-only measurement starts, as expected.

2. Each time you start an activity, there's a "Settings" button on the bottom of the activity screen. Touch this, and you can disable the GPS, for that activity.

I think solution #1 is handier, because I can choose, and even have one set to auto-start (requires GPS on the VA3, IME), and one not.

Thanks for your post pgrey.
Sorry, I think Google Translate did a bad job for me ;)
What I want is to turn off the HR measurement in general. When I start an activity, the HR measurement should turn on automatically. When I finish the activity the HR measurement should turn off automatically.
My Vivomove HR has this setting option.

Hamilton7 I'm pretty sure that's exactly how the VA3 will behave, if you turn off the general HR setting.
Then, when you start an activity with HR enabled, it should auto-start the HR, just for the activity.

I'm not sure, are you saying you've tried this, and it doesn't?

Unfortunately HR can not be activated in the setting of my activity (walking). Such a switch would make me happy :)

Yeah, my bad, I'm used to more of a "per activity" from my FB.
I think this will still work, if you have an external HR source, say from an optical HRM, or similar. Not exactly ideal though.

The consistently-inconsistent interfaces into the settings is a bit confusing, in this regard too, IMO, on Garmin. You can do some stuff on a PC, sort of a super-set on Android, and a handful of settings are watch-only (that I've ever found anyway).