Is it normal to be able to voluntarily slow my heart rate?

I do have anxiety and my heart races on occasion, randomly or with panic attacks, but is it normal to be able to slow my breathing and heart rate easily?
It's almost as if I can feel a coolness rushing through my arms and the rest of my body when I do it.
I've never really talked about it, so I'm not sure if it's something most people can do or not.