I believe it is both. Physically place your hand over your heart and become aware of yourself right this moment. By focusing on your heart, you are distracting your mind from what it was thinking and breaking your current state. This then changes your state and leads to a calming. Once you do this a couple times, it is then a memorable experience (anchored) and can be recalled metaphorically which will also change your state just by thinking about it.
That's my experience of it anyway.