Question about meds and breathing techniques.

Ok, so it seems like when I take my prescribed benzo it will definitely give me the feel of being calm, but sometimes my heart will still be racing anyways even though I feel entirely calm. So then, I do breathing exercises and it seems to effectively lower my heart rate.

So my question is: is it just the manner that I breath in that causes the heart to speed up? Cause the meds calm me but not the heart rate until I change the way I am breathing. So am I just not breathing properly?

For a while now I have felt like it really is just the breathing that causes my heart rate to go up on top of the anxiety as well which is just my theory. So maybe I somehow need to retrain myself to breath normally i.e. not fast and shallow when I am not breathing deliberately and rather by homeostasis?

I'm not sure I just feel like somehow breathing rates and that stuff could have a large part in all of this.

I don't know when I started doing it maybe in military but when I am under stress I tend to hold my breath
like one would playing football just before making contact with one of the other players, or like when expecting to take a punch, kind of a tendency to swell up for a few seconds. During long term stress I start to notice that I feel short winded from not breathing properly, hope I explained this well enough. Peace

Larry ***