I think its the same as biofeedback not sure though. I do a form of it. I don't use machines and so on too expensive but do put my hand on my stomach or over my heart and I slow my breathing down which slows my heart rate down. It really helps during panic attacks. I also use this when I have muscle spasms. my first instinct when one happens is to tighten up and hold by breath through the pain so I instead pay attention to remaining loose and then even looser in that muscle and slowing my heart rate out of the panic/pain mode.