Wanted to add to this question.
In some texts written by instructors it is said that one should transmute (do pranayama) in complete silence and calmness. That is breath slowly, through nose and deeply. But at the same time with minimal noise and try to transmute visually on the deeper level (focusing on the inside leaving outside behind, not having any distractions such as hearing sound of breathing, trying to transmute on subtle level without focusing on physical aspect of breathing for transmutation/pranayama to be effective). It was stated for effective transmutation to happen one must do it silently, without words and etc (only mentally chanting them). Breathing in slowly through nose, holding breath in a comfortable manner, directing energy to head, then to between eyebrows, then slowly exhaling through nose directing energy to heart leaving it there.
Ham-Sah practice is more active and produces more sound.
So the question is does pranayama always transmutes energy or there is some pranayamas for transmutation other for something else?
I sometimes see contradictions in instructions (maybe it is me that does not fully understand, or there is just different ways on doing these things).
Also is holding breath mandatory? I have trouble doing it comfortably as stated in some instruction. I can hold breath for second or two then it becomes stressful (I believe my lung capacity became smaller due to some circumstances and I can't hold much breath and due to that I tend to breath more often than most people).
Also I can't direct energy while holding my breath as the time span is too short.
How should one direct energy in this situation if he can't hold breath for more than couple of seconds? Is it enough to vaguely visualize energy running to brain and retaining it in there or running energy to brain while inhaling and while exhaling run it to heart with intention for it to stay there?
Any more insight would be grateful.