I continue to think about this issue personally.
variously lifted from: http://www.ankerberg.com/Articles/new-age/NA1201W1.htm
We see in every country sects that attempted the control of prana. In this country there are mind-healers, spiritualists, Christian Scientists, hypnotists, and so on. If we examine these different sects, we shall find at the back of each is the control of prana, whether they know it or not. If you boil all the theories down, the residuum will be that. It is one and the same force they are manipulating.... Thus we see that pranayama includes all that is true even of spiritualism. Similarly, you will find that wherever any sect or body of people is trying to discover anything occult, mysterious, or hidden, they are really practicing some sort of yoga to control their prana. You will find that wherever there is any extraordinary display of power, it is the manifestation of prana. 13"
?The concept of prana ("breath") is a key to the process. Pranayama refers to the knowledge and control of prana, or mystical energy, not merely to the control of one's physical breath. 9 Prana is believed to be universal divine energy residing behind the material world (akasa). Prana is said to have five forms, and all energy is thought to be a manifestation of it. Swami Nikhilananada describes it in his Vivekananda—The Yogas and Other Works as "the infinite, omnipresent manifesting power of this universe." 10 Perfect control of prana makes one God. One can have "infinite knowledge, infinite power, now":
What power on earth would not be his? He would be able to move the sun and stars out of their places, to control everything in the universe from the atoms to the biggest suns. This is the end and aim of pranayama. When the yogi becomes perfect there will be nothing in nature not under his control. If he orders the gods or the souls of the departed to come, they will come at his bidding. All the forces of nature will obey him as slaves.... He who has controlled prana has controlled his own mind and all the minds... and all the bodies that exist.… 11
"In other words, prana, God, and occult energy are all one and the same. The one who practices yogic breathing (pranayama) is by definition attempting to manipulate occult ("divine") energy."