Actually theoretically, they say its related to the breath. The amount of breath force u have and how quickly u spend it, that will decide the life span. So by pranayama people learn to slow the breath down and extend the life time or alternatively i think there is one kriya with which u can forcefully spend all the breath force in few breaths only and exit the body. Even in animals its observed that whales and gaint tortoise have less breathing rate and they have much longer life span.
I haven't personally seen anyone doing it but many famous, knwn unkwn incidents i have heard.
The fundamental failure here in logic is that by some cognitive mental exercise, such as: pranayama, or a kriya, one becomes enlightened and empowered. Whereas, we have proven beyond a shadow of a doubt that those schools who are aggressively marketing a cognitive mental exercise have no idea what deep meditation is, nor what the superior attainments are.
There is a video on Jeff's Youtube where they talk about this you may be interested in, and talk about one of the Christian mystics who did this... the conclusion being he let himself die of hypothermia/exposure while OOB, but didn't do it by an act of will.
Thanks, Alexander, that would be Saint Francis of Assisi, who seemed to have born the superior fruit of the contemplative life; whereas, he became quite sickly in his 30s, possibly from too much discipline, from flogging his "donkey" too hard.
Thus we always have to come back to "we know a tree by its fruit." Clearly the schools who have been aggressively marketing a cognitive mental exercise, have not demonstrated that they have any idea what deep meditation is, nor the superior attainments are.