The Sudarshan Kriya is a breathing technique that involves, as part of its cycle, hyperventilation. I came across this interesting video at the bottom of this link: Research on Sudarshan Kriya | The Art of Living The TLDW version is that it lowers cortisol, but increases prolactin, which they thought of as a happiness hormone I practiced this technique for several years and have found that my breathing function has not been the same since, and the health I enjoyed before doing the technique I have not been able to recapture. I was aging at the same time, and vegetarian, sooo who knows exactly how much I was harmed. But I talked to many others who had done the technique for awhile and reported similar losses in health. I think I exhaled a lot of CO2. There were definitely benefits however, like enhanced sensitivity to environmental factors (EMF), but this sensitivity could also be called a curse.