That's what I thought too, but after reading the book "Breath" by James Nestor (as others have mentioned in this thread) I decided to try that. And it really wo

That's what I thought too, but after reading the book "Breath" by James Nestor (as others have mentioned in this thread) I decided to try that. And it really works. I think that if you exhale to fast and inhale immediately, then you are not really getting rid of all the CO2 that you could/should. So, by doing it at a slower rhythm, then you get more efficient in getting air in and CO2 out.