In the interest of attempting to maximize my resources, I've even started targeting my breath as one of many areas of potential waste. lol It occurred to me that it could make sense to re-breathe exhaled air after taking a hit from a vaporizer. I've seen the kind of vaporizers that work together with a balloon as the medium to transfer the 'vapor' from the vaporizer to the patient. This present idea though is about using the same kind of balloon, but in a different way. In this scenario, I'm simply taking the hit directly from my Pax. I'm imagining breathing out into the balloon after taking a hit (thus, filling the balloon), and then breathing that 'already-breathed-air' back in again. I already know it is an effective strategy for the immediate intent (getting more goodies out of the 'vapor' by putting it back in for another round in my lungs). What I'm wondering about is the question of whether it's OK for us. I mean, health-wise....to re-breathe exhaled air which obviously is quite oxygen-poor by now (and all that). Is it one of those kinds of things like, no big deal, as long you're not doing it all day long, or is there something more drastically bad for us about it?