Well, this is all new to me as well but the way I've seen it presented (from multiple sources) it seems to be person-specific. If there is a way to increase you "cup size" either I haven't yet seen it (wouldn't be surprising) or it isn't yet known.
Oh well, I guess it's trial and error then. I was actually doing 5 minute cold showers for a year, alongside HIIT/strength training/cardio and bleeding edge mental work, and I guess I was too optimistic I could handle it and went over my limits (which seem to be pretty high already but still firmly in place...)
