A few notes on this: I'm extremely anxious naturally and cannot bring myself to breath while in pain or exerting myself. Tried for years, just can't do it. I've passed out while exercising due to this. I'm also internally very small and had an eight pound baby. The labour was also very fast: the epidural slowed it, and they gave me additional drugs to slow it, but still everything happened all at once and my body was not prepared for it at all. All of this combined with people telling me to push when I was only 90% dilated led to... bad things. But with the baby intermittently distressed, it was either that or a c-section (not something you want to hear on your birthing bed, let me tell you...)