Sorry to lower the tone somewhat but,
I watched the mens marathon on tv this morning, which was very good.
The chap in second, Mutai, threw up a couple of times near the finish and again after he finished.
To throw up while running must mean you've got to be pushing your whole body to the absolute limt.
Obviously, you could just have a plain old bad gut, but if it's purely down to effort, then that's pretty hard core.
This may sound a very weird question, but have you pushed yourself so hard while running that you've said hello again to your gels and energy drink?
I think I look forward to your replies.