Nick R. Thomas writes about having recently given a presentation while sick (after having walked 45 minutes to reach the venue).
I wrote about a similar experience here, minus the trek, called "the show must go on" and Nick adds another layer to the concept of sucking it up for the audience.
As he took the stage, he was greeted by "Dr. Theatre," that combination of adrenaline and willpower that mysteriously cures a sick speaker for the duration of the presentation.
You may feel mighty "rough," as Nick puts it, but getting up on stage has a stimulating effect that overrides the misery.
I have further proof of this adrenaline effect, by the way, although hardly scientific.
About 17 years ago, I was hit by a car while driving my scooter - without a helmet.
Besides the fact that I was hit head-on and didn't lose an eye or a tooth or even break a bone, the most fascinating thing to me was that I had had a cold before I got on my scooter that day, and when I got home from the emergency room four hours later, it was gone.
Adrenaline is an amazing hormone, so I wouldn't be surprised if that's what knocked out my cold, but I'm no scientist.
I only wish it wasn't also responsible for blushing.