I can sometimes get headaches from prolonged exertion, but I have been putting it down to coming off the 'runners high' of being on endorphins and adrenaline for several hours. I get the same effect after a day of skiing or a really intense day at the paintball field. Decent food and plenty of water will help to minimize the effect, but I can usually tell how big a day I had based on how bad the headache is much later. I'm interested that the delay is about what was mentioned earlier of about 4 to 6 hours. I don't think I have a nervous disorder, I always twitch like that.

The only mad cow around here is my wife!