OK - I'm not sure how this is supposed to work, but this is what happened.

According to my scientific training schedule I was supposed to go on a 45 minute quick run today. So I thought I would do the normal 7-mile route but go faster. So that's exactly what I did. And it was fine. It was a little tiring but overall I didn't seem to mind it too much.
So is it down to the redbull type drink before I set off or is the training finally paying off?

Perhaps I shouldn't read too much into it.

I had a thought on the way to work this morning - it would be quite cool if you're watching one of these things to hang a sign out at the 10 mile mark - TIREDNESS KILLS: TAKE A BREAK.