This morning I went out to complete week 7 full of confidence. Too much confidence. At about 1.5 km I started to struggle to get my breath and my chest didn't feel right. I've had a couple of heart attacks in the past and so know to follow my chest's advice, so I immediately dropped back to a slow walk. Curses!
Later analysis of my GPS data showed that my pace had been much higher than previous runs. D'oh! I hadn't kept my pace down to a sustainable level. School boy error.
Other factors were different about this run to previous ones too - I'd had breakfast and beta blockers only about half an hour before starting - normally it is two to three hours before. And I hadn't felt too great last night.
Now I have to decide whether to simply retry it on Tuesday, or go back to week 6 run 2 for my next attempt.