I'm not totally nuts - just a little nuts

I did use to sprint in high school - and I was definitely going faster than 8 back then on the track. I had been doing consistent jogging on the treadmill before I started the intervals. But you're right, I probably should have stuck with the 6.5, 7.0, 7.5 intervals for a couple more weeks before I pushed it to 8. I just get bored quickly and I wanted to see how fast I could go. I'm looking forward to spring/summer to start getting outside to run.