I found a really interesting (ok, maybe a little dry) article about the different responses to aerobic vs. anaerobic exercise. It really helped to explain a lot of the bizarre fluctuations I’d been having. More details about this in Laura’s thread, lots of other good info there as well.
I finished my first 1/2 marathon in May. My sugars went to 450 at the 9th mile. I had a hard time finishing but I did.