Have youi talked to your doctor? I know that my husbands sugar goes in the 400's sometimes and if he even does any little bit of activity sometimes it will bring it down too low. The only time things like that happen to him if he if sick with a little cold or something then no matter what he does it goes higher he can not eat and it be ski high. I would call your doctor and ask?
why can you not exercise if you have blood sugar greater than 250? I did and it made my blood sugar increase. Why is that?
2 things can raise your blood sugar after exercising...First is that your body senses it needs energy and releases glucogen from your muscles, resultin gin a temporary increase. The second is a rush of adrenaline can cause your liver to release its stores.
I'm no expert, but just started reading up on this, as it mine spiked almost 100 points one morning and I freaked out. It seems to me this is abnormal, and just a byproduct of a dysfunctional blood sugar control system.