Yikeroos ! Like Danny is saying - smaller does of both food and insulin - generally keep things in level for us - it's said then done at times - but the pay offs will reward you. I know from what I've read over the years - high BG's aren't recommended if you plan to exercise - the first thing is to get the BG level down (water can help) - along with a "correct" amount of insulin to lower your BG's (not sure if you are aware of how much 1 unit of insulin lowers your BG). Otherwise - what happened to you will result again as your body looks for fuel to burn off the energy you are using up. It is programmed to survive like you say - with or without it's partner in crime - el pancreaso! Ole!!!
Here's a guide line that I came across that shows where blood sugars should be when exercising. The only area I query is the bit about BG's being okay up to 250 mg/dl (13.9 mmol/L) - for me - it's always been no more then 180 mg/dl (10 mmol/L). I guess it depends on the individual.
* Lower than 100 mg/dL (5.6 mmol/L). Your blood sugar may be too low to exercise safely. Eat a small carbohydrate-containing snack, such as fruit or crackers, before you begin your workout.
* 100 to 250 mg/dL (5.6 to 13.9 mmol/L). You're good to go. For most people, this is a safe pre-exercise blood sugar range.
* 250 mg/dL (13.9 mmol/L) or higher. This is a caution zone. To make sure it's safe to exercise, test your urine for ketones — substances made when your body breaks down fat for energy. Excess ketones indicate that your body doesn't have enough insulin to control your blood sugar. If you exercise when you have a high level of ketones, you risk ketoacidosis - yuck.
* 300 mg/dL (16.7 mmol/L) or higher. DANGER ZONE Your blood sugar may be too high to exercise safely, putting you at risk of ketoacidosis. Waiting to work out until your blood sugar drops to a safe pre-exercise range is best.
It's normal for BG's to rise during exercise due to the muscles quest for more fuel due to them being exercised. In most people the body adjusts after exercising and your BG levels go back to normal. Not in the case of diabetics, because our bodies don't circulate enough insulin to convert the sugar in our blood - along with those crazy hormones of ours being released at the same time which can make your insulin in your body not work properly and actually causes the BG to rise. I know, sounds bizarre huh?