In reply to knighty:
I would add that although keeping blood glucose raised for the duration of short exercise after about 4 hours this stops being an option. I've been diabetic since the age of 5, I'm 21 now and going on my first exped to the greater ranges -Kyrgyzstan- this summer. Pete and Jerry are both far more hardcore than myself by a huge amount but a common misconception that I had myself, and no one has mentioned yet here, and my health care people didn't tell me either, was the danger from Ketones as a result of this. When I first started doing prolonged periods of strenuous exercise I thought that if I kept my BG elevated everything would be okay. I did this by dropping the amount of insulin I was taking on board and eating the same as usual. I had two expeditions of absolute misery from this at points feeling as ill as when first diagnosed. It is essential that you keep insulin intake above a crucial level and you will have to eat more than others to do this. There's a lot of advice online about this but as with everything else to do with diabetes you have to find out what happens to yourself. Other things I would recommend, try and get on a pump waiting list as soon as possible. They make control so much easier and better, the worry that people have about not liking things being attached to them and whatnot seems slightly arbitrary when compared to the benefits they bring. There is a new piece of kit coming out for monitoring BG by an inserted cannula that takes constant levels as well, I'm just starting on this but it promises to be really beneficial as well. For more general exercise advice there's also the "runsweet" website. Its really good for giving a better explanation of the problem of starvation ketones. I would definitely say ask Pete or Jerry before myself, but if there is any advice more generally, or from more of an Amateurs perspective, then don't hesitate! Good Luck!