When I exercise (mostly aerobics or speed walking) I disconnect the pump or at least suspend it so that I'm not getting any insulin during exercise. This isn't enough, however, to prevent my from going low. I also find that I need to eat 30-40 grams of carbs before exercising. Because of this, I've found that exercising after a meal is best. Often times, I don't even bolus to cover the meal. I've also noticed that my bs should be at least 110 before exercising if I plan on making it through the workout (usually 1-1.5 hours).
With all this said, sometimes it's still hit or miss, unfortunatly, and I go low. I test before, during and several times after exercising to see what's happening. Exercising can make my bs drop very quickly.
I took me a long time to figure out what works for me, as I'm sure it does for most people. When you finally get your pump, remember to be patient. It takes a while to fine tune your settings so that you stay in control without too many highs or lows. Quite honestly, I've found a lot of it to be trial and error based on suggestions from my doctor. Keeping a log helps you find patterns.
Good luck! Let us know when you get your pump and how you like it.

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Karen
The longest journey begins with a single step.
Type I since 2001
Paradigm 515 pump