I have “The Diabetic Athlete” but find it too detailed to do me much good. It’s a tough read unless you’re really into biomedical detail. I did manage to glean a few things from it and other exercise blogs. Here’s my 2 cents.
First, the rising blood sugars are typically due to extended anaerobic exercising. If you don’t have one, I would suggest getting a heart rate monitor. They’re a tad pricey, but very valuable. Do some searches on identifying your aerobic heartrate zone. There are some simple formulas based on age that will get you started. Don’t go above your aerobic zone. This is probably what’s giving you the highs (if you’re not dialing down your basal).
My typical aerobic workout is 60 minutes with a target heart rate between 140 and 150. I found this range as the result of a stress test. It will sound high if you look at the age formulas, but it’s the right range for me. I dial my basal down to 20% 1-2 hours before I exercise. I also let it return to normal 30 minutes prior to finnishing. My target starting BG is 160-180. Yeah, it sounds high, but I know it’s going to come down within the next hour. Depending upon how long I’ve had my basal dialed down or if I have the tail end of a bolus on board, my BG can drop like a rock during exercise, so I test every 15 minutes. If my BG hits 100, I dring 22g of carbs via Gatorade. However, if I drank a Gatorade 15 minutes ago, my BG’s above 60 and I only have 15 minutes left, I usually don’t drink another one. That’ll put me high shortly after I work out. Test again 30-60 minutes after you finnish your workout to try to catch an upward trend. If you have one, try to figure out what’s causing it and adjust.
As you can see, most people’s problems are low BGs, so we’re all playing with dialing down basals and suplimenting carbs. If you’re not dialing down basals, you’re not suplimenting carbs and you’re still going high (sounds very odd), but you’re probably working in an anaerobic zone, which you don’t want to do for any length of time anyway, unless you’re a hard core athelete training for an event, and even then, there are rules to how much time to train anaerobically.
I hope this helps.