| Your body has a process called gluconeogenesis (glucose from nowhere, basically) where the liver will react to exercise by releasing glucose into the bloodstream to help your muscles needs for energy during intense exercise. You didn't say, but I bet you were doing anaerobic (ie, weightlifting) exercises for PT, right? If you were, that's why your sugars spiked. We seem to have some evidence here that if you are prone to having a spike due to exercise, it is because of intense "burning muscle" kind of exercise. ON the flip side, if you do lower intensity, less strenuous work like walking or light bike riding, sugars seem to drop, and be lower for extended amounts of time afterwards.
I don't seem to suffer from gluconeogenesis, which would explain why I do not look like Arnold, yet. So I am beginning to inject glucose after workouts...
(kidding, relax)
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I'll mend myself before it gets me... | 
