Aerobic exercise about doubles your insulin sensitivity. If you try to calculate (guesstimate) the amount of IOB you’re bringing into the equation at the beginning of the exercise, please take into account
remaining IOB from previous meal bolus (previous would be pretty significant for anything up to 3 hours ahead, and still non-zero for up to 6 hours)
remaining IOB from your basal rate - if you want to lower your basal IOB at the time of exercising, you’d need to start lowering your basal about 90 minutes ahead. Reducing about 60 minutes beforehand takes care of the worst peak - might fit for Fiasp, you didn’t write what’s in your pump.
I’m trying to adjust my IOB to fit the balance between COB or other aftereffects from my previous meal and my expected ISF during exercise, and keep carbs at hand to fill in anything beyond what I can level at with reducing Basals beforehand. This seems to work well with light (aerobic) exercise that doesn’t cross the anaerobic threshold, and other hypo-magnets such as housekeeping or gardening…
An exception to that would be what is marketed as “life kinetics” - while the exercises can be designed to be entirely non-strenuous, and with little impact on heart-rate or breathing, the combined challenge of consciously discoordinating multiple patterns in movement, and then stealing the mental capabilities by trying to recite a simple poem for example have a truly flooring impact on BGs. I’m using 15 minutes of that when I find that I’ve underestimated a meal, and need a rapid-acting way out of the 200s.
Between T1D and T2D, the major difference in IOB after a mea lies in timing: a T1D can calclulate the amount of acting insulin quite precisely, while a T2D has the additional amount his body was able to produce and considered necessary. If a T2D is waiting too long after a meal, his body wlll have done whatever it could, while if he starts his light workout sooner, he can count on his body to insert less insulin into that equation as his snsitivity rises during the exercise. The benefits of a still working pancreas…