Hi Julia,
Everybody expects exercise to lower blood sugar instantly but that's not the case.
Exercise can more often than not raise your blood sugar
"at that moment in time". Through exercise muscles become less Insulin Resistant and over time this lowers blood sugar. So although you might find when you exercise
"just now" your blood sugar level rises it should have the effect of lowering your blood sugar levels in the long run as your burning of the raised sugar in the blood stream.
I know the thought of raised blood sugar is bad but not in this case, it means your body is breaking down fat stores to supply the energy from sugar to your muscles.
Which means weight loss.