Some people with
diabetes will notice a significantly higher glucose rise directly after more strenuous activity
and/or competitive sports; this is because epinephrine (adrenaline) is a hormone released during exercise, stress, excitement, or illness, and its effect is to cause the liver to release even more glucose to supply the body with the needed energy. Usually, this is a temporary effect, and later the blood glucose will go back to its original level.
I hope this makes it clearer.