The body has more energy stores than glucose. Even if you have a glucose
drink, you will quickly increase blood glucose, insulin will be produced,
and blood sugar will return to normal.

Blood glucose should reach a maximum 30-40 min after ingesting a glucose
drink, and return to normal within 3 hours.

HOWEVER, muscles need ATP (adenosine tri-phpsphate). ATP is generated from
glucose by glycolsis or oxidative phosphorylation. The body can also
synthsise glucose, and store it in the liver as glycogen. The body has
mechanisms to keep processes working steadily (homeostatis) in spite of
food arriving at irregular intervals.

In other words, if you drink a large amount of glucose your body wont
necessarily use it as energy straight away.

gtoomey