Stable blood sugar levels are particularly important for both mental and physical performance. The human body is able to level this itself. To keep blood sugar levels constant, the body stores dextrose in the liver and muscles. When blood sugar levels start to drop, the body calls up a dextrose boost with the help of hormones.

What causes a drop in performance.
However: this storage capacity is limited and the “self-regulation” cannot function if the body’s dextrose reserves are exhausted. At this point, blood sugar levels drop, leading to a minor dextrose deficiency, which causes a lack of concentration and memory gaps, or just a general drop in performance. This is particularly detrimental in situations where you are required to perform at a high level. Dextrose deficiency can have various causes:
imbalanced diet or irregular meals, e.g. long breaks between meals
any kind of special physical or mental exertion.

Dextrose in the classic cube form.