Glucose is the simple form of carbohydrate which is readily used up by our body cells to provide energy. Glucose (dextrose) is the sole source of energy to the brain. Glucose undergoes oxidation inside the cell to produce ATP molecules which are said to be energy coins.
For example, during football match, the person run fast and his body loses some electrolytes along with water by dehydration process. As he consumes glucose, immediately his body gets rehydrated with energy also.