What do you call by a lack of sugar in the blood?

The lack of sugar in the blood is called hypoglycemia. It occurs when the body has less than the normal amount of sugar (glucose) in the bloodstream. Glucose is the body's main source of energy, so low blood sugar can cause various symptoms, including weakness, dizziness, hunger, sweating, and confusion. In severe cases, hypoglycemia can lead to seizures, coma, or even death.