Low blood glucose can be caused by a variety of factors, including exercise, medication, diet and disease. Hypoglycemia is a condition in which the glucose concentration in the blood is less than 2.8mmol/L, resulting in the inability to supply the body cells with the energy needed for normal physiological activities. Severe hypoglycemia can be fatal or produce permanent brain damage and sequelae, such as loss of memory, poor learning ability, and so on. Therefore, we should not ignore the dangers of hypoglycemia, the specific reasons are as follows: 1. Exercise: not replenishing food in time after exercise, resulting in high consumption of glucose and lowering of blood sugar. 2. Drugs: including overdose of oral hypoglycemic drugs and overdose of insulin injections, which cause the blood sugar to drop. 3. Dietary aspects: delayed meal times caused by other reasons, resulting in low intake levels, can also cause hypoglycemia. 4. Disease: Liver and kidney diseases can also cause hypoglycemia. To summarize, if hypoglycemia occurs, it is recommended to go to the regular hospital for diagnosis and treatment according to your own condition.